Journal articles: 'Interface charge mobility'

1

Зайцева, Э. Г., О. В. Наумова, and Б. И. Фомин. "Профилирование компонент подвижности вблизи гетерограниц тонких пленок кремния." Физика и техника полупроводников 54, no. 2 (2020): 124. http://dx.doi.org/10.21883/ftp.2020.02.48891.9272.

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In this paper, we proposed the method for profiling of the components of the effective mobility of charge carriers μeff defined by their scattering by surface phonons and by roughness at the film/insulator interfaces. The method is based on the controlled localization of charge carriers relative to the interface under study due to the coupling effect. The proposed method allows us to independently determine mobility components near different interfaces of films. The use of the proposed method for studying the mobility has allowed us to obtain information on the roughness of the interface and on the structural quality of the ultrathin (1–3-nm) layer of Si near the Si/buried oxide interface.

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Pérez-Tomás, Amador, Michael R. Jennings, Philip A. Mawby, James A. Covington, Phillippe Godignon, José Millan, and Narcis Mestres. "SiC MOSFET Channel Mobility Dependence on Substrate Doping and Temperature Considering High Density of Interface Traps." Materials Science Forum 556-557 (September 2007): 835–38. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.835.

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In prior work we have proposed a mobility model for describing the mobility degradation observed in SiC MOSFET devices, suitable for being implemented into a commercial simulator, including Coulomb scattering effects at interface traps. In this paper, the effect of temperature and doping on the channel mobility has been modelled. The computation results suggest that the Coulomb scattering at charged interface traps is the dominant degradation mechanism. Simulations also show that a temperature increase implies an improvement in field-effect mobility since the inversion channel concentration increases and the trapped charge is reduced due to bandgap narrowing. In contrast, increasing the substrate impurity concentration further degrades the fieldeffect mobility since the inversion charge concentration decreases for a given gate bias. We have good agreement between the computational results and experimental mobility measurements.

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Schrimpf, R. D., K. F. Galloway, and P. J. Wahle. "Interface and oxide charge effects on DMOS channel mobility." Electronics Letters 25, no. 17 (1989): 1156. http://dx.doi.org/10.1049/el:19890776.

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Noll, Stefan, Martin Rambach, Michael Grieb, Dick Scholten, Anton J. Bauer, and Lothar Frey. "Effect of Shallow n-Doping on Field Effect Mobility in p-Doped Channels of 4H-SiC MOS Field Effect Transistors." Materials Science Forum 778-780 (February 2014): 702–5. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.702.

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A high inversion channel mobility is a key parameter of normally off Silicon-Carbide MOS field effect power transistors. The mobility is limited by scattering centers at the interface between the semiconductor and the gate-oxide. In this work we investigate the mobility of lateral normally-off MOSFETs with different p-doping concentrations in the channel. Additionally the effect of a shallow counter n-doping at the interface on the mobility was determined and, finally, the properties of interface traps with the charge pumping method were examined. A lower p-doping in the cannel reduces the threshold voltage and increases the mobility simultaneously. A shallow counter n-doping shows a similar effect, but differences in the behavior of the charge pumping current can be observed, indicating that the nitrogen has a significant effect on the electrical properties of the interface, too.

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Fang, Fang, Junsheng Wu, Yanwen Zhou, and Zhuo Zhao. "Interface construction for charge transportation of ZnO/graphene multilayer films." Functional Materials Letters 14, no. 06 (August 2021): 2150027. http://dx.doi.org/10.1142/s1793604721500272.

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In order to clarify the effect of interface construction on the charge transportation, the interfaces between zinc oxide (ZnO) and graphene layers were designed into the following types: the smooth interface by direct deposition ZnO layer onto the surface of fresh graphene/glass substrate; the nanoscale rough interface by Ar[Formula: see text] bombardment etching the surface of graphene/glass substrate before deposition of a ZnO layer, and rough ZnO/Ag/graphene interface by deposition Ag first and then ZnO layers on the rough graphene/glass substrate. The results showed that, compared to the morphology of the ZnO/graphene film with smooth surface, the particle sizes of the film with rough interface became fine and their shapes changed from sharp to round. The carriers’ mobility increased from 0.3 cm2 ⋅ V[Formula: see text] ⋅ s[Formula: see text] to 0.6 cm2 ⋅ V[Formula: see text] ⋅ s[Formula: see text] due to the enhancement of the nanocontact at the rough interface between ZnO and graphene layers. In order to improve the electrical properties of ZnO/graphene multilayer film, a 10 nm Ag layer was inserted into the rough graphene/glass and ZnO layer to construct the rough metal interface. The carrier concentration was enhanced from 10[Formula: see text] cm[Formula: see text] of ZnO/graphene to 10[Formula: see text] cm[Formula: see text] ZnO/Ag/graphene films, although the carrier mobility reduced slightly from ZnO/graphene 0.6 to ZnO/Ag/graphene 0.2 cm2 ⋅ V[Formula: see text] ⋅ s[Formula: see text]. The sheet resistance and resistivity of the ZnO/Ag/graphene multilayer film decreased dramatically by inserting the conductive Ag layer, which took the roles of both the provider of charge carriers from Ag layer and bridges of the carriers from graphene layer.

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Rao, R. Ramakrishna, Kevin Matocha, and Vinayak Tilak. "Quasi-Charge-Sheet Model for Inversion Layer Mobility in 4H-SiC MOSFETs." Materials Science Forum 615-617 (March 2009): 797–800. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.797.

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The mobility of electrons in the inversion layer of 4H-Silicon Carbide (SiC) MOSFETs is lower than the ideal value due to the various scattering mechanisms that takes place at the surface. These scattering mechanisms are strong function of both the interface-trapped charge density and inversion-layer electron density. In this work, we develop a quasi-charge-sheet model to quantify coulomb scattering due to interface trapped-charge in SiC MOSFET inversion layers and calculate the inversion layer electron mobility.

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Butko A. V., Butko V. Y., and Kumzerov Y. A. "Dependence of charge carrier mobility in hybrid nanostructures at the interface of graphene and molecular ions on their charge density." Physics of the Solid State 63, no. 13 (2022): 1820. http://dx.doi.org/10.21883/pss.2022.13.52327.141.

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Hybrid nanostructures with large interface between nanostructural elements play an important role in the modern electronics. Among these nanostructures are hybrid nanostructures formed at the interface of graphene with ensembles of molecular ions in the solution gated Graphene Field Effect Transistors (GFETs) that are promising for chemical and biological sensor fabrication. Therefore investigation of interfacial effects in electrical transport in these systems is interesting. This work is a theoretical study of dependence of the charge carrier mobility (μ) in these nanostructures on density of the interfacial molecular ions (Nii). We show that dependence μ propto 1/(Nii)1/2 obtained in free charge carrier model with short range scattering in case of the weak interaction between the charge carriers and the interfacial ions is in agreement with experimental transistor characteristics obtained at the high gate voltages. Keywords: graphene, hybrid nanostructures, transistors, mobility, interface.

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Cao, Cheng, Shengru Chen, Jun Deng, Gang Li, Qinghua Zhang, Lin Gu, Tian-Ping Ying, Er-Jia Guo, Jian-Gang Guo, and Xiaolong Chen. "Two-Dimensional Electron Gas with High Mobility Forming at BaO/SrTiO₃ Interface." Chinese Physics Letters 39, no. 4 (April 1, 2022): 047301. http://dx.doi.org/10.1088/0256-307x/39/4/047301.

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Two-dimensional electron gas (2DEG) with high electron mobility is highly desired to study the emergent properties and to enhance future device performance. Here we report the formation of 2DEG with high mobility at the interface between rock-salt BaO and perovskite SrTiO3. The interface consists of the ionically compensated BaO1 – δ layer and the electronically compensated TiO2 layer, which is demonstrated as a perfect interface without lattice mismatch. The so-formed interface features metallic conductivity with ultralow square resistance of 7.3 × 10−4 Ω/◻ at 2 K and high residual resistance ratios R 300 K/R 2 K up to 4200. The electron mobility reaches 69000 cm2⋅V−1⋅s−1 at 2 K, leading to Shubnikov–de Haas oscillations of resistance. Density functional theory calculations reveal that the effective charge transfers from BaO to the Ti 3dxy orbital occur at the interface, leading to the conducting TiO2 layer. Our work unravels that BaO can adapt itself by removing oxygen to minimize the lattice mismatch and to provide substantial carriers to SrTiO3, which is the key to forming 2DEGs with high mobility at the interfaces.

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9

Rescher, Gerald, Gregor Pobegen, Thomas Aichinger, and Tibor Grasser. "Improved Interface Trap Density Close to the Conduction Band Edge of a-Face 4H-SiC MOSFETs Revealed Using the Charge Pumping Technique." Materials Science Forum 897 (May 2017): 143–46. http://dx.doi.org/10.4028/www.scientific.net/msf.897.143.

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We study the interface properties of 4H silicon carbide Si-face 0001 and a-face 11220 power MOSFETs using the charge pumping technique. MOSFETs produced on the a-face show a higher electron mobility than Si-face devices, although their charge pumping signal is 5 times higher, indicating a higher interface/border trap density. We show the main contribution to the interface/border trap density on a-face devices originates from deep states in a wide range around midgap, whereas Si-face devices show a higher and exponentially increasing interface/border state density close to the conduction band edge of 4H silicon carbide, resulting in reduced mobility.

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Jia, Beibei, Jun Zhou, Jiaxin Chen, Zixuan Zhang, Yang Wang, Zepeng Lv, and Kai Wu. "Interfacial Insight of Charge Transport in BaTiO3/Epoxy Composites." Nanomaterials 13, no. 3 (January 19, 2023): 406. http://dx.doi.org/10.3390/nano13030406.

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Space charge accumulation greatly influences the dielectric performance of epoxy composites under high voltage. It has been reported that nano-fillers can suppress the charge accumulation in the bulk of insulation materials. However, it is still unclear how the nano-fillers influence the charge distribution at the interface between the filler and polymeric matrix. In this work, the dielectric properties and the local dynamic charge mobility behavior at the interface of barium titanate/epoxy resin (BTO/EP) composites were investigated from both bulk and local perspectives based on the macroscopic test techniques and in-situ Kelvin probe force microscopy (KPFM) methods. Charge injection and dissipation behavior exhibited significant discrepancies at different interfaces. The interface between BTO and epoxy is easy to accumulates a negative charge, and nanoscale BTO (n-BTO) particles introduces deeper traps than microscale BTO (m-BTO) to inhibit charge migration. Under the same bias condition, the carriers are more likely to accumulate near the n-BTO than the m-BTO particles. The charge dissipation rate at the interface region in m-BTO/EP is about one order of magnitude higher than that of n-BTO/EP. This work offers experimental support for understanding the mechanism of charge transport in dielectric composites.

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11

Furuhashi, Masayuki, Toshikazu Tanioka, Masayuki Imaizumi, Naruhisa Miura, and Satoshi Yamakawa. "Novel Gate Oxide Process for Realization of High Threshold Voltage in 4H-SiC MOSFET." Materials Science Forum 778-780 (February 2014): 985–88. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.985.

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We found that threshold voltage (Vth) of a 4H-SiC MOSFET increases drastically by performing low temperature wet oxidation after nitridation in a gate oxide process. The increment of Vth depends on the wet oxidation conditions. Wet oxidation increases the interface trap density (Dit) at deep level of SiC bandgap and decreases positive charge density inside the gate oxide layer. The amount change of the interface traps and the positive charges in the gate oxide makes Vth higher without a decrease in the channel mobility. We improved the trade-off between Vth and effective carrier mobility (μeff) in the MOSFET channel, and realized a low specific on-resistance (Ron,sp) SiC-MOSFET with Vth over 5 V by using the newly developed process.

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12

Bai, Ziheng, Ying Zhao, Jiawei Wang, Dongyang Liu, Yu Shan, Zean Guo, Yuan Kai, et al. "High mobility achieved in InGaZnO TFT with vacuum-gap as insulating layer." Applied Physics Letters 121, no. 26 (December 26, 2022): 263502. http://dx.doi.org/10.1063/5.0127613.

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In this Letter, an amorphous In-Ga-Zn-O (InGaZnO) thin-film transistor (TFT) structure with a vacuum-gap as a dielectric layer is proposed and investigated. Field-effect conduction at the vacuum/InGaZnO interfaces exhibits extraordinary effective mobility ( μ) up to 65 ± 20 cm2 V−1 s−1, while the μ is only around 10 cm2 V−1 s−1 at the SiO2/InGaZnO interfaces with similar film processing conditions. Temperature-dependent transport is performed for deeper insight of the physical origin of the much higher μ at the vacuum/InGaZnO interface. We have found the density of states (DOS) of tail states is notably lower for the transport near the vacuum (8 × 1017 compared to 1.1 × 1019 cm−3 eV−1 at the SiO2/vacuum interface). These indicate that traditional dielectric materials like SiO2 have strong effects on the charge transport degradation in InGaZnO TFTs by introducing extra energetic disorders, and the intrinsic charge transport in InGaZnO is potentially approaching those in poly-silicon TFTs. Exploring a high-quality dielectric layer should be one effective way to further optimize the electrical performance in TFTs based on amorphous oxide semiconductors.

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13

Park, Youngseo, Jiyeon Ma, Geonwook Yoo, and Junseok Heo. "Interface Trap-Induced Temperature Dependent Hysteresis and Mobility in β-Ga2O3 Field-Effect Transistors." Nanomaterials 11, no. 2 (February 16, 2021): 494. http://dx.doi.org/10.3390/nano11020494.

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Interface traps between a gate insulator and beta-gallium oxide (β-Ga2O3) channel are extensively studied because of the interface trap charge-induced instability and hysteresis. In this work, their effects on mobility degradation at low temperature and hysteresis at high temperature are investigated by characterizing electrical properties of the device in a temperature range of 20–300 K. As acceptor-like traps at the interface are frozen below 230 K, the hysteresis becomes negligible but simultaneously the channel mobility significantly degrades because the inactive neutral traps allow additional collisions of electrons at the interface. This is confirmed by the fact that a gate bias adversely affects the channel mobility. An activation energy of such traps is estimated as 170 meV. The activated trap charges’ trapping and de-trapping processes in response to the gate pulse bias reveal that the time constants for the slow and fast processes decrease due to additionally activated traps as the temperature increases.

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14

Havare, Ali Kemal. "The Effect of Interface Modification by PEDOT: PSS on the Hole Mobility of the LEC Device." International Journal on Organic Electronics 11, no. 1 (February 28, 2022): 1–7. http://dx.doi.org/10.5121/ijoe.2022.11101.

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The purpose of the work is to understand how to effect the interface PEDOT: PSS on the hole mobility of the LEC device by Space Charge Limited Current (SCLC) approaches technique. PEDOT: PSS plays a significant role in organic electronics device as interface modification, particularly on Light-emitting electrochemical cells (LEC) due to fundamental structure of hole only device. This study analyses the hole mobility of the device based on current-voltage characteristic approach at room temperature. It has been observed that the PEDOT: PSS interface increases the hole mobility of the LEC device by a factor of 108 .

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Tilak, Vinayak, Kevin Matocha, Greg Dunne, Fredrik Allerstam, and Einar Ö. Sveinbjörnsson. "Scattering Mechanisms in Silicon Carbide MOSFETs with Gate Oxides Fabricated Using Sodium Enhanced Oxidation Technique." Materials Science Forum 600-603 (September 2008): 687–90. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.687.

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The improvement of the SiC-SiO2 interface has been the main focus of research in SiC MOSFET technology due to the presence of high density of interface traps (Dit) leading to poor threshold voltage temperature stability and poor mobility. In SiC MOSFETs with the gate oxide grown in the presence of sodium, known as sodium enhanced oxidation(SEO), a lower Dit and higher field effect mobility has been observed [1]. Hall effect measurements were performed from 125°K-225°K on such MOSFET samples. The Hall measurements were made as a function of temperature for various sheet charge concentrations. The sheet charge density was measured as a function of gate bias at 225°K and there is very little trapped charge in the sample with oxide grown by SEO while about 50 % of the total charge is trapped in a sample with N2O grown oxide annealed in NO. In samples with oxide grown by SEO, there is a monotonic increase in mobility with sheet charge density and the mobility also increases with temperature. This is an indication that the main scattering mechanism is Coulomb scattering in this regime.

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Еnisherlova, K. L., L. A. Seidman, and S. Yu Bogolyubova. "Effect of treatment in nitrogen plasma on the electrical parameters of AlGaN/GaN heterostructures." Izvestiya Vysshikh Uchebnykh Zavedenii. Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering 25, no. 3 (September 28, 2022): 227–37. http://dx.doi.org/10.17073/1609-3577-2022-3-227-237.

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In this work, the influence of deep levels formed at the SiON/AlGaN interface under the nitrogen plasma action during the deposition of a SiON film on the electrical parameters of SiON/AlGaN/GaN structures were studied. The concentration and mobility of free carriers in 2DEG and the capacitance parameters of the structures were measured. It has been experimentally established that short-term action of nitrogen plasma (25 and 50 sec.) does not change the concentration of free carriers in 2DEG, but leads to a decrease in their mobility. The value of the charge that can form at the SiON/AlGaN interface has been calculated. With the help of C–V measurements, it was experimentally shown how the charge in the SiON/AlGaN/GaN system changes during one measurement cycle at different voltage ranges. Based on the consideration of the energy band diagrams of the system, possible explanations for the charge redistribution processes in the analyzed system under certain actions are proposed.

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Stojadinovic, Ninoslav, Ivica Manic, Vojkan Davidovic, Danijel Dankovic, Snezana Djoric-Veljkovic, Snezana Golubovic, and S. Dimitrijev. "Effects of gate bias stressing in power vdmosfets." Serbian Journal of Electrical Engineering 1, no. 1 (2003): 89–101. http://dx.doi.org/10.2298/sjee0301089s.

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The effects of gate bias stressing on threshold voltage and mobility in power VDMOSFETs and underlying changes in gate oxide-trapped charge and interface trap densities are presented and analyzed in terms of the mechanisms responsible. In the case of positive bias stressing, electron tunneling from neutral oxide traps associated with trivalent silicon ?Sio defects into the oxide conduction band is proposed as the main mechanism responsible for positive oxide-trapped charge buildup, while subsequent hole tunneling from the charged oxide traps ?Sio+ to interface-trap precursors ?Sis-H is shown to be the dominant mechanism responsible for the interface trap buildup. In the case of negative bias stressing, hole tunneling from the silicon valence band to oxygen vacancy defects ?Sio / Sio? is shown to be responsible for positive oxide-trapped charge buildup, while subsequent electro-chemical reactions of interfacial precursors ?Sis?? with the charged oxide traps ?Sio+ Sio? and H+ ions are proposed to be responsible for interface trap buildup.

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Luczak, Adam, Angélina Torres Ruiz, Simon Pascal, Adrian Adamski, Jarosław Jung, Beata Luszczynska, and Olivier Siri. "The Quinonoid Zwitterion Interlayer for the Improvement of Charge Carrier Mobility in Organic Field-Effect Transistors." Polymers 13, no. 10 (May 13, 2021): 1567. http://dx.doi.org/10.3390/polym13101567.

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The interface between the semiconductor and the dielectric layer plays a crucial role in organic field-effect transistors (OFETs) because it is at the interface that charge carriers are accumulated and transported. In this study, four zwitterionic benzoquinonemonoimine dyes featuring alkyl and aryl N-substituents were used to cover the dielectric layers in OFET structures. The best interlayer material, containing aliphatic side groups, increased charge carrier mobility in the measured systems. This improvement can be explained by the reduction in the number of the charge carrier trapping sites at the dielectric active layer interface from 1014 eV−1 cm−2 to 2 × 1013 eV−1 cm−2. The density of the traps was one order of magnitude lower compared to the unmodified transistors. This resulted in an increase in charge carrier mobility in the tested poly [2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT)-based transistors to 5.4 × 10−1 cm2 V−1 s−1.

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Matyushov, Dmitry V. "Electrophoretic mobility without charge driven by polarisation of the nanoparticle–water interface." Molecular Physics 112, no. 15 (February 5, 2014): 2029–39. http://dx.doi.org/10.1080/00268976.2014.882521.

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20

Diouf, Baye Boucar, Woo Sik Jeon, Jung Soo Park, Jin Woo Choi, Young Hoon Son, Dae Chul Lim, Yoo Jin Doh, and Jang Hyuk Kwon. "High hole mobility through charge recombination interface in organic light-emitting diodes." Synthetic Metals 161, no. 19-20 (October 2011): 2087–91. http://dx.doi.org/10.1016/j.synthmet.2011.07.025.

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21

Fiorenza, Patrick, Corrado Bongiorno, A. Messina, Mario Saggio, Filippo Giannazzo, and Fabrizio Roccaforte. "Charge Trapping Mechanisms in Nitridated SiO<sub>2</sub>/ 4H-SiC MOSFET Interfaces: Threshold Voltage Instability and Interface Chemistry." Materials Science Forum 1062 (May 31, 2022): 160–64. http://dx.doi.org/10.4028/p-u08hm8.

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Silicon dioxide (SiO2) layers deposited on 4H-SiC and subjected to different post deposition annealing (PDA) in NO and N2O were studied to identify the key factors influencing the channel mobility and threshold voltage stability in lateral implanted 4H-SiC MOSFETs. Cyclic gate bias stress measurements allowed to separate the contributions of interface states (Nit) and near interface oxide traps (NIOTs) in the two oxides. The reduction of these traps in the NO annealed sample is due to the lower amounts of sub-stoichiometric silicon oxide (~1nm) and carbon-related defects (<1nm) at the interface, as could be demonstrated by Electron Energy Loss Spectroscopy. The experimental results indicate that limiting the SiC re-oxidation during post-deposition annealing in MOSFET technology is a key factor to improve the mobility and threshold voltage stability.

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Hatakeyama, Tetsuo, Hirohisa Hirai, Mitsuru Sometani, Dai Okamoto, Mitsuo Okamoto, and Shinsuke Harada. "Dipole scattering at the interface: The origin of low mobility observed in SiC MOSFETs." Journal of Applied Physics 131, no. 14 (April 14, 2022): 145701. http://dx.doi.org/10.1063/5.0086172.

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In this work, the origin of the low free electron mobility in SiC MOSFETs is investigated using the scattering theory of two-dimensional electron gases. We first establish that neither phonon scattering nor Coulomb scattering can be the cause of the low observed mobility in SiC MOSFETs; we establish this fact by comparing the theoretically calculated mobility considering these effects with experimental observations. By considering the threshold voltages and the effective field dependence of the mobility in SiC MOSFETs, it is concluded that the scattering centers of the dominant mechanism are electrically neutral and exhibit a short-range scattering potential. By considering a charge distribution around a neutral defect at the interface, it is established that an electric dipole induced by the defect can act as a short-range scattering potential. We then calculate the mobility in SiC MOSFETs assuming that there exists a high density of dipoles at the interface. The calculated dipole-scattering-limited mobility shows a similar dependence on the effective field dependence to that observed in experimental results. Thus, we conclude that scattering induced by a high density of electric dipoles at the interface is the dominant cause of the low mobility in SiC MOSFETs.

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Zupac, D., K. F. Galloway, P. Khosropour, S. R. Anderson, R. D. Schrimpf, and P. Calvel. "Separation of effects of oxide-trapped charge and interface-trapped charge on mobility in irradiated power MOSFETs." IEEE Transactions on Nuclear Science 40, no. 6 (1993): 1307–15. http://dx.doi.org/10.1109/23.273537.

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Gámiz, F., J. Banqueri, J. E. Carceller, and J. A. López-Villanueva. "Effects of bulk-impurity and interface-charge on the electron mobility in MOSFETs." Solid-State Electronics 38, no. 3 (March 1995): 611–14. http://dx.doi.org/10.1016/0038-1101(94)00129-4.

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Strenger, Christian, Viktoryia Uhnevionak, Vincent Mortet, Guillermo Ortiz, Tobias Erlbacher, Alexander Burenkov, A. J. Bauer, et al. "Systematic Analysis of the High- and Low-Field Channel Mobility in Lateral 4H-SiC MOSFETs." Materials Science Forum 778-780 (February 2014): 583–86. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.583.

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In this work, we investigate the impact of Al-implantation into n-MOSFET channel regions together with its p-doping concentration upon the mobility limiting scattering mechanisms in the channel. For this purpose, a study of the interface trap density, interface trapped charge density, field-effect mobility, and Hall mobility is carried out for normally-off n-MOSFETs with different doping profiles and concentrations in the channel region. The trend of the field-effect and the Hall mobility as well as the differences thereof will be discussed. Based on the determined mobilities in the range from 11.9 cm2/Vs to 92.4 cm2/Vs, it will be shown that for p-doping concentrations above 5·1016 cm-3 Coulomb scattering is the dominant scattering mechanism for both, low- and high-field mobility. In contrast, for p-doping concentrations below 5·1016, cm-3 further scattering mechanisms will be considered that may account for the observed mobility trend at high electric fields.

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Leonov, Vladimir, and Chris Van Hoof. "Multilayer Inorganic Electrets with SiO2 and Si3N4 Layers for Applications on Heated Machinery." Smart Materials Research 2012 (May 20, 2012): 1–9. http://dx.doi.org/10.1155/2012/904168.

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The physics and basic properties of electrets are discussed, namely, what happens during corona charging of dielectrics, why the surface potential and trapped charge show certain limits, where the trapped charge is stored, why and how the charge is released from traps at high temperatures. The experiments have been conducted on single-layer SiO2 and Si3N4 and on multilayer combination of these materials. A strong lateral mobility of charge trapped near the SiO2/Si3N4 interface was observed at elevated temperatures. The positively and negatively charged electrets are compared to each other. The experiments on charge retention at elevated temperatures have shown the studied electrets are suitable for devices working at temperatures of up to 200–300°C.

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Potbhare, Siddharth, Neil Goldsman, Gary Pennington, Aivars J. Lelis, and J. M. McGarrity. "Time Dependent Trapping and Generation-Recombination of Interface Charges: Modeling and Characterization for 4H-SiC MOSFETs." Materials Science Forum 556-557 (September 2007): 847–50. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.847.

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SiC MOSFETs have very large interface trap densities which degrade device performance. The effect of traps on inversion layer mobility and inversion charge concentration has been studied, and mobility models suitable for inclusion in Drift-Diffusion simulators have been developed for steady state operation of SiC MOSFET devices. Here, we attempt to model the transient behavior of SiC MOSFETs, and at the same time, extract the time constants for the filling and emptying of interface traps. As compared to the inversion layer, interface traps in SiC MOSFETs are slow in reacting to change in gate bias. So, at the positive edge of a gate pulse, we see a large current in the MOSFET, which then decays slowly to the steady state value as the interface traps fill up. We have developed a generation/recombination model for minority carriers in a SiC MOSFET based on the Shockley-Read-Hall recombination model for electrons and holes. In our model, the generation/recombination takes place between minority carriers in the inversion layer, and the traps at the SiC-SiO2 interface. Comparing our simulated current vs. time curves to experiment, we have been able to extract time constants for the filling and emptying of traps at the SiC-SiO2 interface.

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Boulanger, Nicolas, Victor Yu, Michael Hilke, Michael F. Toney, and David R. Barbero. "Graphene induced electrical percolation enables more efficient charge transport at a hybrid organic semiconductor/graphene interface." Physical Chemistry Chemical Physics 20, no. 6 (2018): 4422–28. http://dx.doi.org/10.1039/c7cp07871d.

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GHIBAUDO, G., J. JOMAAH, and F. BALESTRA. "IMPACT OF GATE POLYSILICON INTERFACE ON CARRIER TRAPPING LOW FREQUENCY NOISE IN ADVANCED MOSFET'S." Fluctuation and Noise Letters 06, no. 04 (December 2006): L427—L432. http://dx.doi.org/10.1142/s0219477506003586.

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In this work, we calculate, for the first time, the impact of carrier trapping at the gate polysilicon/oxide interface on the LF noise characteristics of polygate MOSFET's. After extending the channel LF noise analysis, based on carrier number and correlated mobility fluctuations approaches, to include charge variations at the polySi/oxide interface, we derive analytical expressions accounting for the impact of fluctuations of poly/oxide interfacial charge on the channel drain current and input gate voltage noise as a function of gate bias, polysilicon doping concentration and gate oxide thickness.

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Kabir, Muhammad Salahuddin, Eli Powell, Robert G. Manley, and Karl D. Hirschman. "Intrinsic Channel Mobility Associated with Extended State Transport in IGZO TFTs." ECS Transactions 109, no. 6 (September 30, 2022): 25–32. http://dx.doi.org/10.1149/10906.0025ecst.

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There is wide variation in the interpretation of the interaction and/or independence of channel mobility and charge trapping in IGZO TFTs. Electrical measurements reveal temperature-dependent behavior that is not explained by existing TCAD models employed for defect states and carrier mobility. An IGZO TFT device model has been recently developed using Silvaco Atlas, which accounts for the role of donor-like oxygen vacancy defects, acceptor-like BTS, and acceptor-like interface traps, thus properly regulating the amount of free channel charge. The channel mobility is defined as only a function of temperature, and reflects a thermally-activated diffusive mobility with a distinct activation energy Ea = 40 meV. This thermally activated process is clearly intrinsic, as it is constant over all bias conditions and is not dependent on the steady-state trapped charge level. The model demonstrates a remarkable match to transfer characteristics measured at T = 150 K to room temperature.

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Liu, Chieh-I., Pengjie Wang, Jian Mi, Hsin-Yen Lee, Chi Zhang, Xi Lin, Chiashain Chuang, Nobuyuki Aoki, Randolph E. Elmquist, and Chi-Te Liang. "Charge Trapping in Monolayer and Multilayer Epitaxial Graphene." Journal of Nanomaterials 2016 (2016): 1–4. http://dx.doi.org/10.1155/2016/7372812.

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We have studied the carrier densitiesnof multilayer and monolayer epitaxial graphene devices over a wide range of temperaturesT. It is found that, in the high temperature regime (typicallyT≥ 200 K),ln⁡(n)shows a linear dependence of 1/T, showing activated behavior. Such results yield activation energiesΔEfor charge trapping in epitaxial graphene ranging from 196 meV to 34 meV. We find thatΔEdecreases with increasing mobility. Vacuum annealing experiments suggest that both adsorbates on EG and the SiC/graphene interface play a role in charge trapping in EG devices.

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Lee, Gyujeong, Hea-Lim Park, Sin-Hyung Lee, Min-Hoi Kim, and Sin-Doo Lee. "Enhancement of Charge Injection in Organic Field-Effect Transistors Through Semiconducting Organic Buffer Layer." Journal of Nanoscience and Nanotechnology 21, no. 7 (July 1, 2021): 3923–28. http://dx.doi.org/10.1166/jnn.2021.19242.

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We investigate the effect of a semiconducting organic buffer layer (SOBL) on the injection and transport of charges in organic field-effect transistors (OFETs). Here, two different injection barriers at the source/organic semiconductor interface are respectively studied with the aid of a numerical simulation: one is intermediate (0.4 eV), and the other is large energy barriers (0.6 eV). The introduction of nanostructure buffer layer, or SOBL, exhibits the decrease of potential loss at the contact interfaces, improving the electrical performance of the OFETs. It is also found that the energy level as well as the mobility of the SOBL plays an important role in determining the injection properties at the metal/organic hetero-interfaces and thus improving the device performance. Our systematic investigation on the injection barrier by the introduction of the nanostructure buffer layer will provide a useful guideline for the fabrication of high-performance FETs with molecular semiconductors.

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Joshi, R. P. "Temperature‐dependent electron mobility in GaN: Effects of space charge and interface roughness scattering." Applied Physics Letters 64, no. 2 (January 10, 1994): 223–25. http://dx.doi.org/10.1063/1.111511.

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Ji, Zhigang, Jian Fu Zhang, Wei Dong Zhang, Ben Kaczer, Stefan De Gendt, and Guido Groeseneken. "Interface States Beyond Band Gap and Their Impact on Charge Carrier Mobility in MOSFETs." IEEE Transactions on Electron Devices 59, no. 3 (March 2012): 783–90. http://dx.doi.org/10.1109/ted.2011.2177839.

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Sumets, M. "Charge transport in LiNbO3-based heterostructures." Journal of Nonlinear Optical Physics & Materials 26, no. 01 (March 2017): 1750011. http://dx.doi.org/10.1142/s0218863517500114.

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Successful application of the LiNbO3-based heterostructures in the integrated electronics and optoelectronics is mostly determined by the charge transport phenomenon in the LiNbO3 since this affects their basic parameters. Depending on the particular conditions (temperature, applied field, properties of LiNbO3/substrate heterojunction, etc.), various conduction mechanisms occur simultaneously and primarily, they can be divided into two major groups: contact-limited and bulk-limited. Identification and study of the charge transport mechanisms allow deriving the vital physical properties such as the barrier height at LiNbO3 film/substrate interface, charged defect concentration, traps spacing as well as type and drift mobility of the carriers in the LiNbO3 films. In this paper, the conduction mechanisms in LiNbO3-based heterostructures are discussed in detail and electrical parameters are derived.

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Butko A.V., Butko V.Y., and Kumzerov Y.A. "Optimization of graphene transistor sensors based on quantum capacitance and charge carrier mobility analysis." Physics of the Solid State 64, no. 12 (2022): 2041. http://dx.doi.org/10.21883/pss.2022.12.54405.441.

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Charge density of molecules (Nm) in hybrid nanostructures that is formed at the interface of graphene and liquid in solution gated graphene field effect transistors (SGFETs) determines the selective response of chemical and biological sensors based on these SGFETs. For optimization of this response it is important to determine how it depends on characteristics of SGFETs such as quantum capacitance (Cq) and charge mobility (μ) which are functionally linked to Nm. The proposed model shows that when the gate voltage (Vgate) is near the minimum point of graphene conductivity (Dirac point) the sensor response is low and increases with gate voltage until Cq is approximately equal to the capacitance of the formed double layer (Cdl) in SGFETs. A decrease in sensor response is predicted upon further increase of Vgate in cases where there is a stronger dependence of μ on Nm than μ propto 1/Nm. A comparison of the predicted results of the model and literature data obtained in SGFET sensors for lysine in an aqueous solution are in agreement with the assumption that the optimal condition of Cq~ Cdl is reached approximately in the Vgate region of (0.5-1.4) V from the Dirac Point. Keywords: graphene, hybrid nanostructures, transistor sensor, charge mobility, interface.

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Ahyi, Ayayi Claude, S. R. Wang, and John R. Williams. "Gamma Irradiation Effects on 4H-SiC MOS Capacitors and MOSFETs." Materials Science Forum 527-529 (October 2006): 1063–66. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.1063.

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The effects of gamma radiation on field effect mobility and threshold voltage have been studied for lateral n-channel 4H-SiC MOSFETs passivated with nitric oxide. MOS capacitors (n and p) and n-channel lateral MOSFETs were irradiated unbiased (floating contacts) for a total gamma dose of 6.8Mrad (Si). The MOS capacitors were used to study the radiation-induced interface traps and fixed oxide charge that affect the performance of the MOSFETs. Radiationinduced interface traps were observed near the SiC valence band edge and just above mid-gap, and field effect channel mobility was reduced by 18-20% following irradiation. Even so, 4HMOSFETs appear to be more radiation tolerant than Si devices.

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Parfenov P. S., Bukhryakov N. V., Onishchuk D.A., Babaev A. A., Sokolova A. V., and Litvin A. P. "Study of charge carrier mobility in PBS nanocrystal layers using field-effect transistors." Semiconductors 56, no. 2 (2022): 175. http://dx.doi.org/10.21883/sc.2022.02.53049.9734.

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The field-effect transistor method is used to study the mobility of charge carriers in layers of lead sulfide nanocrystals with ligands of tetrabutylammonium iodide and 1,2-ethanedithiol used to create solar cells. The difference between the operating of a transistor in ambient air and in an inert atmosphere is demonstrated. It is shown that, in the ambient air, the processes of charging nanocrystals are activated when current flows, and the influence of the polarization of the interface of nanocrystals and the insulator on the measurement of the mobility is analyzed. Different reactions of the layers with ligands to light have been demonstrated, showing a significant oxidation of the surface of nanocrystals treated with 1,2-ethanedithiol. Keywords: solar cells, trap states, photoconductivity.

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Habersat, Daniel B., Aivars J. Lelis, Siddharth Potbhare, and Neil Goldsman. "Improvements in SiC MOS Processing as Revealed by Studies of Fixed and Oxide Trap Charge." Materials Science Forum 615-617 (March 2009): 769–72. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.769.

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In order to improve Silicon Carbide MOSFET device performance, it is important to minimize the on-state losses by improving the effective channel mobility, which can be done by decreasing interfacial charge consisting of interface traps, fixed charge, and oxide traps, which degrade mobility due to Coulombic scattering. This paper considers a method for distinguishing between oxide traps and fixed charge, and discusses how this charge has varied with processing over the last several years. Our results show that, over the period of study, NF has trended downward. Also, the number of switching oxide traps, which gives a lower bound for Not, appears to have decreased considerably. The trends for improvement in NF and ΔNot are promising, but our data suggests that NF and Not remain much too high and need to be reduced further to realize significant gains in SiC MOSFET performance.

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Neagu, Eugen R., C. J. Dias, M. C. Lança, Rui Igreja, and José N. Marat-Mendes. "Medium Electric Field Electron Injection/Extraction at Metal-Dielectric Interface." Materials Science Forum 636-637 (January 2010): 437–43. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.437.

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The isothermal charging current and the isothermal discharging current in low mobility materials are analyzed either in terms of polarization mechanisms or in terms of charge injection/extraction at the metal-dielectric interface and the conduction current through the dielectric material. We propose to measure the open-circuit isothermal charging and discharging currents just to overpass the difficulties related to the analysis of the conduction mechanisms in dielectric materials. We demonstrate that besides a polarization current there is a current related to charge injection or extraction at the metal-dielectric interface and a reverse current related to the charge trapped into the shallow superficial or near superficial states of the dielectric and which can move at the interface in the opposite way that occurring during injection. Two important parameters can be determined (i) the highest value of the relaxation time for the polarization mechanisms which are involved into the transient current and (ii) the height of the potential barrier W0 at the metal-dielectric interface. The experimental data demonstrate that there is no threshold field for electron injection/extraction at a metal-dielectric interface.

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Dhar, Sarit, Suman Das, Ayayi Ahyi, and Marcelo Kuroda. "(Invited, Digital Presentation) Interface Charge Trapping and Scattering in SiC MOSFET Channels." ECS Meeting Abstracts MA2022-01, no. 31 (July 7, 2022): 1317. http://dx.doi.org/10.1149/ma2022-01311317mtgabs.

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The channel conductivity of SiC MOSFETs is severely limited by charge trapping at interface states and mobility limiting scattering processes. In this talk, the status of interface state passivation for both n- and p-channel 4H-SiC MOSFETs will be presented. First, results from capacitance-based methods to extract interface state density (Dit) across the entire 4H-SiC band gap for thermally grown nitrided silicon dioxide gate dielectrics will be presented, emphasizing the critical importance of the SiO2(N)/SiC interface composition and nitrogen bonding. Next, the scattering mechanisms for channel electrons and holes in these devices will be analyzed and contrasted by Hall measurements. [1] The transport will be characterized as a function of temperature and substrate-bias within an effective transverse electric field model. The final part of the talk will focus on latest development on deposited dielectrics for 4H-SiC. Deposited dielectrics are an attractive alternative to thermal oxidation as it minimizes the release of carbon and the perturbation of surface crystal structure and opens the possibility of ‘high-k’ dielectrics with higher permittivity than SiO2. Herein, the key importance of 4H-SiC surface control prior to dielectric deposition will highlighted using results obtained for atomic layer deposition (ALD) of Aluminum Oxide (Al2O3) [2]. To this end, a systematic variation of SiC surface termination with processes involving oxygen, hydrogen and nitrogen will be presented. The composition of the deposited films and the interfacial bonding will be characterized for various deposition processes and correleated with electrical measurements . It will be demonstrated that surface nitridation followed by H2 annealing prior to ALD results in a factor of 2 higher channel mobility than typical NO annealed thermal SiO2. This is due to the formation of stable sub-nm SiON layers that passivates the surface and enables the formation of high-quality interfaces between SiC and deposited dielectric. In addition, the results indicate that clean Si-H terminated surfaces formed by hydrogen etching and annealing, prior to dielectric deposition leads to uniform nucleation of Al2O3. The reduction of Dit is also accompanied by improvements in oxide charge trapping and bias instability, but dielectric leakage current is significantly higher for Al2O3 compared to SiO2 due to bulk trap-assisted tunneling in Al2O3. The reliability is a significant challenge that need to be overcome to exploit the enhanced mobilities and make deposited dielectrics competitive with traditional nitrided SiO2. Acknowledgments: The authors acknowledge support from the US Army Research Laboratory (grant ARMY-W911NF-18-2-0160) and US Department of Energy (subcontracted to National Renewable Energy Laboratory, grant NREL-AHL-9-92632-01). The authors also acknowledge the support Dr. Leonard C. Feldman (Auburn, Rutgers) and Mr. Hengfei Gu (Rutgers) for help with XPS measurements. The authors also deeply thank Ms. T Isaacs-Smith, Ms. Lu Wang (Auburn), Dr. K. Ramadoss and Dr. D. Morisette (Purdue Univ.) for useful discussions and help with fabrication. [1] S. Das et al., J. Appl. Phys. 130, 225701, (2021). [2] I. U. Jayawardhena et al., J. Appl. Phys. 129, 75702, (2021) Figure 1

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Li, Zhonglei, Jingang Su, Boxue Du, Zhaohao Hou, and Chenlei Han. "Inhibition Effect of Graphene on Space Charge Injection and Accumulation in Low-Density Polyethylene." Nanomaterials 8, no. 11 (November 20, 2018): 956. http://dx.doi.org/10.3390/nano8110956.

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Space charge injection and accumulation is attracting much attention in the field of dielectric insulation especially for electronic devices, power equipment and so on. This paper proposes using the inhibition effect of graphene for the injection and accumulation of space charge in low-density polyethylene (LDPE). Scanning electron microscope (SEM) and transmission electron microscopy (TEM) images were employed to observe the dispersion of graphene with a two-dimensional structure in LDPE. The time-dependent space charge dynamic behaviors of graphene/LDPE nanocomposites with the filler content of 0, 0.003, 0.005, 0.007 and 0.01 wt % were characterized by the pulsed electro-acoustic (PEA) test at 40, 60 and 80 °C, and the charge mobility was evaluated by its depolarization processes. The experimental results show that for the undoped LDPE film, large amounts of space charges were injected from the electrodes into samples, especially at 60 and 80 °C. The graphene/LDPE nanocomposites with a filler content of 0.005 wt % could markedly suppress the space charge injection and accumulation even at 80 °C, which is attributed to the large quantities of graphene-polymer in interface regions. These interface regions introduced numbers of deep trap sites within the forbidden band of nanocomposites, which can reduce the de-trapping rate of charges and suppress the space charge accumulation in the polymer bulks. The graphene/LDPE nanocomposites are suggested for dielectric applications, intending the inhibition of space charge injection and accumulation.

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Bae, Geun Yeol, Jinsung Kim, Junyoung Kim, Siyoung Lee, and Eunho Lee. "MoTe2 Field-Effect Transistors with Low Contact Resistance through Phase Tuning by Laser Irradiation." Nanomaterials 11, no. 11 (October 22, 2021): 2805. http://dx.doi.org/10.3390/nano11112805.

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Due to their extraordinary electrical and physical properties, two-dimensional (2D) transition metal dichalcogenides (TMDs) are considered promising for use in next-generation electrical devices. However, the application of TMD-based devices is limited because of the Schottky barrier interface resulting from the absence of dangling bonds on the TMDs’ surface. Here, we introduce a facile phase-tuning approach for forming a homogenous interface between semiconducting hexagonal (2H) and semi-metallic monoclinic (1T′) molybdenum ditelluride (MoTe2). The formation of ohmic contacts increases the charge carrier mobility of MoTe2 field-effect transistor devices to 16.1 cm2 V−1s−1 with high reproducibility, while maintaining a high on/off current ratio by efficiently improving charge injection at the interface. The proposed method enables a simple fabrication process, local patterning, and large-area scaling for the creation of high-performance 2D electronic devices.

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Chatterjee, Shouvik, Shoaib Khalid, Hadass S. Inbar, Aranya Goswami, Taozhi Guo, Yu-Hao Chang, Elliot Young, et al. "Controlling magnetoresistance by tuning semimetallicity through dimensional confinement and heteroepitaxy." Science Advances 7, no. 16 (April 2021): eabe8971. http://dx.doi.org/10.1126/sciadv.abe8971.

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Controlling electronic properties via band structure engineering is at the heart of modern semiconductor devices. Here, we extend this concept to semimetals where, using LuSb as a model system, we show that quantum confinement lifts carrier compensation and differentially affects the mobility of the electron and hole-like carriers resulting in a strong modification in its large, nonsaturating magnetoresistance behavior. Bonding mismatch at the heteroepitaxial interface of a semimetal (LuSb) and a semiconductor (GaSb) leads to the emergence of a two-dimensional, interfacial hole gas. This is accompanied by a charge transfer across the interface that provides another avenue to modify the electronic structure and magnetotransport properties in the ultrathin limit. Our work lays out a general strategy of using confined thin-film geometries and heteroepitaxial interfaces to engineer electronic structure in semimetallic systems, which allows control over their magnetoresistance behavior and simultaneously provides insights into its origin.

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RASHKEEV, S. N., D. M. FLEETWOOD, R. D. SCHRIMPF, and S. T. PANTELIDES. "HYDROGEN AT THE Si/SiO2 INTERFACE: FROM ATOMIC-SCALE CALCULATIONS TO ENGINEERING MODELS." International Journal of High Speed Electronics and Systems 14, no. 02 (June 2004): 575–80. http://dx.doi.org/10.1142/s0129156404002521.

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Two contrasting behaviors have been observed for H in Si / SiO 2 structures: a) Radiation experiments established that protons released in SiO 2 migrate to the Si / SiO 2 interface where they induce new defects; b) For oxides exposed first to high-temperature annealing and then to molecular hydrogen, mobile positive charge believed to be protons can be cycled to and from the interface by reversing the oxide electric field. First-principles density functional calculations identify the atomic-scale mechanisms for the two types of behavior and conditions that are necessary for each. Using the results of the atomic-scale calculations we develop a model for enhanced interface-trap formation at low dose rates due to space charge effects in the base oxides of bipolar devices. We find that the hole trapping in the oxide cannot be responsible for all the Enhanced Low-Dose-Rate Sensitivity (ELDRS) effects in SiO 2, and the contribution of protons is also essential. The dynamics of interface-trap formation are defined by the relation between the proton mobility (transport time of the protons across the oxide) and the time required for positive-charge buildup near the interface due to trapped holes. The analytically estimated and numerically calculated interface-trap densities are found to be in very good agreement with available experimental data.

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Chambers, S. A., D. Lee, Z. Yang, Y. Huang, W. Samarakoon, H. Zhou, P. V. Sushko, et al. "Probing electronic dead layers in homoepitaxial n-SrTiO₃(001) films." APL Materials 10, no. 7 (July 1, 2022): 070903. http://dx.doi.org/10.1063/5.0098500.

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We combine state-of-the-art oxide epitaxial growth by hybrid molecular beam epitaxy with transport, x-ray photoemission, and surface diffraction, along with classical and first-principles quantum mechanical modeling to investigate the nuances of insulating layer formation in otherwise high-mobility homoepitaxial n-SrTiO3(001) films. Our analysis points to charge immobilization at the buried n-SrTiO3/undoped SrTiO3(001) interface as well as within the surface contamination layer resulting from air exposure as the drivers of electronic dead-layer formation. As Fermi level equilibration occurs at the surface and the buried interface, charge trapping reduces the sheet carrier density ( n2 D) and renders the n-STO film insulating if n2 D falls below the critical value for the metal-to-insulator transition.

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Kemal Havare, Ali. "Electronic Parameters of Diode Based Organometallic Semiconductor Dyes Centered Ruthenium Complexes with Active COOH Terminals." Journal of Nanoscience and Nanotechnology 21, no. 12 (December 1, 2021): 5937–44. http://dx.doi.org/10.1166/jnn.2021.19508.

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In this study, the ruthenium complexes, which is an organometallic N-3 and C-106 semiconductor material, was coated on indium tin oxide (ITO) by using the self-assembled technique and thus a diode containing an organometallic interface was produced. The effects of this interface on the electronic parameters of the diode were investigated. It is aimed to improve the heterogeneity problem of the inorganic/organic interface by chemically bonding these materials from COOH active parts to the ITO surface. In order to understand how the electronic parameters of the diode change with this modification, the Schottky diode electrical characterization approach has been used. The charge mobility of the diode was calculated using the current density-voltage curve (J–V) characteristic with Space Charge Limited Current (SCLC) technique. When the electrical field is applied to the diode, it can be said that the ruthenium complexes molecules create an electrical dipole and the tunneling current is transferred to the anode contact ITO through the ruthenium molecule through the charge carrier, thus contributing to the hole injection. The morphology of these interface modifications was examined by Atomic Force Microscope (AFM) and surface potential energy by KelvinProbe Force Microscope (KPFM). To investigate local conductivity of bare ITO and modified ITO surface, Scanning Spreading Resistance Microscopy (SSRM) that is a conductive AFM analyzing technique were performed by applying voltage to the conductive tip and to the sample. According to the results of this work the diode containing N-3 material shows the best performance in terms of charge injection to the ITO due to possess the lowest barrier height Φb as 0.43 eV.

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Huang, Ting, Yan Zhang, Haonan Liu, Ruiqiang Tao, Chunlai Luo, Yushan Li, Cheng Chang, Xubing Lu, Takeo Minari, and Junming Liu. "Interface scattering dominated carrier transport in hysteresis-free amorphous InGaZnO thin film transistors with high-k HfAlO gate dielectrics by atom layer deposition." Semiconductor Science and Technology 37, no. 2 (December 16, 2021): 025005. http://dx.doi.org/10.1088/1361-6641/ac3e05.

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Abstract In this work, we systematically investigated the carrier transport of hysteresis-free amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) incorporating high-k (HfO2) x (Al2O3) y gate dielectrics with different composition and permittivity by atomic layer deposition. A dielectric surface morphology dominated interface scattering carrier transport mechanism is demonstrated, and the effect of the dielectric polarization and the interface states on the carrier mobility is discovered in TFT devices gated by high quality dielectrics with negligible charge trap effect. Accordingly, an a-IGZO TFT gated by (HfO2)0.5(Al2O3)0.5 dielectric with the smoothest surface exhibits the best performance in terms of a preferable field-effect mobility of 18.35 cm2 V−1 s−1, a small subthreshold swing of 0.105 V decade−1, a high on/off current ratio of 4.6 × 106, and excellent stability under positive bias stress.

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ROMANJEK, KRUNOSLAV, GÉRARD GHIBAUDO, THOMAS ERNST, and JAN A. CHROBOCZEK. "LOW FREQUENCY NOISE IN SUB-0.1μmSiGepMOSFETs, CHARACTERISATION AND MODELING." Fluctuation and Noise Letters 04, no. 02 (June 2004): L309—L318. http://dx.doi.org/10.1142/s0219477504001914.

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Drain current-gate voltage, I d ( V g ) characteristics and the power spectral density, PSD , of I d fluctuations were obtained on SiGe channel pMOSFETs and on their Si homologues, for I d intensities varied from deep sub-threshold to strong inversion values. Devices with 2.2nm thick SiO 2 gates and channel lengths 50 nm <L<10μm were used. In heterostructures, the SiGe layers were 20nm thick and buried under 2nm of Si . The data were simulated, assuming a parallel current flow in the interface and the SiGe channels, with associated noise sources. The transport parameters, extracted from I d ( V g ) characteristics, served for calculating the PSD ( I d ) functions. The latter required adjusting the interface trap density and a parameter α c , accounting for the effect of the interface charge fluctua-tions on the hole mobility fluctuations, significant at high levels of trap filling i.e. high I d . We found that the PSD in the SiGe devices was up to 10 times lower than in the Si controls at sufficiently high I d . The simulation, accounting for the data, required a significant lowering of α c for the SiGe channel. That implies that the LFN reduction in SiGe MOSFETs results from a weaker interaction of the SiGe holes with the interface charges. The sub-0.1μm channel devices show a similar noise lowering, in spite of the hole mobility degradation.

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Бутко, А. В., В. Ю. Бутко, and Ю. А. Кумзеров. "Зависимость подвижности носителей заряда в гибридных наноструктурах на интерфейсе графена с молекулярными ионами от их зарядовой плотности." Физика твердого тела 63, no. 11 (2021): 1960. http://dx.doi.org/10.21883/ftt.2021.11.51603.141.

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A.V. Butko, V.Y. Butko, Y.A.Kumzerov Ioffe Institute, 194021, St. Petersburg, Russia Hybrid nanostructures with large interface between nanostructural elements play an important role in the modern electronics. Among these nanostructures are hybrid nanostructures formed at the interface of graphene with ensembles of molecular ions in the solution gated Graphene Field Effect Transistors (GFETs) that are promising for chemical and biological sensor fabrication. Therefore investigation of interfacial effects in electrical transport in these systems is interesting. This work is a theoretical study of dependence of the charge carrier mobility (µ) in these nanostructures on density of the interfacial molecular ions (Nii). We show that dependence µ~1/(Nii)^1/2 obtained in free charge carrier model with short range scattering in case of the weak interaction between the charge carriers and the interfacial ions is in agreement with experimental transistor characteristics obtained at the high gate voltages.

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Journal articles on the topic 'Interface charge mobility'

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