Journal articles: 'Growth defects'

1

Scandale, Eugenio, Sergio Lucchesi, and Giorgio Graziani. "Growth defects and growth marks in pegmatite beryls." European Journal of Mineralogy 2, no. 3 (June 21, 1990): 305–12. http://dx.doi.org/10.1127/ejm/2/3/0305.

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Agrosí, Giovanna, Eugenio Scandale, and Maria Arcangela Digennaro. "Growth defects of a melanite crystal." Neues Jahrbuch für Mineralogie - Abhandlungen 176, no. 1 (February 26, 2001): 89–107. http://dx.doi.org/10.1127/njma/176/2001/89.

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Agrosì, Giovanna, Gioacchino Tempesta, Eugenio Scandale, and Jeff W. Harris. "Growth and post-growth defects in a diamond from Finsch mine (South Africa)." European Journal of Mineralogy 25, no. 4 (December 20, 2013): 551–59. http://dx.doi.org/10.1127/0935-1221/2013/0025-2301.

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Gao, Jiang-Dong, Jian-Li Zhang, Xin Zhu, Xiao-Ming Wu, Chun-Lan Mo, Shuan Pan, Jun-Lin Liu, and Feng-Yi Jiang. "Detailed surface analysis of V-defects in GaN films on patterned silicon(111) substrates by metal–organic chemical vapour deposition." Journal of Applied Crystallography 52, no. 3 (May 31, 2019): 637–42. http://dx.doi.org/10.1107/s1600576719005521.

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The growth mechanism of V-defects in GaN films was investigated. It was observed that the crystal faces of both the sidewall of a V-defect and the sidewall of the GaN film boundary belong to the same plane family of \{ {{{10\bar 11}}} \}, which suggests that the formation of the V-defect is a direct consequence of spontaneous growth like that of the boundary facet. However, the growth rate of the V-defect sidewall is much faster than that of the boundary facet when the V-defect is filling up, implying that lateral growth of \{ {{{10\bar 11}}} \} planes is not the direct cause of the change in size of V-defects. Since V-defects originate from dislocations, an idea was proposed to correlate the growth of V-defects with the presence of dislocations. Specifically, the change in size of the V-defect is determined by the growth rate around dislocations and the growth rate around dislocations is determined by the growth conditions.

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Jones, D. P., and T. R. Leax. "Fatigue Crack Growth Testing of Sub-Clad Defects." Journal of Pressure Vessel Technology 121, no. 3 (August 1, 1999): 269–75. http://dx.doi.org/10.1115/1.2883702.

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Fatigue crack growth tests were performed on four-point bend specimens with cracklike defects intentionally placed in A302B low-alloy pressure vessel steel clad with 308/309L weld-deposited stainless steel. The defects were placed in the base metal under the cladding by machining a cavity from the side opposite the cladding, electric-discharge machining a very sharp flaw, fatigue precracking the flaw, and then filling up the cavity by a weld repair process. The specimens were stress relieved before fatigue testing. The specimens were fatigue cycled at positive load ratios until the defects broke through to the surface. The specimens were then fractured at liquid nitrogen temperatures to reveal the fracture surfaces. Seven different sub-clad flaw specimens were tested in room temperature air and each test provides a record of cycles to defect breakthrough. Changes in defect size and shape as a function of applied load cycles were obtained by beach-marking the crack at various stages of the load history. The results provide a set of embedded defect data which can be used for qualifying fatigue crack growth analysis procedures such as those in Section XI of the ASME Boiler and Pressure Vessel Code. A comparison between calculated and measured values shows that the ASME B&PV Section XI fatigue crack growth procedures conservatively predict cycles to defect breakthrough for small sub-clad defects.

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Hens, Philip, Julian Müller, Günter Wagner, Rickard Liljedahl, Erdmann Spiecker, and Mikael Syväjärvi. "Defect Generation and Annihilation in 3C-SiC-(001) Homoepitaxial Growth by Sublimation." Materials Science Forum 740-742 (January 2013): 283–86. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.283.

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In this paper we present a concept on the defect generation and annihilation during the homoepitaxial growth step of cubic silicon carbide by sublimation epitaxy on templates grown by chemical vapor deposition on silicon substrates. Several structural defects like stacking faults, twins and star defects show opposite evolution from the template layer into the sublimation grown material. While single planar defects tend to annihilate with increasing layer thickness, the defect clusters assigned to the star defects are enlarging. These issues contribute to a balance of how to achieve the best possible quality on thick layers.

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Maerten, Thibault, Cédric Jaoul, Roland Oltra, Patrice Duport, Christophe Le Niniven, Pascal Tristant, Frédéric Meunier, and Olivier Jarry. "Micrometric Growth Defects of DLC Thin Films." C — Journal of Carbon Research 5, no. 4 (November 14, 2019): 73. http://dx.doi.org/10.3390/c5040073.

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Defects in diamond-like carbon coatings deposited on corrosion sensitive 100Cr6 steel have been studied. Diamond-like carbon (DLC) thin films are promising for corrosion protection due to chemical inertness and low electrical conductivity. Nevertheless, the performance of these coating is highly sensitive to the presence of uncoated areas. These defects represent the primary way of substrate degradation in aggressive environments. An in situ optical microscopy coupled to an electrochemical activation was developed to reveal micrometric growth defects and observe that they were at the origin of corrosion. A square wave voltammetry was applied to increase the sensitivity of electrochemical techniques based on the detection of the dissolution of the bare metal surface triggered by the presence of uncoated spots. This method can be utilized to quantify defect density arising from vapor deposition processes.

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Everson, M. P., and M. A. Tamor. "Investigation of growth rates and morphology for diamond growth by chemical vapor deposition." Journal of Materials Research 7, no. 6 (June 1992): 1438–44. http://dx.doi.org/10.1557/jmr.1992.1438.

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We describe two complementary studies of diamond growth by chemical vapor deposition. In the first, the early stages of growth of randomly distributed nuclei on silicon are studied by scanning tunneling microscopy. For growth times from 1 to 30 min nearly all crystallites are three dimensional, and increase in volume as t1.5. Although this result could be interpreted in terms of diffusion limited growth, the conditions for diamond CVD are more consistent with rate limited growth where the crystals are expected to gain volume as t3. This anomaly can be explained in terms of a two-species growth mechanism in which the rate constant for carbon addition is proportional to the diffusion limited flux of atomic hydrogen. Other mechanisms giving rise to the observed t1.5 dependence are also considered. The second study uses both scanning electron and tunneling microscopies to examine the morphology of a boron-doped film homoepitaxial to the {100} surface of natural type 2a diamond. In regions distant from gross defects, this film is very smooth. However, gross defects appear to initiate growth of new epitaxial layers at a rate much higher than in defect-free regions. This observation suggests that diamond growth is promoted by “enabling defects” and that without such defects nucleation of new layers is a slow process and permits layer-by-layer growth at a much lower rate.

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Kirste, Lutz, Karolina Grabianska, Robert Kucharski, Tomasz Sochacki, Boleslaw Lucznik, and Michal Bockowski. "Structural Analysis of Low Defect Ammonothermally Grown GaN Wafers by Borrmann Effect X-ray Topography." Materials 14, no. 19 (September 22, 2021): 5472. http://dx.doi.org/10.3390/ma14195472.

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X-ray topography defect analysis of entire 1.8-inch GaN substrates, using the Borrmann effect, is presented in this paper. The GaN wafers were grown by the ammonothermal method. Borrmann effect topography of anomalous transmission could be applied due to the low defect density of the substrates. It was possible to trace the process and growth history of the GaN crystals in detail from their defect pattern imaged. Microscopic defects such as threading dislocations, but also macroscopic defects, for example dislocation clusters due to preparation insufficiency, traces of facet formation, growth bands, dislocation walls and dislocation bundles, were detected. Influences of seed crystal preparation and process parameters of crystal growth on the formation of the defects are discussed.

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Sugiyama, Naohiro, Masanori Yamada, Yasushi Urakami, Masakazu Kobayashi, Takashi Masuda, Keisuke Shigetoh, Itaru Gunjishima, Fusao Hirose, and Shoichi Onda. "Characterization of Vacant Broken Line Defects in A-Face Grown Crystals of Silicon Carbide." Materials Science Forum 778-780 (February 2014): 386–89. http://dx.doi.org/10.4028/www.scientific.net/msf.778-780.386.

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A new type of defects, vacant broken line defects, was found to occur in a-face grown crystals of 4H-Silicon Carbide. We characterized the vacant broken line defects by high voltage transmission electron microscope (HV-TEM). The HV-TEM image revealed that the edges of broken line defects were connected by a bundle of dislocations, which elongated to the growth direction on the basal plane. The analysis by gb method for determining Burgers vector indicated that the dislocations were not pure screw dislocations, but complex of screw and edge dislocations. The vacant broken line defect was considered to be a quasi-stable state of a bundle of basal plane dislocations in a-face growth, similar to a micropipe defect in c-face growth.

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11

Das, Hrishikesh, Galyna Melnychuk, and Yaroslav Koshka. "Dislocations and Triangular Defect in Low-Temperature Halo-Carbon Epitaxial Growth and Selective Epitaxial Growth." Materials Science Forum 615-617 (March 2009): 121–24. http://dx.doi.org/10.4028/www.scientific.net/msf.615-617.121.

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Dislocations were investigated in the halo-carbon low-temperature epitaxial growth and low-temperature selective epitaxial growth (LTSEG) conducted at 13000C. The origin of triangular defects was investigated in low-temperature epilayers grown at higher growth rates with HCl addition. Due to the conversion of substrates’ basal plane dislocations (BPD) into threading dislocations, the concentration of BPDs was about an order of magnitude lower than the concentration of threading dislocations at moderate growth rates. An additional order of magnitude conversion of BPDs into threading dislocations was observed at higher grow rates achieved with HCl addition. In LTSEG epilayers, dislocation concentration away from the mesa walls was comparable to the blanket (i.e., regular non-selective) growth. High concentrations of BPDs were found only at mesa edges located on the “upstream” side with respect to the step-flow direction. No substrate defects could be traced to the triangular defects. Instead, the disturbances causing the triangular defect generation are introduced during the epitaxial process.

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Shrivastava, Amitesh, Peter G. Muzykov, B. Pearman, S. Michael Angel, and Tangali S. Sudarshan. "Investigation of Triangular Defects in 4H-SiC 4° Off Cut (0001) Si Face Epilayers Grown by CVD." Materials Science Forum 600-603 (September 2008): 139–42. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.139.

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Triangular defects and inverted pyramid type defects formed during homoepitaxial growth on 4H-SiC Si face, 4° off-cut towards [11-20] direction have been investigated. Growth parameters responsible for triangular defect formation were identified and optimized for its reduction in this study. It was found that although the high temperature reduces the density of inverted pyramid type defects, it is not the only remedy for reducing their density and cleanliness of susceptor along with the initial growth condition plays a major role in the formation of these defects.

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Guo, Ling, Koji Kamei, Kenji Momose, and Hiroshi Osawa. "Evaluation and Reduction of Epitaxial Wafer Defects Resulting from Carbon-Inclusion Defects in 4H-SiC Substrate." Materials Science Forum 897 (May 2017): 39–42. http://dx.doi.org/10.4028/www.scientific.net/msf.897.39.

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In this study, we investigated the epitaxial surface defects resulting from the carbon-inclusion defects in 4H-SiC substrate. Most carbon-inclusion defects developed into one of three types of epitaxial surface defects under normal epitaxial growth conditions. Among them, we found a regular hexagonal pit by high-resolution microscopy, which we regarded as a large-pit defect, and which had an adverse impact on the reverse electrical characteristics of Schottky barrier diodes. Conversion of a carbon-inclusion defect to a large-pit defect or a triangular defect could be reduced by reducing the C/Si ratio.

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14

Shechtman, D., J. L. Hutchison, L. H. Robins, E. N. Farabaugh, and A. Feldman. "Growth defects in diamond films." Journal of Materials Research 8, no. 3 (March 1993): 473–79. http://dx.doi.org/10.1557/jmr.1993.0473.

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Growth defects in diamond films grown by plasma-assisted chemical vapor deposition (CVD) were studied by high resolution electron microscopy. Several features of the microstructure were resolved and their importance to the growth of the diamond film was evaluated. The observations included various twin boundaries of the type ∑ = 3, as well as ∑ = 9, ∑ = 27, and ∑ = 81, which form by an interaction of lower order twins. These higher order boundaries are loci of intersection points of growing planes on two adjacent twins and can serve as an indicator for the local crystal growth direction. The central nucleation site for the growing planes in many cases can be traced back to a quintuplet twin point. A twin quintuplet has five re-entrant angles and thus serves as a preferred nucleation site for new planes as the crystal grows.

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15

Lebedev, Vadim, Jan Engels, Jan Kustermann, Jürgen Weippert, Volker Cimalla, Lutz Kirste, Christian Giese, et al. "Growth defects in heteroepitaxial diamond." Journal of Applied Physics 129, no. 16 (April 28, 2021): 165301. http://dx.doi.org/10.1063/5.0045644.

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Zhao, Xiaoji, Yanlu Li, and Xian Zhao. "Density Functional Theory Study of the Point Defects on KDP (100) and (101) Surfaces." Molecules 27, no. 24 (December 17, 2022): 9014. http://dx.doi.org/10.3390/molecules27249014.

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Surface defects are usually associated with the formation of other forms of expansion defects in crystals, which have an impact on the crystals’ growth quality and optical properties. Thereby, the structure, stability, and electronic structure of the hydrogen and oxygen vacancy defects (VH and VO) on the (100) and (101) growth surfaces of KDP crystals were studied by using density functional theory. The effects of acidic and alkaline environments on the structure and properties of surface defects were also discussed. It has been found that the considered vacancy defects have different properties on the (100) and (101) surfaces, especially those that have been reported in the bulk KDP crystals. The (100) surface has a strong tolerance for surface VH and VO defects, while the VO defect causes a large lattice relaxation on the (101) surface and introduces a deep defect level in the band gap, which damages the optical properties of KDP crystals. In addition, the results show that the acidic environment is conducive to the repair of the VH defects on the surface and can eliminate the defect states introduced by the surface VO defects, which is conducive to improving the quality of the crystal surface and reducing the defect density. Our study opens up a new way to understand the structure and properties of surface defects in KDP crystals, which are different from the bulk phase, and also provides a theoretical basis for experimentally regulating the surface defects in KDP crystals through an acidic environment.

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Noesges, Brenton A., Daesu Lee, Jung-Woo Lee, Chang-Beom Eom, and Leonard J. Brillson. "Nanoscale interplay of native point defects near Sr-deficient Sr_xTiO₃/SrTiO₃ interfaces." Journal of Vacuum Science & Technology A 40, no. 4 (July 2022): 043201. http://dx.doi.org/10.1116/6.0001782.

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SrTiO3 has many applications involving interfaces with other materials, but defects that affect the properties of SrTiO3 films can also play a significant role at its heterointerfaces and even at junctions with nonstoichiometric SrTiO3. Depth-resolved cathodoluminescence spectroscopy (DRCLS) combined with systematic cation Sr content reduction in SrxTiO3 ultrathin films grown on SrTiO3 showed an interplay of native point defects and electronic structure within the Sr-deficient film and how interplay extends tens of nanometers into the substrate below. Understanding how defects form and affect interface electronic structure during epitaxial growth is central to improving complex oxide devices. Controlling the balance of oxygen vacancy defects with strontium vacancies and other acceptor-like defects can improve control over free carrier densities. Likewise, control over nanoscale defect charge distributions can advance new device features such as two-dimensional hole gases and the performance of existing devices such as ferroelectric tunnel junctions. This study shows how DRCLS directly measures the relative densities and spatial distributions of multiple native defects within and extending away from nanoscale SrxTiO3/SrTiO3 junctions and how their interplay varies with controlled epitaxial growth. In turn, these growth-dependent defect variations can help guide SrTiO3 epitaxial growth with other complex oxides.

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Liu, Mingqi, and John M. Cowley. "Growth behavior and growth defects of carbon nanotubes." Materials Science and Engineering: A 185, no. 1-2 (September 1994): 131–40. http://dx.doi.org/10.1016/0921-5093(94)90936-9.

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Khoury, Muin J., J. David Erickson, José F. Cordero, and Brian J. McCarthy. "Congenital Malformations and Intrauterine Growth Retardation: A Population Study." Pediatrics 82, no. 1 (July 1, 1988): 83–90. http://dx.doi.org/10.1542/peds.82.1.83.

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The relationship between congenital malformations and intrauterine growth retardation was investigated using data from the population-based Metropolitan Atlanta Congenital Defects Program. Between 1970 and 1984, the system ascertained 13,074 infants with major structural malformations diagnosed in the first year of life and born to metropolitan Atlanta residents. These infants were classified as having intrautenine growth retardation if their birth weight was below the race-, sex-, and gestational age-specific tenth percentile limits for all Atlanta births. Overall, the frequency of intrauterine growth retardation among malformed infants was 22.3% (relative risk 2.6). Of 48 defect categories evaluated, 46 were associated with excess intrauterine growth retardation, most notably chromosomal anomalies (eg, 83.7% for infants with trisomy 18, relative risk 46) and anencephaly (73.3%, relative risk 25). Only a few isolated defects (such as isolated polydactyly, pylonic stenosis, and congenital hip dislocation) were not associated with excess intrauterine growth retardation. Among infants with multiple malformations, the frequency of intrauterine growth retardation increased markedly with increasing number of defects—from 20% for infants with two defects to 60% for infants with nine or more defects. The relationship between malformations and intrauterine growth retardation can be explained by one or more of three mechanisms: (1) intrauterine growth retardation can be a secondary disturbance to the presence of malformations; (2) intrauterine growth retardation can predispose the fetus to malformations; and (3) intrauterine growth retardation can coexist with malformations because of common etiologic factors. Because the risk of a major defect diagnosed in the first year increases from 3.3% for infants without intrauterine growth retardation to 8.0% for infants with intrauterine growth retardation, the presence of intrauterine growth retardation may help in the prenatal and neonatal detection of congenital malformations.

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Filip, Octavian, Boris M. Epelbaum, Juan Li, Matthias Bickermann, Xian Gang Xu, and Albrecht Winnacker. "Growth on Rhombohedral (01-1n) Plane: An Alternative for Preparation of High Quality Bulk SiC Crystals." Materials Science Forum 600-603 (September 2008): 23–26. http://dx.doi.org/10.4028/www.scientific.net/msf.600-603.23.

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Results on bulk growth of SiC crystals along rhombohedral [01-1n] directions are presented. 6H- and 4H-crystals were grown on rhombohedral planes, which make angles of about 45o with the (0001) plane. Etching features on three differently oriented planes cut from characteristic crystals were compared. Utmost care was concentrated on defect development in the case of non-conventional growth orientation using the seed cut from a “standard” (0001) crystal, containing a typical (standard for [0001] growth) set of crystal defects. We clearly distinguished between a transient layer adjacent to the seed and the main crystal body grown at latter stages. The defect selection and/or transformation in the transient layer appeared strongly depending on the SiC polytype and growth direction. This study brings directly the information on stability of particular defects in the chosen crystal orientation and allows us to distinguish between defects characteristic for [0001] and rhombohedral growth.

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Larsen, Arne Nylandsted. "Growth-Defects and Process-Induced Defects in SiGe-Based Heterostructures." Solid State Phenomena 69-70 (August 1999): 43–52. http://dx.doi.org/10.4028/www.scientific.net/ssp.69-70.43.

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Das, Hrishikesh, Swapna Sunkari, Timothy Oldham, Josh Rodgers, and Janna Casady. "Uniformity and Morphology of 10 x 100mm 4° Off-Axis 4H-SiC Epitaxial Layers and their Effect on Device Performance." Materials Science Forum 740-742 (January 2013): 221–24. http://dx.doi.org/10.4028/www.scientific.net/msf.740-742.221.

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Homoepitaxial layers with very good thickness and doping uniformity were grown on 4 inch 4˚ off-axis substrates in a 10x100mm planetary reactor. Process optimizations resulted in reduction of the size of the triangular defects. Aggressive pre-etching of the substrate prior to growth resulted in further suppression of the triangular defect concentration from 3-5cm-2to 0.5cm-2using the same growth processes. Even imperfect areas of the substrate with scratches show suppressed nucleation of triangular defects. JBS diodes with triangular defects show increased leakage depending on the size of the defects. This effect is more pronounced at higher voltages.

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Tuomisto, Filip. "Vacancy Defects in Bulk and Quasi-Bulk GaN Crystals." Crystals 12, no. 8 (August 9, 2022): 1112. http://dx.doi.org/10.3390/cryst12081112.

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In-grown vacancy defects in bulk and quasi-bulk GaN crystals have been extensively studied with positron annihilation spectroscopy. High concentrations of Ga-vacancy-related defects are found irrespective of the growth method used in crystals with a high O contamination or intentional O doping, and they act as the dominant compensating native defect for n-type conductivity. Low-temperature crystal growth also leads to high concentrations of Ga-vacancy-related defects. Ga vacancies are present in the crystals as a part of the different types of complexes with O, H, and/or VN, depending on the growth conditions.

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Xu, Qing Yan, Bai Cheng Liu, Zuo Jian Liang, Jia Rong Li, Shi Zhong Liu, and Ha Llong Yuan. "Modeling of Unidirectional Growth in a Single Crystal Turbine Blade Casting." Materials Science Forum 508 (March 2006): 111–16. http://dx.doi.org/10.4028/www.scientific.net/msf.508.111.

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Single crystal superalloy turbine blade are widely used in aero-engineering. However, there are often grain defects occurring during the fabrication of blade by casting. It is important to study the formation of microstructure related defects in turbine blades. Single crystal blade sample castings of a nickel-base superalloy were produced at different withdrawal rates by the directional solidification process and investment casting. There was a difference between the microstructure morphology at the top part of the turbine blade sample castings and the one at the bottom. Higher withdrawal rates led to more differences in the microstructure and a higher probability of crystallographic defect formation such as high angle boundaries at locations with an abrupt change of the transversal section area. To further investigate the formation of grain defects, a numerical simulation technique was used to predict the crystallographic defects occurring during directional solidification. The simulation results agreed with the experimental ones.

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CONRAD, EDWARD H. "THE STABILITY OF LOW INDEX METAL SURFACES TO TOPOLOGICAL DEFECTS." International Journal of Modern Physics B 05, no. 03 (February 10, 1991): 427–59. http://dx.doi.org/10.1142/s0217979291000274.

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The study of defect formation at metal surfaces is a fundamental problem in surface physics. An understanding of defect formation is pertinent to growth and diffusion mechanisms. In addition, surface roughening, faceting, and surface melting are all defect mediated phase transitions involving the formation of different topological defects. While the importance of defects at surfaces is well recognized, the study of surface defects has been hampered by the lack of sufficiently accurate experimental techniques. In fact, it is only in the past 6 years that experiments on the thermal generation of defects on metal surfaces have been performed. This review attempts to outline both the theoretical and experimental work on surface defect formation on metal systems.

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Xie, Mingjiang, Yifei Wang, Weinan Xiong, Jianli Zhao, and Xianjun Pei. "A Crack Propagation Method for Pipelines with Interacting Corrosion and Crack Defects." Sensors 22, no. 3 (January 27, 2022): 986. http://dx.doi.org/10.3390/s22030986.

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Corrosion and crack defects often exist at the same time in pipelines. The interaction impact between these defects could potentially affect the growth of the fatigue crack. In this paper, a crack propagation method is proposed for pipelines with interacting corrosion and crack defects. The finite element models are built to obtain the Stress Intensity Factors (SIFs) for fatigue crack. SIF interaction impact ratio is introduced to describe the interaction effect of corrosion on fatigue crack. Two approaches based on extreme gradient boosting (XGBoost) are proposed in this paper to predict the SIF interaction impact ratio at the deepest point of the crack defect for pipelines with interacting corrosion and crack defects. Crack size, corrosion size and the axial distance between these two defects are the factors that have an impact on the growth of the fatigue crack, and so they are considered as the input of XGBoost models. Based on the synthetic samples from finite element modeling, it has been proved that the proposed approaches can effectively predict the SIF interaction impact ratio with relatively high accuracy. The crack propagation models are built based on the proposed XGBoost models, Paris’ law and corrosion growth model. Sensitivity analyses regarding corrosion initial depth and axial distance between defects are performed. The proposed method can support pipeline integrity management by linking the crack propagation model with corrosion size, crack size and the axial distance. The problem of how the interaction between corrosion and crack defects impacts crack defect growth is investigated.

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La Via, Francesco, Massimo Zimbone, Corrado Bongiorno, Antonino La Magna, Giuseppe Fisicaro, Ioannis Deretzis, Viviana Scuderi, et al. "New Approaches and Understandings in the Growth of Cubic Silicon Carbide." Materials 14, no. 18 (September 16, 2021): 5348. http://dx.doi.org/10.3390/ma14185348.

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In this review paper, several new approaches about the 3C-SiC growth are been presented. In fact, despite the long research activity on 3C-SiC, no devices with good electrical characteristics have been obtained due to the high defect density and high level of stress. To overcome these problems, two different approaches have been used in the last years. From one side, several compliance substrates have been used to try to reduce both the defects and stress, while from another side, the first bulk growth has been performed to try to improve the quality of this material with respect to the heteroepitaxial one. From all these studies, a new understanding of the material defects has been obtained, as well as regarding all the interactions between defects and several growth parameters. This new knowledge will be the basis to solve the main issue of the 3C-SiC growth and reach the goal to obtain a material with low defects and low stress that would allow for realizing devices with extremely interesting characteristics.

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Camarda, Massimo, Antonino La Magna, and Francesco La Via. "Evolution of Extended Defects during Epitaxial Growths: A Monte Carlo Study." Materials Science Forum 679-680 (March 2011): 48–54. http://dx.doi.org/10.4028/www.scientific.net/msf.679-680.48.

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Three dimensional kinetic Monte Carlo simulations on super-lattices are applied to study the evolution of stacking faults during epitaxial growths. We show that, in the case of misoriented close packed substrates, these defects can either extend throughout the entire epilayer (i.e. extended from the substrate up to the surface) or close in dislocation loops, in dependence of the deposition conditions. We explain this behavior in terms of a surface kinetic competition between these defects and the surrounding crystal: if the local growth rate of the defect is larger compared with that of the perfect crystal the defect will expands, otherwise it will closes. This mechanisms allows to explain several experimental results on homo and hetero epitaxies.

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Wada, Takahiro, Takayuki Negami, and Mikihiko Nishitani. "Growth defects in CuInSe2 thin films." Journal of Materials Research 9, no. 3 (March 1994): 658–62. http://dx.doi.org/10.1557/jmr.1994.0658.

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CuInSe2 thin film solar cells with an efficiency of about 10% were studied with a cross-sectional high resolution transmission electron microscope (HRTEM). The growth defects such as twins, stacking faults, and intergrowth phase in the CuInSe2 thin films were studied in detail. Polycrystalline CuInSe2 films were deposited on a Mo-coated glass substrate by using the three source evaporation system. The CuInSe2 film contains fivefold multiply twinned crystallites as well as a high density of twins in the {112} plane. The CuInSe2 film also contains intergrowth phase with a long range of periodicities of 10 Å parallel to the [112] direction of the chalcopyrite structure. The intergrowth phase composition is similar to the chalcopyrite phase. The structural model of the intergrowth phase is proposed on the basis of the high resolution electron micrograph.

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Heide, G., H. Follner, R. A. Jackson, and P. J. Wilde. "Computer simulations of crystal growth defects." Radiation Effects and Defects in Solids 151, no. 1-4 (November 1999): 317–23. http://dx.doi.org/10.1080/10420159908245974.

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Bourrat, Xavier, Li Qiao, QingLing Feng, Martine Angellier, Aurore Dissaux, Jean-Michel Beny, Vincent Barbin, Philippe Stempflé, Marthe Rousseau, and Evelyne Lopez. "Origin of growth defects in pearl." Materials Characterization 72 (October 2012): 94–103. http://dx.doi.org/10.1016/j.matchar.2012.07.010.

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Panjan, P., M. Čekada, M. Panjan, and D. Kek-Merl. "Growth defects in PVD hard coatings." Vacuum 84, no. 1 (August 2009): 209–14. http://dx.doi.org/10.1016/j.vacuum.2009.05.018.

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Rosenfeld, Ron G., Alicia Belgorosky, Cecelia Camacho-Hubner, M. O. Savage, J. M. Wit, and Vivian Hwa. "Defects in growth hormone receptor signaling." Trends in Endocrinology & Metabolism 18, no. 4 (May 2007): 134–41. http://dx.doi.org/10.1016/j.tem.2007.03.004.

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Svoboda, Roman, and Daniela Brandová. "Crystal growth from mechanically induced defects." Journal of Thermal Analysis and Calorimetry 127, no. 1 (May 24, 2016): 799–808. http://dx.doi.org/10.1007/s10973-016-5529-0.

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Bretz, K. C., T. S. Kuan, P. D. Agnello, and T. O. Sedgwick. "Effects of surface oxide on low-temperature epitaxial growth of Si." Proceedings, annual meeting, Electron Microscopy Society of America 49 (August 1991): 798–99. http://dx.doi.org/10.1017/s0424820100088300.

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The Si epitaxial growth temperature using Chemical Vapor Deposition (CVD) has been steadily reduced in the last few years to temperatures as low as 600°C. Blanket and selective Si epitaxy at atmospheric pressure is now achieved at low temperature through purification processes which exclude O2 and H2O impurities from the deposition zone. In addition to maintaining the deposition system ultra-clean, the initial Si growth surface must be free of surface oxide to achieve low defect density in the epitaxial layer. Previous experiments have shown that a slight presence of surface oxide leads to generation of extended defects. Therefore, an effective surface cleaning process is as important as an oxygen-free environment for achieving perfect epitaxy at low temperatures. In this work we use electron microscopy to study the structure of defects nucleated from surface oxide and the mechanism of defect formation under different growth conditions. High-resolution observations are made to establish quantitative linkage between surface cleanliness and defect population.

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Liu, Yi Lin. "Recent Progress on Single-Crystal Growth and Epitaxial Growth of 4H Silicon Carbide." Solid State Phenomena 332 (May 30, 2022): 73–84. http://dx.doi.org/10.4028/p-4x61u9.

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The review article describes the recent progress on SiC single-crystal and epitaxial growth technology. SiC is a third-generation semiconducting material with wide bandgap and high electrical breakdown field. Thanks to its excellent properties, it becomes an advantageous material in the field of high-temperature and high-power electronic device applications. Power devices fabricated of SiC are able to be operated at higher power density and higher switching frequency. This review focus on the growth, doping control and defect control of SiC single-crystal ingot and epilayer. The process of PVT, CVD, defect control, doping control and some recent applications of SiC are described. Various types of defects are described, including Micropipes, Dislocations, Stacking Faults etc. The wafering and polishing technology are also described.

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Morikawa, Sergio Ricardo Kokay, Daniel Pontes Lannes, and Antonio Lopes Gama. "Application of Piezoelectric Materials for Monitoring the Growth of Defects in Structures." Materials Science Forum 643 (March 2010): 113–18. http://dx.doi.org/10.4028/www.scientific.net/msf.643.113.

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This paper presents the results of an experimental investigation on the use of piezoelectric materials as a technique for monitoring the growth of defects in structures. The method consists of exciting the structure with piezoelectric actuators while recording the electromechanical responses from sensors placed close to the defect. The piezoelectric sensors detect the damage growth or an incipient defect by monitoring changes in the dynamic strain field, induced by the piezoelectric actuator, near the defect. This technique was evaluated through experiments using an aluminum frame structure. Results show that the piezoelectric active method is capable of detecting small changes in defect depth.

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Huang, Zi Qian, Qing Lian Xie, Guo Hua Huang, and Pei Lan Li. "Growth-Induced Stress in Hard Coating." Advanced Materials Research 393-395 (November 2011): 127–30. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.127.

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Coating and gradient structure can improve the quality of products, but growth-induced stress generates in the forming process of the coating and the gradient structure due to the existence of the defects and metastable phase. The existence of growth-induced stress can conversely affect the quality of the product, even lead to cracking and product failure. This paper shows the model of stress calculation according to the crystal structure’s defect theory.

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Пещерова, С. М., Е. Б. Якимов, А. И. Непомнящих, В. И. Орлов, О. В. Феклисова, Л. А. Павлова, and Р. В. Пресняков. "Зависимость объемных электрофизических свойств мультикремния от параметров разориентации зерен." Физика и техника полупроводников 53, no. 1 (2019): 59. http://dx.doi.org/10.21883/ftp.2019.01.46988.8814.

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AbstractThe recombination activity of intragrain defects in multicrystalline silicon is investigated by the electron or laser beam induced current methods. The interrelation of the grain orientation with the character of the distribution of intragrain defects (dislocations and impurity inclusions) and their recombination activity is revealed. The defect grain structure is investigated using various etching procedures to reveal the defects. It is shown that the defect density and distribution in the grains depend on their orientation relative the growth axis. Therefore, it is intragrain defects and impurities that are to a large degree responsible for degradation of the nonequilibrium carrier lifetime when compared with grain boundaries.

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Farris, T. N., L. M. Keer, and R. K. Steele. "Life Prediction for Unstable Shell Growth in Rails." Journal of Engineering for Industry 112, no. 2 (May 1, 1990): 175–80. http://dx.doi.org/10.1115/1.2899563.

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The growth rate of the relatively benign shell type defects such as horizontal cracks found in the head of railroad rails is calculated. The effect of the residual stresses acting in the vicinity of the shell on the growth rate is significant. The results can be combined with a stability analysis of the tendency of the horizontal defects to turn into a vertical detail fracture to determine the time required for such a transition. Load reversals can cause the shell defect to grow to a length where it has lost its tendency to grow out of the plane. For this case the time required for the horizontal crack to reach the fast fatigue growth rate regime is calculated. The results allow the effect of the shell growth behavior on rail service life to be discussed.

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Zhou, Xiaowang. "Impact of Molecular Dynamics Simulations on Research and Development of Semiconductor Materials." MRS Advances 4, no. 61-62 (2019): 3381–98. http://dx.doi.org/10.1557/adv.2019.360.

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ABSTRACTAtomic scale defects critically limit performance of semiconductor materials. To improve materials, defect effects and defect formation mechanisms must be understood. In this paper, we demonstrate multiple examples where molecular dynamics simulations have effectively addressed these issues that were not well addressed in prior experiments. In the first case, we report our recent progress on modelling graphene growth, where we found that defects in graphene are created around periphery of islands throughout graphene growth, not just in regions where graphene islands impinge as believed previously. In the second case, we report our recent progress on modelling TlBr, where we discovered that under an electric field, edge dislocations in TlBr migrate in both slip and climb directions. The climb motion ejects extensive vacancies that can cause the rapid aging of the material seen in experiments. In the third case, we discovered that the growth of InGaN films on (0001) surfaces suffers from a serious polymorphism problem that creates enormous amounts of defects. Growth on ($11\bar{2}0$) surfaces, on the other hand, results in single crystalline wurtzite films without any of these defects. In the fourth case, we first used simulations to derive dislocation energies that do not possess any noticeable statistical errors, and then used these error-free methods to discover possible misuse of misfit dislocation theory in past thin film studies. Finally, we highlight the significance of molecular dynamics simulations in reducing defects in the design space of nanostructures.

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Mao, Kai Li, Ying Min Wang, Bin Li, and Gao Yang Zhao. "Origin Analysis and Elimination of Obtuse Triangular Defects in 4° Off 4H-SiC Epitaxy." Materials Science Forum 924 (June 2018): 168–71. http://dx.doi.org/10.4028/www.scientific.net/msf.924.168.

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The obtuse triangular defects would result in higher leakage currents and the preferential gate oxide breakdown of SiC devices. The formation and structural features of obtuse triangular defects on the 4° off 4H-SiC epilayers were investigated by confocal microscope and photoluminescence image. Two structrures of obtuse triangular defects were found. By optimizing the growth process, obtuse triangular defect free epitaxial layers were abtained on SiC substrate with serveral stacking fault. The number of triangular SFs defects was less than 0.5/cm2.

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Batstone, J. L. "Structural and electronic properties of defects in semiconductors." Proceedings, annual meeting, Electron Microscopy Society of America 53 (August 13, 1995): 4–5. http://dx.doi.org/10.1017/s0424820100136398.

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The development of growth techniques such as metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy during the last fifteen years has resulted in the growth of high quality epitaxial semiconductor thin films for the semiconductor device industry. The III-V and II-VI semiconductors exhibit a wide range of fundamental band gap energies, enabling the fabrication of sophisticated optoelectronic devices such as lasers and electroluminescent displays. However, the radiative efficiency of such devices is strongly affected by the presence of optically and electrically active defects within the epitaxial layer; thus an understanding of factors influencing the defect densities is required.Extended defects such as dislocations, twins, stacking faults and grain boundaries can occur during epitaxial growth to relieve the misfit strain that builds up. Such defects can nucleate either at surfaces or thin film/substrate interfaces and the growth and nucleation events can be determined by in situ transmission electron microscopy (TEM).

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Bassett, Lee C., Audrius Alkauskas, Annemarie L. Exarhos, and Kai-Mei C. Fu. "Quantum defects by design." Nanophotonics 8, no. 11 (October 4, 2019): 1867–88. http://dx.doi.org/10.1515/nanoph-2019-0211.

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AbstractOptically active point defects in wide-bandgap crystals are leading building blocks for quantum information technologies including quantum processors, repeaters, simulators, and sensors. Although defects and impurities are ubiquitous in all materials, select defect configurations in certain materials harbor coherent electronic and nuclear quantum states that can be optically and electronically addressed in solid-state devices, in some cases even at room temperature. Historically, the study of quantum point defects has been limited to a relatively small set of host materials and defect systems. In this article, we consider the potential for identifying defects in new materials, either to advance known applications in quantum science or to enable entirely new capabilities. We propose that, in principle, it should be possible to reverse the historical approach, which is partially based on accidental discovery, in order to design quantum defects with desired properties suitable for specific applications. We discuss the biggest obstacles on the road towards this goal, in particular those related to theoretical prediction, materials growth and processing, and experimental characterization.

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Panjan, Peter, Aljaž Drnovšek, and Goran Dražić. "Influence of Growth Defects on the Oxidation Resistance of Sputter-Deposited TiAlN Hard Coatings." Coatings 11, no. 2 (January 22, 2021): 123. http://dx.doi.org/10.3390/coatings11020123.

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This paper reports the results of an investigation of the oxidation of a sputter-deposited TiAlN hard coating in air at temperatures of 800 and 850 °C for times ranging from 15 min to 2 h. The study is focused on the role of growth defects in the oxidation process. The mechanism of oxidation at the site of the defect was studied on cross-sections made by the consecutive sectioning of oxidized coatings with the FIB technique. We found that in the early stage of oxidation, the locally intense oxidation always starts at such defects. Although the growth defects reduce the oxidation resistance of the coating locally, we believe that they do not have a decisive influence on the global oxidation resistance of the coating. There are several reasons for this. The first is that the surface area covered by growth defects is relatively low (less than 1%). Secondly, the coating is permeable only at those defects that extend through the entire coating thickness. Thirdly, the permeability at the rim of some defects strongly depends on the density of pores at the rim of defects and how open they are. The size and density of such pores depend on the shape and size of topographical irregularities on the substrate surface (e.g., seeds, pits), which are responsible for the formation of growth defects. We also found that oxidation of the TiAlN coating is accelerated by oxygen and titanium diffusion through the pores formed by crystal grain growth in the outer alumina overlayer. Such pores are formed due to the compressive stresses in the Ti-rich oxide layer, which are caused by the large difference in molar volumes between the oxide and nitride phases.

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Smardon, Anne M., Heba I. Diab, Maureen Tarsio, Theodore T. Diakov, Negin Dehdar Nasab, Robert W. West, and Patricia M. Kane. "The RAVE complex is an isoform-specific V-ATPase assembly factor in yeast." Molecular Biology of the Cell 25, no. 3 (February 2014): 356–67. http://dx.doi.org/10.1091/mbc.e13-05-0231.

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The regulator of ATPase of vacuoles and endosomes (RAVE) complex is implicated in vacuolar H+-translocating ATPase (V-ATPase) assembly and activity. In yeast, rav1∆ mutants exhibit a Vma− growth phenotype characteristic of loss of V-ATPase activity only at high temperature. Synthetic genetic analysis identified mutations that exhibit a full, temperature-independent Vma− growth defect when combined with the rav1∆ mutation. These include class E vps mutations, which compromise endosomal sorting. The synthetic Vma− growth defect could not be attributed to loss of vacuolar acidification in the double mutants, as there was no vacuolar acidification in the rav1∆ mutant. The yeast V-ATPase a subunit is present as two isoforms, Stv1p in Golgi and endosomes and Vph1p in vacuoles. Rav1p interacts directly with the N-terminal domain of Vph1p. STV1 overexpression suppressed the growth defects of both rav1∆ and rav1∆vph1∆, and allowed RAVE-independent assembly of active Stv1p-containing V-ATPases in vacuoles. Mutations causing synthetic genetic defects in combination with rav1∆ perturbed the normal localization of Stv1–green fluorescent protein. We propose that RAVE is necessary for assembly of Vph1-containing V-ATPase complexes but not Stv1-containing complexes. Synthetic Vma− phenotypes arise from defects in Vph1p-containing complexes caused by rav1∆, combined with defects in Stv1p-containing V-ATPases caused by the second mutation. Thus RAVE is the first isoform-specific V-ATPase assembly factor.

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Thota, Sravan, Shutang Chen, Yadong Zhou, Yong Zhang, Shengli Zou, and Jing Zhao. "Structural defect induced peak splitting in gold–copper bimetallic nanorods during growth by single particle spectroscopy." Nanoscale 7, no. 35 (2015): 14652–58. http://dx.doi.org/10.1039/c5nr03979g.

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Krishnan, Bharat, Hrishikesh Das, Huang De Lin, and Yaroslav Koshka. "Selective Epitaxial Growth of 4H-SiC with SiO₂ Mask by Low-Temperature Halo-Carbon Homoepitaxial Method." Materials Science Forum 556-557 (September 2007): 149–52. http://dx.doi.org/10.4028/www.scientific.net/msf.556-557.149.

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Previously reported CVD epitaxial growth of 4H-SiC at temperatures down to and below 13000C using CH3Cl precursor offered a promise of new device applications that could benefit from lower-temperature growth process. In this work, selective epitaxial growth (SEG) of 4H-SiC mesas using conventional SiO2 low temperature mask is reported. Virtually no nucleation on the mask could be observed after SEG at 13000C. The mask could be easily removed after the growth, with no degradation of the surface of SiC substrate under the mask. For the growth conditions that normally resulted in growth rate of 2 /m/hr and defect-free epilayer morphology during regular full-wafer (non-SEG) epitaxy, the epilayer morphology during SEG was significantly degraded by the appearance of oriented triangular defects, while the growth rate increased more than three times in comparison to the blanket epitaxial growth due to the loading effect. The growth at optimized growth conditions and lower growth rate resulted in significant reduction of the surface defects, making this approach promising for obtaining device-quality mesas. The crystal quality of the mesas, defects at the mesa walls, formation of facets during SEG, and other effects are reported.

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Hsu, Julia W. P. "Semiconductor Defect Studies Using Scanning Probes." Microscopy and Microanalysis 6, S2 (August 2000): 704–5. http://dx.doi.org/10.1017/s1431927600036011.

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Understanding how defects alter physical properties of materials has lead to improvements in materials growth as well as device performance. Transmission electron microscopy (TEM) provides an invaluable tool for structural characterization of defects. Our current knowledge of crystallographic defects, such as dislocations, would not have been possible without TEM. Recently, scanning tunneling microscopy and scanning force microscopy (SFM) have shown the capability of imaging surface defects with atomic or near-atomic resolution in topographic images. What is more important is to gain knowledge on how the presence of a certain type of defects changes the physical properties of materials. For example, how is the carrier lifetime altered near electrically active defects? How does photoresponse vary near grain boundaries? Where are defect levels in the forbidden bandgap? This talk will discuss several examples of how scanning probe microscopies (SPMs) can contribute to this aspect of defect studies in semiconductors.

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Alshareef, Mohammed, Ahmed Alshareef, Tyler Vasas, Aakash Shingala, Jonathan Cutrone, and Ramin Eskandari. "Pediatric Cranioplasty Using Hydroxyapatite Cement: A Retrospective Review and Preliminary Computational Model." Pediatric Neurosurgery 57, no. 1 (November 30, 2021): 40–49. http://dx.doi.org/10.1159/000520954.

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Introduction: Cranioplasty is a standard technique for skull defect repair. Restoration of cranial defects is imperative for brain protection and allowing for homeostasis of cerebral spinal fluid within the cranial vault. Calcium phosphate hydroxyapatite (HA) is a synthetic-organic material that is commonly used in cranioplasty. We evaluate a patient series undergoing HA cement cranioplasty with underlying bioresorbable mesh for various cranial defects and propose a preliminary computational model for understanding skull osteointegration. Methods: A retrospective review was performed at the institution for all pediatric patients who underwent HA cement cranioplasty. Seventeen patients were identified, and success of cranioplasty was determined based on clinical and radiographic follow-up. A preliminary computational model was developed using bone growth and scaffold decay equations from previously published literature. The model was dependent on defect size and shape. Patient data were used to optimize the computational model. Results: Seventeen patients were identified with an average age of 6 ± 5.6 years. Average defect size was 11.7 ± 16.8 cm2. Average time to last follow-up computer tomography scan was 10 ± 6 months. Three patients had failure of cranioplasty, all with a defect size above 15 cm2. The computational model developed shows a constant decay rate of the scaffold, regardless of size or shape. The bone growth rate was dependent on the shape and number of edges within the defect. Thus, a star-shaped defect obtained a higher rate of growth than a circular defect because of faster growth rates at the edges. The computational simulations suggest that shape and size of defects may alter success of osteointegration. Conclusion: Pediatric cranioplasty is a necessary procedure for cranial defects with a relatively higher rate of failure than adults. Here, we use HA cement to perform the procedure while creating a preliminary computational model to understand osteointegration. Based on the findings, cranioplasty shape may alter the rate of integration and lead to higher success rates.

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Journal articles on the topic 'Growth defects'

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