共查询到20条相似文献,搜索用时 46 毫秒
1.
G. Patrick Watson Dieter G. Ast Timothy J. Anderson Yasuhiro Hayakawa Balu Pathangey 《Journal of Electronic Materials》1991,20(7):703-708
Patterning and etching substrates into mesas separated by trenches before the growth of mismatched (by about 1% or less) epitaxial
layers considerably reduces the interface misfit dislocation density when the layer thickness exceeds the critical thickness.
Such films are in a metastable state, since misfit dislocations allow the epitaxial layers to relax to an in-plane lattice
parameter closer to its strain-free value. Thermal annealing (from 600 to 850° C) has been used to study the stability of
these structures to explore the properties of the misfit dislocations and their formation. The misfit dislocation density
was determined by counting the dark line defects at the InGaAs/GaAs interface, imaged by scanning cathodoluminescence. InGaAs
epitaxial layers grown on patterned GaAs substrates by organometallic chemical vapor deposition possess a very small as-grown
misfit dislocation density, and even after severe annealing for up to 300 sec at 800° C the defect density is less than 1500
cm−1 for a In0.04Ga0.96As, 300 nm thick layer (about 25% of the dislocation density found in unpatterned material that has not been annealed). The
misfit dislocation nucleation properties of the material are found to depend on the trench depth; samples made with deeper
(greater than 0.5 μm) trenches are more stable. Molecular beam epitaxially grown layers are much less stable than the above
material; misfit dislocations nucleate in much greater numbers than in comparable organo-metallic chemical vapor deposited
material at all of the temperatures studied. 相似文献
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用电流控制液相外延(CCLPE)方法首次在(100)InP衬底上成功地生长出In1-xGaxAsyP1-y(0.30<x<0.47,0.70<y<0.96)外延层,并对外延层特性进行了详细研究,提出在InP衬底上生长电外延层的机理,推导出生长动力学的理论模型,该模型与上述实验结果十分吻合。 相似文献
5.
Wang Dangchao Zhang Yuming Zhang Yimen Lei Tianmin Guo Hui Wang Yuehu Tang Xiaoyan Wang Hang 《半导体学报》2011,32(11)
This article investigates the formation mechanism of epitaxial graphene on 6H-SiC (000(1)) substrates under low pressure of 2 mbar environment.It is shown that the growth temperature dramatically affects the formation and quality of epitaxial graphene.The higher growing temperature is of great benefit to the quality of epitaxial graphene and also can reduce the impact of the substrate for graphene.By analyzing Raman data,we conclude that epitaxial graphene grown at 1600 ℃ has a turbostratic graphite structure.The test from scanning electron microscopy (SEM) indicates that the epitaxial graphene has a size of 10μm.This research will provide a feasible route for fabricating larger size ofepitaxial graphene on SiC substrate. 相似文献
6.
Feng Wu Shai Zamir Boris Meyler Joseph Salzman Yuval Golan 《Journal of Electronic Materials》2002,31(1):88-93
Lateral confined epitaxy (LCE) is an epitaxial growth method on substrates patterned to form uniform mesas separated by trenches
for laterally restricting growth area. In this work, plan view and cross-sectional transmission electron microscopy (TEM)
were used in order to characterize the microstructure of GaN films grown by metal-organic chemical vapor deposition on patterned
Si (111) using the LCE method. Two kinds of propagation modes of the dislocations were observed. The dislocations in the center
of the mesa mainly propagate vertically to the surface. On the other hand, dislocations close (1–2 μm) to the mesa edges tend
to bend laterally, allowing dislocation reactions that result in a lower dislocation density. This suggests that the overall
material quality improves with decreasing mesa size, which is consistent with the observed increase in photoluminescence band
edge peak intensity. 相似文献
7.
T. George W. T. Pike M. A. Khan J. N. Kuznia P. Chang-Chien 《Journal of Electronic Materials》1995,24(4):241-247
The initial growth by low pressure metalorganic chemical vapor deposition and subsequent thermal annealing of A1N and GaN
epitaxial layers on SiC and sapphire substrates is examined using high resolution transmission electron microscopy and atomic
force microscopy. Growth under low pressure conditions on sapphire substrates is significantly different from that reported
for conventional (atmospheric pressure) conditions. Smooth, single crystal A1N and GaN layers were deposited on sapphire in
the initial low temperature (600°C) growth step. Interfacial bonding and not lattice mismatch was found to be the determin
ing factor for obtaining good crystallinity for the epitaxial layers as indicated by the growth results on SiC substrates. 相似文献
8.
T. Hsu L. Breaux B. Anthony S. Banerjee A. Tasch 《Journal of Electronic Materials》1990,19(4):375-384
Defect characterization of epitaxial silicon films grown by low temperature remote plasmaenhanced chemical vapor deposition
(RPCVD) under various conditions is discussed. The film morphology and crystallinity have been examined by defect etching/Nomarski
optical microscopy and transmission electron microscopy. Prior to epitaxial growth, anex situ wet chemical clean and anin situ remote hydrogen plasma clean were performed to remove the native oxide as well as other surface contaminants such as carbon.
A damage-free (100) Si surface with extremely low concentrations of carbon and oxygen as confirmed byin situ Auger electron spectroscopy can be achieved using this cleaning technique at temperatures as low as 250°. Low temperature
Si homoepitaxy was achieved by RPCVD on lightly doped (100) Si substrates. Growth parameters such as silane flow rate (partial
pressure), chamber pressure, and substrate temperature were varied during epitaxial growth to investigate the dependence of
film quality on these parameters. For comparison,in situ remote hydrogen plasma and epitaxial growth were also performed on heavily dopedp-type (100) Si substrates. Finally, the results of epitaxial growth at temperatures as low as 150° are presented. 相似文献
9.
J. C. Molstad J. D. Benson J. K. Markunas J. B. Varesi P. R. Boyd J. H. Dinan 《Journal of Electronic Materials》2005,34(9):1242-1248
(211) oriented silicon substrates were patterned and etched to give mesas of various sizes and shapes. Cadmium telluride epitaxial
layers were deposited on the patterned substrates by molecular beam epitaxy (MBE). Dislocation termini in the epilayer were
found to be concentrated in the trenches that formed the mesa boundaries. Mesa sizes up to 17 μm were found to be nearly free
of threading dislocation termini. Threading dislocation termini are observed to congregate in lines parallel to the 〈321〉
crystallographic directions. Evidence of subsurface, horizontal dislocations running through the mesa is given. 相似文献
10.
Journal of Communications Technology and Electronics - The growth of epitaxial (111) NiO films on (0001) LiNbO3 substrates by reactive magnetron sputtering has been reported for the first time.... 相似文献
11.
The liquid-phase epitaxial growth of Pb1−xSnx Te on PbTe (100) substrates has been investigated over a range of growth temperatures from 600-400°C, and has been found
to produce material with good uniformity and reproducibility of carrier concen-tration and alloy composition. The assessment
of the epitaxial layers by such techniques as x-ray diffraction, dislocation etching and thermo-electric power measurements
is described. Various features of the epitaxial layers such as interface irregularity, dislocation and diffusion effects are
discussed, and likely mechanisms for their existence are proposed. The hole concentrations of the epitaxial layers, obtained
by thermoelectric power measurements, are shown to have a similar dependence on preparation temperature as for bulk annealed
material, suggesting that native defects are the dominant source of carriers above~ 2×10* cm-3. 相似文献
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13.
The liquid-phase epitaxial growth of Pb1−xSnx Te on PbTe (100) substrates has been investigated over a range of growth temperatures from 600-400°C, and has been found
to produce material with good uniformity and reproducibility of carrier concen-tration and alloy composition. The assessment
of the epitaxial layers by such techniques as x-ray diffraction, dislocation etching and thermo-electric power measurements
is described. Various features of the epitaxial layers such as interface irregularity, dislocation and diffusion effects are
discussed, and likely mechanisms for their existence are proposed. The hole concentrations of the epitaxial layers, obtained
by thermoelectric power measurements, are shown to have a similar dependence on preparation temperature as for bulk annealed
material, suggesting that native defects are the dominant source of carriers above~ 2×10* cm-3.
The online version of the original article can be found at 相似文献
14.
As part of a systematic investigation of the effects of substrate surfaces on epitaxial growth, the transient behavior of
Hg1−xCdxTe film growth on (111)B CdTe by chemical vapor transport (CVT) has been studied as a function of growth time under vertical
stabilizing (hot end on top) and vertical destabilizing (hot end at bottom) ampoule orientations. The experim ental results
show the morphological transition of the Hg1−xCdxTe deposition on (111)B CdTe at 545°C from three-dimensional islands to layers within about 0.5 and 0.75 h for the growth
under vertical stabilizing and destabilizing conditions, respectively. The combined effects of small convective flow disturbances
on the growth morphology and defect formation are measurable. The overall trends of the time dependent growth rates and compositions
of the Hg1−xCdxTe epitaxial layers under stabilizing and destabilizing conditions are similar. The system atically higher growth rates of
the Hg1−xCdxTe films by about 10% under vertical destabilizing conditions could be influenced by a small convective contribution to the
mass transport. The combined results show that improved Hg1−xCdxTe epitaxial layers of low twin density on (111)B CdTe substrates can be obtained by CVT under vertical stabilizing conditions. 相似文献
15.
G. B. Stringfellow P. F. Lindquist R. A. Burmeister 《Journal of Electronic Materials》1972,1(4):437-457
Single crystal epitaxial layers of Gaxln1−xP alloys have been grown by the steady-state liquid phase epitaxial growth technique on (111)B GaAs substrates. The crystal
growth process has been studied in detail and the resultant epitaxial layers have been characterized with respect to their
structural, electrical and optical properties. Epitaxial layers of good structural quality could be grown only in the composition
range x = 0.48 to 0.53, where the lattice parameter is close to that of the GaAs substrate. The band gap of these crystals
was in the range 1.86 – 1.92 eV as determined by optical absorption and photoluminescence measurements. 相似文献
16.
Current status of large-area MOVPE growth of HgCdTe device heterostructures for infrared focal plane arrays 总被引:2,自引:0,他引:2
C. D. Maxey J. C. Fitzmaurice H. W. Lau L. G. Hipwood C. S. Shaw C. L. Jones P. Capper 《Journal of Electronic Materials》2006,35(6):1275-1282
This paper reviews the current status of the growth of fully doped HgCdTe (MCT) devices by metalorganic vapor phase epitaxy
(MOVPE). The current reactor system has been developed to produce 3-inch diameter epitaxial layers compatible with slice-scale
processing. The new reactor system has achieved routine epitaxial growth of MCT with good morphology onto both gallium arsenide
(GaAs) and GaAs on silicon (Si) wafers that were oriented (2–8°) off (100) orientation. The density of surface defects (so-called
“hillocks”), typical of MOVPE growth on such orientation substrates, has been reduced to <5 cm−2 at a sufficient yield to make the production of low cluster defect 2D arrays possible. Alternative growth experiments onto
cadmium telluride (CdTe) on Si substrates with (211)B orientation have also been performed to investigate their usefulness
for infrared focal plane array (IRFPA) applications. Si substrates give better thermal expansion match to the read out Si
circuits (ROIC). The horizontal reactor cell design has a graphite susceptor with a rotating platen capable of using substrates
up to 4-inch diameter. Work, however, has concentrated on 3-inch diameter GaAs and GaAs on Si wafers substrates in the reactor,
and these reproducibly demonstrated good compositional and thickness uniformity. Cut-off wavelength and thickness uniformity
maps showed that there was sufficient uniformity to produce twelve sites of large format 2D arrays (640×512 diodes on 24-μm
pitch) per slice. Minority carrier lifetimes in heterostructures is an important parameter and some factors affecting this
are discussed, with special emphasis on As-doped material grown under various growth conditions in an attempt to reduce Shockley-Read
(S-R) trap densities. New data are presented on trap densities and theoretical fitting of lifetimes in MOVPE material. Fully
doped heterostructures have been grown to investigate the device performance in the 3–5 μm medium-wave IR (MWIR) band and
8–12 μm long-wave IR (LWIR). These layers have been fabricated into mesa arrays and then indium-bumped onto Si multiplexers.
A summary of the 80-K device results shows that state-of-the-art device performance has been demonstrated in MOVPE-grown device
structures. 相似文献
17.
Constant composition InGaAsP epitaxial layers can be grown on (100) InP substrates at a constant temperature using the diffusion-limited
step-cooling growth technique, and in general, compositionally graded layers result when the diffusion-limited equilibrium-cooling,
supercooling, and two-phase-solution growth techniques are used. The lattice constant and energy gap of the epitaxial layers
grown using the step-cooling technique are nearly independent of small variations of X
p
l
and the amount of step cooling, but are dependent on growth temperature. The dependence of lattice constant and energy gap
of the epitaxial layers on X
Ga
l
and X
As
l
has been determined for the step-cooling and supercool ing techniques. 相似文献
18.
The preparation of silicon double-drift millimetre-wave IMPATT diodes by the epitaxial growth of n- and p-type layers successively on n-type substrates is described. Carrier-concentration profiles comparable with those reported for double layers formed by ion implantation are obtained; a microwave output power of 560 mW with 11% efficiency has been achieved at 48 GHz. 相似文献
19.
Electric current controlled liquid phase epitaxy (LPE) of GaAs has been performed on both n+ and semi-insulating substrates. Growth is induced by current flow across the substrate-melt interface. The furnace temperature
is held constant during growth so that direct electrical control of the growth process is achieved. The dependence of the
growth rate on both the electric current density across the substrate-melt interface and the ambient furnace temperature was
determined. Current densities from 5 to 20 A/cm2 were employed and furnace temperatures ranging from 680 to 800°C were used. Sustained steady state growth rates as small
as 0.022μm/min and as large as 1.4μm/min were obtained. For a given furnace temperature and current density, the measured
growth rates on semi-insulating substrates range from 48% to 77% of the rates obtained on n+ n substrates. The surface morphology of the epitaxial layers is observed to depend on the electric current density employed
during growth. Electric current controlled doping modulation was studied in epitaxial layers grown from unintentionally doped
melts. The degree of doping modulation achieved is approximately proportional to the change in applied current density. Approximately
a 40% increase in the net electron concentration is obtained by changing the current density from 10 to 30 A/cm2 during growth. Preliminary experiments with tin doped epitaxial layers indicate that similar changes in the amount of tin
incorporation can be achieved. 相似文献
20.
Si基外延Ge薄膜中残余应变的检测与分析 总被引:1,自引:1,他引:0
研究了Si衬底上外延Ge薄膜中的应变。在超高真空化学气相沉积系统中生长Ge薄膜,采用高精度X射线衍射(XRD)和拉曼散射光谱检测薄膜的组份和应变。结果表明,外延薄膜的组份为纯Ge,没有Si的扩散;Ge薄膜中存在少量应变。Ge薄膜XRD峰位和拉曼散射峰位的偏移是由残余应变引起的。定量计算了热膨胀失配引入的张应变和晶格失配引入的压应变与Ge薄膜生长参数的关系,张应变随着生长温度的升高而近似线性增加,压应变随着生长厚度的增加按反比例减小,Ge薄膜最终应变状态由两者共同决定。理论计算值与实验结果吻合良好。 相似文献