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Internal reflection spectroscopy spectra show that NH3 and ND3 chemisorb onto (100) and (111)A GaAs surfaces. Adsorption occurs by the formation of Ga—N bonds via Lewis acid-base reactions
which are identified by an absorption band between 1325 and 1100 cm−1 with peaks near 1285, 1220 and 1150 cm−1. No NH3 absorption bands are detected when the (111)B surface is exposed. TMGa also chemisorbs onto the (100) GaAs surface. The adsorption
spectra of NH3 + TMGa is a function of the order in which the reactants are introduced. When NH3 is introduced first, the reactivity is much greater as is evidenced by the almost total elimination of absorption peaks associated
with N—H and CH3 peaks which suggests that the reactions are surface catalyzed methane elimination reactions. Implications of the requirement
that the hydride be adsorbed and the methyls react with the hydrogen atoms from the hydride to ALE and MOMBE growth are discussed.
Also, consistent explanations are presented for why growth on the (111)B surface is difficult, the growth rate is independent
of the hydride partial pressure under normal growth conditions, the incorporation of C into GaAs has an orientational dependence,
and As is more preferentially incorporated into GaAsP at the lower growth temperatures. 相似文献
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D. Mazzarese A. Tripathi W. C. Conner K. A. Jones L. Calderon D. W. Eckart 《Journal of Electronic Materials》1989,18(3):369-377
Using a combination of in situ FTIR spectroscopy and detailed surface analysis, we find that TMGa decomposes at the same rate
in either hydrogen or nitrogen forT < 300° C. Although ammonia does not decompose under these conditions, mixing TMGa with ammonia increases the rate of methane
formation. Reacting perdeutroammonia with TMGa shows that hydrogen from the ammonia is incorporated into the product methane
(whereas deuterium in the gas phase is not incorporated into the gaseous product). TMGa and ND3 do react; however, nitrogen incorporation in the growing film is temperature dependent. Further, although the decomposition
of TMGa occurs in the gas phase, the last steps of the decomposition/reaction occur on the substrate surface. 相似文献
4.
本文首次报导了生长温度为550℃,以三甲基镓(TMGa)和三甲基铟(TMIn)为Ⅲ族源,用低压金属有机物气相沉积(LFMOCVD〕技术,高质量1.62um和1.3umInGaAsP及In0.57Ga0.43As0.98P0.04/In0.73Ga0.27As0.6P0.4量子阶结构的生长,并给出了1.55umGaAsP/InP分别限制应变量子阱结构激光器的生长条件,激光器于室温下脉冲激射,其阈值电流密度为2.4kA/cm2. 相似文献
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Hyukju J. Moon Thomas G. Stoebe Brian K. Chadwick 《Journal of Electronic Materials》1990,19(12):1351-1355
Carbon incorporation in GaAs epitaxial layers grown by low pressure metalorganic chemical vapor deposition (MOCVD), using
trimethylgallium (TMGa) as the gallium source and trimethylarsenic (TMAs) and AsH3 as the arsenic sources, has been studied over a wide range of growth parameters. Carbon incorporation is identified by secondary
ion mass spectroscopy (SIMS), Hall measurement, and C-V analysis. Active carbon levels between 2 × 1015 cm-3 and 7 × 1020 cm-3 are obtained. The carbon incorporation is more sensitive to the partial pressure of TMGa than of TMAs in the growth temperature
range 500 ~ 610° C. Carbon incorporation is increased as growth temperatures are decreased to 500° C for growth pressures
near 10000 Pa. Results indicate that surface-adsorbed methyl radicals from the dissociation of TMGa controls carbon incorporation
in this temperature range. 相似文献
6.
采用自行研制的立式MOCVD生长系统 ,以TMGa、TEGa为Ga源 ,在不同的生长条件下生长GaN单晶膜。然后对样品进行室温光致发光光谱测试、范德堡霍尔测量和X射线双晶衍射测试。实验结果表明 ,缓冲层的Ga源不同对GaN单晶膜质量影响很大 ;以TEGa为Ga源生长缓冲层及外延层 ,外延层不连续 ;以TMGa为缓冲层Ga源、TEGa为外延层Ga源 ,在此得到室温载流子浓度为 4 5× 1 0 17cm-3 ,迁移率为 1 98cm2 /V·s的电学性能较好的GaN单晶膜。研究结果表明 :使用TEGa为外延层Ga源生长GaN ,能有效地抑制不期望的蓝带的出现。 相似文献
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Akihiko Ishibashi Hidemi Takeishi Masaya Mannoh Yasufumi Yabuuchi Yuzaburoh Ban 《Journal of Electronic Materials》1996,25(5):799-803
Residual impurities in GaN films on sapphire (A12O3) substrates grown by two-step metalorganic vapor phase epitaxy (MOVPE) have been investigated. We have mainly investigated
the incorporation of carbon into the GaN films with GaN buffer layers on A12O3 during MOVPE growth, comparing trimethygallium (TMGa) and triethygallium (TEGa) as the typical gallium precursors. The films
were characterized by secondary ion mass spectroscopy analysis, photolu-minescence, and Hall measurements. The carbon, hydrogen,
and oxygen concentrations increase with decreasing growth temperature in using TMGa. Especially the carbon concentration increases
with decreasing a V/III ratio, for both TMGa and TEGa. There is about two times more carbon in the GaN films grown using TEGa
than those using TMGa. The carbon from TMGa mainly enhances the D-A pair emission (∼378 nm), which shows the carbon makes
an acceptor level at nitrogen sites in GaN. On the other hand, the carbon from TEGa enhances a deep emission (∼550 nm), which
shows the carbon makes not only an acceptor level but deep levels at interstitial sites in GaN. The carbon impurities originate
from methyl radicals for TMGa, or ethyl radicals for TEGa. It is supposed that, in the case of TEGa, the carbon impurities
are not always located at nitrogen sites, but are also located at interstitial sites because of the C-C bonding in ethyl radicals. 相似文献
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