用乙硅烷及固态锗源外延生长应变GeSi／Si合金

采用气态源分子束外延（ＧＳＭＢＥ）法成功地生长出应变ＧｅｘＳｉ１－ｘ／Ｓｉ异质结合金，所使用的源分别是乙硅烷和固态锗。用固态锗取代气态锗烷，即保留了生长中由氢化物裂解产生的氢原子在生长表面上的活化作用（ｓｕｒｆａｃｔａｎｔ ｅｆｆｅｃｔ），又利用了固态源炉通过挡板能够迅速切断分子束流的优点。样品的Ｘ射线双晶衍射，透射电子显微镜及光荧光测量表明ＧｅｘＳｉ１－ｘ合金具有较好的晶格完整性及平坦的异质结界     

1.3—1.55μm GeSi异质结红外探测器的研制

采用快速加热，超低压化学气相淀积方法，在－Ｇｅ衬底上外延生长－ＧｅＳｉ－Ｓｉ薄层，首次研制成功了１．３－１．５５μｍ波段的ＧｅＳｉ异质结红外探测器，其主要参数性能优于该波段的同类型Ｇｅ探测器。     

光电导型混晶Si1-xGex波导探测器

首次报导了光电导型混晶Ｓｉ－ｘＧｅｘ波导探测器。混晶Ｓｉ１－ｘＧｅｘ是在硅基ＳｉＯＮ／ＳｉＯ２／Ｓｉ上用快速加热超低压化学气相淀积生长并经６５０℃退火３０ｍｉｎ得到的。探测器宽１０μｍ,长２ｍｍ。探测器加２０Ｖ偏置电压是,探测灵敏在０．０２２－０．０１０Ａ／Ｗ之间。混晶Ｓｉ１－ｘＧｅｘ造成探测器的光谱响应曲线发生蓝移。当锗组分ｘ＝０．３５、０．４、０．５、和０．６时,探测器峰值波长分别对应为８７５     

Ga－Al－As－Si系统中Si的两性掺杂行为的研究

对Ｓｉ在电液相外延Ｇａ－Ａｌ－Ａｓ－Ｓｉ系统中的两性掺杂行为进行了研究。提出了一种恒温生长Ｇａ＿（１－ｘ）Ａｌ＿ｘＡｓ：Ｓｉｐ－ｎ结的新方法，对这种ｐ－ｎ结的成因作了定性的解释，并对这种ｐ－ｎ结的电特性加以观察。     

MOCVD外延生长Ga_(1-x)Al_xAs_(1-y)Sb_y半导体薄膜气固平衡和人工神经网络预报

本文研究了ＭＯＣＶＤ外延生长Ｇａ１－ｘＡｌｘＡｓ１－ｙＳｂｙ半导体薄膜的生长条件与外延层组成的关系，并用人工神经网络法总结有关气固平衡规律。结果表明，用气相组成，载气流量和生长温度等影响外延层组成的主要参数作为人工神经网络的输入，以固相Ｇａ１－ｘＡｌｘＡｓ１－ｙＳｂｙ中的Ａｌ和Ｓｂ的含量ｘ、ｙ作为输出，训练的人工神经网络可以预报固相组成ｘ、ｙ，得到满意结果。     

MOCVD外延生长Ga1—xAlAs1—ySby半导体薄膜气固平衡和人工神经网络预报

本文研究了ＭＯＣＶＤ外延生长Ｇａ１－ｘＡｌｘＡｓ１－６Ｓｂｙ半导体薄膜的生长条件与外延层组成的关系，并用人工神经网络法总结有关气固平衡规律。结果表明，用气相组成，载气流量和生长等影响外延层组成的主要参数作为人工神经网络的输入，以固相Ｇａ１－ｘＡｌｘＡｓ１－ｙＳｂｙ中的Ａｌ和Ｓｂ的含量ｘ、ｙ作为输出，训练的人工神经网络可以预报固相组成ｘ、ｙ，得到满意结果。     

硅基β-SiC薄膜外延生长的温度依赖关系研究

采用常压化学气相淀积（ＡＰＣＶＤ）工艺在１０００～１４００℃温度范围内的（１００）Ｓｉ衬底上进行了β－ＳｉＣ薄膜的异质外延生长．实验结果表明,随着淀积温度的升高,外延层由多晶硅向β－ＳｉＣ单晶转变,结晶情况变好;但同时单晶生长速率却反而有所下降．     

SiGe／Si光电探测器研究进展

本文综述了目前国内外在工作波长１．３－１．５μｍ的ＳｉＧｅ／Ｓｉ超晶格探测器的工作波长为８－１２μｍ的ＳｉＧｅ／Ｓｉ异质结长波长红外探测器方面的研究进展，并分析了存在的问题和材料的各种生长方法。     

Al_xGa_（1－x）As外延层中Si平面掺杂的SIMS研究

利用二次离子质谱（ＳＩＭＳ）系统地研究了生长温度，Ａｌ组份ｘ值和Ａｓ＿４压强对Ｓｉδ掺杂Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ的ＳＩＭＳ深度剖面，Ｓｉ原子表面分凝和向衬底扩散的影响。实验发现，在外延生长Ｓｉδ掺杂Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ时，随着生长温度的提高或Ａｌ组份Ｘ值增加，Ｓｉ掺杂分布ＳＩＭＳ峰都非对称展宽，表面分凝作用加强，但不影响Ｓｉ原子的扩散，因此ＳＩＭＳ剖面的展宽与扩散无关。另外，我们还发现Ａｓ＿４压强高于１．５×１０￣（－５）ｍｂａｒ时，Ａｓ＿４压强对δ掺杂空间分布影响不大，而Ａｓ＿４压强低于此压强时，Ｓｉ掺杂分布峰宽度增加很快，这主要由杂质扩散作用引起。生长温度对掺杂分布峰影响最大，其次是Ａｌ组份影响，而较小Ａｓ＿４压强的影响不可忽视。这些研究结果对外延生长Ｓｉδ掺杂Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ材料是有价值的。     

能隙阶梯缓变结构Si1-xGex/Si光电探测器

提出了一种新结构Ｓｉ１－ｘＧｅｘ／Ｓｉ光电探测器－能隙阶梯缓变结构的Ｓｉ１－ｘＧｅｘ／ＳｉＰＩＮ新近红外光电探测器。理论分析表明,能隙缓变增大了载流子的离化率。价带的不连续则有利于空穴离化,从而对载流子的收集有利,可获得高的光电响应。实验结果表明,该探测器具有良好的Ｉ－Ｖ特性,反向漏电低达０．１μＡ／ｍｍ＾２（－２Ｖ。该探测器主峰值波长在０．９６μｍ。其光电流响应随着反应偏压的增加有明显的增大,在     

Atomically controlled processing in silicon-based CVD epitaxial growth

One of the main requirements for Si-based ultrasmall device is atomic-order control of process technology. Here, we show the concept of atomically controlled processing for group IV semiconductors based on atomic-order surface reaction control in Si-based CVD epitaxial growth. Self-limiting formation of 1-3 atomic layers of group IV or related atoms after thermal adsorption and reaction of hydride gases on Si(1-x)Gex(100) (x = 0-1) surface are generalized based on the Langmuir-type model. Moreover, Si-based epitaxial growth on N, P or C atomic layer formed on Si(1-x)Gex(100) surface is achieved at temperatures below 500 degrees C. N atoms of about 4 x 10(14) cm(-2) are buried in the Si epitaxial layer within about 1 nm thick region. In the Si(0.5)Ge(0.5) epitaxial layer, N atoms of about 6 x 10(14) cm(-2) are confined within about 1.5 nm thick region. The confined N atoms in Si(1-x)Gex preferentially form Si-N bonds. For unstrained Si cap layer grown on top of the P atomic layer formed on Si(1-x)Gex(100) with P atomic amount of below about 4 x 10(14) cm(-2) using Si2H6 instead of SiH4, the incorporated P atoms are almost confined within 1 nm around the heterointerface. It is found that tensile-strain in the Si cap layer growth enhances P surface segregation and reduces the incorporated P atomic amount around the heterointerface. Heavy C atomic-layer doping suppresses strain relaxation as well as intermixing between Si and Ge at the nm-order thick Si(1-x)Gex/Si heterointerface. These results open the way to atomically controlled technology for ULSIs.     

One-step Ge/Si epitaxial growth

Fabricating a low-cost virtual germanium (Ge) template by epitaxial growth of Ge films on silicon wafer with a Ge(x)Si(1-x) (0 < x < 1) graded buffer layer was demonstrated through a facile chemical vapor deposition method in one step by decomposing a hazardousless GeO(2) powder under hydrogen atmosphere without ultra-high vacuum condition and then depositing in a low-temperature region. X-ray diffraction analysis shows that the Ge film with an epitaxial relationship is along the in-plane direction of Si. The successful growth of epitaxial Ge films on Si substrate demonstrates the feasibility of integrating various functional devices on the Ge/Si substrates.     

Diameter dependent growth rate and interfacial abruptness in vapor-liquid-solid Si/Si1-xGex heterostructure nanowires

A strong diameter dependence is observed in the interfacial abruptness and growth rates in Si/Si 1- x Ge x axial heterostructure nanowires grown via Au-mediated low pressure CVD using silane and germane precursors. The growth of these nanowires has similarities to that of heterostructure thin films with similar compositional interfacial broadening, which increases with and is on the order with diameter. This broadening may reveal a fundamental challenge to fabrication of abrupt heterostructures via VLS growth.     

用电诱导液相外延法制备铝组分稳定的高铝值镓铝砷外延层

本文对用于制造高效率半导体发光器件的材料──Ｇａ_（１－ｘ）Ａｌ_ｘＡｓ（ｘ＝０．７５）外延层沿生长方向上铝组分的分布进行了详细地讨论。采用电液相外延法能获得铝组分高度稳定的Ｇａ_（１－ｘ）Ａｌ_ｘＡｓ外延层，并用电流诱导效应作了初步理论解释。     

Ge oxidation in the remaining cores of Si(1-x)Ge(x) nanowires after prolonged oxidation

For this investigation of the Ge behavior of condensed Si(1-y)Ge(y) (y > x) cores during the oxidation of Si(1-x)Ge(x) nanowires, Si(1-x)Ge(x) nanowires were grown in a tube furnace by the vapor-liquid-solid method and thermally oxidized. The test results were characterized using several techniques of transmission electron microscopy. The two types of Ge condensation are related to the diameter and Ge content of the nanowires. The consumption of Si atoms in prolonged oxidation caused the condensed SiGe cores to become Ge-only cores; and the continuous oxidation resulted in the oxidation of the Ge cores. The oxidation of Ge atoms was confirmed by scanning transmission electron microscopy.     

GexSi1-x/Si中应变的会聚束电子衍射研究

介绍了会聚束电子衍射（ＣＢＥＤ）技术与计算机模拟相结合测定ＧｅｘＳｉ１－ｘ／Ｓｉ化学梯度层中应变分布的实验结果,提供了一种高空间分辨率,高灵敏度,且适用于任何材料系中微区晶格常数测定及应变分布研究的技术途径。     

Diameter-dependent composition of vapor-liquid-solid grown Si(1-x)Ge(x) nanowires

Diameter-dependent compositions of Si(1-x)Ge(x) nanowires grown by a vapor-liquid-solid mechanism using SiH(4) and GeH(4) precursors are studied by transmission electron microscopy and X-ray energy dispersive spectroscopy. For the growth conditions studied, the Ge concentration in Si(1-x)Ge(x) nanowires shows a strong dependence on nanowire diameter, with the Ge concentration decreasing with decreasing nanowire diameter below approximately 50 nm. The size-dependent nature of Ge concentration in Si(1-x)Ge(x) NWs is strongly suggestive of Gibbs-Thomson effects and highlights another important phenomenon in nanowire growth.     

Composition controlled synthesis and Raman analysis of Ge-rich Si(x)Ge(1-x) nanowires

Here, we report the synthesis of Si(x)Ge(1-x) nanowires with x values ranging from 0 to 0.5 using bulk nucleation and growth from larger Ga droplets. Room temperature Raman spectroscopy is shown to determine the composition of the as-synthesized Si(x)Ge(1-x) nanowires. Analysis of peak intensities observed for Ge (near 300 cm(-1)) and the Si-Ge alloy (near 400 cm(-1)) allowed accurate estimation of composition compared to that based on the absolute peak positions. The results showed that the fraction of Ge in the resulting Si(x)Ge(1-x) alloy nanowires is controlled by the vapor phase composition of Ge.     

Electrical transport of bottom-up grown single-crystal Si(1-x)Ge(x) nanowire

In this work, we fabricated an Si(1-x)Ge(x) nanowire (NW) metal-oxide-semiconductor field-effect transistor (MOSFET) by using bottom-up grown single-crystal Si(1-x)Ge(x) NWs integrated with HfO(2) gate dielectric, TaN/Ta gate electrode and Pd Schottky source/drain electrodes, and investigated the electrical transport properties of Si(1-x)Ge(x) NWs. It is found that both undoped and phosphorus-doped Si(1-x)Ge(x) NW MOSFETs exhibit p-MOS operation while enhanced performance of higher I(on)～100?nA and I(on)/I(off)～10(5) are achieved from phosphorus-doped Si(1-x)Ge(x) NWs, which can be attributed to the reduction of the effective Schottky barrier height (SBH). Further improvement in gate control with a subthreshold slope of 142?mV?dec(-1) was obtained by reducing HfO(2) gate dielectric thickness. A comprehensive study on SBH between the Si(1-x)Ge(x) NW channel and Pd source/drain shows that a doped Si(1-x)Ge(x) NW has a lower effective SBH due to a thinner depletion width at the junction and the gate oxide thickness has negligible effect on effective SBH.     

On the formation and photoluminescence of Si(1-x)Ge(x) nanoparticles

Si(1-x)Ge(x) nanoparticles were prepared from two annealed alloy ingots at the compositions of Si:Ge = 9.5:0.5 and 9:1 using a vapor condensation technique under Ar atmosphere. These nanoparticles are all spherical, and increasing the working pressure leads to an increased particle size and size dispersion. Comparing to the alloy ingots, the nanoparticles have a higher average content of Ge. In addition, increasing the working pressure also causes the Si(1-x)Ge(x) nanoparticles to become more Ge-rich. This can be ascribed to the lower melting point and higher kinetic energy of Ge than Si during the evaporation process. The photoluminescence of Si(1-x)Ge(x) nanoparticles ranges from visible light to infrared region, and the luminescence peak exhibits a red shift as the Ge content in the nanoparticles increases. This indicates that the incorporation of Ge into Si has a dominant effect in the radiative recombination process, in comparison with the constant luminescence peak position in the case of pure Si nanoparticles with similar size distribution.