薄膜界面粗糙对双晶摇摆曲线的影响

用X射线衍射动力学理论,模拟计算InP衬底上InGaAs/AllnAs超晶格和InGaAs单层膜的X射线双晶摇摆曲线,计算结果表明:薄膜界面粗糙对单层膜的衍射峰和超晶格的零级衍射峰影响较小,但却明显影响单层膜衍射干涉条纹和超晶格的±1级卫星峰,随着平均界面粗糙度的增大,单层膜衍射干涉条纹强度减弱并趋于消失;超晶格的±1级卫星峰变弱并逐渐展宽,理论计算的模拟双晶摇摆曲线与超晶格实验曲线比较表明:高质量匹配In_0.53Ga_0.47As(85?)/Al_{0.4 关键词：}     

低压MOCVD生长参量对Ⅱ型InAs/GaSb超晶格材料表面形貌的影响

采用自制低压金属有机源化学气相沉积设备,在（100）面GaSb单晶衬底上生长了Ⅱ型InAs/GaSb超晶格材料.利用双晶X射线衍射、光学显微镜、原子力显微镜和光致发光谱等分析手段对材料特性进行了表征,获得了表面光亮的晶体质量较好的Ⅱ型InAs/GaSb超晶格材料,在77 K下得到光致发光谱峰值波长为3.25 μm.研究了生长温度、过渡层、界面层对其表面形貌的影响,得出生长温度在500 ℃~520 ℃,无过渡层,使用InAsSb界面层有利于改善材料的表面形貌.     

低压MOCVD生长参量对Ⅱ型InAs/GaSb超晶格材料表面形貌的影响

采用自制低压金属有机源化学气相沉积设备,在(100)面GaSb单晶衬底上生长了Ⅱ型InAs/GaSb超晶格材料.利用双晶X射线衍射、光学显微镜、原子力显微镜和光致发光谱等分析手段对材料特性进行了表征,获得了表面光亮的晶体质量较好的Ⅱ型InAs/GaSb超晶格材料,在77 K下得到光致发光谱峰值波长为3.25 μm.研究了生长温度、过渡层、界面层对其表面形貌的影响,得出生长温度在500 ℃～520 ℃,无过渡层,使用InAsSb界面层有利于改善材料的表面形貌.     

引入n型InGaN/GaN超晶格层提高量子阱特性研究

利用金属有机物化学气相淀积技术在蓝宝石衬底上生长了InGaN/GaN量子阱结构. 研究了引入n型InGaN薄层或InGaN/GaN超晶格层的量子阱特性,结果表明通过引入n型InGaN薄层或InGaN/GaN超晶格层缓解了量子阱有源区中的应力,改善了多量子阱表面形貌,减少了V型缺陷密度,而且提高了多量子阱的光致发光强度,从而也改进了LED的发光效率. 关键词： InGaN/GaN多量子阱 原子力显微镜 X射线双晶衍射 光致发光     

MBE[(GaAs)l(Ga1-λAlxAs)m]n/GaAS(001)一维超晶格的X射线双晶衍射测量

本文着重介绍了MBE[(GaAs)l(Ga1-xAlxAs)m]n/GaAs(001)一维超晶格的X射线双晶衍射测量方法。根据卫星峰的出现,证明超晶格的存在。基于超晶格的台阶模型和X射线衍射的运动学理论,推导出超晶格多结构参数的计算方法。并对X射线双晶给出的其他信息做了必要的讨论。     

MBE[(GaAs)_l(Ga_(1-λ)Al_xAs)_m]_n/GaAS(001)一维超晶格的X射线双晶衍射测量

本文着重介绍了MBE[(GaAs)_l(Ga_(1-x)Al_xAs)_m]_n/GaAs(001)一维超晶格的X射线双晶衍射测量方法。根据卫星峰的出现,证明超晶格的存在。基于超晶格的台阶模型和X射线衍射的运动学理论,推导出超晶格多结构参数的计算方法。并对X射线双晶给出的其他信息做了必要的讨论。     

高分辨X射线双晶衍射技术在半导体薄膜材料研究中的应用

本文介绍了Ｘ射线双晶衍射技术的原理和对半导体外延膜的检测；对普遍关心的衬底与外延膜的 点阵失配、膜厚和成分及其变化的测定、衬底和外延膜完美性的检测以及超晶格结构和非常薄的外延膜 的评价等作了扼要的综述．     

In1-xGaxAsyP1-y/InP异质界面晶格失配对外延晶体质量的影响

用X-射线双晶衍射,双晶形貌术和光致发光方法综合研究了In1-xGaxAsyP1-y/InP异质界面晶格失配对LPE晶体质量的影响。实验表明,异质界面晶格失配是导致外延层中位错和缺陷增多,杂质凝聚和辐射复合深中心增多的重要因素。     

GexSi1-x/Si应变层超晶格的分子束外延生长及其特性研究

在Si(100)衬底上用分子束外延在不同的温度下生长了不同组份的Ge_xSi_1-x/Si应变层超晶格。用反射式高能电子衍射、X射线双晶衍射、卢瑟福背散射、透射电子显微镜以及Raman。散射等测试方法研究了Ge_xSi_1-x/Si超晶格的生长及其结构特性。结果表明,对不同合金组份的超晶格,其最佳生长温度不同。x值小,生长温度高;反之,则要求生长温度低。对于x为0.1—0.6,在400—600℃的生长温度范围能够长成界面平整、 关键词：     

Ge_xSi_1-x_/Si应变层超晶格的分子束外延生长及其特性研究

在 Si (l00) 衬底上用分子束外延在不同的温度下生长了不同组份的GeGe_xSi_1-x_/Si 应变层超晶格.用反射式高能电子衍射、x 射线双晶衍射、卢瑟福背散射、透射电子显微镜以及Raman散射等侧试方法研究了Ge Ge_xSi_1-x_/Si超晶格的生长及其结构特性. 结果表明, 对不同合金组份的超晶格, 其最佳生长温度不同. x值小, 生长温度高; 反之, 则要求生长温度低. 对于x为0. 1-0. 6 , 在400-600℃ 的生长温度范围能够长成界面平整、晶格完好和周期均匀的GeGe_xSi_1-x_/Si应变层超晶格. 关键词：     

Growth of strain-compensated InGaAs/GaAsP multiple quantum wells by MOVPE

InGaAs/GaAsP strain-compensated multiple quantum wells (SCMQWs) and strained InGaAs/GaAsmultiple quantum wells (MQWs) were grown on GaAs substrates by metal organic vapor phase epitaxy(MOVPE). The results of double crystal X-ray diffraction (DCXRD) revealed that strain relief had beenpartly accommodated by the misfit dislocation formation in the strained MQW material. It led to thatthe full width half maximums (FWHMs) of superlattice satellite peaks are broader than those of SCMQWstructures, and there was no detectable room temperature photoluminecence(RT-PL)for the strained     

The defect structure of AlGaN/GaN superlattices grown on sapphire by the MOCVD method

High-resolution x-ray diffractometry and electron microscopy are used to study the defect structure and relaxation mechanism of elastic stresses in AlGaN/GaN superlattices grown by the MOCVD method on sapphire covered with a preliminarily deposited GaN and AlGaN buffer layer. Based on an analysis of the half-widths of three-crystal scan modes of x-ray reflections measured in different diffraction geometries, the density of different dislocation families is determined. For all the dislocation families, the density is shown to increase with the Al concentration in the solid-solution layers and depend only weakly on the superlattice period. From the electron-microscopic patterns of planar and cross sections, the types of dislocations and their distribution in depth are determined. It is shown that, in addition to high-density vertical edge and screw dislocations, which nucleate in the buffer layer and propagate through the superlattice layers, there are sloped intergrowing dislocations with a large horizontal projection and bent mixed dislocations with a Burgers vector $\left\langle {11\overline 2 3} \right\rangle $ at the interface between individual superlattice layers. The former dislocations form at the interface between the buffer layer and the superlattice and remove misfit stresses between the buffer and the superlattice as a whole, and the latter dislocations favor partial relaxation of stresses between individual superlattice layers. In samples with a high Al concentration (greater than 0.4) in AlGaN layers, there are cracks surrounded by high-density chaotic horizontal dislocations.     

Edge misfit dislocation formation at the interface of a nanopore and infinite substrate with surface/interface effects

The model of an edge misfit dislocation at the interface of the hollow nanopore and the infinite substrate with surface/interface stress is investigated. Using the complex variable method, analytical solutions for complex potentials of a film due to an edge misfit dislocation located in the film with surface/interface effect are derived, and the stress fields of the film and the edge misfit dislocation formation energy can be obtained. The critical conditions for edge misfit dislocation formation are given at which the generation of an edge misfit dislocation is energetically favourable. The influence of the ratio of the shear modulus between the film and the infinite substrate, the misfit strain, the radius of the nanopore and the surface/interface stress on the critical thickness of the film is discussed.     

GaAs/AlGaAs分子束外延材料的X射线双晶形貌观察

本文介绍了用非平行非对称(+、-)双晶X射线形貌术研究Ⅲ—Ⅴ族化合物外延晶体的设置和原理。分析了外延后形成的弯曲样品造成的衍射效应。对分子束外延(MBE)法生长的GaAs/AlGaAs衬底和外延层分别进行了X射线形貌术观察。讨论了外延层中存在的失配位错、生长小丘、沾污和局部微差取向等缺陷。对位错的组态和来源进行了初步分析。本实验结果也表明,有应变超晶格过渡层的MBE法对生长优质的GaAs/AlGaAs外延片是有利的。     

Determination of strain in epitaxial semiconductor structures by high-resolution X-ray diffraction

High-resolution X-ray diffraction is used to obtain the strain profile of a wide range of epitaxial semiconductor samples. The samples are divided into five categories: Strained layers on a substrate, (partly) relaxed layers on a substrate, strained-layer superlattice structures, multiple relaxed layers and relaxed superlattice structures and ionimplanted samples. For each category a measurement strategy and analysis method is given. Representative examples for each category are shown.     

The influence of AlN/GaN superlattice intermediate layer on the properties of GaN grown on Si（111） substrates

AlN/GaN superlattice buffer is inserted between GaN epitaxial layer and Si substrate before epitaxial growth of GaN layer. High-quality and crack-free GaN epitaxial layers can be obtained by inserting AlN/GaN superlattice buffer layer. The influence of AlN/GaN superlattice buffer layer on the properties of GaN films are investigated in this paper. One of the important roles of the superlattice is to release tensile strain between Si substrate and epilayer. Raman spectra show a substantial decrease of in-plane tensile strain in GaN layers by using AlN/GaN superlattice buffer layer. Moreover, TEM cross-sectional images show that the densities of both screw and edge dislocations are significantly reduced. The GaN films grown on Si with the superlattice buffer also have better surface morphology and optical properties.     

Morphological instability in InAs/GaSb superlattices due to interfacial bonds

Synchrotron x-ray diffraction is used to compare the misfit strain and composition in a self-organized nanowire array in an InAs/GaSb superlattice with InSb interfacial bonds to a planar InAs/GaSb superlattice with GaAs interfacial bonds. It is found that the morphological instability that occurs in the nanowire array results from the large misfit strain that the InSb interfacial bonds have in the nanowire array. Based on this result, we propose that tailoring the type of interfacial bonds during the epitaxial growth of III-V semiconductor films provides a novel approach for producing the technologically important morphological instability in anomalously thin layers.     

双势垒超晶格结构的同步辐射及X射线双晶衍射研究

利用高精度的Ｘ射线双晶衍射和同步辐射散射对可用于半导体红外探测器的双势垒超晶格材料进行了研究，并运用Ｘ射线衍射动力学理论进行模拟计算，得到了与实验结果符合得很好的理论曲线．同时发现包络函数节点处的卫星峰对结构参数的变化极为灵敏．以此进行模拟计算，可准确地确定出样品的结构参数，厚度误差范围为±０.１ｎｍ．并利用Ｘ射线衍射运动学理论对实验中观测到的卫星峰调制现象给予了解释     

半导体应变超晶格结构与界面的X射线双晶衍射研究

本文应用X射线在畸变晶体中的动力学衍射理论,分析了超晶格衍射峰强度分布的规律,计算了应变超晶格中界面变化,层厚波动对双晶摇摆曲线的影响,并初步探讨了超晶格衍射峰之间的小峰消失以及衍射峰宽化的原因,研究表明,衍射峰强度分布依赖于超晶格周期中层厚、成份及应变的综合效果,界面和层厚波动将对摇摆曲线产生一定影响,而晶格弯曲是使衍射峰宽化的主要原因。