Study of Heteroepitaxial Growth Dynamic on Compound Semiconductor substrates

我们用透射电子衍射（TED）、反射高能电子衍射（RHEED）和俄歇电子能谱（AES）对金属/InSb系统的异质外延生长过程进行了动态观察。首先，在动态al过程观察之前，作为衬底的InSb（111）InSb（001）的表面结构基于与TED相关的Patterson函数、傅立叶分析和最小二乘精细化来确定：一方面，对于InSb（111）A-2 × 2，根据空位屈曲模型计算得到的表面结构强度与实测值吻合较好;对于InSb（111）B-2 × 2，提出了Sb三聚体吸附在最外层Sb层四重顶位的新模型。另一方面，关于InSb（OOl），观察到的强度的Patterson分析显示在InSb（OOl）-c4 x4的最外层的顶部上清楚地存在二聚体。TED强度的分布 ...更多信息 很好地解释了六原子团簇模型，而不是四原子团簇模型。其次，我们利用超高真空原位TED观察了In和Au在InSb（111）表面的生长过程，得到如下结果：[I]In/InSb（111）（1）In在室温下以岛状生长，并且在生长的非常早期阶段具有fcc结构。(2)In粒子在InSb（111）A-2 × 2上经历了普通的外延生长，而在InSb（111）B-2 × 2上它们旋转了一定程度，可能是由于Sb三聚体的存在。In/InSb（001）在InSb（001）上，In颗粒以类似于In/InSb（111）A的情况生长;（i）岛状生长，具有金字塔形状和（ii）面心立方结构。另外，不同的生长特征如下：In颗粒在InSb（001）-c4 × 4和InSb（001）-c8 × 2表面上均沿二聚体阵列沿着。此外，它们的晶体形态呈帐篷状，与金字塔的初始生长形式不同。[III]Au/InSb（111）A-2 × 2在该体系中，<3><3>首次在生长初期观察到了aROO-xROO -Au吸附结构。第三，利用RHEED和AES研究了Ag和Sn的生长过程，结果如下：[IV]Ag/InSb（111）A-2x2 Ag薄膜在InSb（111）A-2x2表面以Stranski-Krastanov模式生长。另一方面，在生长的早期阶段，薄膜的（110）面以Ag //InSb的取向平行于InSb（111）生长<111><110>，而在随后的生长中，平行取向与Ag<110>//InSb共存<211>。[V]Sn/InSb（111）Sn薄膜以逐层方式生长，随着覆盖率的增加，薄膜的稳定性降低。在InSb（111）A上，薄膜表面不可逆地经历了从3x 3结构到2x2结构，再到1x 1结构，最后熔化的过程。然而，在InSb（111）B上观察到主要不同的生长特征;指示与相应理论曲线的大偏差的俄歇信号证明Sb扩散到Sn覆盖层中。这种扩散行为严重影响了生长在InSb（111）B-2 × 2上的α-Sn膜的表面相变。少

We have used transmission electorn diffraction (TED), reflection high energy electron diffraction (RHEED) and Auger electron spectroscopy (AES) to dynamically observe the heteroepitaxial growth processes in the metals/InSb system. Firstly, prior to the dynamic al process observations, surface structures of InSb(111) InSb(001) that used as a substrate were determined on the basis of the Patterson function, Fourier analysis and least-squares refinement associated with TED : On one hand, for InSb(111)A-2x2, the measured intensities agreed well with the kinematically calculated ones of the surface structure referring to the vacancy buckling model ; for InSb(111)B-2x2, a new model where Sb trimers are adsorbed at a fourfold atop site of the outermost Sb layer has been proposed. On the other hand, regarding InSb(OO1), the Patterson analysis of observed intensities showed the clear presence of dimers on the top of the outermost layer of InSb(OOl)-c4x4. The distribution of the TED intensities … More explained well a six atom cluster model rather than a four atom cluster model. Moreover, the present TED analysis suggested that several ordered arrangements simultaneously exist on one and the same surface of InSb(OOl)-c8x2 as well as c4x4.Secondarly, we have observed growth processes of In and Au on such established InSb(111) InSb(OOI) surfaces by using ultra high vacuumin-situ TED : The results obtained are as follows :[I]In/InSb(111)(1) In grew in an island-state at room temperature and had a fcc structure at the very early stage of growth.(2) In particles experienced an ordinary epitaxial growth on InSb(111)A-2x2, whereas on InSb(111)B-2x2 they rotated to, some extent of degrees, probably being caused by the existence of Sb trimers.[II]In/InSb(001)On InSb(001), In particles grew with situation similar to In/InSb(111)A ; (i) island growth, having a pyramidal shape and (ii) fcc structure. Otherwise, different growth features are as follows : In partilces were arranged along the dimer array in both InSb(001)c4x4 and InSb(OOl)-c8x2 surfaces. In addition, their crystal habit exhibited tent-like, different from the initial growth form of a pyramid.[III]Au/InSb(111)A-2x2In this system, aROO<3>xROO<3>-Au adsorption structure has been for the first time observed at the early stage of growth. From the TED analysis, the structure was determined to be of honeycomb trimer-missing first layer (HT-MFL) type.Thirdly, we have surveyed Ag and Sn growth processes by RHEED and AES : The results are summarized as follows :[IV]Ag/InSb(111)A-2x2Ag films were found to grow with a Stranski-Krastanov mode on the InSb(111)A-2x2 surface. On the other hand, at the very early stage of growth the (110) plane of the film grew parallelly to InSb(111) with the orientation of Ag<111>//InSb<110>, whereas with the subsequent growth, the parallel orientation coexisted with Ag<110>//InSb<211>.[V]Sn/InSb(111)The stability of Sn films which grew with a layer-by-layer mode was lowered with an increase of the coverage. On InSb(111)A, the surface of the film irreversibly underwent from the 3x3 structure, via the 2x2 and subsequently the lxl, finally the melt. However, on the InSb(111)B the predominantly different growth features were observed ; the Auger signals that were indicative of a large deviation from the corresponding theoretical curves evidenced diffusion of Sb into the Sn overlayer. This diffusion behavior heavily influenced the surface phase transition of the alpha-Sn film grown on InSb(111)B-2x2. Less