Sub-Atomic-Layr Epitaxy of Si/Ge Semiconductors

原子层外延（ALE）是一种外延膜生长技术，利用该技术，使用单层饱和吸附反应（自限制功能）逐层生长膜。氢化物分子因其不含杂质物质而具有吸引力。然而，由于它们的饱和覆盖率小于一个单层，因此通常难以使用氢化物分子实现ALE。在1993年，苏达（首席研究员）等人提出了一种亚原子层外延（销售）方法，利用该方法，通过重复氢化物分子的亚单层暴露和由表面热激发引起的吸附原子迁移过程，在亚单层外延生长膜。吸附原子迁移过程是ALE外延中一个尚未被关注的关键过程，而利用它实现了亚单层-亚单层外延。在本研究中，我们获得了销售生长条件与生长特性（包括生长模式、生长速率和生长形态）之间的关系。 关于我们 研究了Si_（001）上Si_（001）H_6体系。在此基础上，提出了一个销售生长模型。通过这些工作，得到了销售生长的基本机理和生长控制方法。结果表明，当氢化物分子的饱和覆盖度在0 ~ 2单层范围内时，销售生长具有饱和覆盖度的生长单元。本文还研究了Si/Ge ALE的方法。本工作首次应用热裂解法，发现热裂解的Si_<>H_6物种在Si（001）和Ge（001）上均饱和于单层。在Ge（001）上的Si ALE中，Si/Ge界面是突变的。结果表明，热裂解GeH_4也是制备Ge ALE的一种很有前途的方法，随着我们提出的销售和氢化物分子热裂解ALE技术的发展，IV族半导体的原子控制外延技术有望得到广泛的推广，并将对Si/Ge量子阱器件的发展做出巨大贡献。少

Atomic Layr Epitaxy (ALE) is an epitaxial film growth technique with which a film is grown layr-by-layr using an one-monolayr saturation adsorption reaction ; a self -limiting function. Hydride molecules are attractive for their being free of impurity species. However, since their saturation coverages are less than one monolayr, it is generally difficcult to realize ALE using the hydride molecules. In 1993, Suda (head investigator) et al. proposed that a sub-atomic-layr epitaxy (SALE) method with which a film is epitaxially grown submonolayr by submonolayr repeating an exposure of hydride molecules and an adatom migration process induced by surface thermal excitation. The adatom migration process is a key process which has not been focused on for ALE and with it, submonolayr-by submonolayr epitaxy is relized. In this research, the relationship between the SALE prowth conditions and growth characteristics including growth modes, growth rates, and growth morphologies has been obtained us … More ing a Si_<>H_6-on-Si (001) system. On the basis of the results, a SALE growth model has been proposed Through these work, fundamental growth mechanisms and a growth control method for SALE has been obtained. The results suggest that SALE growth with a growth unit of saturation coverage if the saturation coverage of a hydride molecule is in the rangeof 0 to 2 monolayr. In this resesarch, a method for Si/Ge ALE has been also investigated. Through this work, thermally cracking method was first applied and it has been found that thermally cracked Si_<>H_6 species saturate at one monolayr on both Si (001) and Ge (001). In the case of Si ALE on GE (001), Si/Ge interface is abrupt. The results imply that thermally cracked GeH_4 is also promising for Ge ALE.With the SALE and thermal cracking ALE using hydride molecules proposed by the head investigator, atomically controlled epitaxy technologies for IV-group semiconductors are expected to be widely promoted and the methods will give a great contribution to the progress of Si/Ge quantum well devices. Less