Sub-Atomic-Layr Epitaxy of Si/Ge Semiconductors

原子层外延(ALE)是一种外延薄膜生长技术，利用单层饱和吸附反应逐层生长薄膜；自限功能。氢化物分子因其不含杂质物种而具有吸引力。然而，由于它们的饱和覆盖率不到一个单层，利用氢化物分子实现ALE通常是困难的。1993年，苏达(首席调查员)等人。提出了一种亚原子层外延(SALE)方法，通过重复曝光氢化物分子和表面热激发诱导的吸附原子迁移过程，通过亚单层外延生长薄膜。吸附原子的迁移过程是ALE中尚未被关注的关键过程，随着它的出现，实现了亚单层到亚单层的外延。在这项研究中，我们得到了销售状况与生长方式、生长速度和生长形态等生长特征之间的关系，即…进一步研究了Si_&lt；&gt；H_6-on-Si(001)系统。在此基础上，提出了销售增长模型，得出了销售增长的基本机理和销售增长控制方法。结果表明，当氢化物分子的饱和覆盖率在0~2个单层范围内时，销售量以饱和覆盖率为增长单位。在这项研究中，还研究了一种制备Si/Ge ALE的方法。通过这项工作，首次应用了热裂解方法，发现热裂解的Si_1和Gt；H_6物种在Si(001)和Ge(001)上都是单层饱和的。对于Ge(001)面上的SiAe，Si/Ge界面是陡峭的。研究结果表明，热裂解GeH4对Ge ALEs也有很好的应用前景。随着首席研究员提出的利用氢化物分子的销售和热裂解技术，IV族半导体的原子控制外延技术有望得到广泛推广，这些方法将对Si/Ge量子阱器件的发展做出重大贡献。较少

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