The Si (001) substrate with sub-nano streaky surface: Preparation and its application to high-quality growth of GaAs heteroepitaxial-layer

The Si (001) substrates with a kind of special sub-nano streaky surface were prepared and applied to high-quality growth of GaAs heteroepitaxial-layers. The morphology of each of them features a series of parallel but randomly intermittent streaks along a common fixed direction and individually with their own saw-tooth cross-sections. The lateral interval between any two adjacent streaks is bound to be in sub-nano scale and both the two side facets of every cross-section sawtooth are {111} planes. It has been found that the direct growth of GaAs epilayers on this kind of substrates, especially on exactly (001) oriented ones, can not only completely prevent the antiphase boundaries (APBs) generation, but also significantly reduce the threading dislocation density (TDD). This advancement could be regarded as a nearly perfect solution to APBs elimination and, moreover, provides better basis for further TDD reduction in the preparation of III-V/Si epilayers and for relevant device fabrications.