气态源分子束外延生长Ge_xSi_(1-x)/Si异质结合金

Gas Source Molecular Beam Epitaxy Growth of Ge x Si 1- x /Si Alloys

采用气态源分子束外延法成功地生长了ＧｅｘＳｉ１－ｘ／Ｓｉ异质结合金材料，所使用的气体分别是乙硅烷和锗烷。高能电子衍射被用于原位监控生长层的表面重构状态。在一定的生长温度下，ＧｅｘＳｉ１－ｘ合金组分ｘ取决于锗烷和乙硅烷的流量比。外延层的表面形貌与锗组分的大小、生长层的厚度及生长温度有关。结果表明，较大的锗组分和较高的生长温度利于由二维模式向三维模式转变的外延生长。

Strained Ge x Si 1- x alloys were grown successtully on Si(100) substrate in gas source molecular beam epitaxy system using disilane (Si 2H 6) and germane (GeH 4). The surface reconstructions were monitored by in situ reflection high energy electron diffraction during epitaxy. At a fixed substrate temperature, the Ge composition in the alloys increases with GeH 4/(GeH 4+2Si 2H 6) gas flow ratio. Surface morphologies of the grown samples show a strong dependence on the Ge composition, substrate temperature and Ge x Si 1- x epilayer thickness. Results indicated that high substrate temperature and large Ge composition are favorable for the growth mode transition from two dimensional to three dimensional growth.