摘要
用气态源分子束外延（ＧＳＭＢＥ）法研究了ＧｅｘＳｉ１－ｘ合金的低温（≤５００℃）生长动力学问题，所使用的源分别是乙硅烷和固态锗．在恒定的乙硅烷流量（４ｓｃｍ）Ｇｅ源炉温度（１２００℃）下，合金中的Ｇｅ组分ｘ随衬底温度的降低而升高；另一方面，当衬底温度（５００℃）和乙硅烷流量（４ｓｃｍ）保持恒定时，合金中的Ｇｅ组分ｘ最初随Ｇｅ源炉温度的升高而增大，当Ｇｅ源炉温度升高到一定值以上时，ｘ值不再随Ｇｅ源炉温度的升高而增大，而趋向于饱和在０．４５附近．基于乙硅烷及Ｈ原子在Ｓｉ原子和Ｇｅ原子表面上不同的吸附和脱附过程。
Abstract Low temperature (≤500℃) growth kinetics of SiGe alloys by disilane and germanium molecular beam epitaxy has been studied. It is found that the germanium composition x increases with the decrease of substrate temperature in SiGe layers grown with constant disilane flow rate and fixed germanium cell temperature. On the other hand, in SiGe layers grown at a substrate temperature of 500℃ and a constant disilane flow rate, germanium composition x first increases with germanium cell temperatures, and then saturates at about 0.45 when further increase with germanium cell temperatures. This composition dependence behavior on substrate temperature and germanium cell temperature is different from that of SiGe grown using disilane and germane, which may be explained by the H atoms desorption limited growth kinetics.
基金
国家八五攻关项目
