Effects of mixing germane in silane gashyphen;source molecular beam epitaxy

摘要

Growth of SiGe gashyphen;source molecular beam epitaxy (GSMBE) using silane/germane mixture has been investigated for the germane content of 0percnt;, 0.8percnt;, and 2.6percnt;. From detailed measurements on the growth rate, a separation into highhyphen; and lowhyphen;temperature regions of the growth rate, as in silanehyphen;GSMBE system, has been found to exist in this silane/germane system. A simultaneous measurement on the surface hydrogen coverage has revealed that the growth in the lowhyphen;temperature region is rate limited by the surface hydrogen desorption process, reasoning the enhanced growth rate with germane in terms of the reduced coverage of the surface hydrogen. All the growth rates followed a same fourth power dependence on the freehyphen;adsorption site, which suggests a validity of the fourhyphen;site adsorption model, established for silanehyphen;GSMBE, in silane/germane GSMBE.