EFFECTS OF A PREDEPOSITED BORON LAYER DURING THE EPITAXIAL-GROWTH OF GE ON CAF2

Using a thin predeposited B layer prior to the epitaxial growth of Ge on CaF2, we have obtained significantly improved Ge crystalline qualit y and surface morphology for Ge/CaF2/Si(111) and Ge/CaF2/Si(100) StruC tUres. Although B acts as a surfactant in suppressing island formation , it does not migrate to the growth front during Ge growth, which was widely observed in the surfactant-assisted epitaxial growth of Ge on S i. The B predeposit also prevents Ca from migrating to the Ge surface, and promotes A-type epitaxy of Ge (111) when Si (111) substrates are used.