Solid phase epitaxial grouth (SPE) of vacuum-deposited amorphous silicon (a-Si) has been examined using transmission electron microscopy (TEM) and electron spin resonance (ESR). We have demonstrated that the surface cleanliness of the crystalline silicon (c-Si) substrate and impurities introduced during deposition have a great influence on the SPE process of a-Si. For a-Si deposited on a c-Si surface cleaned by iterative sputtering and annealing in ultra high vacuum, we have obtained good epitaxiai grcth layers comparable to bulk c-Si.
Behavior of the EPR signal dvring annealing can be well explained on the basis of the TEM observation that there are void networks in an a-Si film deposited on c-Si having the native oxide No such structure exists in an a-Si film on c-Si with a clean surface. the structure of a-Si, where SPE occurs at a high rate, is compared with that of ion bombarded a-Si. We have discussed a mechanism of SPE on the basis of an a-Si/(100) c-Si interface model not having any dangling bonds.