Nucleation and growth mechanism of hemispherical grain polycrystalline silicon

Abstract

The formation of the nucleus [Watanabe et al., Extended Abstracts of the 22nd Conference on Solid State Devices and Materials (1990), p. 873] is performed at low O2 partial pressure during annealing and the density of HSG nuclei increases as the annealing time becomes longer. HSGs grow upward from the amorphous silicon surface, and twin formations are generated in almost all the HSGs. For approximately 50% of whole HSGs, polycrystalline silicon grows downward from the bottom of the HSG. A common heterogeneous material both for the nucleus formation of HSG and for that of polycrystalline silicon growing downward is thought to be formed at the interface between HSG and polycrystalline silicon.