Stress-Induced Nucleation of Microcrystalline Silicon from Amorphous Phase

Abstract

We have demonstrated that a high intrinsic stress in the hydrogenated amorphous silicon (a-Si:H) phase is essential for microcrystalline silicon (µc-Si:H) nucleation from the amorphous phase at low temperatures (<450°C). In plasma-enhanced chemical vapor deposition at high hydrogen dilution, µc-Si:H nucleation was observed only when compressive stress inside a-Si:H exceeds ∼750 MPa, regardless of deposition temperature. As the result of alternating a-Si:H deposition and H2-plasma treatment, we confirmed that the high compressive stress in a-Si:H originates from H inserted into the a-Si:H network. The high compressive stress in a-Si:H was found to enhance the formation of a SiHn (n=1-2) complex that has been proposed to be a precursor for µc-Si:H nucleation. Based on the above results, we present a broad overview of stress-induced µc-Si:H nucleation from the amorphous phase.