Nucleation mechanism of microcrystalline silicon from the amorphous phase

Low-temperature formation (<400 °C) of microcrystalline silicon (μc-Si:H) using plasma-enhanced chemical vapor deposition (PECVD) has been investigated. We find that a high intrinsic stress in the hydrogenated amorphous silicon (a-Si:H) phase is essential for μc-Si:H nucleation from the amorphous phase and μc-Si:H nucleation was observed only when compressive stress inside a-Si:H exceeds ∼750 MPa, regardless of deposition temperature. Detailed studies employing real-time spectroscopic ellipsometry and infrared spectroscopy revealed the unique role of H for stress generation and μc-Si:H nucleation. In this article, based on our recent studies, we review the nucleation mechanism of μc-Si:H from the amorphous phase.