Influence of ultrathin amorphous silicon layers on the nucleation of microcrystalline silicon films under hydrogen plasma treatment

Microstructures of phosphorus-doped hydrogenated microcrystalline silicon $(μc-Si:H)$ thin films deposited by plasma-enhanced chemical vapor deposition are certainly dependent on the thickness of the $H2$ plasma-treated amorphous silicon (a-Si:H) layers. An ultrathin H-treated a-Si:H layer is beneficial in obtaining a very thin $μc-Si:H$ film with high conductivity. Experimental results indicate that $H2$ plasma treatment induces the occurrence of high-pressure $H2$ in microvoids and causes compressive stress inside the ultrathin a-Si:H layers, thereby enhancing the generation of strained Si–Si bonds and nucleation sites and consequently accelerating the nucleation of $μc-Si:H$ films.