Microcrystalline Silicon Film Growth Using a High-Density Microwave Plasma of SiH4-and-D2 Mixture

Abstract

The role of hydrogen dilution for fast deposition of microcrystalline silicon (µc-Si) films is demonstrated using a high-density SiH4 and deuterium D2 mixture microwave plasma. Raman crystallinity of µc-Si films is significantly improved by using a D2 dilution rather than H2, although the film microstructure is still random. The degree of preferred (220) orientation, however, is poor in the D2-diluted films compared with H2-diluted films. The plasma potential Vs, corresponding to the degree of ion bombardment impinging on the film surface is lower in the D2 plasma rather than the H2 plasma. The film microstructure is discussed as a function of deposition parameters, along with plasma diagnostics for fast deposition of µc-Si films with preferred (220) orientation while maintaining a high deposition rate.