Raman scattering and electrical characterizations studies of hydrogenated amorphous silicon-germanium alloys prepared by 40 MHz plasma-enhanced CVD

摘要

This paper presents results on Raman scattering and electrical characterizations in a-SiGe:H films prepared by 40 MHz very-high frequency plasma-enhance chemical vapor deposition (VHF-PECVD) technique from various gas mixtures of silane and germane. We found that when GeH_4/SiH _4 + GeH_4 ratio increases, Raman spectrum results observed that the Si-Si peaks intensity decreases and the Ge-Ge peaks intensity increase, respectively. This can be attributed to incorporation of Ge, an increase disorder in a-SiGe:H film. The conductivity characterizations were shown that when GeH_4/SiH_4 + GeH_4 ratio increases, the deterioration of a-SiGe:H films also increases, which is in agreement with Raman spectrum analysis results.