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

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 GeH4/SiH4 + GeH4 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 GeH4/SiH4 + GeH4 ratio increases, the deterioration of a-SiGe:H films also increases, which is in agreement with Raman spectrum analysis results.