Hydrogenated microcrystalline silicon germanium (μc-SiGe:H) thin films with high Ge content (≈50%) are prepared by radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) at the sub strate temperature ranging from 180°C to 260°C.The effects of substrate temperatur e on the electrical and structural properties of the films are investigated.Resu lts indicate that the preferential growth on the (220) plane is suppressed at the low substrate temperature.However,if the substrate temperature is too high (≥ 220℃),the oxygen content and the microstructure factor of the film become larger.Finally, the μc-SiGe:H thin film prepared at the substrate temperature of 200℃ exhibi ts good electrical and st ructural properties.A conversion efficiency of 3.31% (J_sc=22.5mA/cm²,V_oc=0.32V,FF=0.46) for μc-SiGe:H solar cell with 600-nm-thick i-layer is achieved.The quantum efficiency of th e solar cell at 1100nm is as high as 5.49%.