Influence of reaction gas flows on the properties of SiGe:H thin film prepared by plasma assisted reactive thermal chemical vapour deposition

A new preparing technology, very high frequency plasma assisted reactive thermal chemical vapour deposition （VHFPA-RTCVD）, is introduced to prepare SiGe：H thin films on substrate kept at a lower temperature. In the previous work, reactive thermal chemical vapour deposition （I~TCVD） technology was successfully used to prepare SiGe：H thin films, but the temperature of the substrate needed to exceed 400℃. In this work, very high frequency plasma method is used to assist RTCVD technology in reducing the temperature of substrate by largely enhancing the temperature of reacting gases on the surface of the substrate. The growth rate, structural properties, surface morphology, photo- conductivity and dark-conductivity of SiGe：H thin films prepared by this new technology are investigated for films with different germanium concentrations, and the experimental results are discussed.     

H2， He混合稀释生长微晶硅锗薄膜

采用H₂,He混合气体稀释等离子辅助反应热化学气相沉积法生长微晶硅锗薄膜,并在生长过程中对等离子体进行光发射光谱在线监测.结果表明：混合气体稀释法可以有效提高等离子体中的原子氢数目,降低等离子体中的电子温度;用XRD和光暗电导率表征样品的微结构和光电特性时发现,通过优化混合稀释气体中He和H₂气体的比例,能够减少薄膜中的缺陷态,促进薄膜<220>择优取向生长,有效改善微晶硅锗薄膜结构,提高光电吸收性能. 关键词： 化学气相沉积 微晶硅锗薄膜 光发射光谱 X射线衍射