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

Investigation of microcrystalline silicon germanium prepared by hydrogen and helium gas mixture diluted VHFPA-RTCVD

H₂ and He gas mixture diluted very high frequency plasma assisted reactive thermal chemical vapor deposition (VHFPA-RTCVD) is used to prepare μc-SiGe:H thin films, and the optical emission spectrum is used to in situ monitor the reacting plasma during the growing process. It is observed that H₂ and He gas mixture dilution is effective in increasing the number of Hα^* and reducing the temperature of electrons in the plasma. X-ray diffraction (XRD) and photo- and dark-conductivity measurement show that by optimizing the fractions of H₂ and He in the mixture the defect states are reduced, which prompted the growth of <220> and improved the structure, and the optical-electronical properties of the film are enhanced.