Characterization of electronic and optical properties of device quality a-Si:H and a-(Si,Ge):H grown by remote plasma electron cyclotron resonance deposition

The electronic and optical properties of device quality a-Si:H and a-(Si,Ge):H films grown by remote plasma electron cyclotron resonance (ECR) deposition were studied together with the plasma characteristics during growth. 100–350 W microwave plasmas, which were formed by introducing hydrogen and helium into the ECR chamber, were used to decompose silane and germane downstream of the ECR source. Use of hydrogen allows selective etching of the growth surface by reactive ion species. The plasma properties near the deposition surface are characterized using movable plane and cylindrical Langmuir probes and are correlated with the light and dark photoconductivity, optical gap, stability, and silicon–hydrogen bonding distribution of the deposited film in an effort to understand the influence that plasma species have on film quality.