Influence of Hydrogen Plasma on the Defect Passivation of Polycrystalline Si Thin Film Solar Cells

Abstract

Abstract Hydrogen passivation (HP) of polycrystalline silicon (poly‐Si) thin film solar cells was performed in a parallel plate radio‐frequency (rf) plasma setup. The influence of hydrogen pressure p and electrode gap d on breakdown voltage V brk is presented showing that the minimum in V brk shifts with higher pressures towards higher p · d values. Cell test structures provided by CSG Solar AG were used to examine the influence of p and d on the open circuit voltage V OC . The highest V OC 's were achieved for p · d values that correspond to a minimum in V brk . HP strongly improved the V OC . After the hydrogen plasma treatment the V OC improved significantly by a factor of 2 and amounted to 450 mV. Optimized parameters were then applied to different poly‐Si solar cells prepared by electron beam evaporation.