Properties of Microcrystalline Silicon Prepared at High Growth Rate

Silicon thin films were grown by PECVD at high-pressure (700 Pa), high-power (4 - 8 W/cm²) depletion regime using a multi-hole powered electrode. Series of samples were deposited varying hydrogen/silane ratio, plasma power and film thickness to study evolution of film structure and transport properties around a-Si: H / μc-Si:H transition. We suggest a simple figure-of-merit for the films based on α(1eV)/α(1.4eV) ratio from CPM, which correlates well with the values of ambipolar diffusion length measured by surface photovoltage method (SPV) perpendicular to the substrate, i e., the direction of the photogenerated carriers collection in solar cells.