Investigation of growth mechanisms of microcrystalline silicon in the very high frequency range

Very high frequency low pressure plasma was applied to deposit intrinsic microcrystalline silicon layers using a resonance plasma source operating at 43, 70, 116 and 165 MHz. Silane concentration, substrate temperature, plasma power and excitation frequency were varied. Samples were investigated by Raman scattering, infrared spectroscopy and X-ray diffraction. Growth rates of up to 0.5 Å/s for predominantly crystalline films were attained. For substrate temperatures between 80°C and 510°C microcrystalline layers were obtained. All microcrystalline layers had a 〈1 1 0〉-texture in the growth direction. Surface processes, such as diffusion and etching, proposed for the growth of microcrystalline silicon, will be discussed in context with the results achieved here. The results of a simple 2D-Monte-Carlo-simulation of the growth process will be presented.