The effect of initial discharge conditions on the properties of microcrystalline silicon thin films and solar cells

This paper studies the effects of silane back diffusion inthe initial plasma ignition stage on the properties ofmicrocrystalline silicon ($mu $c-Si:H) films by Raman spectroscopyand spectroscopic ellipsometry, through delaying the injection ofSiH$_{4}$ gas to the reactor before plasma ignition. By comparingwith standard discharge condition, delayed SiH$_{4}$ gas conditioncould prevent the back diffusion of SiH$_{4}$ from the reactor tothe deposition region effectively, which induced the formation of athick amorphous incubation layer in the interface between bulk filmand glass substrate. Applying this method, it obtains theimprovement of spectral response in the middle and long wavelengthregion by combining this method with solar cell fabrication.Finally, results are explained by modifying zero-order analyticalmodel, and a good agreement is found between model and experimentsconcerning the optimum delayed injection time.