Input silane concentration effect on the a-Si:H to uc-Si:H transition width

In this work the microstructure transition width from amorphous to microcrystalline silicon is discussed. It is shown that the width of the transition depends on the input silane concentration level and indirectly on the silane depletion level. The higher the input silane concentration and depletion, the wider the transition. Experimental results are then compared to an analytical model and good agreement is obtained with a semi-empirical approach that takes into account the e®ect of the silane density in the plasma on the electron density.