TEMPERATURE-DEPENDENCE OF THE CRYSTALLITE SIZE AND CRYSTALLINE FRACTION OF MICROCRYSTALLINE SILICON DEPOSITED FROM SILANE BY PLASMA CVD

Exact evaluation of the crystallite size of plasma deposited nanocrystalline silicon requires the application of the Warren-Averbach analysis to the X-ray diffraction peak profiles. Use of the simple Scherrer formula leads to incorrect values due to mechanical stress in the films. The crystallite size increases monotonously with the deposition temperature. The apparent transition to the amorphous phase at T(dep) almost-equal-to 450 - 500-degrees-C, which has been reported by other workers and explained in terms of an insufficient chemical potential of atomic hydrogen previously, is an artefact caused by oxygen impurities in the plasma during the deposition.