The crystalline properties of nitrogen doped hydrogenated microcrystalline silicon thin films

The crystalline properties of nitrogen doped hydrogenated microcrystalline silicon thin films deposited by plasma enhanced chemical vapor deposition were studied. Gas phase doping density in the order of 10(-2) and 10(-1) leads to changes in the crystalline properties of the films. Raman scattering signals indicate that nitrogen doping causes a more significant reduction in crystallite size than does an increase in SiH4 concentration. In addition; the size reduction occurs with a less significant increase in amorphous fraction volume than in the case of SiH4 concentration increase. The N in the Si crystalline induces disorder or stress as a result of the higher electronegativity and smaller atomic size of N compared to Si. Thus, the crystallite size reduction is thought to occur to reduce the disorder in crystalline grain induced by doped nitrogen. (C) 1997 Elsevier Science S.A.