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.