LPCVD silicon films were deposited at temperatures between $560^{circ}C$ and $650^{circ}C$ Structure, surface roughness, films thickness and residual stress were measured by using XRD, SEM, ellipsometer, $Tektak^3$, Tencor FLX-2320 and other techniques. Polysilicon films of low stress, small surface roughness were obtained when the films are deposited at $560^{circ}C$ in the amorphous phase and subsequently annealed to make polycrystalline silicon layers at $900^{circ}C$ -$1100^{circ}C$. The silicon films deposited in amorphous phase and crystallized by post thermal treatment showed better mechanical properties.