Effects of electron temperature (T-e) on the quality of deposited silicon thin film were investigated using a modified magnetron typed plasma source equipped with a T-e control system. Two kinds of Si films were prepared amorphous silicon (a-Si:H) and micro-crystalline silicon (pc-Si). In the a-Si:H deposition, T-e reduction from 4.75 eV to 0.4 eV increased the ratio of photo to dark conductivity, sigma(p)/sigma(d), by a factor of 30 and decreased the SiH2 Concentration by a factor of two. In the muc-Si deposition, the crystallinity was also improved by a slight reduction of T-e. However, we found a presence of an optimum T-e(=3.9 eV) at which the crystal fraction becomes maximum.