Abstract: In this paper, a new method for improving the crystalline quality of SOS films is developed.lt consists of three steps:(1) A thin amorphous silicon layer is prepared by electron beam evaporation. (2) The wafer is annealed in a hydrogen atmosphere. (3) The required thickness (0.6-0.8μm) of SOS film is deposited by the standard OVD method on the thin silicon layer. The resulting SOS films are examined by reflection electron diffraction, Nomarski phase interference microscopy, carrier concentration measurement and optical absorption measurement. The results show that the crystalline perfection of the film is good,the optical absorption factor F_A ≤ 140×10⁶cm^-2. The autodoping is expressed and the carrier concentration is lower than 1×10¹³cm^-3.