Laminated composite passivation film used on back surface of monocrystalline silicon solar cell

The invention discloses a laminated composite passivation film used on the back surface of a monocrystalline silicon solar cell, which is characterized in that: the back light surface, namely the lower surface, of a solar-cell monocrystalline silicon substrate (1) is sequentially provided with a silicon oxide film (2) and an amorphous silicon film (3) from inside to outside. The laminated composite passivation film disclosed by the invention adopts an amorphous silicon-silicon oxide combined film structure, thereby making up for the shortcomings of silicon oxide films; and meanwhile, a long-term high temperature process is avoided in the process of preparation. By using the structure, a passivation film with an excellent passivation effect is obtained, a long-term high temperature process of a cell wafer is avoided, and the conversion efficiency of the cell wafer can reach more than 18.5%.