A method of directly depositing a polysilicon film at a low temperature is disclosed. The method comprises providing a substrate and performing a sequential deposition process. The sequential deposition process comprises first and second deposition steps. In the first deposition step, a first bias voltage is applied to the substrate, and plasma chemical vapor deposition is utilized to form a first polysilicon sub-layer on the substrate. In the second deposition step, a second bias voltage is applied to the substrate, and plasma chemical vapor deposition is utilized to form a second polysilicon sub-layer on the first sub-layer. The first and second sub-layers constitute the polysilicon film, and the first bias voltage differs from the second bias voltage.