To provide a high definition and compact active matrix panel excellent in reliability at a low cost by implanting a first impurity into first to third silicon thin films, covering the third silicon thin film with a mask and implanting a second impurity into the first and second silicon thin films in higher density than that of the first impurity.

An acceptor impurity 120 such as boron is implanted all over by an ion implanting method and then activated to become an acceptor by heat-treatment to produce a P-type semiconductor. Thus, the source-drain region 121, 122 of the P-type TFT is formed. Also an acceptor is added to the region 123 to 126 which is to be used as the source-drain region of a N-type TFT. Then the P-type TFT is covered, for example, with a masking material such as a photoresist 128, and a donor impurity 127 such as phosphorus and arsenic is implanted in a higher density than the acceptor impurity 120 to form the source-drain region 123 to 126 of the N-type TFT.