A semiconductor device is provided in which a semiconductor film having a leveled main surface is used as an active layer. A semiconductor film (5) having the leveled main surface with an rms of less than 10 nm and a P-V value of less than 70 nm which each indicate a surface roughness is formed by crystallizing a silicon film (3) containing germanium in a concentration of several %, preferably 0.1 to 10 atoms % and irradiating the film with a laser light. In a case of performing a crystallization by use of a metal element for accelerating the crystallization, the semiconductor film high in an orientation rate of the crystal as well as in levelness is obtained. |