Patent ID: 7563698

Claim:
A method for manufacturing a semiconductor device including both of a grooved gate transistor and a planar gate transistor on a same semiconductor substrate, the method comprises: (a) forming a groove in the semiconductor substrate in the forming region of the grooved gate transistor, (b) filling the groove provided in the semiconductor substrate in the forming region of the grooved gate transistor to form an amorphous silicon layer on the entire surface, (c) ion injecting an impurity of a first conductivity type into the amorphous silicon layer in the forming region of the grooved gate transistor, (d) entirely heating the semiconductor substrate to convert the amorphous silicon layer to a polysilicon layer, (e) amorphousizing a surface layer of the polysilicon layer, and (f) ion injecting an impurity of a second conductivity type into the amorphousized surface layer and the polysilicon layer in the forming region of the planar gate transistor.