Method for manufacturing a semiconductor device

DETAILED DESCRIPTION It is an object of the present invention to provide a method for manufacturing a semiconductor device, wherein channel-cut regions are readily and uniformly formed respectively on the side surfaces of an element region extending above any other surface portions of a semiconductor substrate.
According to an embodiment of the present invention, there is provided a method for manufacturing a semiconductor device, comprising the steps of: forming a first mask member which has an opening to expose a desired portion of one major surface of a semiconductor substrate; doping an impurity which has the same conductivity type as a conductivity type of said semiconductor substrate through said opening of said first mask member to form an impurity region of a high concentration in a surface layer of said semiconductor substrate; forming a second mask member on a side surface of said opening of said first mask member while said first mask member is left as it is; forming a groove by selectively etching said semiconductor substrate using said first and second mask members, and at the same time leaving an impurity region of the high concentration at least on a side surface of said groove; and burying an insulating isolation material in said groove.
According to another embodiment of the present invention, there is also provided a method for manufacturing a semiconductor device, comprising the steps of: forming a first mask member which has an opening to expose a desired portion of one major surface of a semiconductor substrate; forming a second mask member on a side surface of said opening; forming a groove by selectively etching said semiconductor substrate using said first and second mask members; removing said second mask member; doping an impurity which has the same conductivity type as a conductivity type of said semiconductor substrate through said opening of said first mask member to form an impurity region of a high concentration at least on a side surface of said groove; and burying an insulating isolation material in said groove