| 摘要 |
A method for manufacturing a semiconductor device, capable of forming, with good controllability, impurity regions of a low impurity concentration, includes the steps of: forming a gate electrode on a surface of a semiconductor substrate through a gate oxide film; forming a first film on the surfaces of the gate electrode and the semiconductor substrate; forming a non-single-crystalline silicon film to cover the entire surface; forming a second film to cover the entire surface; performing anisotropic etching of the second film to form residual second films on the side walls of that step portion non-single-crystalline silicon film which is formed corresponding to a shape of the gate electrode; performing etching of the non-single-crystalline silicon film by using the residual second films as masks to form residual non-single-crystalline silicon films on the side walls of the gate electrode through the first film; ion-implanting an impurity having a conductivity type opposite to that of the semiconductor substrate by using as masks the gate electrode and the residual non-single-crystalline silicon films; removing the residual non-single-crystalline silicon films; and annealing a resultant structure to activate the impurity so as to form source and drain regions each of which comprises an impurity region of a high impurity concentration and an impurity region of a low impurity concentration which is adjacent to the impurity region of the high impurity concentration and which is located under a structure area corresponding to one of the removed non-single-crystalline silicon films.
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