| 摘要 |
PURPOSE:To improve positional accuracy, by forming a semiconductor base layer of a first conductivity type on the surface of a semiconductor layer of a second conductivity type, introducing respective dopants for producing a highly doped semiconductor layer of the first conductivity type and a source layer of the second conductivity type into the base layer, and producing these layers simultaneously. CONSTITUTION:A window is opened in a polysilicon layer 8a which is to be a gate. A dopant 20 is introduced by using this polysilicon layer as a mask so that a P-type base layer 4 is formed. Then, a dopant 21 for producing a P<++> layer 5 is introduced. The window in the polysilicon layer 8a is enlarged and a dopant 23 for producing an N<+> source layer 6 is introduced by using the layer 8a as a mask again, The P<++> layer 5 and the N<+> source layer 6 are produced simultaneously by heat treatment. Accordingly, the P<++> layer 5 is formed in a self aligned manner to the edge of a polysilicon gate 8 without deviation as caused by erroneous registering of mask when it is used. Thus, positional accuracy in formation of a device can be improved remarkably. |
