SEMICONDUCTOR DEVICE AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To actualize a deep expansion type diffusion area at low cost without increasing the number of processes as much as possible. SOLUTION: On the surface of an n-type epitaxial growth layer 12, a mask 13M for ion implantation is formed. The mask 13M for ion implantation is sued to perform the selective ion implantation of boron (<11> B<+> ) deep into the n-type epitaxial growth layer 12. Further, the mask 13M for ion implantation is used to carry out the selective ion implantation of aluminum (<27> Al<+> ) from the surface of the n-type epitaxial growth layer 12 shallower than the boron. Then p-type deep expansion diffusion areas 15a and 15b are formed by activating heat-treatment. The diffusion areas 15a and 15b increase in lateral diffusion width perpendicular to the depth toward an ohmic contact area 11.