Semiconductor device and method of manufacturing the same

Abstract

A p-type base layer (2) is formed on a surface of an n-type silicon substrate (1). First and second n+-type buffer layers (8,9) 9 are formed on a back surface of the n-type silicon substrate (1). The first n+-type buffer layer (8) is formed by a plurality of implantations of protons at different accelerating voltages and has a plurality of peak concentrations with different depths from the back surface of the n-type silicon substrate (1). The second n+-type buffer layer (9) is formed by an implantation of a phosphorus. A position of a peak concentration of the phosphorus is shallower from the back surface of the n-type silicon substrate (1) than positions of peak concentrations of the protons. The peak concentration of the phosphorus is higher than the peak concentrations of the protons. A concentration of the protons is higher than a concentration of the phosphorus at the positions of the peak concentrations of the protons.

Dependencies are inferred from the claim text.