Method of manufacturing a semiconductor device having a high breakdown voltage and low on-resistance

Abstract

A semiconductor device includes a semiconductor substrate of a first conductivity type, in which an extended drain region of a second conductivity type and a source region of the second conductivity type are formed with an interval therebetween, wherein the extended drain region includes a plurality of buried layers, each formed by burying an impurity layer of the first conductivity type, the plurality of buried layers extending substantially parallel to a substrate surface and with an interval therebetween in a depth direction. A concentration of an impurity of the second conductivity type in the extended drain region at a depth of about 6 μm from the substrate surface is about 1×1015/cm3 or more and is about 30% or more of that at a depth of about 2 μm from the substrate surface.

Dependencies are inferred from the claim text.