Lateral DMOS transistor device having an injector region

Claim 1

A lateral DMOS transistor having a semiconductor substrate of a first conductivity type, an epitaxial surface layer of a second conductivity type opposite to that of the first on a first major surface of said substrate, a surface-adjoining channel region of said first conductivity type in said epitaxial layer and forming a p-n junction therewith, a surface-adjoining source region of said second conductivity type in said channel region, a surface-adjoining drain region of said second conductivity type in said epitaxial layer and spaced apart from said channel region, an insulating layer on said surface layer and covering at least that portion of said channel region located between said source region and said drain region, a gate electrode on said insulating layer, over said portion of the channel region and electrically isolated from said surface layer, source and drain electrodes connected respectively to the source and drain regions of said transistor, and a substrate electrode on a second major surface of said substrate opposite to the first, characterized in that a surface-adjoining injector region of said first conductivity type is provided in said epitaxial surface layer of the second conductivity type and forms a p-n junction therewith, said injector region being located between said channel region and said drain region and closer to said channel region than said drain region, and that an injector electrode is electrically connected to said injector region so that an external voltage can be applied directly to said injector region.