Patent ID: 6864533

Claim:
A MOS field effect transistor wherein a current path extends from a first principal plane of a semiconductor substrate to a second principal plane opposite to the first principal plane, said MOS field effect transistor comprising: a semiconductor substrate of first conductive type having a first principal plane and a second principal plane opposite to said first principal plane; a first semiconductor region of said first conductive type formed on said first principal plane of said semiconductor substrate; a second semiconductor region of said first conductive type formed in said first semiconductor region; a third semiconductor region of second conductive type formed in said second semiconductor region; a fourth semiconductor region of said second conductive type formed in said first semiconductor region opposite to said third semiconductor region by sandwiching part of said second semiconductor region; a fifth semiconductor region of said second conductive type formed in said first semiconductor region sandwiched between said fourth semiconductor region and said second semiconductor region, said fifth semiconductor region being shallower than said fourth semiconductor region; a gate electrode formed, via a gate insulator, on said second semiconductor region sandwiched between said third semiconductor region and said fifth semiconductor region; a first main electrode connected to said fourth semiconductor region; a second main electrode formed on said second principal plane of said semiconductor substrate; a sixth semiconductor region of said first conductive type extending to said semiconductor substrate from the surface of said first semiconductor region near said third semiconductor region; and a short circuit electrode formed on said third semiconductor region and on said sixth semiconductor region, wherein said first main electrode is formed on said gate electrode and on said short circuit electrode with an insulator interposed between said first main electrode and said gate electrode, and also interposed between said first main electrode and said short circuit electrode.