Semiconductor device

Claim 1

A semiconductor device comprising: (a) a semiconductor substrate of a first conductivity type including a first semiconductor region of said first conductivity type exposed to one of the principal surfaces of said semiconductor substrate, said first semiconductor region having an impurity concentration higher than that of said semiconductor substrate, a second semiconductor region of a second conductivity type formed in said first semiconductor region to be exposed to said one principal surface, a third semiconductor region of said second conductivity type formed at a position spaced apart from said first semiconductor region to be exposed at said one principal surface, and a fourth semiconductor region of said second conductivity type formed between said first and third semiconductor regions to make contact therewith and to be exposed to said one principal surface, said fourth semiconductor region having an impurity concentration lower than that of said third semiconductor region; (b) a passivation film covering said one principal surface of said semiconductor substrate; and (c) first, second and third electrodes making ohmic contact with said first, second and third semiconductor regions through openings in said passivation film, respectively, said second electrode extending on said passivation film beyond a portion of said first semiconductor region between said second and fourth semiconductor regions and to a point on said passivation film under which said fourth semiconductor region exists, said first electrode being in ohmic contact with said first semiconductor region at a portion thereof remote from said fourth semiconductor region, and a portion of said third electrode remote from said first and second electrodes extending to a point on said passivation film under which said semiconductor substrate is exposed.