Semiconductor device having a groove and a junction termination extension layer surrounding a guard ring layer

Abstract

In a termination structure in which a JTE layer is provided, a level or defect existing at an interface between a semiconductor layer and an insulating film, or a minute amount of adventitious impurities that infiltrate into the semiconductor interface from the insulating film or from an outside through the insulating film becomes a source or a breakdown point of a leakage current, which deteriorates a breakdown voltage. A semiconductor device includes: an ntype semiconductor layer formed on an ntype semiconductor substrate; a first electrode that is formed on the ntype semiconductor layer and functions as a Schottky electrode; a GR layer that is a first p type semiconductor layer formed on a surface of the ntype semiconductor layer below an end of the first electrode and a perimeter thereof; a JTE layer that is formed of a second p type semiconductor layer formed on a bottom and a lateral surface of a groove arranged in a ring shape around the GR layer apart from the GR layer, in a surface of the ntype semiconductor layer; an insulating film provided so as to cover the GR layer and the JTE layer; and a second electrode that is an Ohmic electrode formed below a rear surface of the ntype semiconductor substrate.