Super-junction semiconductor device

Abstract

A method of manufacture reduces costs and provides an excellent mass-productivity, a super-junction semiconductor device, that facilitates reducing times of heat treatment of the alternating conductivity type layer subjects, and preventing the characteristics of the alternating conductivity type layer from being impaired. A surface MOSFET structure, including p-type base regions, p -type contact region in p-type base region, an n -type source region in p-type base region, a gate electrode layer and a source electrode, is formed in the surface portion of an n-type semiconductor substrate through the usual double diffusion MOSFET manufacturing process. An oxide film is deposited by the CVD method on the back surface of the semiconductor substrate, a resist mask for defining p-type partition regions is formed on the oxide film, oxide film is removed by ion etching, and trenches are dug. The p-type epitaxial layers are buried in the trenches by selective epitaxial growth, and the remaining oxide film is removed. The portions of n-type semiconductor substrate not etched off remain as n-type drift regions, resulting in an alternating conductivity type layer formed of n-type drift regions and p-type partition regions. A drain electrode is deposited on the back surface of alternating conductivity type layer.