Patent ID: 6100140
Filing Date: 2000-08-08
Classification: H01L

Abstract:
A manufacturing method of a semiconductor device, comprising the steps of:preparing a wafer having a semiconductor substrate of a high impurity concentration and a first conductivity type semiconductor layer of a lower impurity concentration than that of said semiconductor substrate;forming a local oxide film by locally oxidizing a specified region of a main surface of said semiconductor layer of said wafer;forming a second conductivity type body region and a first conductivity type source region by double-diffusion using said local oxide film as a mask, whereby a channel region is defined at a surface of said body region to which a side part of said local oxide film faces;forming a concavity at said main surface of said semiconductor layer by removing said local oxide film;forming an insulated gate structure by thermally oxidizing an inner wall of said concavity including a part to be said channel region to form a gate oxide film and disposing a gate electrode thereon; andafter said double-diffusion and prior to said removing of said local oxide film, covering a back surface side of said semiconductor substrate with a material film unremovable when said local oxide film is removed.