Manufacture of semiconductor device

Abstract

Abstract PURPOSE:To obtain the device fine and high in performance by a method wherein a P layer surrounded by an N layer is provided on an N<+> type substrate, an N type island layer formed in the P layer, which is covered selectively with HF resisting film, thus made porous and insulated, and the surface of the N type island is thereby flattened to remove a crystal strain. CONSTITUTION:A P layer 51 and N layer 52 are subjected to epitaxial formation on an N<+> type substrate 50, and the N layer 52 is changed to the P layer 51 through B diffusion by means of two layers of oxidized film and nitrified film. Next, an N layer 57 and a part of peripheral P layer 60 and N layer 58 are covered with a nitrified film mask 59, and a light 61 is irradiated thereto to anodizing. A porosity beings from an opening 54' and develops quick sideways under the N type island 58, thus producing a uniform porous layer 62. Then, it is changed to an oxidized film 63 in a short time through heat treatment in an oxidized atmosphere, thus the N layer 58 is isolated. In this case the surface of the N layer 58 is flat to accept a fine working thereon, a crystal of the N layer 58 has little strain to allow a large carrier mobility, thus obtaining such device as is high in density and performance.

Inventors

• 👤 Masabumi Kubota
• 👤 Kazutoshi Nagano
• 👤 Seiji Onaka

Bibliographic Details