Manufacture of semiconductor device

Abstract

Abstract PURPOSE:To contrive uniformity of characteristics of elements by forming the second semiconductor layer on a back surface of the semiconductor substrate which is made thin by removing the back surface after forming grooves on a surface of a semiconductor substrate and covering the substrate with an insulating film. CONSTITUTION:After a front surface of an N<+> Si substrate 21 is etched to form a groove 22, the first oxide film 23 is formed and then a polysilicon layer 24 is formed to fill said groove 22. Next, a back surface of the N<+> Si layer 21 is ground away gradually and the first oxide film 23 which is formed at the bottom of the groove 22 is exposed to form an island-shaped N<+> layer 21'. On the ground plane of N<+> layer 21, an N type Si layer 25 is formed and then the thin second oxide film 26 and a nitride film 27 are formed on said layer 25, after which apertures 28 are arranged on them. Subsequently, the N type Si layer 25 is oxidized by thermal oxidation and the third oxide film 29 for element isolation whose lower end is in contact with the first oxide film 23 which is formed at the bottom of the groove 22 is formed. Consequently, the N type Si layer 25 becomes an island-shaped N type element forming region 25' thereby facilitating the control of a thickness of said region 25'.

Inventors

• 👤 Kunio Aomura
• 👤 青村　國男

Bibliographic Details