Semiconductor device

Abstract

Abstract PURPOSE:To reduce a device area occupying a main face of a semiconductor, to reduce a drain extraction resistance and to reduce an ON resistance per unit area by a method wherein this device is constituted as an LDMOS in which a drain electrode is extracted from the side of the main face of the semiconductor of a first conductivity type and a groove is formed so as to project in a transverse direction. CONSTITUTION:A drain electrode 13 composed of a metal such as Al or the like is connected directly to an n<+> buried layer 2 inside a groove 11; an n-type diffusion region does not exist. Regarding the groove 11, when Si is etched by using an alkali-based anisotropic etchant, an etch rate becomes extremely slow at a 111 plane; this etching operation is stopped at a place where the 111 plane is exposed; the groove is spread in a transverse direction so as to be wide at a shallow angle of about 35 deg. inside a substrate and encroaches up to the n<+> buried layer 2 at the lower part of a p-channel region 4. A length of the n<+> buried layer 2 on a drain current route is reduced by this encroachment. Consequently, a drain extraction resistance is reduced as compared with conventional cases.

Inventors

• 👤 Tsutomu Matsushita
• 👤 松下　努

Bibliographic Details