Manufacture of semiconductor device

Abstract

Abstract PURPOSE:To enable a plurality of MOS type devices having different characteristics to be formed within a single groove by excavating grooves in a semiconductor substrate in two steps, and forming an impurity diffusion layer of the conductivity type opposite to the substrate in a limited side wall part of the groove formed in the latter step at an arbitrary depth from the substrate surface. CONSTITUTION:With three layer films 12-14 and a silicon nitride film 15 formed in the side wall as a mask, the silicon substrate part exposed in the bottom of a first groove 2 is anisotropically etched to newly form a second groove 2'. Then phosphorus is diffused to form an N-type impurity diffusion layer 3 in the side and bottom surfaces of the newly formed second groove 2'. The bottom of this groove 2' is further excavated by means of an anisotropic etching to form a third groove 2''. Subsequently boron ions are implanted into the bottom surface part of the third groove 2'' by the ion implantation method. In the trench type capacity, a P-type impurity diffusion layer 4 formed in the groove bottom acts as a device isolating region, and the P-type silicon substrate is exposed in the side surface of the upper groove part, in which part a device having different characteristics from the MOS capacity, for instance, a MOSFET of the enhancement type is formed.

Inventors

• 👤 Nobuyuki Takenaka
• 👤 竹中　信之

Bibliographic Details