US 5,854,509 A · Method of fabricating semiconductor device and semiconductor device

Abstract

Ordinary anisotropic etching is performed up to a depth (d1) while anisotropic etching is performed to form an inward taper from the depth (d1) by changing etching conditions such as components in a vapor phase and the temperature of a silicon substrate (1), thereby forming a groove (20). Thereafter silicon is epitaxially grown in the groove (20), thereby forming an epitaxial silicon layer (4). An NMOS transistor is formed on an upper layer part of the epitaxial silicon layer (4). At this time, the taper of the groove (20) is located under a part of an n.sup.+ layer (8) forming the NMOS transistor. Thus, a method of fabricating a semiconductor device capable of performing element isolation with neither halation nor formation of bird's beak in fabrication while minimizing a leakage current flowing across elements is obtained.

Claims19

Dependent claims

A method of fabricating a semiconductor device which is subjected to element isolation by an oxide film, said method comprising the steps of:

(a) preparing a semiconductor substrate;
(b) forming an oxide film on said semiconductor substrate;
(c) selectively removing said oxide film to form a groove in the oxide film to a prescribed depth d1 and continuing the removal of said oxide film in an inward taper downwardly toward the semiconductor substrate;
(d) filling the groove with a material to form a semiconductor region;
and
(e) forming a semiconductor element in a region of the semiconductor region within the prescribed depth d1, at least a portion of which is underneath the semiconductor element.

3 more elements

Dependencies are inferred from the claim text.

Method of fabricating semiconductor device and semiconductor device

Life of this patent

Method of fabricating semiconductor device and semiconductor device

Life of this patent

Abstract

Claims19