Method for fabricating semiconductor device

Abstract

A method for fabricating a semiconductor device including a silicon region and a cobalt silicide film, the cobalt silicide film being in contact with at least a part of the silicon region. The method includes the steps of: doping at least part of the silicon region with boron by setting a doping level of boron in the part at 1.times.10.sup.15 cm.sup.-3 or more; depositing a cobalt film over a surface of the silicon region; conducting a first heat treatment for producing a silicidation reaction in a contact region between the cobalt film and the silicon region and thereby forming the cobalt silicide film; selectively removing unreacted portions of the cobalt film that have not been turned into silicide; and conducting a second heat treatment at a temperature higher than a temperature set for the first heat treatment step, thereby inducing a phase transition in the cobalt silicide film. The first heat treatment step is performed within a reducing ambient gas, and the temperature set for the first heat treatment step is in the range from about 400.degree. C. to about 600.degree. C., both inclusive.