Patent ID: 6277735
Filing Date: 2001-08-21
Classification: H01L

Abstract:
A method for fabricating a semiconductor device, comprising the steps of:forming field oxide films and a gate oxide film on a surface of a silicon substrate;selectively forming a gate electrode on a predetermined area of said gate oxide film;selectively forming side wall oxide films on opposite sides of said gate electrode;carrying out an ion implantation of an impurity having an opposite conductivity type to a conductivity type of said silicon substrate into said silicon substrate by use of said field oxide films, said side wall oxide films and said gate electrode as masks to form self-aligned source and drain regions;forming a first layer made of a refractory metal on an entire surface of said silicon surface;forming a second layer which extends over said first layer, said second layer being made of a nitrogen containing refractory metal, wherein a ratio in composition of nitrogen to said refractory metal is less than 1:1;subjecting said silicon surface and said first and second layers to a heat treatment in a nitrogen free atmosphere having a pressure of not less than ultra high vacuum to form a refractory metal silicide layer on an interface between said silicon surface and said first layer;removing said first and second layers to leave said refractory metal silicide layer on said silicon surface; andsubjecting said refractory metal silicide layer to a secondary heat treatment in a nitrogen free atmosphere to cause a phase transition of said refractory metal silicide layer thereby reducing a resistivity of said refractory metal silicide layer.