Fabrication method for a semiconductor device

A method of fabricating a semiconductor device comprising the steps of:

• forming a gate electrode polysilicon overlying a gate insulating film on a silicon semiconductor substrate;
• (a)' forming a silicon nitride film directly on a surface of the silicon semiconductor substrate and the rate electrode;
• (b)' implanting impurity ions into desired areas of the silicon semiconductor substrate and the electrode, whereby nitrogen atoms and silicon atoms from the silicon nitride film are incorporated into the surface of the silicon semiconductor substrate together with introduction thereinto of the impurity ions;
• (c)' removing the silicon nitride film;
• (d)' forming a titanium film on the silicon semiconductor substrate;
• and (e)' subjecting the silicon semiconductor substrate having the titanium film to a heat treatment so as to transform the titanium film into a titanium silicide film containing nitrogen atoms.

A method of fabricating a semiconductor device comprising the steps of (a)" forming a silicon nitride film on a silicon semiconductor substrate, which has well regions of a first conductivity type and a second conductivity type formed in the surface layer thereof, and a gate dielectric film, a gate electrode of silicon, and an isolation layer formed on the surface layer;

• (b)" implanting impurity ions into desired areas of the silicon semiconductor substrate through the silicon nitride film, in order to prevent oxygen atoms from being knocked into the desired areas, wherein
• (1) masking the first-conductivity well region with a photo-resist layer and implanting impurity ions of the first conductivity type to cause incorporation of nitrogen atoms and silicon atoms from the silicon nitride film into the second-conductivity well region of the surface layer together with introduction thereinto of the impurity ions;
• (2) removing the photo-resist layer from the first-conductivity well region and masking the second-conductivity well region with a photo-resist layer to implant impurity ions of the second conductivity type so as to cause incorporation of nitrogen atoms and silicon atoms from the silicon nitride film into the surface layer of the second-conductivity well region together with introduction thereinto of the impurity ions;
• (3) removing the photo-resist layer from the second-conductivity well region and forming side wall spacers on side walls of respective one of the gate electrodes, and thereafter masking the first-conductivity type well region with a photo-resist layer to implant impurity ions of the first conductivity type so as to cause incorporation of nitrogen atoms and silicon atoms from the silicon nitride film into the surface layer of the second-conductivity well region together with introduction thereinto of the impurity ions;
• (4) removing the photo-resist layer from the first-conductivity well region and masking the second-conductivity well region with a photo-resist layer to implant impurity ions of the second conductivity type so as to cause incorporation of nitrogen atoms and silicon atoms from the silicon nitride film into the surface layer of the second-conductivity well region together with introduction thereinto of the impurity ions, and then removing the photo-resist layer from the second-conductivity well region;
• (c)" removing the silicon nitride film;
• (d)" forming a titanium film on the silicon semiconductor substrate;
• (e)" subjecting the silicon semiconductor substrate having the titanium film to a first heat treatment so as to transform the titanium film into a titanium silicide film containing nitrogen atoms;
• (f) removing untransformed part of the titanium film;
• and (g) subjecting the silicon semiconductor substrate having the titanium silicide film to a second heat treatment so as to transform the titanium silicide film into a TiSi.sub.2 C54-crystal structure which is stoichiometrically stable.

A method of fabricating a semiconductor device comprising the steps of:

• (a)"' forming a first silicon nitride film on a silicon semiconductor substrate, the silicon semiconductor substrate having a gate dielectric film and a gate electrode of polysilicon having a thickness of 100-200 nm formed thereon;
• (b)"' (1) implanting impurity ions of a conductivity type opposite to that of a channel region present beneath the gate electrode into desired areas of the silicon semiconductor substrate so as to incorporate nitrogen atoms and silicon atoms from the first silicon nitride film into a surface layer of the silicon semiconductor substrate together with introducing of the impurity ions thereinto, in order to prevent oxygen atoms from being knocked into the desired areas:
• (2) removing the first silicon nitride film and depositing an insulation film to a thickness of 200-300 nm over the silicon semiconductor substrate, subjecting the insulation film to isotropic etching to form side wall spacers on side walls of the gate electrode, and forming a second silicon nitride film on the silicon semiconductor substrate to implant impurity ions of the conductivity type opposite to that of the channel region so as to cause incorporation of nitrogen atoms and silicon atoms from the second silicon nitride film into the gate electrode as well as the surface layer to be formed into source and drain regions of the silicon semiconductor substrate together with introducing of the impurity ions thereinto;
• (c)"' removing the second silicon nitride film to perform a heat treatment for restoration from crystal defects;
• (d)"' forming a titanium film on the silicon semiconductor substrate;
• and (e)"' subjecting the silicon semiconductor substrate having the titanium film to further heat treatment so as to transform by self-aligning the titanium film into a titanium silicide film containing nitrogen atoms.