METHOD FOR FORMING SILICIDE

摘要

PURPOSE: A method for forming a silicide is provided to improve a sheet resistance and a thermal stability of the silicide comprising a cobalt by growing a grain size of a P-type polysilicon. CONSTITUTION: According to the method, a polysilicon layer comprising a number of grains which are not doped on a substrate is formed. And the polysilicon layer is doped with a P-type impurity ion to give a conductivity. The polysilicon layer is re-doped with an ion which increases the grain size of the polysilicon layer if a heat is applied. A metal layer for forming a silicide is formed on the re-doped polysilicon layer. Then, silicide layers(40,41) for reducing a sheet resistance and a contact resistance respectively are formed by making a part of the polysilicon layer respond to the metal layer. The doping density of the redoped ion increasing the grain size is within a range of a critical doping density so that the doped ion shall not be precipitated out of the grain boundary.