Patent ID: 7109115

Claim:
A method of providing ohmic contact between a silicon-containing layer and a conductive layer in an integrated circuit, the method comprising: forming a first refractory metal material on the silicon-containing layer, wherein the first refractory metal material is a conductive material containing a first refractory metal and a first impurity capable of forming a chemical bond with the first refractory metal, and wherein the first refractory metal material contains the first impurity at a level less than a stoichiometric level; forming a second refractory metal material on the first refractory metal material, wherein the second refractory metal material is a conductive material containing a second refractory metal and a second impurity capable of forming a chemical bond with the second refractory metal, and wherein the second refractory metal material has a lower affinity for the first and second impurities than does the first refractory metal material; annealing to form a refractory metal silicide interface between the first refractory metal material and the silicon-containing layer; and forming the conductive layer on the second refractory metal material, wherein the conductive layer comprises a third refractory metal.