Patent ID: 8575023

Claim:
A method of forming a contact of a metal semiconductor compound on a predetermined region of a semiconductor device, comprising the steps of: selecting a first metal in relation to a semiconductor type of the predetermined region; forming a layer of the first metal on the predetermined region; forming, on the layer of the first metal, a layer of a second metal for preventing oxidation of the first metal; and compounding only the first metal with a semiconductor by heat treatment while the first metal is covered with the layer of the second metal, to thereby form the contact of the metal semiconductor compound which has a contact resistance of 10 −9 Ωcm 2 or less; wherein, when the predetermined region is an n-type semiconductor region, the first metal is selected from a metal which has a work function whose absolute value is smaller than a value obtained by adding 0.3 eV to an absolute value of an energy level at the bottom of a conduction band of the semiconductor; wherein, when the predetermined region is a p-type semiconductor region, the first metal is selected from a metal which has a work function whose absolute value is greater than a value obtained by subtracting 0.3 eV from an absolute value of an energy level at the top of a valence band of the semiconductor; and wherein the second metal is of tungsten while the layer of the second metal has a thickness between 50 nm and 300 nm.