Patent ID: 7615839

Claim:
A semiconductor device comprising: a semiconductor substrate of a first general conductivity type; a plurality of impurity regions of a second general conductivity type formed in the semiconductor substrate so as to define depletion regions in which depletion layers are formed around corresponding impurity regions under a reverse bias; a patterned metal layer of a first metal that is in contact with portions of the semiconductor substrate where the depletion layers are not formed under the reverse bias; and a metal layer of a second metal that is in contact with portions of the semiconductor substrate corresponding to the impurity regions and the depletion regions, wherein the patterned metal layer of the first metal forms a Schottky junction with the semiconductor substrate and the metal layer of the second metal forms another Schottky junction with the semiconductor substrate, a difference in work function between the first metal and the semiconductor substrate is larger than a difference in work function between the second metal and the semiconductor substrate, and the metal layer of the second metal completely covers the impurity regions of the second general conductivity type in plan view of the semiconductor device.