A Schottky diode structure includes a semiconductor substrate having an anode region and a cathode region. A lightly doped region with a predetermined conductivity type is in the semiconductor substrate. A metal contact overlies the lightly doped region and corresponds to the cathode region to serve as a cathode. A metal silicide layer is beneath and electrically connected to the metal contact, wherein the metal silicide layer, directly under the metal contact, is in direct contact with the lightly doped region. A heavily doped region with the predetermined conductivity type is in the lightly doped region and corresponds to the anode region to serve as an anode.