A Schottky barrier contact includes a thin layer of high carrier concentration impurities ion implanted over the contact surface of the semiconductor. This reduces the electronic barrier height, increases the tunneling component, and thus reduces the forward-bias turn-on voltage of the diode. The implanted layer has a carrier concentration at least ten times that of the semiconductor substrate, and a thickness smaller than the width of the inherent depletion region resulting from the internally generated electric field at the metal-semiconductor interface. An implanted layer of the opposite conductivity type raises the barrier height.