Ohmic electrode and method for forming it.

摘要

An ohmic electorde of the present invention comprises a contact electrode layer formed on a p-type diamond semiconductor layer formed on a substrate so as to be in ohmic contact with the p-type diamond semiconductor layer and to have low contact resistance and high heat resistance, and a lead electrode layer formed on the contact electrode layer so as to have low lead wire resistance and high heat resistance. Specifically, the contact electrode layer is made of either a carbide of at least one metal selected from a metal group comprising Ti, Zr, and Hf, or a carbide of an alloy containing at least one metal selected from the metal group. Since the carbide of the metal or alloy forming the contact electrode layer is stabler in respect of energy because of reduced formation enthalpy than the metal or alloy itself, it is very unlikely to diffuse. Therefore, little metal or alloy forming the contact electrode layer precipitates on the surface of the lead electrode layer formed on the contact electrode layer, thus improving the device performance, based on the reduced lead wire resistance.