Patent ID: 9634107
Date: 2017-04-25
CPC Classifications: H01L

Claim:
1. A method for manufacturing an Au-free ohmic contact for a III-N device comprising: providing a semiconductor substrate and thereon a buffer layer, a channel layer, a barrier layer, and a passivation layer, wherein a two-dimensional electron gas (2DEG) layer is formed at an interface between the channel layer and the barrier layer; forming a recess at least extending through the passivation layer; forming a silicon layer at least at and in contact with a bottom of the recess; forming an Au-free metal stack in the recess after forming the silicon layer, wherein the metal stack includes a Ti/Al bi-layer, with a Ti layer overlying and in contact with the silicon layer, and an Al layer overlying and in contact with the Ti layer, wherein a thickness ratio of the Ti layer to the Al layer is between 0.01 to 0.1, and wherein the silicon layer forms a eutectic melt with the Ti/Al bi-layer; and after forming the Au-free metal stack, performing an anneal thereby forming the Au-free ohmic contact.