Efficient dual metal contact formation for a semiconductor device

Abstract

A method of forming contacts to an n-type layer and a p-type layer of a semiconductor device includes depositing a dielectric layer on the n-type layer and the p-type layer. A pattern is formed in the dielectric layer, the pattern having a plurality of metal contact patterns for the semiconductor device. A first metal layer is deposited into the plurality of metal contact patterns, and a second metal layer is deposited directly on the first metal layer. External contacts for the semiconductor device are formed, where the external contacts include the second metal layer.

What is claimed is: 
     
         1 . A method of forming contacts to an n-type layer and a p-type layer of a semiconductor opto-electronic device, comprising:
 providing an opto-electronic device structure with an n-type layer, a p-type layer and a light generating structure between the n-type layer and the p-type layer;   depositing a first metal layer directly on the opto-electronic device structure;   depositing a second metal layer directly onto the first metal layer; and   performing a masked etch removal of the first metal layer and the second metal layer, using a single mask on both the first metal layer and the second metal layer to form device contacts for the opto-electronic device.   
     
     
         2 . The method of  claim 1 , further comprising:
 depositing a passivation layer directly onto the opto-electronic device structure and the device contacts; and   patterning the passivation layer to expose the device contacts.   
     
     
         3 . The method of  claim 1 , wherein the first metal layer is titanium. 
     
     
         4 . The method of  claim 3 , wherein the masked etch removal comprises removing the first metal layer using hydrofluoric acid (HF) at approximately 25° C. for up to 10 minutes. 
     
     
         5 . The method of  claim 4 , wherein the hydrofluoric acid is a 10:1 dilute solution. 
     
     
         6 . The method of  claim 1 , wherein the second metal layer is AlCuSi. 
     
     
         7 . The method of  claim 6 , wherein the masked etch removal comprises removing the second metal layer using phosphoric acid (H 3 PO 4 ) at approximately 70-120° C. for up to 10 minutes. 
     
     
         8 . The method of  claim 1 , wherein the masked etch removal comprises removing the first metal layer and the second metal layer using a plasma etch.