Semiconductor Device with Reduced Contact Resistance

Abstract

A semiconductor device that includes an electrode of one material and a conductive material of lower resistivity formed over the electrode and a process for fabricating the semiconductor device.

1 - 37 . (canceled) 
     
     
         38 . A semiconductor device comprising:
 a semiconductor body comprising a first power electrode and a second power electrode;   a first barrier layer over said first power electrode;   a second barrier layer over said second power electrode;   a first metallic body having a resistivity less than a resistivity of said first power electrode formed over said first barrier layer, wherein said first metallic body is configured for flip-chip mounting;   a second metallic body formed over said second barrier layer, wherein said second metallic body is configured for flip-chip mounting.   
     
     
         39 . The semiconductor device of  claim 38 , wherein said second metallic body has a resistivity less than a resistivity of said second power electrode. 
     
     
         40 . The semiconductor device of  claim 38 , wherein said first and second power electrodes comprise aluminum. 
     
     
         41 . The semiconductor device of  claim 38 , wherein said first and second power electrodes comprise AlSi. 
     
     
         42 . The semiconductor device of  claim 38 , wherein said first and second power electrodes comprise AlSiCu. 
     
     
         43 . The semiconductor device of  claim 38 , wherein said first and second barrier layers comprise titanium. 
     
     
         44 . The semiconductor device of  claim 38 , wherein said first and said second metallic bodies comprise copper. 
     
     
         45 . The semiconductor device of  claim 38 , further comprising a nickel layer over at least one of said first and second metallic bodies. 
     
     
         46 . The semiconductor device of  claim 38 , further comprising a stress balancing body disposed on at least one of said first and second metallic bodies. 
     
     
         47 . The semiconductor device of  claim 38 , wherein said semiconductor device is a power MOSFET, and said first and said second power electrodes are, respectively, a source electrode and a drain electrode. 
     
     
         48 . The semiconductor device of  claim 38 , further comprising a control electrode, a third barrier layer over said control electrode, and a third metallic body formed over said third barrier layer. 
     
     
         49 . The semiconductor device of  claim 38 , further comprising a solderable body over said first metallic body. 
     
     
         50 . The semiconductor device of  claim 38 , further comprising a solderable body over said second metallic body. 
     
     
         51 . The semiconductor device of  claim 49 , wherein said solderable body comprises a nickel layer. 
     
     
         52 . The semiconductor device of  claim 50 , wherein said solderable body comprises a nickel layer. 
     
     
         53 . The semiconductor device of  claim 49 , wherein said solderable body comprises NiAg. 
     
     
         54 . The semiconductor device of  claim 49 , wherein said solderable body comprises NiAu. 
     
     
         55 . The semiconductor device of  claim 50 , wherein said solderable body comprises NiAg. 
     
     
         56 . The semiconductor device of  claim 50 , wherein said solderable body comprises NiAu. 
     
     
         57 . The semiconductor device of  claim 38 , wherein said first barrier layer prevents contamination of said first power electrode by said first metallic body.