Electrode for silicon carbide semiconductor, silicon carbide semiconductor element comprising the electrode, and production method therefor

Abstract

An ohmic electrode for an SiC semiconductor includes a p-type Si layer formed on the surface of a p-type SiC semiconductor, and a metal silicide layer formed on the surface of the Si layer, the metal silicide layer being formed from a metal silicide such as PtSi. The p-type Si layer is preferably formed from p-type Si having a carrier concentration equal to or higher than that of the aforementioned p-type SiC. Preferably, the ohmic electrode is formed as follows: deposition of Si is performed; deposition of a metal silicide is performed by means of laser ablation; laser irradiation is performed to thereby improve ohmic properties and enhance adhesion between the resultant deposition layer and the p-type SiC semiconductor; and then further deposition of the metal silicide is performed by means of laser ablation.

What is claimed is:  
     
         1 . An electrode adapted for use with a silicon carbide semiconductor, which electrode serves as an ohmic electrode and comprises a p-type silicon layer formed on the surface of a semiconductor formed from p-type silicon carbide, and a metal silicide layer formed on the p-type silicon layer.  
     
     
         2 . The electrode as claimed in  claim 1 , wherein the p-type silicon layer is formed from p-type silicon having a carrier concentration equal to or higher than that of the p-type silicon carbide.  
     
     
         3 . The electrode as claimed in  claim 1 , wherein the metal silicide layer contains at least one metallic element selected from the group consisting of platinum group elements, Group IVa elements, Group Va elements, Group VIa elements, and Group VIII elements.  
     
     
         4 . A method for producing the electrode as claimed in  claim 1 , which method comprises forming the metal silicide layer by means of laser ablation.  
     
     
         5 . The method as claimed in  claim 4 , which further comprises subjecting the metal silicide layer to at least one of laser irradiation and heat treatment, subsequent to formation of the metal silicide layer by means of laser ablation.  
     
     
         6 . The method as claimed in  claim 4 , which further comprises subjecting the metal silicide layer to at least one of laser irradiation and heat treatment, subsequent to formation of the metal silicide layer by means of laser ablation; and then depositing a metal silicide on the surface of the laser-irradiated or heat-treated metal silicide layer by means of laser ablation.  
     
     
         7 . A silicon carbide semiconductor element comprising: a semiconductor formed from p-type silicon carbide; and an electrode adapted for use with a silicon carbide semiconductor, the electrode comprising an ohmic electrode including a p-type silicon layer formed on the surface of the p-type silicon carbide semiconductor, and a metal silicide layer formed on the p-type silicon layer.  
     
     
         8 . The silicon carbide semiconductor element as claimed in  claim 7 , wherein the p-type silicon layer is formed from p-type silicon having a carrier concentration equal to or higher than that of the p-type silicon carbide.  
     
     
         9 . The silicon carbide semiconductor element as claimed in  claim 7 , wherein the metal silicide layer contains at least one metallic element selected from the group consisting of platinum group elements, Group IVa elements, Group Va elements, Group VIa elements, and Group VIII elements.  
     
     
         10 . A method for producing the silicon carbide semiconductor element as in  claim 7 , which method comprises forming the metal silicide layer by means of laser ablation.  
     
     
         11 . The method as claimed in  claim 10 , which further comprises subjecting the metal silicide layer to at least one of laser irradiation and heat treatment, subsequent to formation of the metal silicide layer by means of laser ablation.  
     
     
         12 . The method as claimed in  claim 10 , which further comprises subjecting the metal silicide layer to at least one of laser irradiation and heat treatment, subsequent to formation of the metal silicide layer by means of laser ablation; and then depositing a metal silicide on the surface of the laser-irradiated or heat-treated metal silicide layer by means of laser ablation.