Systems and methods for in-situ doped semiconductor gate electrodes for wide bandgap semiconductor power devices

Abstract

In an embodiment, a wide bandgap semiconductor power device, includes a wide bandgap semiconductor substrate layer; an epitaxial semiconductor layer disposed above the wide bandgap semiconductor substrate layer; a gate dielectric layer disposed directly over a portion of the epitaxial semiconductor layer; and a gate electrode disposed directly over the gate dielectric layer. The gate electrode includes an in-situ doped semiconductor layer disposed directly over the gate dielectric layer and a metal-containing layer disposed directly over the in-situ doped semiconductor layer.

1 . A wide bandgap semiconductor power device, comprising:
 a wide bandgap semiconductor substrate layer;   an epitaxial semiconductor layer disposed above the wide bandgap semiconductor substrate layer;   a gate dielectric layer disposed directly over a portion of the epitaxial semiconductor layer; and   a gate electrode disposed directly over the gate dielectric layer, wherein the gate electrode comprises:
 an in-situ doped semiconductor layer disposed directly over the gate dielectric layer; and 
 a metal-containing layer disposed directly over the in-situ doped semiconductor layer. 
   
     
     
         2 . The wide bandgap semiconductor power device of  claim 1 , wherein a doping concentration of a portion of the in-situ doped semiconductor layer that is disposed nearest the gate dielectric layer is less than or equal to a doping concentration of other regions of the in-situ doped semiconductor layer of the gate electrode. 
     
     
         3 . The wide bandgap semiconductor power device of  claim 1 , wherein the gate electrode comprises polycrystalline silicon. 
     
     
         4 . The wide bandgap semiconductor power device of  claim 3 , wherein the gate electrode comprises low-pressure chemical vapor deposition (LPCVD) polysilicon. 
     
     
         5 . The wide bandgap semiconductor power device of  claim 1 , wherein the wide bandgap semiconductor substrate and the epitaxial semiconductor layer comprise silicon carbide. 
     
     
         6 . The wide bandgap semiconductor power device of  claim 1 , wherein the metal-containing layer of the gate electrode comprises a tantalum silicide (TaSi 2 ) layer. 
     
     
         7 . The wide bandgap semiconductor power device of  claim 1 , wherein a sheet resistance of the gate electrode is less than approximately 4.2 ohms per square centimeter (ohms/cm 2 ). 
     
     
         8 . The wide bandgap semiconductor power device of  claim 7 , wherein a sheet resistance of the gate electrode is less than approximately 4 ohms/cm 2 . 
     
     
         9 . The wide bandgap semiconductor power device of  claim 8 , wherein a sheet resistance of the gate electrode is between approximately 3.6 ohms/cm 2  and approximately 3.8 ohms/cm 2 . 
     
     
         10 . The wide bandgap semiconductor power device of  claim 1 , wherein the epitaxial layer comprises a source region and a well region, and wherein the wide bandgap semiconductor power device comprises a nickel silicide (NiSi) layer disposed directly over portions of the source region and portions of the well region of the epitaxial layer.