Vertical channel silicon carbide metal-oxide-semiconductor field effect transistor with self-aligned gate for microwave and power applications, and method of making

A method for fabricating a silicon carbide (SiC) depletion mode metal-oxide-semiconductor field effect transistor (MOSFET), comprising the steps of:

• providing a first SiC semiconductor contact layer, having a first conductivity type;
• providing a SiC semiconductor channel layer supported by said first SiC semiconductor contact layer and having the first conductivity type;
• providing a second SiC semiconductor contact layer supported by said SiC semiconductor channel layer and having the first conductivity type;
• patterning said second SiC semiconductor contact layer and SiC semiconductor channel layer to form a plurality of gate region grooves, each of said plurality of gate region grooves extending through said second SiC semiconductor contact layer and said SiC semiconductor channel layer and having a base surface and side surfaces;
• depositing a base groove oxide layer on said second SiC semiconductor contact layer and in said plurality of gate region grooves;
• etching said base groove oxide layer to form a flat portion of said base groove oxide layer in the bottom of each of said plurality of gate region grooves;
• growing a side groove oxide layer on each of said plurality of gate region grooves;
• providing a plurality of metal gate layers, each one of said plurality of metal gate layers being supported in a respective one of said plurality of gate region grooves over said base groove oxide layer and having first and second surfaces, the first surface being situated on a plane above said first SiC semiconductor contact layer and the second surface being situated on a plane below said second SiC semiconductor contact layer during fabrication of the SiC MOSFET;
• and
• providing a plurality of deposited oxide segments, each one of said plurality of deposited oxide segments being supported by said each one of said plurality of metal gate layers and substantially coplanar with said second SiC semiconductor contact layer.