SiC trench MOSFET with low on-resistance and switching loss

A SiC power device comprising a plurality of unit cells with each unit cell in an active area comprising:

• an epitaxial layer of a first conductivity type onto a substrate;
• at least one stripe gate trench surrounded by a source region of said first conductivity type encompassed in a body region of a second conductivity type near a top surface of said epitaxial layer;
• said stripe gate trench having a first type gate trench and a second type gate trench;
• said first type gate trench is above said second type gate trench and has a trench width wider than a trench width of said second type gate trench;
• a gate electrode disposed in said first gate trench surrounded with a first insulating film on bottom of said first type gate trench, and with a second insulating film on sidewalls of said first type gate trench;
• said first insulating film having a thickness greater than a thickness of said second insulating film;
• a P-shield region of said second conductivity type for gate oxide electric-field reduction surrounding with said second type gate trench filled up with said first insulating film;
• at least one grounded P region of said second conductivity type surrounding sidewalls and bottom of said first type gate trench, connecting with said body region and said P-shield gate region;
• and
• said body region and said source region being shorted to a source metal through source contacts.