SiC MOSFET Device and Method for Manufacturing the Same

An SiC MOSFET device, wherein a device unit comprises:

• an SiC epitaxial layer of first conductive type doping, wherein a trench gate is formed in the SiC epitaxial layer;
• the trench gate comprises a gate trench, a gate dielectric layer formed on an inner side surface of the gate trench, and a gate conductive material layer filled in the gate trench;
• a first bottom doped region is formed in the SiC epitaxial layer below a bottom surface of the gate trench, the first bottom doped region is of second conductive type doping, and a top surface of the first bottom doped region is in contact with a bottom surface of the gate dielectric layer on the bottom surface of the gate trench;
• a channel region of second conductive type doping is formed in the SiC epitaxial layer, the channel region extends downwards from a top surface of the SiC epitaxial layer, the gate conductive material layer longitudinally passes through the channel region;
• a second deep doped region of second conductive type doping is formed in the SiC epitaxial layer, and there is spacing between the second deep doped region and the gate trench;
• a source region consisting of a region of first conductive type heavy doping is formed on a surface of the channel region;
• a top of the gate conductive material layer is connected to a gate consisting of a front metal layer;
• a top of the source region is connected to a source consisting of a front metal layer;
• the first bottom doped region is connected to the source so that a voltage borne by the gate dielectric layer on the bottom surface of the gate trench is determined by a voltage difference between the source and the gate to reduce an electric field intensity borne by the gate dielectric layer on the bottom surface of the gate trench;
• the second deep doped region extends downwards from the top surface of the SiC epitaxial layer, and a bottom surface of the second deep doped region is located below a bottom surface of the first bottom doped region;
• a top of the second deep doped region is connected to the source;
• the SiC epitaxial layer at a bottom of the channel region forms a drift region;
• the first bottom doped region and the second deep doped region increase depletion of the drift region at the bottom of the channel region between the first bottom doped region and the second deep doped region to reduce depletion between the channel region and the drift region at the bottom to reduce a short channel effect.