Sic mosfet with improved high current on-resistance performance

A method of forming a semiconductor structure, comprising:

• forming a semiconductor substrate of a first conductivity type, the semiconductor substrate including a silicon carbide substrate;
• forming a drift layer of the first conductivity type above an upper surface of the semiconductor substrate;
• forming a junction field-effect transistor (JFET) region of the first conductivity type above the drift layer;
• forming base regions of a second conductivity type on opposite sides of a top portion of the JFET region, each base region being formed above and in contact with a bottom portion of the JFET region, wherein the second conductivity type is opposite to the first conductivity type;
• forming a hard mask above the top portion of the JFET region located between the base regions;
• and
• conducting a localized tilted ion implantation on the JFET region to implant nitrogen ions, wherein the localized implantation forms first doped regions of the first conductivity type within the JFET region, the first doped regions being formed at an interface between the base regions and the JFET region, the first doped regions extending into the JFET region such that a width of the top portion of the JFET region is reduced by the first doped regions.

A semiconductor structure comprising:

• a semiconductor substrate of a first conductivity type, the semiconductor substrate including a silicon carbide substrate;
• a drift layer of the first conductivity type disposed above an upper surface of the semiconductor substrate;
• a JFET region including a top portion and a bottom portion, the JFET region being disposed above the drift layer;
• a pair of base regions disposed on opposite sides of the top portion of the JFET region;
• a pair of first doped regions located at an interface between the pair of base regions and the JFET region, the pair of first doped regions extending into the top portion of the JFET region such that width of the top portion of the JFET region is reduced by the pair of first doped regions;
• and
• a pair of second doped regions located on a bottom portion of the pair of base regions adjacent to the pair of first doped regions.