Patent ID: 11901446
Assignee: UNITY POWER TECHNOLOGY LIMITED
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 18:
19. A method of producing a silicon carbide MOSFET device, comprising the steps of:
a) providing a first silicon carbide layer of a first dopant type on top of a silicon carbide substrate; the first silicon carbide layer comprises first epitaxy layer and second epitaxy layer, which have same or different doping but both have lower doping than the silicon carbide substrate;
b) providing a second silicon carbide layer of a second dopant type embedded in a top portion of the first silicon carbide layer;
c) providing a third silicon carbide layer of the first dopant type embedded in a top portion of the second silicon carbide layer; the third silicon carbide layer having higher doping than the first silicon carbide layer; the third silicon carbide layer comprising a plurality of third portions that run substantially along a first direction;
d) providing a gate oxide layer overlapped to the first silicon carbide layer, the second silicon carbide layer and the third silicon carbide layer; and in touch with a polysilicon layer; and
e) providing a fourth silicon carbide layer at least partially overlapping with the second silicon carbide layer along a direction normal to the silicon carbide substrate; the fourth silicon carbide layer, which has higher doping than the second silicon carbide layer, comprises a plurality of fourth portions that run substantially along a second direction perpendicular to the first direction; the first and second directions each being parallel to the silicon carbide substrate;
wherein the first dopant type is N and the second dopant type is P: the third silicon carbide layer being a N+ layer, and the third portions of the third silicon carbide layer being separated from each other along the second direction; the fourth silicon carbide layer being a P+ layer, and the fourth portions are P+ portions which are separated from each other along the first direction; and
wherein the second silicon carbide layer comprises a plurality of P-well regions separated from each other along the second direction.