Patent ID: 7221010

Claim:
A silicon carbide metal-oxide semiconductor field effect transistor unit cell, comprising: an n-type silicon carbide drift layer; a first p-type silicon carbide region in close proximity to the drift layer; a first n-type silicon carbide region within the first p-type silicon carbide region; an oxide layer on the drift layer, the first p-type silicon carbide region, and the first n-type silicon carbide region; and an n-type silicon carbide limiting region disposed between the drift layer and the first p-type silicon carbide region, wherein the n-type limiting region comprises a first portion disposed in close proximity to a floor of the first p-type silicon carbide region and a second portion disposed in close proximity to a sidewall of the first p-type silicon carbide region, wherein the n-type limiting region has a carrier concentration that is greater than a carrier concentration of the drift layer and wherein the first portion has a carrier concentration greater than a carrier concentration of the second portion.