Transistor with A-face conductive channel and trench protecting well region

摘要

A transistor structure optimizes current along the A-face of a silicon carbide body to form an AMOSFET that minimizes the JFET effect in the drift region during forward conduction in the on-state. The AMOSFET further shows high voltage blocking ability due to the addition of a highly doped well region that protects the gate corner region in a trench-gated device. The AMOSFET uses the A-face conduction along a trench sidewall in addition to a buried channel layer extending across portions of the semiconductor mesas defining the trench. A doped well extends from at least one of the mesas to a depth within the current spreading layer that is greater than the depth of the trench. A current spreading layer extends between the semiconductor mesas beneath the bottom of the trench to reduce junction resistance in the on-state. A buffer layer between the trench and the deep well further provides protection from field crowding at the trench corner.

主权项

1. A transistor having an insulated control contact within a trench, the transistor comprising:
a pair of semiconductor mesas defining the trench, each semiconductor mesa of the pair of semiconductor mesas comprising at least one p-n junction; a drift layer of a first conductivity type extending between the pair of semiconductor mesas and beneath the trench; a first doped well of a second conductivity type extending from a first semiconductor mesa of the pair of semiconductor mesas to a depth within the drift layer that is greater than a depth of the trench, wherein the first doped well is laterally separated from the trench; and a source contact in direct contact with the first doped well.