DMOS TRANSISTOR WITH TRENCH SCHOTTKY DIODE

摘要

A DMOS transistor integrates a trench Schottky diode into the body contact of the transistor where the body region surrounding the Schottky metal layer forms a guard ring for the Schottky diode.

主权项

1. A vertical DMOS transistor comprising:
a semiconductor layer of a first conductivity type forming a drain region of the DMOS transistor; a body region of a second conductivity type formed in the semiconductor layer; a conductive gate formed on a first surface of the semiconductor layer and insulated from the semiconductor layer by a gate dielectric layer; a source region of the first conductivity type formed in the body region on one side of the conductive gate; a heavily doped body contact region formed in the body region on the same side of the conductive gate as the source region and adjacent the source region in a lateral direction along the surface of the semiconductor layer; a trench formed in the heavily doped body contact region and the body region, a bottom of the trench reaching through the body region into the semiconductor layer; a Schottky metal layer formed in the sidewall of the trench; a metal layer filling the trench to form a body contact, the Schottky metal layer and the metal layer being formed without physically contacting the source region, wherein the body contact provides electrical connection to the body region of the DMOS transistor and a Schottky diode is formed having the Schottky metal as the anode and the semiconductor layer as the cathode, and the body region surrounding the trench forms a guard ring for the Schottky diode.