Patent ID: 9722069
Date: 2017-08-01
CPC Classifications: H01L

Claim:
1. A transistor, comprising: a semiconductor body; a body region of a first conductivity type formed in the semiconductor body; a gate electrode formed partially overlapping the body region on a first side of the gate electrode and insulated from the semiconductor body by a gate dielectric layer; a source diffusion region of a second conductivity type formed in the body region on the first side of the gate electrode; a trench formed in the semiconductor body on a second side, opposite the first side, of the gate electrode, the trench is formed adjacent and next to the second side of the gate electrode without any intervening doped region, the trench being lined with a thin dielectric layer as a sidewall dielectric layer, the trench being filled with a bottom dielectric layer at a lower portion of the trench and a conductive layer above the bottom dielectric layer, the conductive layer being electrically connected to the gate electrode or to the source electrode; a doped sidewall region of the second conductivity type formed in the semiconductor body along only the sidewall of the trench outside of the trench, the doped sidewall region forming a vertical drain current path for the transistor, the drain current of the transistor flowing in the doped sidewall region in the semiconductor body outside of the trench; a second trench formed in the semiconductor body remote from the trench and reaching at least the buried layer, the second trench being lined with a second sidewall dielectric layer and filled with a second conductive layer; and a trench bottom doped region of the second conductivity type being formed in the semiconductor body beneath the second trench, wherein the second conductive layer of the second trench is in electrical contact with the trench bottom doped region and the buried layer, the second conductive layer forming a trench drain electrode conducting the drain current of the transistor flowing from the doped sidewall region through the buried layer and to the trench drain electrode.