Patent ID: 8816431
Filing Date: 2014-08-26
Classification: H01L

Abstract:
1. A metal-oxide-semiconductor field-effect transistor (MOSFET) device, comprising: a funnel-shaped trench having a flared rim etched in a semiconductor substrate, the flared rim having an upper edge at a wider cross section trench opening at about a top surface of the semiconductor substrate and having a lower edge at a top opening of a narrower cross section trench body portion that terminates in the semiconductor substrate; a gate electrode disposed in the funnel-shaped trench on a gate dielectric layer formed on the flared rim, the gate electrode having a split structure with a first gate electrode portion being separated from a second gate electrode portion by an insulator material; and a source region, a gate region, and a drain region disposed in the semiconductor substrate, the gate region abutting a lower portion of the flared rim, the drain region abutting a sidewall of the narrower cross section trench body portion with a top of the drain region being aligned with a lower edge of the gate electrode.