Fairchild Semiconductor Corporation

Hossein Paravi

Dean E Probst

James N Pan

Qi Wang

Ihsiu Ho

Hui Chen

Scott L Hunt

Briant Harward

Amber Crellin-Ngo

Stacy W Hall

A semiconductor structure comprises trenches extending into a semiconductor region. Portions of the semiconductor region extend between adjacent trenches forming mesa regions. A gate electrode is in each trench. Well regions of a first conductivity type extend in the semiconductor region between adjacent trenches. Source regions of a second conductivity type are in the well regions. Heavy body regions of the first conductivity type are in the well regions. The source regions and the heavy body regions are adjacent trench sidewalls, and the heavy body regions extend over the source regions along the trench sidewalls to a top surface of the mesa regions.

High density trench field effect transistor

A method for forming a semiconductor structure includes the following steps. A hard mask layer is formed over a semiconductor region. The hard mask layer has inner portions that are thinner than its outer portions, and the inner portions define an exposed surface area of the semiconductor region. A portion of the semiconductor region is removed through the exposed surface area of the semiconductor region. The thinner portions of the hard mask layer are removed to expose surface areas of the semiconductor region underlying the thinner portions. An additional portion of the semiconductor region is removed through all exposed surface areas of the semiconductor region thereby forming a trench having an upper portion that is wider than its lower portion.

Method for forming trenches with wide upper portion and narrow lower portion

A semiconductor device includes a silicon substrate heavily-doped with phosphorous. A spacer layer is disposed over the substrate and is doped with dopant atoms having a diffusion coefficient in the spacer layer material that is less than the diffusion coefficient of phosphorous in silicon. An epitaxial layer is also disposed over the substrate. A device layer is disposed over the substrate, and over the epitaxial and spacer layers.

Semiconductor device having a spacer layer doped with slower diffusing atoms than substrate

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Sandy, UT, United States of America

Hossein Paravi