Power device with self-aligned source regions
AssigneeFairchild Semiconductor Corporation
InventorsRobert Herrick, Becky Losee, Dean Probst
Life of this patent
Estimating the term…
Abstract
A field effect transistor (FET) includes a plurality of trenches extending into a silicon layer, each trench having upper sidewalls that fan out. Contact openings extend into the silicon layer between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall portion. Body regions extend between adjacent trenches. Source regions that are self-aligned to corresponding trenches extend in the body regions adjacent opposing sidewalls of each trench, and have a conductivity type opposite that of the body regions.
Claims20
A field effect transistor (FET), comprising:
- a trench extending into a silicon layer, the trench having an upper sidewall that fans out;
- a contact opening extending into the silicon layer adjacent the trench such that the trench and the contact opening form a common upper sidewall portion;
- a body region adjacent the trench;
- and
- a source region extending in the body region, the source region having a conductivity type opposite that of the body region, the source region being self-aligned to the trench, a majority of the source region being disposed below the common upper sidewall.
A field effect transistor (FET) comprising:
- a trench extending through a body region and terminating within an epitaxial layer below the body region, the trench having an upper portion wider than a lower portion of the trench;
- a gate electrode disposed in the lower portion of the trench, the upper portion substantially being disposed above a top surface of the gate electrode;
- a contact opening extending into the body region adjacent the trench such that the trench and a contact opening adjacent the trench define a common upper sidewall, the common upper sidewall being above an upper surface of the body;
- and
- a source region of a conductivity type extending in the body region adjacent a sidewall of the trench.
An apparatus, comprising:
- a trench disposed in a silicon layer, the trench having an upper sidewall portion that fans out;
- a gate electrode disposed in the trench;
- a contact opening defined, at least in part by, the upper sidewall portion, the upper sidewall being disposed substantially above a bottom surface of the contact opening;
- and
- a source region in contact with at least a portion of the upper sidewall portion.
Dependencies are inferred from the claim text.