Power device with trenches having wider upper portion than lower portion
First Claim
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1. A field effect transistor (FET) comprising:
- a plurality of trenches extending into a silicon layer, each trench having upper sidewalls that fan out with a substantially vertically-extending top portion;
contact openings extending into the silicon layer between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall portion corresponding to the substantially vertically-extending top portion;
body regions extending between adjacent trenches; and
source regions extending in the body regions adjacent opposing sidewalls of each trench, the source regions having a conductivity type opposite that of the body regions.
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Abstract
A field effect transistor includes a plurality of trenches extending into a silicon layer. Each trench has 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, and source regions extend in the body regions adjacent opposing sidewalls of each trench. The source regions have a conductivity type opposite that of the body regions.
282 Citations
31 Claims
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1. A field effect transistor (FET) comprising:
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a plurality of trenches extending into a silicon layer, each trench having upper sidewalls that fan out with a substantially vertically-extending top portion; contact openings extending into the silicon layer between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall portion corresponding to the substantially vertically-extending top portion; body regions extending between adjacent trenches; and source regions extending in the body regions adjacent opposing sidewalls of each trench, the source regions having a conductivity type opposite that of the body regions. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A field effect transistor (FET) comprising:
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an epitaxial layer of a first conductivity type extending over a substrate of the first conductivity type, the epitaxial layer having a lower doping concentration than the substrate; a body region of a second conductivity type extending in an upper portion of the epitaxial layer, the second conductivity type being opposite the first conductivity type; a plurality of trenches extending through the body region and terminating within the epitaxial layer below the body region, each trench having upper sidewalls that fan out with a substantially vertically-extending top portion; contact openings extending into the body region between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall corresponding to the substantially vertically-extending top portion; and source regions of the first conductivity type extending in the body region adjacent opposing sidewalls of each trench. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A field effect transistor (FET) comprising:
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an epitaxial layer of a first conductivity type extending over a substrate of the first conductivity type, the epitaxial layer having a lower doping concentration than the substrate; a body region of a second conductivity type extending in an upper portion of the epitaxial layer, the second conductivity type being opposite the first conductivity type; a plurality of trenches extending through the body region and terminating within the epitaxial layer below the body region, each trench having upper sidewalls that fan out with a substantially vertically-extending top portion; contact openings extending into the body region between adjacent trenches such that each trench and an adjacent contact opening form a common upper sidewall portion corresponding to the substantially vertically-extending top portion; a gate electrode recessed in each trench; a gate dielectric insulating each gate electrode from adjacent body regions; a dielectric region extending over the gate electrode; source regions of the first conductivity type extending in the body region adjacent opposing sidewalls of each trench; a highly doped region of the second conductivity type extending in the body region below each contact opening; and a metal layer extending over the dielectric region, the metal layer further extending into each contact opening for contacting the highly doped region along a bottom of each contact opening and for contacting the source regions along sidewalls of the source regions. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification