Trench Gate FET with Self-Aligned Features
First Claim
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1. A method for forming a trench gate field effect transistor, comprising:
- forming trenches in a semiconductor region of a first conductivity type;
forming a gate electrode recessed in each trench;
using a first mask, forming a body region of a second conductivity type in the semiconductor region by implanting dopants; and
using the first mask, forming source regions of the first conductivity type in the body region by implanting dopants.
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Abstract
A field effect transistor is formed as follows. Trenches are formed in a semiconductor region of a first conductivity type. A gate electrode recessed in each trench is formed. Using a first mask, a body region of a second conductivity type is formed in the semiconductor region by implanting dopants. Using the first mask, source regions of the first conductivity type are formed in the body region by implanting dopants.
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Citations
28 Claims
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1. A method for forming a trench gate field effect transistor, comprising:
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forming trenches in a semiconductor region of a first conductivity type; forming a gate electrode recessed in each trench; using a first mask, forming a body region of a second conductivity type in the semiconductor region by implanting dopants; and using the first mask, forming source regions of the first conductivity type in the body region by implanting dopants. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14-20. -20. (canceled)
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21. A method for forming a field effect transistor (FET) comprising:
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forming a mask over a semiconductor region of a first conductivity type, the mask having openings through which the semiconductor region is exposed; forming trenches extending in the semiconductor region by recessing the semiconductor region through the mask openings; forming a gate dielectric layer lining sidewalls of each trench; forming a gate electrode recessed in each trench; using the first mask, forming a body region of a second conductivity type in the semiconductor region by implanting dopants, the first mask covering a top surface of the semiconductor region between adjacent trenches such that a substantial amount of the implant dopants enter the semiconductor region through upper trench sidewalls not covered by the recessed gate electrode; and using the first mask, forming source regions of the first conductivity type in the body region by implanting dopants. - View Dependent Claims (22, 23, 24, 25, 26, 27)
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28-33. -33. (canceled)
Specification