THICKER BOTTOM OXIDE FOR REDUCED MILLER CAPACITANCE IN TRENCH METAL OXIDE SEMICONDUCTOR FIELD EFFECT TRANSISTOR (MOSFET)
First Claim
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1. A semiconductor device formed in a semiconductor substrate comprising:
- a trench opened in the semiconductor substrate having a trench bottom surface covered by a first bottom insulation layer and a bottom poly-REOX oxide layer;
the trench further having sidewalls covered by a first sidewall insulation layer and further having a first polysilicon layer covering the first sidewall insulation layer; and
the trench is filled with a second polysilicon layer constituting a trench gate for the semiconductor device.
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Abstract
Semiconductor device fabrication method and devices are disclosed. The semiconductor power device is formed on a semiconductor substrate having a plurality of trench transistor cells each having a trench gate. Each of the trench gates having a thicker bottom oxide (TBO) formed by a REOX process on a polysilicon layer deposited on a bottom surface of the trenches.
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Citations
20 Claims
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1. A semiconductor device formed in a semiconductor substrate comprising:
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a trench opened in the semiconductor substrate having a trench bottom surface covered by a first bottom insulation layer and a bottom poly-REOX oxide layer; the trench further having sidewalls covered by a first sidewall insulation layer and further having a first polysilicon layer covering the first sidewall insulation layer; and the trench is filled with a second polysilicon layer constituting a trench gate for the semiconductor device. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for manufacturing a semiconductor device in a semiconductor substrate comprising:
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opening a trench in the semiconductor substrate and forming a first insulation layer covering trench sidewalls and a trench bottom surface; depositing a first polysilicon layer covering over the first insulation layer on the trench bottom surface and the trench sidewalls; depositing a protective spacer layer covering over the first polysilicon layer on the bottom surface and the trench sidewalls followed by a selective etching to etch the protective spacer layer to expose the first polysilicon layer on the trench bottom surface while covering the first polysilicon layer on trench sidewalls; and carrying out a poly REOX process for oxidizing the exposed first polysilicon layer on the trench bottom surface forming a poly-REOX layer followed by removing the protective spacer layer from the trench sidewalls and filling the trench with a second polysilicon layer. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A semiconductor device formed in a semiconductor substrate comprising:
a trench opened in the semiconductor substrate having a thicker trench bottom oxide (TBO) wherein a trench bottom surface covered by a first bottom oxide layer and a bottom poly-REOX oxide layer.
Specification