Semiconductor Power Switches Having Trench Gates
First Claim
1. A method of fabricating a trench device, comprising:
- forming a first trench, forming a hardmask layer on sidewalls of said trench, and etching a second trench, which is narrower than said first trench, into the bottom of said first trench;
growing a dielectric material to substantially fill said second trench, using a reaction process to which said hardmask material is substantially inert; and
forming a conductive layer over said dielectric material;
whereby said dielectric material in said second trench provides smooth gradation of voltage differences, within said semiconductor material, which may be caused by potential differences between said gate and various portions of said semiconductor material.
1 Assignment
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Accused Products
Abstract
A method of fabricating a trench device includes forming a first trench and forming a hardmask layer on sidewalls of the trench. A second trench may be etched narrower than the first trench, into the bottom of the first trench. A dielectric material may be grown to substantially fill the second trench, using a reaction process to which the hardmask material is substantially inert. The growing action also grows tapered portions of the dielectric material upwardly under part of the hardmask. A conductive layer may be formed over said dielectric material. The dielectric material in the second trench, in combination with the tapered portions which extend upward from the dielectric material may provide smooth gradation of voltage differences within the semiconductor material. The gradation may be caused by potential differences between the gate and various portions of the semiconductor material.
89 Citations
21 Claims
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1. A method of fabricating a trench device, comprising:
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forming a first trench, forming a hardmask layer on sidewalls of said trench, and etching a second trench, which is narrower than said first trench, into the bottom of said first trench; growing a dielectric material to substantially fill said second trench, using a reaction process to which said hardmask material is substantially inert; and forming a conductive layer over said dielectric material; whereby said dielectric material in said second trench provides smooth gradation of voltage differences, within said semiconductor material, which may be caused by potential differences between said gate and various portions of said semiconductor material. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A power MOSFET comprising;
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a trench having at least an upper and a lower part, said lower part being filled with an insulating material; tapered insulating extensions in said lower part of said trench, extending upwardly from said insulating material; and a conductive electrode in said upper part of said trench. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A power device comprising:
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a source electrode; a trench adjoining said source electrode, said trench having at least an upper and a lower part, said lower part being filled with an insulating material; and tapered extensions in said lower part of said trench, extending upwardly from said insulating material; and a gate electrode in said upper part of said trench. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21-77. -77. (canceled)
Specification