Semiconductor device with a field plate trench having a thick bottom dielectric
First Claim
Patent Images
1. A power semiconductor device comprising:
- a field plate trench;
a first trench dielectric situated in and contacting a bottom of said field plate trench;
a second trench dielectric situated over said first trench dielectric and directly contacting sidewalls of said field plate trench;
a field plate situated over said first trench dielectric and within said second trench dielectric;
a combined thickness of said first and second trench dielectrics at said bottom of said field plate trench being greater than a sidewall thickness of said second trench dielectric.
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Abstract
Disclosed is a power device, such as a power MOSFET, and methods for fabricating same. The device includes a field plate trench. The device further includes first and second trench dielectrics inside the field plate trench. The device also includes a field plate situated over the first trench dielectric and within the second trench dielectric. A combined thickness of the first and second trench dielectrics at a bottom of the field plate trench is greater than a sidewall thickness of the second trench dielectric.
17 Citations
20 Claims
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1. A power semiconductor device comprising:
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a field plate trench; a first trench dielectric situated in and contacting a bottom of said field plate trench; a second trench dielectric situated over said first trench dielectric and directly contacting sidewalls of said field plate trench; a field plate situated over said first trench dielectric and within said second trench dielectric; a combined thickness of said first and second trench dielectrics at said bottom of said field plate trench being greater than a sidewall thickness of said second trench dielectric. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of fabricating a power semiconductor device, said method comprising:
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forming a field plate trench in a semiconductor substrate; forming a first trench dielectric; forming a sacrificial mask within said first trench dielectric; etching said first trench dielectric situated on said sidewalls to a depth; removing said sacrificial mask; depositing a second trench dielectric over said first trench dielectric, such that a combined thickness of said first and second trench dielectrics at a bottom of said field plate trench is greater than a sidewall thickness of said second trench dielectric; forming a field plate in said field plate trench. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of fabricating a power semiconductor device, said method comprising:
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forming a field plate trench; forming a first trench dielectric in and contacting a bottom of said field plate trench; partially etching said first trench dielectric on sidewalls of said field plate trench; forming a second trench dielectric over said first trench dielectric and directly contacting said sidewalls of said field plate trench without filling said field plate trench; forming a field plate in said field plate trench; wherein a combined thickness of said first and second trench dielectrics at a bottom of said field plate trench is greater than a sidewall thickness of said second trench dielectric. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification