Structure and method for forming power devices with high aspect ratio contact openings
First Claim
1. A field effect transistor (FET), comprising:
- body regions of a first conductivity type over a semiconductor region of a second conductivity type, the body regions forming p-n junctions with the semiconductor region;
source regions of the second conductivity type over the body regions, the source regions forming p-n junctions with the body regions;
gate electrodes extending adjacent to but being insulated from the body regions by a gate dielectric;
contact openings extending into the body regions between adjacent gate electrodes;
a seed layer extending along a bottom of each contact opening, the seed layer serving as a nucleation site for promoting growth of conductive fill material;
a conductive fill material filling a lower portion of each contact opening, wherein an upper surface of the conductive fill material is below a bottom surface of the source regions; and
an interconnect layer filling an upper portion of each contact opening and being in direct contact with the conductive fill material, the interconnect layer also being in direct contact with corresponding source regions along upper sidewalls of the contact openings.
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Abstract
A field effect transistor (FET) includes body regions of a first conductivity type over a semiconductor region of a second conductivity type. Source regions of the second conductivity type extend over the body regions. Gate electrodes extend adjacent to but are insulated from the body regions by a gate dielectric layer. Contact openings extend into the body regions between adjacent gate electrodes. A seed layer extends along the bottom of each contact opening. The seed layer serves as a nucleation site for promoting growth of conductive fill material. A conductive fill material fills a lower portion of each contact opening. An interconnect layer fills an upper portion of each contact opening and is in direct contact with the conductive fill material. The interconnect layer is also in direct contact with corresponding source regions along upper sidewalls of the contact openings.
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Citations
20 Claims
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1. A field effect transistor (FET), comprising:
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body regions of a first conductivity type over a semiconductor region of a second conductivity type, the body regions forming p-n junctions with the semiconductor region; source regions of the second conductivity type over the body regions, the source regions forming p-n junctions with the body regions; gate electrodes extending adjacent to but being insulated from the body regions by a gate dielectric; contact openings extending into the body regions between adjacent gate electrodes; a seed layer extending along a bottom of each contact opening, the seed layer serving as a nucleation site for promoting growth of conductive fill material; a conductive fill material filling a lower portion of each contact opening, wherein an upper surface of the conductive fill material is below a bottom surface of the source regions; and an interconnect layer filling an upper portion of each contact opening and being in direct contact with the conductive fill material, the interconnect layer also being in direct contact with corresponding source regions along upper sidewalls of the contact openings. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of forming a field effect transistor (FET), comprising:
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forming body regions of a first conductivity type in a semiconductor region of a second conductivity type, the body regions forming p-n junctions with the semiconductor region; forming gate electrodes adjacent to but insulated from the body regions; forming source regions of the second conductivity type in the body regions, the source regions forming p-n junctions with the body regions; forming contact openings extending into the body regions; forming a seed layer extending along a bottom of each contact opening; filling a lower portion of each contact opening with a conductive fill material, wherein the seed layer serves as a nucleation site for promoting growth of the conductive fill material and an upper surface of the conductive fill material is below a bottom surface of the source regions; and forming an interconnect layer filling an upper portion of each contact opening and being in direct contact with the conductive fill material, the interconnect layer also being in direct contact with corresponding source regions along upper sidewalls of the contact openings. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification