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US 6,274,905 B1Granted
Trench structure substantially filled with high-conductivity material
AssigneeFairchild Semiconductor Corporation
InventorBrian S. Mo
Life of this patent
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Abstract
A trench structure that is substantially filled with high-conductivity material such as refractory metal particularly suitable for fast switching trench MOSFET applications. The trench is first lined by a dielectric material such as silicon dioxide. A layer of polysilicon is then formed on the dielectric material and provides buffering for stress relief. The trench is then filled substantially with refractory metal such as tungsten.
Claims19
A trench structure comprising:
- a trench formed in a substrate;
- a dielectric material lining at least a wall of the trench to form a dielectric layer;
- a buffer layer in the trench and formed on the dielectric layer, the buffer layer having a first conductivity;
- a high-conductivity metal layer in the trench and formed adjacent to and electrically coupled to the buffer layer, the high-conductivity metal layer having a second conductivity greater than the first conductivity;
- and
- a layer of polycide in the trench and disposed between the buffer layer and the high-conductivity metal layer.
3 more elements
A trench metal-oxide-semiconductor field effect transistor (MOSFET) comprising:
- a trench formed in a silicon substrate;
- a gate oxide layer lining side-walls and bottom of the trench;
- a polysilicon buffer layer lining the gate oxide layer;
- a metal layer filling a center portion of the trench;
- and
- a polycide layer in the trench and disposed between the metal layer and the polysilicon buffer layer.
3 more elements
A trench transistor comprising:
- a trench extending into a bulk silicon portion of a substrate;
- a gate oxide layer lining the trench walls and bottom;
- a fluorinated interface region between the bulk silicon portion of the substrate and the gate oxide layer;
- a buffer polysilicon layer in the trench and lining the gate oxide layer;
- a metal layer filling a center portion of the trench;
- and
- a polycide layer in the trench and being between the buffer layer and the metal layer.
4 more elements
Dependencies are inferred from the claim text.