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US 6,472,274 B1Granted
MOSFET with self-aligned channel edge implant and method
AssigneeInternational Business Machines Corporation
InventorsJohn Walter Golz, Fumihiko Satoh
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Abstract
A MOSFET device and method, the method involves forming the MOSFET device by selectively doping bordering channel regions in the device such that, in operation, the threshold, or turn-on, voltage is equalized across the channel. The device structure comprises a self-aligned channel edge implant region for equalizing threshold voltages in the channel edge region with threshold voltages in the channel interior region, thereby virtually eliminating sub-threshold leakage current in low voltage applications.
Claims4
A method for forming a MOSFET device, comprising the steps of:
- a) depositing a masking layer over a planar surface of a silicon substrate;
- b) patterning and etching through said masking layer into said silicon substrate to form first and second trenches defining a MOSFET device active area;
- c) selectively etching back said masking material to expose regions of un-etched silicon at border regions of said MOSFET device active area, said border regions defining MOSFET device channel edges;
- d) selectively doping said exposed border regions to form drain and source portions each including a respective MOSFET channel edge;
- e) filling said trench with an electrically insulating material and removing remaining masking layer;
- f) forming a MOSFET gate on and in un-etched areas of said MOSFET device active area, wherein a said MOSFET device exhibits reduced or eliminated threshold leakage current in low-voltage applications.
3 more elements
Dependencies are inferred from the claim text.