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US 6,191,017 B1Granted
Method of forming a multi-layered dual-polysilicon structure
AssigneeLucent Technologies Inc.
InventorsSailesh Chittipeddi, Michael J. Kelly
Life of this patent
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Abstract
A method of forming a multi-layered dual-polysilicon structure that forms a polysilicon gate prior to formation of an ion implantation barrier and that requires fewer steps, is more economical, and permits fabrication of more compact semiconductor circuits and devices than prior art methods.
Claims25
A method of forming a multi-layered semiconductor structure including a substrate having a first insulating layer disposed thereon, the first insulating layer having a top surface, said method comprising the steps of:
- (a) forming a first trench and a second trench of differing depths in the first insulating layer;
- (b) forming a second insulating layer in the first and second trenches;
- (c) forming a polysilicon material in the first and second trenches such that the first and second trenches are substantially filled with polysilicon material;
- (d) removing a portion of the polysilicon material from the first and second trenches so that the top surface of the first insulating layer is not co-planar with a top surface of the polysilicon material remaining in each of the first and second trenches;
- (e) forming an implantation barrier in the first and second trenches;
- and
- (f) processing the implantation barrier in the first and second trenches so that a top surface thereof is substantially co-planar with the top surface of the first insulating layer.
4 more elements
Dependencies are inferred from the claim text.