Method and structure to reduce CMOS inter-well leakage
AssigneeInternational Business Machines Corporation
InventorsLyndon R. Logan, James A. Slinkman
Life of this patent
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Abstract
A method of forming a semiconductor device with improved leakage control, includes: providing a semiconductor substrate; forming a trench in the substrate; forming a leakage stop implant in the substrate under the bottom of the trench and under and aligned to a sidewall of the trench; filling the trench with an insulator; and forming an N-well (or a P-well) in the substrate adjacent to and in contact with an opposite sidewall of the trench, the N-well (or the N-well) extending under the trench and forming an upper portion of an isolation junction with the leakage stop implant, the upper portion of the isolation junction located entirely under the trench. The leakage control implant is self-aligned to the trench sidewalls.
Claims42
A method of forming a semiconductor device with improved leakage control, comprising in the sequence recited:
- providing a semiconductor substrate having a top surface;
- forming a trench in said substrate, said trench having a bottom, a first sidewall and an opposite second sidewall;
- forming a blocking layer on said first and second sidewalls of said trench;
- removing said blocking layer from said second sidewall of said trench;
- forming a leakage stop implant in said substrate under a less than whole portion of the bottom of said trench, a first side of said leakage stop implant self-aligned to said blocking layer on said first sidewall of said trench and a second and opposite side of said leakage stop implant self-aligned to said second sidewall of said trench;
- filling said trench with an insulator;
- and
- forming an N-well in said substrate adjacent to and in contact with said first sidewall, said N-well extending under said trench and forming an upper portion of an isolation junction with said leakage stop implant, said upper portion of said isolation junction located entirely under said trench.
A method of forming a semiconductor device with improved leakage control, comprising in the sequence recited:
- providing a P doped semiconductor substrate having a top surface;
- forming a trench in said substrate, said trench having a bottom, a first sidewall and an opposite second sidewall;
- forming a modulating layer on the first and second sidewalls of said trench;
- forming a blocking layer on said modulating layer on said first and second sidewalls of said trench;
- removing said blocking layer from said modulating layer on said second sidewall of said trench;
- forming a leakage stop implant in said substrate under a less than whole portion of the bottom of said trench, a first side of said leakage stop implant self-aligned to said blocking layer on said first sidewall of said trench and a second and opposite side of said leakage stop implant self-aligned to said modulating layer on said second sidewall of said trench;
- filling said trench with an insulator;
- and
- forming an N-well in said substrate adjacent to and in contact with said first sidewall, said N-well extending under said trench and forming an upper portion of an isolation junction with said leakage stop implant, said upper portion of said isolation junction located entirely under said trench.
A method of forming a semiconductor device with improved leakage control, comprising in the order recited:
- providing a semiconductor substrate having a top surface;
- forming a trench in said substrate, said trench having a bottom, a first sidewall and an opposite second sidewall;
- forming a blocking layer on said first sidewall of said trench;
- removing said blocking layer from said second sidewall of said trench;
- forming a leakage stop implant in said substrate under a less than whole portion of the bottom of said trench, a first side of said leakage stop implant self-aligned to said blocking layer on said first sidewall of said trench and a second and opposite side of said leakage stop implant self-aligned to said second sidewall of said trench;
- filling said trench with an insulator;
- and
- forming a P-well in said substrate adjacent to and in contact with said first sidewall, said P-welt extending under said trench and forming an upper portion of an isolation junction with said leakage stop implant, said upper portion of said isolation junction located entirely under said trench.
A method of forming a semiconductor device with improved leakage control, comprising in the order recited:
- providing an N doped semiconductor substrate having a top surface;
- forming a trench in said substrate, said trench having a bottom, a first sidewall and an opposite second sidewall;
- forming a modulating layer on the first and second sidewalls of said trench;
- forming a blocking layer on said modulating layer on said first and second sidewalls of said trench;
- removing said blocking layer from said modulating layer on said second sidewall of said trench;
- forming a leakage stop implant in said substrate under a less than whole portion of the bottom of said trench, a first side of said leakage stop implant self-aligned to said blocking layer on said first sidewall of said trench and a second and opposite side of said leakage stop implant self-aligned to the said modulating layer on said second sidewall of said trench;
- filling said trench with an insulator;
- and
- forming a P-well in said substrate adjacent to and in contact with said first sidewall, said P-well extending under said trench and forming an upper portion of an isolation junction with said leakage stop implant, said upper portion of said isolation junction located entirely under said trench.
Dependencies are inferred from the claim text.