Method of doping sidewall of isolation trench
AssigneeProMOS Technologies Inc.
InventorChao-Chueh Wu
Life of this patent
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Abstract
A method of doping sidewalls of an isolation trench is provided. A substrate having a trench thereon is provided. A blocking layer is formed within the trench such that the top surface of the blocking layer is lower than the top surface of the substrate. A sidewall doping process is performed to form a doped region in the substrate at the upper trench sidewall. The blocking layer is removed from the trench. Because the blocking layer prevent dopants from reaching the bottom half of the trench during the sidewall doping process, junction leakage at the bottom section of the trench is prevented.
Claims33
A method of doping sidewalls of an isolation trench, comprising the steps of:
- providing a substrate having a plurality of trenches thereon;
- forming a blocking layer in each trenches such that the top surface of the blocking layer is lower than the top surface of the substrate;
- performing a sidewall doping process to form a doped region in the substrate at only the upper trench sidewall;
- and
- removing the blocking layers within the trenches.
A method of doping sidewalk of an isolation trench, comprising the steps of:
- providing a substrate divided into a first region and a second region, wherein the substrate has a plurality of trenches in the first region and the second region;
- forming a blocking material layer over the substrate that completely fills the trenches;
- forming a mask layer over the substrate to cover the second region;
- performing an etching operation to remove a portion of the blocking material layer so that the top surface of the blocking material layer within the trenches in the first region is lower than the top surface of the substrate;
- performing a sidewall doping process to form a doped region in the substrate at only the upper trench sidewall;
- and
- removing the mask layer and to blocking material layer.
A method of doping sidewalls of an isolation trench, comprising the steps of:
- providing a substrate divided into a first region and a second region, wherein the first region and the second region of the substrate have a plurality of wenches thereon;
- forming a blocking layer over the substrate, wherein the blocking layer in the second region completely fills the trenches and covers the substrate surface whereas the blocking layer in the first region fills the trenches but exposes the top surface of the substrate, and the top surface of the blocking layer within the first region is lower than the top surface of the substrate;
- performing a sidewall doping process to form a doped region in the substrate at only the upper trench sidewall;
- and
- removing the blocking layer.
Dependencies are inferred from the claim text.