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US 5,489,543 AGranted
Method of forming a MOS device having a localized anti-punchthrough region
AssigneeUnited Microelectronics Corp.
InventorGary Hong
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Abstract
A method of forming a MOS device having a localized anti-punchthrough region, which is adjacent to but is not in contact with source/drain regions of the MOS device. A trench is formed by depositing a conducting layer on an oxide layer located on a channel region of the MOS device. The trench is used as a self-alignment mask for a subsequent implantation process to form the localized anti-punchthrough region.
Claims13
A method of forming a MOS device having a localized anti-punchthrough region, comprising the steps of:
- (a) providing a silicon substrate doped with impurities of a first conductivity type and having a predetermined channel region defined by a barrier layer;
- (b) forming an oxide layer on said channel region, and then forming a first conducting layer on said oxide layer and said barrier layer, to form a trench on said channel region;
- (c) applying ion implantation to implant ions of a first conductivity type through said trench into said substrate to form said localized anti-punchthrough region therein by using said first conducting layer as a mask;
- (d) forming a second conducting layer on said first conducting layer to fill up said trench;
- (e) removing said barrier layer to form a gate;
- and
- (f) applying ion implantation to implant ions of a second conductivity type into said substrate to form source/drain regions.
4 more elements
Dependencies are inferred from the claim text.