Radiation hardened semiconductor device
AssigneeAeroflex Colorado Springs Inc.
InventorsRichard L. Woodruff, Scott M. Tyson, John T. Chaffee, David B. Kerwin
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Abstract
A method for manufacturing a radiation hardened semiconductor device, having defined active region and isolation region. The isolation region containing an isolation material and active region containing a transition region between active and isolation region, sometimes denoted a bird's beak region. Wherein the transition region is implanted with germanium and boron, to prevent formation of leakage paths between active devices, or within an active device. The implanted area can be further limited to that area of the transition region that is adapted to be covered by a gate material, such as polysilicon.
Claims19
A method of manufacturing a radiation hardened semiconductor device including a substrate and epitaxial layer, wherein the epitaxial layer includes germanium, the epitaxial layer including an active region and an isolation region therein, the active region including an upper surface and the isolation region including an upper surface, the active region further including a bird's beak therein, comprising:
- depositing a first implant blocking layer on the upper surface of the isolation region and the upper surface of the active region;
- removing a section of said first implant blocking layer to expose at least a portion of the upper surface of the isolation region and the bird's beak;
- implanting the exposed portion of the isolation region and the bird's beak with a dopant;
- and
- removing said first implant blocking layer.
A method of forming a radiation hardened semiconductor device including a semiconductor substrate having an upper surface, comprising:
- depositing a masking layer on the upper surface;
- removing a portion of said masking layer to expose an isolation region, wherein a remaining portion of said masking layer defines an active region;
- implanting an upper surface of the isolation region with an implant comprising germanium;
- oxidizing said isolation region to form a field oxide, wherein a portion of said implant is incorporated into said field oxide, and wherein a portion of said field oxide underlies the active region, said portion of said field oxide known as a bird's beak;
- removing said remaining portion of said masking layer;
- applying a first implant blocking layer on said upper surface of the isolation region and an upper surface of the active region;
- removing a section of said first implant blocking layer to expose at least a portion of said upper surface of said isolation region and said bird's beak
- implanting said exposed portion of said isolation region and said bird's beak with a dopant;
- and
- removing said first implant blocking layer.
Dependencies are inferred from the claim text.