Radiation Hardened MOS Devices and Methods of Fabrication

A method, comprising:

• forming a field oxide layer above a substrate;
• patterning the field oxide layer to remove a portion of the field oxide layer above a moat region of the substrate and define a tapered edge surrounding the moat region;
• and
• forming a gate layer above the substrate and within the moat region;
• and
• patterning the gate layer to form an implantation mask defining an opening for accessing a diffusion region of a device, the implantation mask extending along a channel region of the device and abutting the tapered edge of the moat region to laterally surround the diffusion region.

A method, comprising:

• forming a field oxide layer above a substrate;
• patterning the field oxide layer to remove a portion of the field oxide layer above a moat region of the substrate and define a tapered edge surrounding the moat region;
• and
• forming a gate layer above the substrate and within the moat region;
• and
• patterning the gate layer to form an implantation mask defining an opening for accessing a diffusion region of a device, the implantation mask extending along a channel region of the device and abutting the tapered edge only along a device length direction such that the implantation mask is free of contact from the tapered edge along a channel width direction of the device.