REDUCED DOPING ADJACENT FIELD IMPLANT
Original Publication Date: 1987-Oct-31
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
A field implant is conventionally formed to prevent leakage between neighboring diffused regions of a silicon semiconductor substrate. For example, Fig. 1 shows very lightly P-doped substrate 10, with heavily N-doped diffused regions 12 and 14 separated by heavily P-doped field implant 16. Field oxide 18 is formed over implant 16 between diffused regions 12 and 14 for device isolation. Reducing device dimensions requires increasing the P-concentration necessary for implant 16 to prevent inversion or leakage around oxide 18. This high concentration decreases the breakdown voltage at junctions 20 and 22 and leads to narrow width effects. Therefore, device dimensions cannot be reduced below the level at which avalanche breakdown occurs.