Method for Fabrication of Bird's Beak-Less ROI Using Nitrogen Ion Implant and High Pressure Oxidation
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
A "bird's beak" is formed from lateral diffusion of oxygen under an oxide pad in conventional recessed oxide isolation (ROI) growth. This bird's beak can be reduced by decreasing the oxide pad, which removes silicon nitride from the silicon surface. This method, however, has been shown to result in low leakage-limited yield due to dislocations produced from high stress of nitride directly on silicon. Described is a method using low dose ion implantation of nitrogen into the single crystal silicon which serves to inhibit growth of ROI in non-isolation regions. This effect lasts [*] approximately 2 hours at 1000ŒC depending on implant dose and energy. To grow reasonable ROI without losing this barrier, it is necessary to use high pressure oxidation to decrease oxidation time from 6 hours to 1 hour.