Enhanced GOI Degradation and Reliability Improvement of Nitrogen and Indium Co-Implant for Advanced Dual-Gate Oxide Application

Indium and nitrogen implant were used to form the NMOSFET retrograde channel and low-threshold thin-oxide devices respectively. These two impurities are implanted into the same MOSFET channel before gate oxidation for an advanced low cost DRAM technology. High dose of indium implant degrades the oxide integrity, and with the acceding of the nitrogen impurities, enhanced GOI (gate oxide integrity) degradation were observed such as inducing abnormal Fowler-Nordheim (F-N) leakages, increasing ratio of near zero BVd defects. These phenomena were verified in both our 200mm and 300mm baseline. Fluorine impurities can be used to heal the implant-induced damage and improve the reliability of the gate oxides