A novel technique to tailor the nitrogen profile in HfO/sub 2/ gate dielectric has been developed. Nitrogen was incorporated in the upper layer of HfO/sub 2/ using a reactive sputtering method, followed by a reoxidation anneal. The resulting dielectrics showed good thermal stability, boron penetration suppression, low interfacial trap density, plus lower hysteresis and improved MOSFET characteristics, in comparison to both non-nitrided and bottom nitrided (via Si-surface nitridation with NH/sub 3/) devices.
H. J. Cho, Kang, C. S., Onishi, K., Dr. Sundararaman Gopalan, Nieh, R., Choi, R., Dharmarajan, E., and Lee, J. C., “Novel nitrogen profile engineering for improved TaN/HfO/sub 2//Si MOSFET performance”, in International Electron Devices Meeting. Technical Digest (Cat. No.01CH37224), 2001.