Ultrathin gate oxide grown on nitrogen-implanted silicon for deep submicron CMOS transistors

Nitrogen implantation on the silicon substrate was performed before the gat e oxidation at the fixed energy of 30 keV and with the split dose of 1.0 x 10(14)/cm(2) and 2.0 x 10(14)/cm(2). Initial O-2 injection method was appli ed for gate oxidation. The method is composed of an O-2 injection/N-2 annea l/main oxidation, and the control process is composed of a N-2 anneal/main oxidation. CMOS transistors with gate oxide thickness of 2 nm and channel l ength of 0.13 mum have been fabricated by use of the method. Compared to th e control process, the initial O-2 injection process increases the amount o f nitrogen piled up at the Si/SiO2 interface and suppresses the growth of g ate oxide effectively. Using this method, the oxidation retarding effect of nitrogen was enhanced. Driving currents, hot carrier reliability, and time -zero dielectric breakdown (TZDB) characteristics were improved.