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.