Nitrogen implantation in silicon substrate at fixed energy of 35keV and split dose of 10 14～5×10 14cm -2 is performed before gate oxidation.The experiment results indicate that with the increasing of implantation dose of nitrogen,oxidation rate of gate decreases.The retardation in oxide growth is weakened due to thermal annealing after nitrogen implantation.After nitrogen is implanted at the dose of 2×10 14cm -2,initial O 2 injection method which is composed of an O 2 injection/N 2 annealing/main oxidation,is applied for preparation of 3 4nm gate oxide.Compared with the control process,which is composed of N 2 annealing/main oxidation,initial O 2 injection process suppresses leakage current of the gate oxide.But Q bd and HF C-V characteristics are almost identical for the samples fabricated by two different oxidation processes.
