In order to improve the total-dose radiation har dness of the buried oxides(BOX) in the structure of separation-by-implanted-oxygen(SIMOX) silicon-on-insulator(SOI),nitrogen ions are implanted into the buried oxides with two different doses,2×10 15 and 3×10 15 cm -2 ,respectively.The experimental results show that the radiation hardness of the buried oxides is very sensitive to the doses of nitrogen implantation for a lower dose of irradiation with a Co-60 source.Despite the small difference between the doses of nitrogen implantation,the nitrogen-implanted 2×10 15 cm -2 BOX has a much higher hardness than the control sample (i.e.the buried oxide without receiving nitrogen implantation) for a total-dose irradiation of 5×104rad(Si),whereas the nitrogen-implanted 3×10 15 cm -2 BOX has a lower hardness than uhe control sample.However,this sensitivity of radiation hardness to the doses of nitrogen implantation reduces with the increasing total-dose of irradiation (from 5×104 to 5×105rad (Si)).The radiation hardness of BOX is characterized by MOS high-frequency (HF) capacitance-voltage (C-V) technique after the top silicon layers are removed.In addition,the abnormal HF C-V curve of the metal-silicon-BOX-silicon(MSOS) structure is observed and explained.
