Effect of the technology of implanting nitrogen into buried oxide on the radiation hardness of the top gate oxide for partially depleted SOI PMOSFET
埋氧注氮工艺对部分耗尽SOI PMOSFET顶栅氧的辐射硬度的影响

The effect of implanting nitrogen into buried oxide on the top gate oxide hardness against total irradiation does has been investigated with three nitrogen implantation doses (8×1015, 2×1016 and 1×1017cm-2) for partially depleted SOI PMOSFET. The experimental results reveal the trend of negative shift of the threshold voltages of the studied transistors with the increase of nitrogen implantation dose before irradiation. After the irradiation with a total dose of 5×105rad(Si) under a positive gate voltage of 2V, the threshold voltage shift of the transistors corresponding to the nitrogen implantation dose 8×1015cm-2 is smaller than that of the transistors without implantation. However, when the implantation dose reaches 2×1016 and 1×1017cm-2, for the majority of the tested transistors, their top gate oxide was badly damaged due to irradiation. In addition, the radiation also causes damage to the body-drain junctions of the transistors with the gate oxide damaged. All the results can be interpreted by tracing back to the nitrogen implantation damage to the crystal lattices in the top silicon.