Synergic Effects Of Ionization Damage And Displacement Damage On Gate-controlled PNP Transistors

In this paper,the gate-controlled PNP bipolar transistor was studied.40 Me V Si ion and Co⁶⁰ ?-ray were chosen as the irradiation source to study the displacement effect,ionizing irradiation effect and displacement/ionization synergistic effect of PNP BJT.The electrical performance test and the gate scan test are used as analysis methods.The electrical performance and the changes of the micro-defects are combined to reveal the radiation effect mechanism of GPNP Transistors.The experimental results show that the displacement damage of the GPNP transistors is mainly caused by the displacement defects in the silicon bulk.The displacement defects can increase the recombination of carriers,resulting in a large increase in the base current,and a decrease in the current gain.The ionizing effectsare mainly caused by oxide charges and interface states in the emitter-base space-charge region when transistors are irradiated at high dose rate ionization.The interface states increase the surface recombination rate and reduce the current gain,while the oxide charges surpress the effect caused by interface states.The combined effects result in gain degradation increasing.Enhanced Low Dose Rate Sensitivity is also found in GPNP transistors.It's caused by the annealing of oxide charges and the enhancing of interface states.The enhancing of interface states plays a more important role in ELDRS.The ionization / displacement synergistic effect was studied.It was found that the generation of subsequent ionization defects was affected by the existing displacement defects,and the displacement defects were also annealed by ionizing radiation.In both high dose rateand low dose rate ionizing radiation,initial displacement defects can suppress the generation of oxide charges at the beginning of subsequent ionizing radiation.But displacement defects accelerate the production ofinterface states at high dose rate ionizing radiation,and the production ofinterface states atlow dose rate ionizing radiation.It shows the displacement defects can decreasing ELDRS by reducing the differences of interface states produced by different dose rate ionizing radiation.Both theories of ELDRS and the ionization/displacement synergistic effect aren't mature yet.In this paper,they are studied in detail and it's useful to designing and testing of space devices.