P型栅增强型GaN功率开关器件的中子辐照效应

Neutron Radiation Effects of P-Gate Normally-Off GaN Power Switching Transistor

对采用P型栅增强型技术的GaN功率晶体管进行了反应堆1MeV等效中子辐照效应实验。结果表明,在注量为1.5×10^(15)cm^(-2)的中子辐照后,器件的阈值电压没有发生明显变化;栅压较大时,辐照后的饱和漏电流变小,这与沟道电子迁移率降低和二维电子气2DEG的退化有关;当漏极电压小于200V时,器件的关态漏电流明显增加,表明中子辐照重掺杂P型栅发生的载流子去除效应弱化了P型栅在零栅压下对沟道电子的耗尽,但器件栅极反向泄漏电流在辐照后没有变化,说明其对中子辐照具有一定的免疫能力。

Neutron radiation effects of a novel normally-off GaN power switching transistor known as GITs （gate injection transistors） were studied experimentally in this paper. The unbiased transistors were irradiated by 1 MeV neutrons produced by a reactor with the neutron fluence up to 1.5×10^15 cm^-2 . After irradiation, the threshold voltage of the transistor changes lightly, the drain saturation current decreases as a result of degradation of 2DEG, and the off-state drain current increases significantly when V ds is below 200 V, which implies that the carrier removal effect of P-gate of GITs decays the function of P-gate. Furthermore, experimental results indicate that the gate reverse leakage current of GITs remains unchanged. It is concluded that the displacement damage mechanism and neutron radiation effects of GITs are different from the conventional GaN HEMTs due to their sophisticated structures, and off-state drain current is the sensitive parameter to intense neutron radiation environment.