To explore the role of hydrogen in radiation degradation of AlGaN/GaN high-electron-mobility transistors (HEMTs), the performance degradation of the hydrogen untreated and pretreated devices is compared under the exposure of carbon ions. The energy of carbon ions is chosen as 7.6 MeV, and the maximum fluence reaches $4 \times 10^{12}$ cm ⁻² . By electrical character measuring, it is found that the positive shift of the threshold voltage and the decrease of the transconductance occur after to the irradiation. Hydrogen pretreatment accelerates the shift of threshold voltage and the decrease of the transconductance. The threshold voltage of the device is almost unchanged under 1-MeV electron irradiations. This means that the displacement damage leads to the shift of the threshold voltage. The height of Schottky barrier hardly changes in the hydrogen pretreated devices, showing that the ionization defects such as the formation of interface states under the gate are not the main cause of device degradation. Deep level transient spectrum (DLTS) results show that the irradiations cause the increase of gallium vacancies, and the hydrogen pretreatment inhibits its formation. According to the first principle calculation, the existence of hydrogen in GaN layer can reduce the formation energy of and the number of charges of the defects. It is speculated that hydrogen atoms participate in the evolution of radiation defects, which changes the types and number of defects in the devices.

中文翻译：

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氢对 AlGaN/GaN HEMT 中辐射诱导位移损伤的影响

为了探索氢在 AlGaN/GaN 高电子迁移率晶体管 (HEMT) 辐射降解中的作用，比较了在碳离子暴露下氢未处理和预处理器件的性能下降。碳离子能量选择为7.6 MeV，最大注量达到 $4 \times 10^{12}$ 厘米 ^-2 . 通过电特性测量发现，辐照后阈值电压发生正移，跨导下降。氢气预处理加速了阈值电压的移动和跨导的降低。在 1-MeV 电子辐照下，器件的阈值电压几乎没有变化。这意味着位移损伤导致阈值电压的偏移。在经过氢预处理的器件中，肖特基势垒的高度几乎没有变化，表明栅极下界面态的形成等电离缺陷不是器件退化的主要原因。深能级瞬态光谱（DLTS）结果表明，辐照导致镓空位增加，而氢预处理抑制了其形成。根据第一原理计算，GaN层中氢的存在可以降低缺陷的形成能和电荷数。推测氢原子参与了辐射缺陷的演化，从而改变了器件中缺陷的类型和数量。