Radiation damage in electronic devices is known to be influenced by physics, design, and materials system. Here, we report the effects of biasing state (such as ON and OFF) and pre-existing damage in GaN high electron mobility transistors exposed to γ radiation. Controlled and accelerated DC biasing was used to prestress the devices, which showed significant degradation in device characteristics compared to pristine devices under ON and OFF states after γ irradiation. The experiment is performed in situ for the ON-state to investigate transient effects during irradiation until the total dose reaches 10 Mrad. It shows that threshold voltage, maximum transconductance, and leakage current initially decrease with dosage but slowly converge to a steady value at higher doses. After 10 Mrad irradiation, the OFF-state device demonstrates larger R_ON and one order of magnitude increased leakage current compared to the ON-state irradiated device. The micro-Raman study also confirms that the ON-state operation shows more radiation hardness than OFF and prestressed devices. Prestressed devices generate the highest threshold voltage shift from −2.85 to −2.49 V and two orders of magnitude higher leakage current with decreased saturation current after irradiation. These findings indicate that high electric fields during stressing can generate defects by modifying strain distribution, and higher defect density can not only create more charges during irradiation but also accelerate the diffusion process from the ionizing track to the nearest collector and consequently degrade device performances.

中文翻译：

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氮化镓高电子迁移率晶体管在开、关和预应力条件下的伽马辐射

众所周知，电子设备的辐射损伤会受到物理、设计和材料系统的影响。在这里，我们报告了暴露于γ辐射的 GaN 高电子迁移率晶体管中偏置状态（例如开和关）和预先存在的损坏的影响。受控和加速的 DC 偏置用于对器件施加预应力，与γ辐照后处于 ON 和 OFF 状态的原始器件相比，器件特性显着下降。实验在原地进行对于 ON 状态，以研究辐照期间的瞬态效应，直到总剂量达到 10 Mrad。它表明阈值电压、最大跨导和漏电流最初随着剂量的增加而降低，但在较高剂量时缓慢收敛至稳定值。经过 10 Mrad 辐照后，OFF 状态器件表现出更大的 R _ON与通态辐照装置相比，漏电流增加了一个数量级。显微拉曼研究还证实，ON 状态操作显示出比 OFF 和预应力设备更高的辐射硬度。预应力器件产生从-2.85 到-2.49 V 的最高阈值电压偏移和两个数量级的漏电流以及辐照后降低的饱和电流。这些发现表明，应力过程中的高电场可以通过改变应变分布产生缺陷，而较高的缺陷密度不仅可以在辐照过程中产生更多的电荷，还可以加速从电离轨道到最近的收集器的扩散过程，从而降低器件性能。