In this work, the influence of the Fe and Fe/C co-doped buffer on the AlGaN/GaN HEMTs is systematically investigated and compared. Due to the pronounced Fe tail in the unintentionally doped layer of the Fe-doped buffer compared to the Fe/C co-doped buffer, and the utilization of a two-step C doping process in the Fe/C co-doped buffer, it results in effectively reducing leakage current and increasing breakdown voltage without sacrificing saturation current and peak transconductance. Meanwhile, the RF characteristics of the Fe/C co-doped buffer are also superior to the Fe-doped buffer. More importantly, Drain Transient Current measurements indicate that the current collapse in the Fe/C co-doped buffer is smaller than that in the Fe-doped buffer. Through simulation analysis, the reason was identified: In the near-channel region, the weaker Fe tail effect in Fe/C co-doped buffer leads to a lower acceptor trap ionization. When the concentration of C exceeds 1 × 1016 cm−3, the ionization of traps introduced by Fe is suppressed. Additionally, the two-step C impurity distribution in the Fe/C co-doped buffer design modulates the electric field and potential, reducing the effective range of the electric field and potential, thereby effectively reducing the trap effects. These results are highly meaningful for the design of high-power amplifier epitaxial structures.

中文翻译：

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具有 Fe 和 Fe/C 共掺杂 GaN 缓冲层的 AlGaN/GaN HEMT 的电特性和捕获效应


在本工作中，系统研究和比较了 Fe 和 Fe/C 共掺杂缓冲液对 AlGaN/GaN HEMTs 的影响。由于 Fe/C 共掺杂缓冲器相比，Fe 掺杂缓冲器的无意掺杂层中具有明显的 Fe 尾部，并且在 Fe/C 共掺杂缓冲器中采用了两步 C 掺杂工艺，因此可以在不牺牲饱和电流和峰值跨导的情况下有效降低漏电流并增加击穿电压。同时，Fe/C 共掺杂缓冲器的射频特性也优于 Fe 掺杂缓冲器。更重要的是，漏极瞬态电流测量表明，Fe/C 共掺杂缓冲器中的电流崩溃小于 Fe 掺杂缓冲器中的电流崩溃。通过仿真分析，确定了原因：在近通道区域，Fe/C 共掺杂缓冲液中较弱的 Fe 尾效应导致较低的受体陷阱电离。当 C 的浓度超过 1 × 1016 cm-3 时，Fe 引入的陷阱电离受到抑制。此外，Fe/C 共掺杂缓冲器设计中的两步 C 杂质分布调制了电场和电势，降低了电场和电势的有效范围，从而有效降低了陷阱效应。这些结果对于高功率放大器外延结构的设计具有重要意义。