This paper presents a detailed investigation of the degradation of two (Pt/Au)–Al_0.2Ga_0.8N/GaN/Al₂O₃ high-electron-mobility transistor(HEMT) structures, denoted as HEMT1 and HEMT2, by capacitance–voltage (C–V), forward current–voltage (I–V), and capacitance deep-level transient spectroscopy (DLTS)measurements in the temperature range of 40–320K. The C–V measurements confirmed the Fermi level pinning in our structures. In addition, the C–V measurements showed abnormal behaviors such as residual capacitance variation, capacitance hysteresis, and pinch-off voltage shift. These parasitic effects are explained by the thermal activation of trap centers in the Al_0.2Ga_0.8N/GaN/Al₂O₃ HEMTs. Moreover, the consideration of the various current transport mechanisms and numerical adjustments of forward I–V curves showthat the tunnel effect assisted by defects is preponderant in our structures. Using the DLTS technique, we verified the existence of two hole traps, H1 and H2, in HEMT1 and HEMT2,respectively.They extended from the GaN layer to the (Pt/Au)–AlGaN interface.A detailed analysis of these results is presented.

本文详细研究了两种 (Pt/Au)–Al _0.2 Ga _0.8 N/GaN/Al ₂ O ₃高电子迁移率晶体管 (HEMT) 结构（表示为 HEMT1 和 HEMT2）的电容-电压退化( C–V )、正向电流–电压 ( I–V ) 和电容深能级瞬态光谱 (DLTS) 测量在 40–320K 的温度范围内。在C-V的测量证实了费米能级在我们的结构牵制。此外，C-V测量显示异常行为，例如残余电容变化、电容滞后和夹断电压偏移。这些寄生效应可以通过 Al _0.2 Ga _0.8 N/GaN/Al ₂ O ₃ HEMT中陷阱中心的热激活来解释。此外，考虑各种电流传输机制和正向I-V曲线的数值调整表明，缺陷辅助的隧道效应在我们的结构中占主导地位。使用 DLTS 技术，我们分别验证了 HEMT1 和 HEMT2 中两个空穴陷阱 H1 和 H2 的存在。它们从 GaN 层延伸到 (Pt/Au)-AlGaN 界面。提供了对这些结果的详细分析.