Jiang Guangyuan, Cui Peng, Fu Chen, Lv Yuanjie, Yang Ming, Cheng Qianding, Liu Yang, Zhang Guangyuan
School of Information Science and Electrical Engineering, Shandong Jiaotong University, Jinan 250357, China.
Institute of Novel Semiconductors, Shandong University, Jinan 250101, China.
Micromachines (Basel). 2024 Sep 13;15(9):1148. doi: 10.3390/mi15091148.
The small-signal S parameters of the fabricated double-finger gate AlGaN/GaN high electron mobility transistors (HEMTs) were measured at various direct current quiescent operating points (DCQOPs). Under active bias conditions, small-signal equivalent circuit (SSEC) parameters such as and , and intrinsic parameters were extracted. Utilizing and the SSEC parameters, the effective electron velocity (νe-eff) and intrinsic electron velocity (νe-int) corresponding to each gate bias (V) were obtained. Under active bias conditions, the influence mechanism of V on νe-eff was systematically studied, and an expression was established that correlates νe-eff, νe-int, and bias-dependent parasitic resistances. Through the analysis of the main scattering mechanisms in AlGaN/GaN HEMTs, it has been discovered that the impact of V on νe-eff should be comprehensively analyzed from the aspects of νe-int and parasitic resistances. On the one hand, changes in V influence the intensity of polar optical phonon (POP) scattering and polarization Coulomb field (PCF) scattering, which lead to changes in νe-int dependent on V. The trend of νe-int with changes in V plays a dominant role in determining the trend of νe-eff with changes in V. On the other hand, both POP scattering and PCF scattering affect νe-eff through their impact on parasitic resistance. Since there is a difference in the additional scattering potential corresponding to the additional polarization charges () between the gate-source/drain regions and the region under the gate, the mutual effects of PCF scattering on the under-gate electron system and the gate-source/drain electron system should be considered when adjusting the PCF scattering intensity through device structure optimization to improve linearity. This study contributes to a new understanding of the electron transport mechanisms in AlGaN/GaN HEMTs and provides a novel theoretical basis for improving device performance.
在不同的直流静态工作点（DCQOPs）下测量了所制备的双指栅AlGaN/GaN高电子迁移率晶体管（HEMTs）的小信号S参数。在有源偏置条件下，提取了诸如 和 等小信号等效电路（SSEC）参数以及本征参数。利用 和SSEC参数，获得了对应于每个栅极偏置（V）的有效电子速度（νe-eff）和本征电子速度（νe-int）。在有源偏置条件下，系统地研究了V对νe-eff的影响机制，并建立了一个将νe-eff、νe-int和与偏置相关的寄生电阻相关联的表达式。通过对AlGaN/GaN HEMTs中主要散射机制的分析，发现应从νe-int和寄生电阻方面综合分析V对νe-eff的影响。一方面，V的变化影响极性光学声子（POP）散射和极化库仑场（PCF）散射的强度，这导致νe-int随V变化而变化。νe-int随V变化的趋势在决定νe-eff随V变化的趋势中起主导作用。另一方面，POP散射和PCF散射都通过对寄生电阻的影响来影响νe-eff。由于栅源/漏区与栅极下方区域之间对应于附加极化电荷（）的附加散射势存在差异，因此在通过器件结构优化调整PCF散射强度以提高线性度时，应考虑PCF散射对栅极下方电子系统和栅源/漏电子系统的相互影响。这项研究有助于对AlGaN/GaN HEMTs中的电子传输机制有新的理解，并为提高器件性能提供了新的理论基础。
