自热效应下P-GaNHEMT的阈值漂移机理

Threshold Shift Mechanism of P-GaN HEMT Under Self-Heating Effect

随着GaN功率应用朝着更高集成度与更高功率密度的方向发展,器件的自热效应及可靠性问题将变得更加严重。提出了一种开态漏极电流注入技术,模拟器件自热状态用以研究100 V P-GaN HEMT器件在自热效应下的可靠性问题。研究结果表明,应力中器件自热温度可达40~150℃,阈值电压在应力后发生0.2~0.8 V的显著正向漂移。进一步通过室温与高温下的器件恢复研究以及电热仿真分析,证明了栅下区域与栅漏接入区域的高温极值点增强了该区域的受主型电子陷阱俘获行为并改变了栅极处载流子输运,这是导致P-GaN HEMT在自热效应下阈值电压不稳定性的主要原因,并建立了相对应的物理机理模型。

With the higher integration and higher power density development of GaN power application,self-heating effect and reliability problems of devices will be more serious.An on-state drain current injection technique is proposed to study the self-heating induced instability in commercial 100 V P-GaN HEMT.The research results show that the device self-heating temperature during the stress can reach 40-150℃,and significant threshold voltage positive shift after the stress can reach 0.2-0.8 V.Characteristic recovery experiments at room temperature and high temperature and electrothermal simulation results reveal that the high temperature extreme points both in gate region and gate-to-drain access region enhance the acceptor traps behavior and change the carrier transport in the gate,which are responsible for the threshold voltage instability in P-GaN HEMT under the self-heating effect.The corresponding physical mechanism model is established.