【摘要】 AlGaN/GaN高电子迁移率晶体管(HEMT)的栅特性会受到温度应力和电应力的影响.在高温栅偏置(HTGB)应力下，器件的栅特性会发生退化，如栅极泄漏电流增大.为了研究退化机理，分析了AlGaN/GaN HEMT在栅电压为-2 V时，250℃高温应力作用后的栅极泄漏电流机制.随着HTGB时间的增加，栅极泄漏电流持续增大，受到应力器件在室温下静置后栅极泄漏电流密度恢复约20%.结果表明，在正向偏置范围内，栅极泄漏电流是由热电子发射(TE)引起的.在反向偏置范围内，普尔-弗伦克尔(PF)发射在小电压范围内占主导地位.阈值电压附近的范围由势垒层中的陷阱辅助隧穿(TAT)引起；在大电压范围内，福勒-诺德海姆(FN)隧穿导致栅极发生泄漏.更多还原

【Abstract】 The gate characteristics of AlGaN/GaN high electron mobility transistors(HEMT) are affected by both temperature stress and electrical stress. Under the high temperature gate bias(HTGB) stress, the gate characteristics of the device are degraded, for example the gate leakage current is increased. To study the degradation mechanism, the mechanism of gate leakage current of AlGaN/GaN HEMT is analyzed after high temperature stress at 250 ℃ while the gate voltage is-2 V. With the increase of HTGB time, the gate leakage current increases continuously, and the gate leakage current density of stressed device recovers about 20% after standing at room temperature. The result shows that the gate leakage current is caused by thermionic emission(TE) in the forward bias range. In the reverse bias range, the Poole-Frenkel(PF) emission dominates in the small voltage range; In the range near the threshold voltage, the gate leakage current is caused by the trap assisted tunneling(TAT) in the barrier layer; In the large voltage range, the Fowler-Nordheim(FN) tunneling causes the gate leakage.更多还原