漏极注入HPM对高电子迁移率晶体管的损伤机理

Damage mechanism of the high electron mobility transistor induced by HPM from drain electrode

针对典型GaAs高电子迁移率晶体管(HEMT)低噪声放大器,利用半导体仿真软件Sentaurus-TCAD建立了HEMT低噪声放大器二维电热模型,考虑高电场下的载流子迁移率退化和载流子雪崩产生效应,分析了由漏极注入高功率微波(HPM)情况下器件内部的瞬态响应,通过分析器件内部电场强度、电流密度、温度分布随信号作用时间的变化,研究了其损伤效应与机理。研究结果表明,当漏极注入幅值17.5V、频率为14.9GHz的微波信号后,峰值温度随信号作用时间的变化呈现周期性"增加—减小—增加"的规律。在正半周期降温,在负半周期升温,总体呈上升趋势,正半周电场峰值主要出现在漏极,负半周电场峰值主要出现在栅极靠漏侧,端电流在第二周期之后出现明显的双峰现象。由于热积累效应,栅极下方靠漏侧是最先发生熔融烧毁的部位,严重影响了器件的可靠性,而漏极串联电阻可以有效提高器件抗微波损伤能力。最后,对微波信号损伤的HEMT进行表面形貌失效分析,表明仿真与试验结果基本相符。

A two-dimensional electro-thermal model of the typical HEMT was established by simulation software Sentaurus-TCAD. Mobility degradation in high electric field, Avalanche generate effect and self-heating effect were considered, by analyzing the distributions and variations of the electric field, the current density and the temperature, a detailed investigation of the damage effect and mechanism of high power microwave （HPM） on AIGaAs/GaAs pseudomorphic high-electron-mobility transistor （pHEMT） under the injection of14. 9 GHz equivalent voltage signals from the drain electrode was performed. The simulation results suggest that intrinsic excitation, avalanche breakdown, thermal breakdown all contribute to damage process, the temperature behaves as periodic ＂ increasing-decreasing- increasing” oscillation and the whole trend continuously increases with time and it decreasesduring positive half cycle and increases during negative cycle. The gate current density appears double peak phenomenon because avalanche breakdown and thermal excitation. Heat accumulation occurs during the negative half cycle and below the gate near the drain side ismost susceptible to burn-out. Meanwhile,the drain terminal series resistance can enhance the capability of the device to withstand microwave damage effectively.