Hot-electron-induced degredation of high efficiency AlGaAs / InGaAs / AlGaAs PHEMTs

摘要

Hot - electron - induced degradation of high efficiency PHEMT was investigated. Compared to the MESFET, a similar decrease of open chanel current, small increase of near pinch - off current, increase of breakdown voltage and on - resistance were observed as a result of stress. For both types of devices hot electron injection into SiN passivation and hot hole injection into the buffer was responsible for degradation. No new GaAs / SiN interface traps were formed as a result of stress, therefore, formation of the bulk SiN traps was confirmed to be the physical mechanism of degradation. For PHEMT the (Stress) x (Lifetime) figure of merit was 1.3 A centre dot hr / cm which is one order of magnitude lower then that for MESFET. Lower SiN deposition temperature in PHEMT is partially responsible for it's worse hot-electron reliability compared to MESFET.