Effects of thermal stress on the performance of benzocyclobutene-passivated In0.52Al0.48As/In0.53Ga0.47As high electron mobility transistors

Abstract

The effects of thermal stress on benzocyclobutene (BCB)-passivated In0.52Al0.48As/In0.53Ga0.47As high electron mobility transistors (HEMTs) were investigated and compared with those on silicon nitride and polyimide-passivated devices by DC, RF and microwave power characterization for the first time. In order to investigate the thermal stress effects on the devices passivated by different layers, DC and small-signal S-parameters were measured and characterized. Moreover, the variation of parameters, which are related to the RF performance of the devices, was analyzed based on small-signal parameters extracted during thermal stress. Compared to the polyimide-passivated devices, the BCB-passivated HEMTs exhibited more stable DC-g(m) and access resistance (R-d + R-s) as functions of thermal stress time. The BCB-passivated HEMTs also showed a device performance comparable to that of the silicon nitride-passivated HEMTs that were stabilized by stabilization bake. In addition, the BCB-passivated HEMTs demonstrated better microwave power characteristics before and after 100 It thermal stress, indicating that BCB is an attractive passivation layer for In0.52Al0.48As/In0.53Ga0.47As HEMTs.