Influence of BCB Protection on Irradiation Response of InP-Based HEMTs: A Comparative Study

This article investigates the influence of benzocyclobutene (BCB) passivation on the irradiation response of InP-based high electron mobility transistors (HEMTs). An abnormal behavior is observed, in which the threshold voltage is initially shifted negatively and then positively with proton fluence. Severe transconductance collapse and an increased breakdown voltage are observed at high proton fluence. RF characteristics exhibit a more robust radiation resistance compared to the dc characteristics. By conducting TCAD simulation, two defects responsible for the degradation behavior of threshold voltage are identified: the process-related traps activated by irradiation (donor) in the barrier and the surface states directly induced by irradiation (acceptor) on the gate-recess. Additionally, the effectiveness of BCB passivation in mitigating device degradation is demonstrated, resulting in a more stable threshold voltage and cutoff frequency. This improvement can be attributed to the reduced introduction rate of surface states on the gate-recess. This study provides valuable insights into the effects of proton irradiation on InP-based HEMTs and highlights the potential of BCB passivation for improving their radiation resistance.