Reliability evaluation of MOCVD grown AlInAs-GaInAs-InP HEMTs

We report on the reliability evaluation of MOCVD grown single and double delta doped AlInAs-GaInAs-InP HEMTs. It is found that HEMTs with thin InP top surface layer provide high threshold voltage uniformity, and less thermal stress degradation compared to conventional AlInAs-GaInAs-InP HEMTs. Furthermore, hot electron stress measurements have been conducted on passivated and unpassivated HEMTs. A temporary negative shift in the threshold voltage for unpassivated HEMTs and permanent negative shift in the threshold voltage for passivated HEMTs has been obtained. The shift in the threshold voltage is related to the build-up of holes inside the Schottky layer (temporary) and/or at the semiconductor-passivation layer interface (permanent)