Reliability testing of GaAs MMICs

GaAs MMICs were reliability life tested under accelerated high temperature conditions while operating under normal bias conditions under RF drive. These circuits (EG6010 power amplifiers) were standard evaluation circuit (SEC) deliverables on the US Department of Defense ARPA MIMIC Program. The median life, t50, was found to be 1×10⁷ hours at a channel temperature of 140°C, with an activation energy of 1.4 eV. Failure analysis revealed that circuit degradation and burnout were the result of failure of the field effect transistors (FETs). Hot spots were found to occur at the FET fingers that were covered by air bridges and could not be plated with gold for better heat dissipation. Excess leakage currents at the hot spots were found to be responsible for circuit degradation and burnout