ACCELERATED LIFE TESTING AND FAILURE ANALYSIS OF SINGLE-STAGE MMIC AMPLIFIERS

Single stage monolithic microwave integrated circuit (MMIC) amplifiers have been high temperature accelerated life tested under dc + RF bias ing conditions. Most of the circuits failed parametrically due to a gr adual decrease in RF output power. Failure analysis revealed localized reduction of the gate breakdown characteristics of the metal semicond uctor field effect transistor (MESFET). This was occurring through deg radation of the GaAs surface Si3N4 passivation layer interface in the channel region of the MESFET, resulting in a reduction in the number o f surface states. The few catastrophically failed MMIC's are believed to represent a special case of this degradation process which occurred very rapidly. In contrast to the transistor, the other components of the circuits were unchanged following life test.