Reliability of Silicon and Gallium Arsenide KA-Band Impatt Diodes

Fixed junction temperature operating tests have been conducted on two types of Ka-band IMPATT diodes: commercially available silicon devices, and gallium arsenide devices fabricated in-house. Median operational life of 106 hours at a junction temperature of 200°C has been predicted for the silicon devices, and the dominant failure mechanism has been identified as a localized penetration weakness of the platinum barrier layer. Experiments on the metallization layers of the GaAs devices have produced diodes with lower operating temperatures for a given added power, and longer life at the only operating temperature where the two devices have been compared, 350°C.