Investigation Of Acc Cci Tunnel Diodes

A tunnel-diode RF detector failed in DMSP system-level testing. An investigation was initiated by the prime contractor (Aerojet) with the assistance of The Aerospace Corporation. Destructive physical analyses carried out by Aerospace's Electronics Technology Center and by a commercial laboratory at the direction of Aerojet revealed a number of problems in the manufacturing process. Aerojet and Aerospace personnel visited the manufacturers of the detector module and the diodes and made recommendations that reduced or eliminated many of these difficulties. A search of the literature indicated that mechanical stress in the mesa region of the tunnel diodes was known to cause degradation and further suggested that elevated-temperature exposure would effectively screen out defective devices. Aerospace recommended such a screen. The implementation of this screen and the measures taken to clean up the manufacturer's process have greatly improved the reliability of the tunnel-diode detectors. The efficacy of the steps taken has been demonstrated clearly by comparison of electrical test results on the old and the improved components. Some time after our evaluation of the DMSP diodes, Aerospace was asked by NASA to examine diodes from the same vendor used for detectors on the AMSU/A mission. These diodes Tunnel diodes, Reliability.