COMBINED ENVIRONMENTAL TESTING OF SEMICONDUCTOR DEVICES REPORT NR.4

摘要

Preliminary experiments were conducted to select cable type, configuration, and instrumentation techniques for the primary experiment. The primary experiment yielded over 500 transient response measurements and △h FE on 2N559, 2N599, 2N708, and 2N914 devices.nResults of the primary experiment were analyzed and explanations of the observed phenomenon were developed. Collector-base leakage for each of the four devices increased during the radiation pulse and afterward returned to essentially its initial value. Magnitude of the peak leakage for silicon transistors was proportional to the square root of the absolute temperature.nWhen the leakage pulse was considered as added base drive, equivalent device gain was reduced during the pulse. The germanium units showed little permanent damage while the silicon units suffered a 15 percent -25 percent permanent gain reduction at the highest flux level. A lifetime damage constant of 1.4 X 106 Nvt-sec was obtained for P-type silicon. The damage constant appeared highly temperature sensitive, however, the dependence was not explicitly separated from the other terms of the damage equation.nThe saturation voltage of the germanium units decreased during the pulse as a result of the drive provided by the leakage current. No permanent trend was noted. The silicon transistors exhibited a small increase which followed the integrated dose.nAppendixed are results of preliminary experiments to select cable type, configuration, and instrumentation techniques for minimum radiation effects in telemetry cables. Effects were less in cables perpendicular to the radia¬tion source than in cables run radially. Balanced lines, avoidance of scatter¬ing, and preirradiation also helped.