An accelerated ageing experiment on germanium p¿n¿p alloy-type transistors

A total of 660 transistors, purchased to a specification involving 100% initial testing, including damp heat cycling, have been placed on life test in groups with junction temperatures at 50, 60, 70, 80, 90 and 100°C, with power dissipations such as to give junction temperature rises of 0, 10 or 20°C above the temperature of the mounting, and with collector voltages of 0, ¿1, ¿4 and some of ¿20 volts. From the data so far accumulated and analysed it appears that most of the units will end their lives owing to excessive rise of collector leakage current, that there is no significant correlation between life and initial value of collector leakage current, and that positive correlation exists between deterioration of noise figure at 1 kc/s and deterioration of leakage current, the deterioration being markedly more common for units aged at the higher voltages.