Avalanche transistor selection for long term stability in streak camera sweep and pulser applications.

摘要

We have identified the Motorola 2N4014 and 2N5551 and the Raytheon RS3944 as three transistor types that exhibit avalanche characteristics and have long term collector breakdown voltage stability superior to other transistors tested. Stability on all types has been improved by power burnin. An automatic avalanche transistor burnin tester has been constructed to allow power burnin of up to 1008 transistors at a time. The tester is controlled by an IBM Personal Computer (PC) and can be programmed to acquire data, unattended, at any desired rate or period. Data are collected from each run and stored on a floppy disk in ASCII format. The data analysis software, RS/1, was used for analysis and display. Data runs were typically 3 to 4 months long, with readings taken weekly. The transistors were biased into the avalanche or Zener region by individual current sources set to about 20% of the self-avalanche current for each type of transistor. Motorola, Zetex and National transistors were operated at 100 microamperes ((mu)A), and the Raytheon units were operated at 20 (mu)A. The electric field causes migration of material in the high field region at the surface near the collector-base junction, creating the voltage instability. 7 refs., 9 figs., 1 tab. (ERA citation 16:001232)