Production Engineering Measure (Pem) for Transistor, Pnp, Silicon, Switching Type El-2n(X-12)

摘要

A small adjustment in epitaxial film resistivity was sufficient to raise BVsubCBO and BVsubCEO well within the PEM requirements for these parameters. As a result of the improved breakdown levels, the reverse leakage characteristics for the fourth engineering sample were an order of magnitude better than the third engineering group. The collector saturation voltage increased over the previous samples but 98 percent of the units were still below the 0.25 volt maximum. Delay and rise times did not meet the required minimum values of 3 and 4 nanoseconds, respectively. Typical values were t sub d = 3.4 ns and t sub r = 6.6 ns. Storage time averaged 8.8 ns and fall time was approximately 4.9 ns. Device current gain exerted a major influence on storage time. An attempt to improve current capability with a larger geometry was unsatisfactory due to switching speeds. The use of excess gold in the device structure appeared to produce lower storage time values, but also caused the overall current gain distribution to peak at a lower level. Molybdenum-gold proved to be unacceptable for a contact system on the small device area of the PEM transistor. An evaporation rate monitor system shows promise as a means of eliminating operator error during high volumn metalization procedures. The system offers an automation capability as well as close control of the evaporation rate. (Author)