ENGINEERING SERVICES ON TRANSISTORS.
Rept. no. 18 (Quarterly progress rept. no. 6), 1 Jul-30 Sep 64,
BELL TELEPHONE LABS INC MURRAY HILL N J
Pagination or Media Count:
Planar germanium transistors with 0.2-mil-wide emitter stripes and a 0.1-mil base-contact-to-emitter separation were fabricated. Terminal f sub T values from 3 to 5 Gc, unilateral gain of 14 db at 1 Gc, and a gain figure of 32 db at 1 Gc were measured. Although this performance is comparable to that of good mesa units, an appreciably higher performance should be achievable with this structure. Base contact resistance is a primary limitation on performance of these devices. Beam-lead technology has potential application in microwave transistor assembly. Relatively large beam-lead parasitics 0.3 nh inductance, 0.1 pf capacitance-to-collector will cause some degradation in high-frequency performance of structures under current development but can probably be tolerated in the low-microwave region. More advanced beam-lead designs, in which the total inductance of lead and package is 0.15 nh or less, offer the possibility of achieving a performance equal or superior to that obtainable with conventional bonded-wire mounting. Increasing the disparity between emitter and collector barrier heights slowly degrades the collector efficiency when electron-phononinduced collector back-scatter in a hot-electron transistor is considered. Si is shown to be preferable to Ge and GaAs as a collector and appears capable of 85-percent collector efficiency with a collector field of 300,000 vcm. Author