L5 System: Ultralinear Transistors

Ultralinear Transistors By F. A. D'ALTROY, R. M. JACOBS, J. M. NACCI, and E. J. PANNER (Manuscript received N o v e m b e r 9, 1973) A family of ultralinear npn transistors has been developed for use in the L5 coaxial-carrier system. These 3-GHz devices are characterized by extremely low distortion and noise figure. The transistor comprises an inter digitated base-emitter structure with a heavily doped base grid connected to the peripheral base metal contact. The emitter contact is overlaid on the base-emitter region. Contact metallurgy consists of a platinum silicide, titanium, platinum, and gold system. The transistor is a highly reliable device and meets all the performance requirements of the L5 system.