Ultra-high-speed current switch using 12.6 GHz silicon transistors

A silicon monolithic current switch emitter follower circuit with switching speed of 300 picoseconds has been fabricated. The transistors employed have the following characteristics: emitter size = 0.075 × 0.5 mil; the collector junction depth = 0.55 micron; metallurgical base width = 1200Å: gain bandwidth product = 12.6 GHz (at VCB=2.0 v); collector base capacitance = 0.08 pf: emitter transition capacitance = 0.045 pf. The dc and ac characteristics of the transistor are presented in detail. New measurement techniques are described, and oseillograms of switching response are included.