On-chip picosecond time-domain measurement of silicon bipolar transistor characteristics using integrated GaAs photoconductive devices

Picosecond time-domain measurements of silicon bipolar transistors have been performed using thin-film GaAs photoconductive switches integrated on-chip. Low temperature MBE (molecular beam epitaxy) growth techniques were used to fabricate the GaAs-on-silicon structures. These devices produced 5 ps full width at half maximum (FWHM) electrical pulses when excited by high-speed laser pulses. Results of using these optical switches to characterize 4 GHz bipolar transistors are presented. It is noted that the technique used here allows local testing of high-speed devices with a minimum for on-chip parasitics. Precise control of sampling using variable-length optical paths (off-chip) are not only convenient but isolate the device from the measurement set-up.<>