Picosecond optoelectronic gating of silicon bipolar transistors by locally integrated GaAs photoconductive devices

Integration of picosecond GaAs photoconductive devices with silicon bipolar transistors to provide a high-performance optoelectronic gating element is demonstrated. GaAs photoconductive circuit elements (PCEs) with approximately 15-ps FWHM photocurrent transient responses have been integrated in base-drive circuit configurations. Results have demonstrated that approximately 70-ps FWHM pulses of >1 mA (5 V switching across 5 k Omega ) are possible using approximately 3-4 pJ of optical input at 820 nm. Furthermore, for the silicon bipolar transistor process which has a nominal f/sub t/ > 10 GHz, gating pulses with approximately 50-ps rise times, limited by the input optical pulse, have been observed.<>