Heavy ion and pulsed laser SET measurements in ultrahigh speed MSM GaAs photodetectors

Single Event Transient (SET) measurements using both focused MeV heavy ions and pulsed picosecond lasers are employed to examine the injection and spatial dependence of SETs in high speed GaAs MSM photodetectors. Ion track structure and its influence on the average electron-hole pair density result in space-charge effects which determine the SET duration and possible BER contamination over more than one decision cycle of a GHz modulation based communication system. Laser probing is used to confirm the existence of space-charge effects and scanned SET measurements using an MeV ion microbeam are used to examine the spatial dependence of SET formation. Finally, ISE-TCAD simulations are performed to examine signal generation under high-injection conditions where space-charge effects prevail.