FAST CHARGE COLLECTION IN GAAS-MESFETS

Time-resolved charge collection measurements on 1 µm gate length digital GaAs MESFETs with a variety of energetic ions and picosecond laser pulses exhibit risetimes as short as 25 ps with pulsewidths of ~35 ps. Evidence is presented for the presence of three distinct-timescale charge collection processes, with time constants ranging from less than 25 ps to >1 µs. The effects of radiation damage on the charge-collection transients are presented, and the use of above band-gap picosecond laser excitation is demonstrated as a viable alternative to ion excitation for characterization of the dynamical response of high-frequency, radiation-sensitive devices to rapid charge deposition. © 1990 IEEE