Sub-Nanosecond Detection of Heavy Ions Using Single-Crystal, Natural Type IIA Diamond

Abstract

The sub-nanosecond electrical transients induced by 5-MeV He+ and 10-MeV Si 3 + ions have been measured in single-crystal, natural type Ila diamonds. The detectors were fabricated into conductivity modulated devices and were incorporated into 50-f4 high bandwidth transmission line structures. The electrical signals were recorded with a system based on a 70 GHz random sampling oscilloscope with the total recording rise time of 18.6 ±:0.6 ps.Signal rise times are less than 70 ps and fall times are less than 200 ps for electric fields in the range 3.8x10 4 -lxl0 5 V/cm. The plasma time appears to play a key role in defining the initial stages of the charge transport because signal rise times are much greater than the recording system rise time, especially with the Si-ion excitation. Furthermore, incomplete charge collection is quite severe even at the highest applied electric fields due to the dominance of carrier trapping/recombination at the defect sites.