Experimental Characterization of Radiation-Induced Charge Sharing

Charge collection by multiple junctions is investigated using broadbeam heavy-ion and backside laser current transient measurements. The probability that significant charge is collected by more than one junction is greater for laser-generated events compared to heavy-ion measurements, which is attributed to the larger carrier generation track radius for the laser. With both sources, the probability of collecting charge on multiple junctions saturates at high charge generation levels. Effects caused by the interaction between junctions on the transient current waveforms is determined using position-correlated two-photon absorption laser analysis. The total charge collected for ion strikes between four adjacent junctions is shown to be approximately the same as for a direct strikes on a single junction, even though the incident ion does not pass through the depletion region of a biased junction.