Charge Collection in N-Type GaAs Schottky-Barrier Diodes Struck by Heavy Energetic Ions

Charge collection was measured as a function of reverse-bias voltage on GaAs Schottky-barrier diodes bombarded with heavy, energetic ions. Ion species included in the study were copper (57 MeV), chlorine (62 MeV), oxygen (18 MeV), and, to establish a baseline for comparisons, 241Am-decay alpha particles (5.4 MeV). Measurements of the drift component of collected charge are compared to funneling predictions based on the McLean-Oldham model. Results show that significant funneling occurs, in reasonable agreement with predictions for the lighter ions, but to a lesser extent than predicted for the heavier ions. Measurements at the higher biases show evidence of charge multiplication.