Evaluation of the effect of the thermal cycling temperature on the conduction current in alumina substrates

Charging and discharging currents have been measured in an alumina substrate before and after thermal treatment consisting in applying thermal step of negative and positive values (¿20°C-50°C). Both transient and steady-state current have been analysed. The average applied voltage ranged from 0 to 5kV. Transient currents suggested a phenomenon generating space charges in the bulk of the material at high fields. Below the high field regime, ohmic and sub-ohmic regime are been identified. Anyway, it was obvious that the thermal treatment increased hugely the conduction current with a factor of almost two decades. No usually Schottky-type injection or tunnel-type was found from our measurements.