Effect of the pressure on the self healing breakdown phenomena in plasma polystyrene thin films

The effect of pressure on time lag to breakdown of plasma polystyrene thin films have been reported. It has been shown that at moderate pressures (P< 100 bars), the material can withstand higher fields, or at given field, time lags are longer. Moreover, a pressure over 600 bars leads to the disappearance of the self healing breakdown and the development of trees in plane parallel to the electrodes. It has been proposed that this behaviour is observed when the external pressure balance the pressure of gaseous species created in the breakdown canal.