Surface temperature measurement and analysis of thermal breakdown with ethylene-vinyl acetate copolymer in room-temperature region

To understand the dc breakdown characteristics of an ethylene-vinyl acetate copolymer (EVA) film at room temperature, the temperature distribution of the film surface was observed by thermograph until electric breakdown occurred. The conduction current of the EVA film was also measured and correlated with the thermograph measurements. From the conduction current, the hopping distance was estimated as 2.1 nm. The internal potential barrier was calculated as 1.1 eV. The heat generation was estimated by the equation of hopping conduction using the hopping distance and inner potential barrier. The heat dissipation was also determined from the thermal proper-ties of the EVA film. A good agreement was obtained between the estimated heat balance and the observed temperature rise, suggesting that thermal breakdown takes place in the room-temperature region.