Analysis of thermal breakdown process with EVA film in room temperature region

In order to understand dc breakdown characteristics of ethylene-vinyl acetate copolymer (EVA) film at the room temperature, temperature distribution of film surface until the electric breakdown was observed by thermograph. Conduction current of EVA film was also measured and correlated with the thermograph. From the conduction current, hopping distance was estimated as 2.1/spl times/10/sup -9/ [m]. The potential barrier was calculated as 1.I [eV]. The heat generation was estimated by the equation of hopping conduction using hopping distance and potential barrier. The heat dissipation was also determined by thermal properties of the EVA film. A good agreement was found between the estimated heat balance and the observed temperature rise, suggesting that thermal breakdown takes place in room temperature region.