ELECTRICAL-CONDUCTION IN POLYIMIDE BETWEEN 20-DEGREES AND 350-DEGREES-C

Although conduction in polyimides at elevated temperatures has been widely reported, measurements at ordinary device temperatures have been less well documented. Quantitatively reproducible low field conduction measurements on two device-grade polyimides (PMDA-ODA, BTDA-ODA/MPDA) in the temperature range of 20-350 degree C and under dry conditions are reported. For PMDA-ODA the transport current has an activation energy (E//a) of 0. 5 eV below 175 degree C and 1. 5 eV above that temperature. For BTDA-ODA/MPDA the E//a is 0. 6 up to 250 degree C and 2. 1 eV above. This corresponds to a resistivity of 9 multiplied by 10**1**8 OMEGA -cm at 23 degree C and 3. 5 multiplied by 10**1**4 OMEGA -cm at 200 degree C for PMDA-ODA and 5 multiplied by 10**1**9 OMEGA -cm at 23 degree C and 5. 6 multiplied by 10**1**3 OMEGA -cm at 300 degree C for BTDA-ODA/MPDA. This work demonstrates that the low temperature behavior of polyimide cannot be extrapolated from high temperature measurements.