ELECTRICAL-PROPERTIES OF MIM JUNCTIONS WITH ULTRA-THIN POLYIMIDE LANGMUIR-BLODGETT-FILMS

The electrical properties of MIM junctions with an ultrathin polyimide (PI) Langmuir-Blodgett film have been examined at a temperature from 20 to 300 K. For A1/PI/A1 junctions, native aluminum oxide makes a signiicant contribution to the electrical resistance of A1/PI/A1 junctions with an electrical resistance as high as 109 Ω mm2, even when the number of deposited layers is zero. For Au/PI/Au junctions, the current-voltage (I — V) characteristic shows the existence of metallic pathways when the number of deposited layers is n < 30, while the I — V characteristic shows the electrical conduction mechanism ruled by the tunneling theory when the number n ≳ 30. From the experimental results described above, it was concluded that PI ultrathin LB films become good electrical insulating barriers when the deposited LB films have a thickness of more than 12 nm. Further, breakdown voltage of the PI layers sandwiched between both aluminum electrodes and gold electrodes are also investigated. © 1990 IEEE