Polymer Gate Dielectrics for High Performance Organic Field-Effect Transistors

ABSTRACTSolution-processed bottom-gate organic field-effect transistors (OFET) with different dielectric materials were produced and characterized. As the active semiconductor layer, regioregular poly(3-hexylthiophene) (rr-P3HT) was used. In addition to the dielectrics which have been reported in literature, various other materials with simple processing conditions were used as gate-dielectrics. Also, the dielectric properties of the polymeric layers were investigated in metal-insulator-metal capacitor structures, where the thicknesses of the films were exactly the same as they were in the OFETs. The specific volume resistivity and dielectric constant values determined were then used to explain the electrical behavior of OFETs. The devices having BCB, SU-8 and NOA74 as the dielectric layers exhibited the desired transistor characteristics, whereas the transistors with Avatrel dielectric did not, due to higher gate-leakages. As a result, SU-8 and NOA74 resins were proven to be good candidates for gate-dielectric usage in solution-processed all-polymer OFETs.