Low-voltage pentacene field-effect transistors based on P(S-r-BCB-r-MMA) gate dielectrics

One of the key issues in the research of organic field-effect transistors (OFETs) is the low-voltage operation. To address this issue, we synthesized poly(styrene-r-benzocyclobutene-r-methyl methacrylate) (P(S-r-BCB-r-MMA)) as a thermally cross-linkable gate dielectrics. The P(S-r-BCB-r-MMA) showed high quality dielectric properties due to the negligible volume change during the cross-linking. The pentacene FETs based on the 34 nm-thick P(S-r-BCB-r-MMA) gate dielectrics operate below 5 V. The P(S-r-BCB-r-MMA) gate dielectrics yielded high device performance, i.e. a field-effect mobility of 0.25 cm ²/Vs, a threshold voltage of -2 V, an sub-threshold slope of 400 mV/decade, and an on/off current ratio of ~10 ⁵. The thermally cross-linkable P(S-r-BCB-r-MMA) will provide an attractive candidate for solution-processable gate dielectrics for low-voltage OFETs.