Plasma-enhanced chemical vapor-deposited organic dielectric layer for low voltage, flexible organic thin-film transistor

We investigated the electronic properties of pentacene-based organic thin-film transistors (OTFTs) incorporated with an organic dielectric layer (ODL) fabricated using a homemade, cold plasma-enhanced chemical vapor deposition system. Ar-carried trimethylaluminum monomer was introduced into an evaporator mixer controlled at 130 °C, and an ODL was deposited on Si- or indium tin oxide (ITO)-coated plastic substrate under N2 plasma. High radio frequency power (100 W)-deposited ODL (dielectric constant κ = 1.6) supported the fabrication of pentacene-based OTFT on Si substrate at low voltages (< 1.5 V). The decreased deposition time (10 min) reduced the film thickness of the ODL (95 nm), thereby increasing its dielectric constant to 3.3. We also deposited ODL on ITO-coated plastic substrate to fabricate a flexible OTFT with a mobility of 2.1 cm2/Vs and an on/off current ratio (Ion/Ioff) of 103.