High performance flexible pentacene thin-film transistors fabricated on titanium silicon oxide gate dielectrics

Abstract

Pentacene thin-film transistors (TFTs) with a high dielectric constant gate insulator, titanium silicon oxide (TiSiO2), were fabricated on flexible polyethylene naphthalate films coated with indium tin oxide layers. In order to define the device characteristics, the thickness dependence of the gate dielectric properties was studied. The pentacene TFT with a 132-nm-thick TiSiO2 film showed high performance with a threshold voltage of −0.88V, an inverse subthreshold slope of 317mV/decade. From the current-voltage characteristics, the field-effect mobility was obtained, resulting in an impressive mobility of 0.67cm2∕Vs at an operating voltage as low as −5V.

Fully transparent flexible transistors built on metal oxide nanowires

“…TFTs fabricated by using organic semiconductors as the channel materials were widely investigated over the past years due to their materials variation, compatible to plastic substrate, good transparency, and good printable nature [8][9][10][11][12][13][14][15][16]. Organic TFTs (OTFTs) based on conjugated polymers, oligomers, or fused aromatics act as a viable alternative to traditional inorganic TFTs.…”

High Performance Organic Thin-Film Transistors and Nonvolatile Memory Devices Using High-Dielectric Layers

“…The low operation voltage of -2.4 V is due to the low V t and small sub-threshold swing. Such small sub-threshold swing is better than other reported values for flexible OTFTs , Kang et al, 2005Klauk et al, 2005;Mizukami et al, 2006;Na et al, 2007), which is due to the using high- HfLaO dielectric with a high capacitance density of 450 nF/cm 2 and a small EOT of 7.7 nm. The smaller mobility and I on /I off than similar OTFT fabricated on SiO 2 /Si were due to the rougher HfLaO surface of 4.2 nm measured by Atomic Force Microscopy (AFM), which was originated from the poor 9.0 nm surface roughness of low cost polyimide substrate (Kapton HPP-ST, Dupont).…”

Low-voltage-operating organic complementary circuits based on pentacene and C60 transistors

“…A high capacitance gate insulator is required to induce a large charge density at relatively low voltages. We have suggested a promising high-k material titanium silicon oxide (TiSiO 2 ), covered with SiO 2 layer, as a gate insulator for low-voltage-operating organic transistors [6,7]. Here, we employ a triple layer dielectric structure SiO 2 /TiSiO 2 /SiO 2 .…”

“…In general, carrier mobility of n-channel organic TFTs is much lower compared to those of p-channel transistors, which is a serious drawback for the development of organic complementary circuits. We have recently demonstrated high performance n-channel organic TFTs with field-effect mobility of~1 cm 2 /V s at an operating voltage of 5 V using an amorphous phase C 60 films [4], comparable to those of high performance p-channel pentacene TFTs with self-assembled monolayers (SAM) [5] or high dielectric constant (high-k) gate insulators [6,7]. The high mobility of n-channel TFTs yields complementary inverters and inverted-AND gates with fairly balanced operations in static characteristics [8,9].…”