Pentacene thin-film transistors with HfO2 gate dielectric annealed in NH3 or N2O

Pentacene-based organic thin-film transistor (OTFT) with HfO₂ as gate dielectric is studied in this work. The HfO₂ dielectric was prepared by RF sputtering at room temperature, and subsequently annealed in N₂O or NH₃ at 200degC. The OTFTs were characterized by IV measurement and 1/f noise measurement. The OTFTs show small threshold voltage and can operate at as low as 3 V. Results indicate that the OTFT annealed in NH₃ shows higher carrier mobility, larger on/off current ratio, smaller sub-threshold swing and smaller Hooge parameter than the OTFT annealed in N₂O. Therefore, NH₃-annealed HfO₂ is a promising gate dielectric for the fabrication of high-performance OTFTs.