Improved carrier mobility for pentacene TFT by NH3 annealing of gate dielectric

The carrier mobility of pentacene OTFT is enhanced by annealing its gate dielectric (SiO2) in NH3. The device has a field-effect mobility of 0.53 cm2/V s, with on/off current ratio of 106, and subthreshold slope of 2.4 V per decade. When compared with the control sample with N2-annealed SiO2 as gate dielectric, the mobility of the proposed pentacene OTFT is increased by over 50%. AFM micrographs show that the higher mobility should be due to the smoother gate-dielectric surface passivated by the NH3 annealing, and also larger pentacene grains grown on the smoother gate-dielectric surface.