Effects of Different Annealing Gases on Pentacene OTFT With HfLaO Gate Dielectric

Abstract

Pentacene organic thin-film transistors (OTFTs) with HfLaO high-κ gate dielectric were fabricated. The dielectric was prepared by a sputtering method and then annealed in N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> , or NO at 400 °C. The carrier mobility of the NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -annealed OTFT could reach 0.59 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> /V · s, which is higher than those of the other three devices. Moreover, the NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -annealed OTFT obtained the smallest subthreshold swing of 0.26 V/dec among them. Furthermore, 1/f noise measurement indicated that the NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> -annealed OTFT achieved the smallest 1/f noise. All these should be attributed to the improved interface between the gate dielectric and the organic semiconductor associated with the passivation effects of the NH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> annealing on the dielectric surface.