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

Pentacene organic thin-film transistors (OTFTs) with HfLaO high-kappa gate dielectric were fabricated. The dielectric was prepared by a sputtering method and then annealed in N(2), NH(3), O(2), or NO at 400 degrees C. The carrier mobility of the NH(3)-annealed OTFT could reach 0.59 cm(2)/V . s, which is higher than those of the other three devices. Moreover, the NH(3)-annealed OTFT obtained the smallest subthreshold swing of 0.26 V/dec among them. Furthermore, 1/f noise measurement indicated that the NH(3)-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(3) annealing on the dielectric surface.