Pentacene-Thin Film Transistors with ZrO[sub 2] Gate Dielectric Layers Deposited by Plasma-Enhanced Atomic Layer Deposition

Abstract

The effect of the dielectric constant and surface roughness of gate dielectrics on the electrical performance of pentacene-thin-film transistor (TFT) was investigated using high-K ZrO 2 films deposited by plasma-enhanced atomic layer deposition. The dielectric constant of ZrO 2 (κ ZrO 2 ) was in the range of 15.6-33.0, and the surface roughness was increased with κ ZrO 2 in the presently reported devices. Threshold voltage and subthreshold swing were effectively reduced with increasing κ ZrO 2 and were remarkably low, with values of -0.42 V and 0.15 V/dec, respectively, when κ ZrO 2 = 33.0. To the contrary, the carrier mobility was determined by the surface roughness of ZrO 2 gate dielectrics.