Low temperature atomic layer deposited Al-doped ZnO thin films and associated semiconducting properties

Abstract

Semiconducting Al-doped ZnO films were deposited by atomic layer deposition at low deposition temperatures of less than 100 degrees C and used to fabricate transistors. At deposition temperatures of less than 100 degrees C, the carrier concentrations of the Al:ZnO thin films were below 10(18) cm(-3), which corresponds to the transparent semiconducting oxide region. The reduced carrier concentrations at low deposition temperatures were attributed to the activation energy for carrier generation of similar to 0.7 eV. The devices characteristics of the semiconducting Al:ZnO consisted of mobilities of 1.95 cm(2)/V s and on-off ratios of over 10(6). At a positive gate stress of less than 10 V, the V-th shift of the Al:ZnO after 3000s was similar to 3 V, which is almost I order of magnitude lower than that of ZnO thin-film transistors.