Characteristics of ZnO thin film transistor prepared by two different methods

Abstract

AbstractWe succeeded the fabrication of bottom gate ZnO‐TFT on thermal oxidized n‐type Si substrate with the high‐resistivity ZnO active layer which was prepared by two different methods. The first preparation methods was LP‐CVD using the fibrous bis(acetylacetonato)‐zinc(II) (Zn(C5H7O2)2) and ozone(O3). The second one was RF(13.56 MHz) sputtering using a ceramic oxide target ZnO with a purity of 99.99% and 2 in. diameter. For all the ZnO films prepared by different methods, the ZnO (0001) peak at 2θ ≈ 34.4° was mainly observed. The films are polycrystalline with a hexagonal structure and a preferred orientation with the c‐axis perpendicular to the substrate.The ZnO‐TFT prepared by LP‐CVD shows electrical properties with a field effect mobility of 6 cm2/V s, an on to off ratio greater than 106, the off current of less than 10‐10A. Zn, O, Si elerment in the interface of ZnO and SiO2gate insulator were analyzed by using X‐ray photoelectron spectroscopy. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)