The deposition of amorphous indium zinc oxide (IZO) thin films on glass substrates with n-type carrier concentrations between and 3x10 20 cm -3 by sputtering from single targets near room temperature was investigated as a function of power and process pressure. The resistivity of the films with In/Zn of~ 0.7 could be controlled between 5x Ω- cm by varying the power during deposition. The corresponding electron mobilities were 4-18 cm 2.V -1 -s -1.The surface root-mean-square roughness was < 1nm under all conditions for film thicknesses of 200 nm. Thin film transistors with 1 µm gate length were fabricated on these IZO layers, showing enhancement mode operation with good pitch-off characteristics, threshold voltage 2.5V and a maximum transconductance of 6 mS/mm. These films look promising for transparent thin film transistor applications. Abstract Good and controllable electrical conductivity Wide transmittance window( nm) Higher chemical etching rate in comparison with indium tin oxide (ITO) Large work function Low deposition temperature Indium Zinc Oxide (IZO) Transparent conducting oxides extensively studied for transparent electrodes in optoelectronic devices –Application to solar cells, solar heat collectors, gas sensors, liquid- crystal displays, photodetectors, and light-emitting diodes SnO 2 doped In 2 O 3 (ITO), the most commonly used TCO for transparent electrodes –Search for alternatives as the scarcity of In imparts a high cost to ITO –Numerous studies on novel compound oxides composed of combinations of In, Zn, Cd, Sn and Ga In 2 O 3 : ZnO (IZO), a new alternative to ITO ? –Absence of toxic cadmium, use of inexpensive zinc –Larger work function, superior transmission in the µm range Motivations to TCOs  IZO layers deposited on glass substrate by rf -magnetron sputtering  High purity In 2 O 3 (ZnO) k targets  Deposition temperature : RT  Working pressure : 3-18mTorr  Sputtering power : W  Characterization of the IZO films by XRD, X-ray Microprobe, Hall measurement and AFM Experimental Results Conclusions Wantae Lim : Indium Zinc Oxide Thin Films Deposited by Sputtering at Room Temperature 1 Dept. of Materials Science and Engineering, 2 Dept of Chemical Engineering, 3 Dept. of Physics, University of Florida, Gainesville, Florida, USA 4 Electronics Division, US Army research Office, Research Triangle Park, North Carolina W. T. Lim 1, Y. L. Wang 1, F. Ren 2, D. P. Norton 1, I. I Kravchenko 3 and J. M. Zavada 4 and Stephen J. Pearton 1 Effect of IZO target power on the deposition rate of the IZO films, the resulting In/Zn ratio in the films and the root-mean-square (RMS) roughness (left) and also the carrier density, mobility and resistivity (right) - Deposition rate depended on IZO target power - RMS and In/Zn ratio were independent of sputtering power XRD θ-2θ scans of IZO films deposited at room temperature with different powers IZO films were amorphous over the entire set of deposition conditions Transmittance > 70% AFM scans on 200nm thick IZO films deposited at different powers RMS roughnesses were all well below 1 nm Advantage of amorphous films relative to poly or nanocrystalline films Effect of process pressure on the deposition rate of the IZO films, the resulting In/Zn ratio in the films and the root-mean-square (RMS) roughness (left) and also the carrier density, mobility and resistivity (right) - carrier density was fairly constant at ~10 20 cm deposition rate was inversely dependent on pressure XRD θ-2θ scans of IZO films deposited at room temperature with different pressure All films were amorphous I DS and gm as a function of V GS for a device with 12.5 nm SiN X gate E-mode with a threshold votage of ~2V Maximum transconductance ~ 6mS/mm On-Off ratio >10 5 µ FE ~ 12.5 cm 2 /V.s (Hall mobility ~ 15 cm 2 /V.s) IZO films with conductivity controlled over a range of more than six orders of magnitude have been deposited at room temperature on glass substrates by sputtering from a single IZO target. The electron mobility in the films is typically in the range 4-18 cm 2 /V-s. These films looks promising for TFT applications on low cost substrates. The work is partially supported by DOE under grant DE-FC26-04NT42271 (Ryan Egidi), Army Research Office under grant no. DAAD and NSF (DMR , Dr. L. Hess).We thank MAIC staff for their help in the performance of this work. Acknowledgement