Applied Surface Science, Vol.254, No.9, 2878-2881, 2008
Indium zinc oxide thin films deposited by sputtering at room temperature
The deposition of amorphous indium zinc oxide (IZO) thin films on glass substrates with n-type carrier concentrations between 10(14) and 3 x 10(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 similar to 0.7 could be controlled between 5 x 10(-3) and 10(4) Omega 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 < 1 nm under all conditions for film thicknesses of 200 nm. Thin film transistors with 1 mu m gate length were fabricated on these IZO layers, showing enhancement mode operation with good pitch-off characteristics, threshold voltage 2.5 V and a maximum transconductance of 6 mS/mm. These films look promising for transparent thin film transistor applications. (c) 2007 Elsevier B.V. All rights reserved.