Two-Dimensional Numerical Simulation Of Radio Frequency Sputter Amorphous In-Ga-Zn-O Thin-Film Transistors

We reported on a two-dimensional simulation of electrical properties of the radio frequency (rf) sputter amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs). The a-IGZO TFT used in this work has the following performance: field-effect mobility (mu(eff)) of similar to 12 cm(2)/V s, threshold voltage (V-th) of similar to 1.15 V, subthreshold swing (S) of similar to 0.13 V/dec, and on/off ratio over 10(10). To accurately simulate the measured transistor electrical properties, the density-of-states model is developed. The donorlike states are also proposed to be associated with the oxygen vacancy in a-IGZO. The experimental and calculated results show that the rf sputter a-IGZO TFT has a very sharp conduction band-tail slope distribution (E-a = 13 meV) and Ti ohmic-like source/drain contacts with a specific contact resistance lower than 2.7 x 10(-3) Omega cm(2). (C) 2009 American Institute of Physics. [doi:10.1063/1.3234400]