Effect of gate barrier and channel buffer layer on electric properties and transparence of the a-IGZO thin film transistor

Different structures of a-IGZO (amorphous indium gallium zinc oxide) transparent thin film transistor (TTFT) were developed on glass substrate for study of gate barrier and channel buffer layer effects. The used gate barrier and the channel buffer layer are high energy band gap dielectric Al2O3 and the rapid thermally annealed ZnO film, respectively. With both gate barrier and channel buffer layers, the TTFT promoted ∼3 orders in on/off current ratio and reduced leakages current ∼800 times. Furthermore, the average transparence was also enhanced from 84% to 86.4% in the range of 500-800 nm wavelengths. The improvement mechanisms are interpreted with comprehensive models in details.