Stability of IZO and a-Si:H TFTs Processed at Low Temperature (200 ∘C)

Mixed-oxide thin-film transistors (TFTs) have been extensively researched due to their improved stability under electrical bias stress compared to amorphous-silicon TFTs. However, there are many challenges before they can reach the manufacturing stage. At the Flexible Display Center (FDC), Arizona State University, Tempe, we are developing a low temperature indium-zinc-oxide (IZO) TFT process suitable for flexible substrates such as polyethylene naphthalate (PEN). We report the effect of bias stress on the performance of these IZO TFTs and compare it with a-Si:H TFTs. We also report the design and fabrication of a 3.8-in QVGA electrophoretic display on PEN substrate using IZO TFT backplane.