Precise patterning of large-scale TFT arrays based on solution-processed oxide semiconductors : a comparative study of additive and subtractive approaches

Abstract

Precise patterning of solution-processed oxide semiconductors is critical for cost-effective, large-scale, and high throughput fabrication of circuits and display application. In this paper, demonstration and comparison are made using the additive and subtractive patterning strategies to precisely fabricate wafer-scale thin film transistor arrays (1600 devices), which are based on high-quality solution-processed indium zinc oxide (IZO) and indium gallium zinc oxide (IGZO). The IZO and IGZO TFTs exhibit field-effect mobility up to 8.0 and 5.2 cm2 V−1 s−1 when using the additive method, whereas the highest mobility of 24.2 and 13.7 cm2 V−1 s−1 for IZO and IGZO TFTs is achieved when using the subtractive method. The X-ray photoelectronic spectroscopy studies and quantitative 2D device simulations together reveal that good device performance is attributed to moderate shallow donor-like states (providing electrons) from oxygen vacancy and few accepter-like states (trapping electrons) resulted from the dense structural framework of M-O bonds. After examining the uniformity and reliability of the devices, the solution-patterned inverters are demonstrated using negative-channel metal oxide semiconductors, which show full swing output transfer characteristics and thus provide a promising method for solution-based fabrications of circuits.