Study of Highly Stable Nitrogen-Doped a-InGaSnO Thin-Film Transistors

Abstract

Herein, highly stable nitrogen (N) doped amorphous indium gallium tin oxide (a-IGTO) thinfilm transistors (TFTs) are prepared and the effects of N-doping are investigated. Compared with undoped a-IGTO TFTs, a-IGTO TFTs with 6 min N plasma treatment exhibit superior bias stress stability and a threshold voltages ( $V_{\mathrm {th}}$ ) closer to 0 V with almost no decline in mobility. In particular, the positive/negative bias stress threshold shift of N-doped a-IGTO TFTs is substantially reduced in both dark and light environment. The X-ray photoelectron spectroscopy analysis (XPS) and low frequency noise (LFN) are employed to study the mechanism of N-doping in a-IGTO TFTs. The XPS results indicate that appropriate amount of N-doping could enhance the bias stress stability and control the $V_{\mathrm {th}}$ efficiently by passivating the defects such as oxygen vacancy in a-IGTO films. The LFN results illustrate that the average interfacial trap density could be reduced by N-doping. Overall, the strategy presented here is effective for preparing a-IGTO TFTs with enhanced stability for potential applications in future optoelectronic displays.

Keywords

• Amorphous indium gallium tin oxide (a-IGTO)
• thin-film transistors (TFTs)
• N doping
• bias stress stability
• low frequency noise (LFN)