The Effects of N₂O Plasma Treatment on the Device Performance of Solution-Processed a-InMgZnO Thin-Film Transistors

Abstract

In this paper, the effects of N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O plasma treatment (PT) at various temperatures on the performances of InMgZnO (IMZO) thin-film transistors (TFTs) were investigated. As a result, the TFTs with N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O plasma-treated (10 W) IMZO channel layers at 100° for 10 min showed five times higher linear field-effect mobility compared to the untreated IMZO. The N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O PT did not cause any significant changes to the crystal structure, surface roughness of the IMZO thin films. However, an X-ray photoelectron spectroscopy study confirmed that the oxygen-vacancy defect density of the channel layer decreases via the N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O PT with temperature increased, and the reduction of oxygen vacancies leads to a decrease of off-current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ). It was found out that the refractivity of the channel layer increases with PT temperature increased, and the improvement of the film density makes the on-current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> ) higher, resulting in high mobility and high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ratio. Our study suggests that moderate N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O PT temperature can be adopted to improve the device performances.