Oxygen Radical Control via Atmospheric Pressure Plasma Treatment for Highly Stable IGZO Thin-Film Transistors

In this article, the atmospheric pressure plasma (APP) treatment method is proposed to solve the instability problem under a long-term electrical bias stress through the semiconductor surface treatment without degrading the excellent electrical characteristics of oxide thin-film transistors (TFTs). The high-energy oxygen radicals produced by the APP without a vacuum system affect the electrical properties by quickly and easily changing the chemical state of the oxygen-related bonds in the semiconductor. Consequently, the amorphous indium gallium zinc oxide TFTs with suitable APP treatment showed excellent bias stress stability and electrical characteristics in comparison with the APP-untreated oxide TFTs. The threshold voltage shift after the negative gate bias stress and positive gate bias stress duration of 1 h significantly reduced from -9.9 to -0.7 V and from +6.7 to +0.5 V, respectively. In addition, the average field-effect mobility remarkably enhanced from 10.8 to 14.8 cm(2)/Vs and the hysteresis behavior reduced from 0.31 to 0.12 V while maintaining the key parameters of TFTs such as subthreshold swing, ON/OFF ratio, and V-ON.