Vertical oxide thin-film transistor with interfacial oxidation
Yeong Jo Baek, In Hye Kang, Sang Ho Hwang, Ye Lin Han, Min Su Kang, Seok Jun Kang, Seo Gwon Kim, Jae Geun Woo, Eun Seong Yu, Byung Seong Bae
Abstract
A vertical oxide thin-film transistor was developed with interfacial oxidation for low voltage operation. The gate metal was used as a spacer for the definition of the transistor's channel as well as the gate electrode. After definition of the vertical side wall, an IGZO (In-Ga-Zn Oxide) layer was deposited, followed by the interfacial oxidation to form a thin gate insulator. Ta was used for the gate material due to the low Gibbs free energy and high dielectric constant of tantalum oxide. A 15 nm tantalum oxide layer was obtained by the interfacial oxidation of Ta at 400 °C under oxygen atmosphere. The thin gate oxide made it possible to operate the transistor under 1 V. The low operation voltage enables low power consumption, which is essential for mobile application.