Surrounding Gate Vertical-Channel FET With a Gate Length of 40 nm Using BEOL-Compatible High-Thermal-Tolerance In-Al-Zn Oxide Channel

We have demonstrated, for the first time, a surrounding gate vertical-channel field-effect transistor (FET) with a gate length of 40 nm by introducing back-end-of-line (BEOL) process-compatible oxide semiconductor (OS) In-Al-Zn-O as a channel material. Fabricated FETs exhibited high scalability by excellent thermal stability (~420 °C) compared to conventional In-Ga-Zn-O-channel FETs, with high-mobility (12.7 cm
²
/V.s) characteristics. Furthermore, the vertical-channel FET also exhibited excellent reliability and stable operation without floating body effect. Endurance of over 10
¹¹
cycles was also demonstrated. Our work opens a pathway to realization of high-performance BEOL transistor for 3-D-large-scale integration (LSI) applications.