Record RF Performance of Ultra-thin Indium Oxide Transistors with Buried-gate Structure

Ultra-thin indium oxide (In2O3) from several nanometers to sub-nanometer thick has recently been revealed as an excellent n-type semiconductor channel material for back-end-of-line (BEOL) compatible transistors due to its low thermal budget, low subthreshold swing (SS), high on current and Ion/Ioff ratio, and high mobility [1]–[3]. However, a critical question that has not yet been addressed is that of the maximum frequency at which these devices can operate, which will play a deciding role in their analog applications. This work reports for the first time the detailed radio frequency (RF) characterization of some of these In2O3 RF transistors scaling down to 150 nm channel lengths.