p‑Type\nOxide Thin-Film Transistor with Unprecedented\nHole Field-Effect Mobility for an All-Oxide CMOS CFET-like Inverter\nSuitable for Monolithic 3D Integration

The lack of low temperature processable, high-performance\np-type\noxide thin-film transistors (TFTs) limits their implementation in\nmonolithically integrated back-end-of-line (BEOL) CMOS circuitries.\nIn this work, we demonstrate a reactive magnetron-sputtered SnO<sub><i>x</i></sub> TFT with unprecedented hole field-effect\nmobility (μ<sub><i>FE‑hole</i></sub>) of 38.7\ncm<sup>2</sup>/V·s, as well as an on/off current ratio (<i>I</i><sub><i>on/off</i></sub>) of 2.5 × 10<sup>3</sup> and lower subthreshold swing (SS) of 240.9 mV/dec when compared\nto reported works on p-type oxide-based TFTs. Material characterization\ncorrelated with the SnO<sub><i>x</i></sub> TFTs’\nelectrical behavior elucidated the performance to the structural and\ncompositional phase modulation of the SnO<sub><i>x</i></sub> thin films, modulated by O<sub>2</sub> partial pressure during deposition\nand post-encapsulation annealing. By integrating the SnO<sub><i>x</i></sub> TFT with an IGZO TFT in both planar and stacked\ncomplementary FET-like form, we demonstrated a true oxide-based CMOS\ninverter, achieving one of the highest voltage gains of 57 and the\nlowest static power consumption down to 34 pW for both on and off\nstates.