p-Type Oxide Thin-Film Transistor with Unprecedented Hole Field-Effect Mobility for an All-Oxide CMOS CFET-like Inverter Suitable for Monolithic 3D Integration

The lack of low temperature processable, high-performance p-type oxide thin-film transistors (TFTs) limits their implementation in monolithically integrated back-end-of-line (BEOL) CMOS circuitries. In this work, we demonstrate a reactive magnetron-sputtered SnOx TFT with unprecedented hole field-effect mobility (μFE-hole) of 38.7 cm2/V·s, as well as an on/off current ratio (Ion/off) of 2.5 × 103 and lower subthreshold swing (SS) of 240.9 mV/dec when compared to reported works on p-type oxide-based TFTs. Material characterization correlated with the SnOx TFTs' electrical behavior elucidated the performance to the structural and compositional phase modulation of the SnOx thin films, modulated by O2 partial pressure during deposition and post-encapsulation annealing. By integrating the SnOx TFT with an IGZO TFT in both planar and stacked complementary FET-like form, we demonstrated a true oxide-based CMOS inverter, achieving one of the highest voltage gains of 57 and the lowest static power consumption down to 34 pW for both on and off states.