BEOL Three-Dimensional Stackable Oxide Semiconductor CMOS Inverter with a High Voltage Gain of 233 at Cryogenic Temperatures

Targeting high-performance computing at cryogenic temperatures, we report back-end-of-line (BEOL)-compatible p-type Te-TeO_<i>x</i> field effect transistors (FETs) deposited using a sputtering method that is cost-effective, large-scale manufacturable, and highly controllable. Combined with the indium tin oxide channel n-FETs employing a common gate and HfO₂ gate dielectric, BEOL three-dimensional stackable oxide semiconductor complementary metal oxide semiconductor (CMOS) inverters were further realized, demonstrating excellent threshold voltage matching, with a high voltage gain of 132 with a 2 V supply voltage (<i>V</i>_DD) at room temperature. At cryogenic temperatures, the CMOS inverter exhibits significantly enhanced performance, achieving a voltage gain of 233 at a <i>V</i>_DD of 2 V with a wide noise margin of 86%. Even at an ultralow <i>V</i>_DD of 0.5 V, the CMOS inverter maintains solid performance with an exceptionally low power consumption of <60 pW.