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

Nano Lett. 2024 Dec 20. doi: 10.1021/acs.nanolett.4c04701. Online ahead of print.

Abstract

Targeting high-performance computing at cryogenic temperatures, we report back-end-of-line (BEOL)-compatible p-type Te-TeOx 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 (VDD) at room temperature. At cryogenic temperatures, the CMOS inverter exhibits significantly enhanced performance, achieving a voltage gain of 233 at a VDD of 2 V with a wide noise margin of 86%. Even at an ultralow VDD of 0.5 V, the CMOS inverter maintains solid performance with an exceptionally low power consumption of <60 pW.

Keywords: CMOS inverters; cryogenic temperatures; indium tin oxide (ITO); oxide semiconductor transistors; tellurium (Te).