Lowest I_OFF < 3×10⁻²¹ A/μm in capacitorless DRAM achieved by Reactive Ion Etch of IGZO-TFT

Abstract

We demonstrate that the retention of IGZO-based 2T0C devices is boosted by patterning the active module by RIE. While IBE generates Al redeposition on the device sidewalls creating an extrinsic conductive path, RIE enables a clean process which suppresses metal redeposition. With RIE, we achieve the lowest $\mathrm{I}_{\mathrm{O}\mathrm{F}\mathrm{F}}$ ever reported for 2T0C cells (<3× 1$0^{-21}$A/$\mu$m), and we successfully perform multi-level and multiply-accumulate operations enabling machine-learning applications. We also demonstrate device functionality down to $\mathrm{L}_{\mathrm{G}}$=25nm.