Monolithic Integration of Hybrid 2T0C DRAM/FeRAM With In-Situ Weight Transfer

Abstract

In this work, we demonstrate a monolithically integrated hybrid memory that stacks 2T0C DRAM on FeRAM and enables in-situ weight transfer within a single cell. Leveraging an MIS stack enabled by the monolithic all-ALD process, the 2T0C DRAM achieves an off-state leakage of $8.48\times 10^{-{14}}$ A/ $\mu $ m, retention >200 s, endurance $\gt 10^{{11}}$ cycles, and stress immunity >10000 s. Meanwhile, the all-ALD TiN/HZO/TiN FeRAM exhibits 2P ${}_{\text {r}} \gt 50~\mu $ C/cm², with projected retention >10 years and endurance $\gt 10^{{10}}$ cycles. Beyond co-integration, bidirectional in-situ transfer is realized without external circuits. Specifically, the large read window (high I_ON/I ${}_{\text {OFF}}\text {)}$ of the 2T0C DRAM programs its “0”/“1” states into distinct FeRAM polarization states via controlled polarization reversal, while the large displacement current during FeRAM switching is exploited to reload the FeRAM state back into the 2T0C DRAM. This hybrid cell enables in-cell bidirectional volatile–nonvolatile transfer, serving as a compact primitive for hybrid memory hierarchies, compute-in-memory, and energy-efficient AI with rapid updates and persistent storage.