Towards DRAM-Flash hybrid: Dual-speed low-voltage ferroelectric and charge memory

We present a one-transistor low-voltage hybrid ferroelectric and charge nonvolatile memory with dual switching speed. The device can be operated in two modes: 1) fast (10 ns-1 μs) DRAM-like mode with hours of retention, benefiting from ferroelectric (FE) switching, and 2) slow Flash-like mode (100 μs-1 ms) with long retention, resulting from charge injection. The combined FE and charge mechanisms offer additive memory window (MW) and cancelling retention fields. The hybrid memory was fabricated with PZT as the FE and Au nanocrystals (NCs) as charge storage nodes. Simulations incorporating FE switching dynamics were performed to corroborate the two-step program process as well as provide useful insight into hybrid design.