R&D: Multi-Level Operation of Ferroelectric FET Memory Arrays for Compute-In-Memory Applications

2023 IEEE International Memory Workshop (IMW) has published an article written by Franz Müller, Sourav De, Maximilian Lederer, Raik Hoffmann, Ricardo Olivo, Thomas Kämpfe, Konrad Seidel, Fraunhofer Institute for Photonic Microsystems, Dresden, Germany, Tarek Ali, Halid Mulaosmanovic, Stefan Dünkel, Johannes Müller, Sven Beyer, GlobalFoundries, Dresden, Germany, and Gerald Gerlach, Technische Universität Dresden, Dresden, Germany.

Abstract: “We report on the multi-level-cell (MLC) operation of AND-connected ferroelectric FET (FeFET) arrays and their suitability for Compute-in-Memory (CiM) applications. The switching behavior and device variation of FeFETs in a passive AND array test-structure configuration is investigated. From this, we derive suitable write schemes and inhibit schemes capable of protecting any FeFET state. This enables the MLC operation of the AND arrays, yielding a performance suitable for CiM applications. We investigate the impact of the obtained bit-error-rate (BER) of 4% in inference-only operation, which shows only a 1% degradation from the floating-point (FP) accuracy for CIFAR-10 datasets with LeNET.“