Hafnium Oxide-Based Ferroelectric Devices for In-Memory Computing: Resistive and Capacitive Approaches

The integration of ferroelectric hafnium oxide (HfO2) into semiconductor device structures has been a breakthrough in the development of state-of-the-art in-memory computing (IMC) technology. The high compatibility of ferroelectric HfO2 with backend-of-the-line (BEOL) as well as conventional complementary metal-oxide-semiconductor (CMOS) process technologies enables the development of highly efficient embedded IMC applications. In this work, we consider both resistive and capacitive approaches to the realization of IMC-compatible devices using ferroelectric HfO2. Process optimization and device integration concepts based on ferroelectric HfO2 are presented in this context. This Spotlight on Applications also reviews the reliability and reproducibility of HfO2-based ferroelectric devices. IMC architectures involving resistive systems are well established and mature. We discuss the capabilities and remarkable progress toward the integration of memristive ferroelectric HfO2 devices in these IMC architectures. Special attention is also given to the recently emerged ferroelectric capacitor (Fe-Cap)-based memcapacitive systems, which offer low-power consumption based on their open-circuit nature. Distinguished by their nondestructive readout capability, Fe-Caps stand out from other capacitive memories that require switching memory states and refresh cycles during access operations. Finally, we compare the electrical performance of Fe-Cap devices with other memristive technologies for IMC applications. This provides insights into the potential of ferroelectric HfO2-based devices for the development of highly efficient and advanced IMC systems.