BEoL-integrated ferroelectric RAM for advanced semiconductor technology nodes

Ferroelectric memory technology has again moved into the focus of academic and industrial R&D due to the discovery of ferroelectricity in HfO2. This paper gives an overview of FRAM-type as well as FeFET-type memory cells with particular focus on integrating ferroelectric capacitors (FeCAPs) in the Back-End-of-Line (BEoL) of a semiconductor manufacturing process. For FRAM memory cells, different capacitor types and integration schemes are described as well as considerations for access transistors and high-density implementations are discussed. For FeFET memory cells, advanced node floating gate memory cells with BEoL integrated FeCAPs are presented, and also back-gate approaches are reviewed.