MFSFET with Ferroelectric HfN for Analog Memory Application

Ferroelectric HfO2 (Fe-HfO2) thin film has much attention for the Metal-Ferroelectrics-Si Field-Effect Transistor (MFSFET) application because of its Si compatibility [1], [2]. One of the critical issues of Fe-HfO2 is the SiO2 interfacial layer (IL) formation which degrades the memory device characteristics [1]–[3]. We have reported the ferroelectric HfN (Fe-HfN) formed on Si(100) which is crystallized in rhombohedral phase [4], [5]. The IL formation is expected to be suppressed in case of Fe-HfN compared to Fe-HfO2 from the thermodynamics point of view. In this paper, we have investigated the memory characteristics of MFSFETs utilizing Fe-HfN gate insulator. The effect of Si surface flattening process [6] was investigated to improve the interface property for analog memory application.