Temperature Dependence in Coercive Field of Ferroelectric AlScN Integrated on Si Substrate

This work presents the temperature dependence in the coercive field $(\boldsymbol{E}_{\mathbf{c}})$ of ferroelectric Al0.8Sc0.2N integrated on Si substrate. This fabricated AlScN-based metal-ferroelectric-semiconductor (MFS) capacitor shows a remnant polarization $(\boldsymbol{P}_{\mathbf{r}})$ exceeding $\mathbf{143}\ \boldsymbol{\mu}\mathbf{C}/\mathbf{cm}^{\mathbf{2}}$ and $\boldsymbol{E}_{\boldsymbol{c}}$ of 8 MV/cm at 300 K. Furthermore, both the maximum $\boldsymbol{E}_{\mathbf{c}}\ \ (\boldsymbol{E}_{\mathbf{c},\ \ \mathbf{max}})$ and the concentrated $\boldsymbol{E}_{\mathbf{c}}\ \ (\boldsymbol{E}_{\mathbf{c},\ \ \mathbf{con}})$ exhibit a linear decrease with a temperature coefficient of - 0.0126 MV/cm.K as the temperature increases. These results provide a reference for the prediction of variable temperature in wurtzite ferroelectric memory.

I. Introduction

The nitride wurtzite ferroelectric materials represented by III-V AlScN have a significant application prospect in the field of ferroelectric nonvolatile memory due to their quasi-single crystal, substantial remnant polarization, low thermal budget, large coercive field , superior thermal stability, and CMOS compatibility [1], [2]. For high-density, low-cost, and high read margin ferroelectric memory applications, the integration of ferroelectric AlScN films on semiconductor substrates becomes particularly critical, especially on silicon platform [3]–[5]. Our previous research work confirmed the feasibility of Si-based integrated ferroelectric AlScN films [5]. In addition, the high Curie temperature of AlScN makes it attractive for high-temperature applications, such as oil/gas exploration, aviation, and aerospace systems [6].