Effect of Insertion of Dielectric Layer on the Performance of Hafnia Ferroelectric Devices

Hafnia-based ferroelectric (FE) devices have attracted significant attention as nonvolatile memory devices due to their compatibility with complementary metal- oxide-semiconductor processes. Among them, the FE tunnel junction (FTJ) has been considered as the next-generation of nonvolatile memory devices owing to its neuromorphic characteristics and nondestructive read operation as well as the high-density integration. However, degradation of ferroelectricity in a thin hafnia film causes a reduced tunneling electroresistance (TER) ratio. In this work, we inserted a TiO2 layer into the metal-FE-metal capacitor to provide an asymmetric structure for FTJ operations and recorded the enhanced remnant polarization with enhanced ferroelectricity. In this study, a high 2P(r) value of 44.4 mu C/cm(2) and a notable TER ratio of 11.6 were observed for 6-nm thick hafnia films with 1-nm thick TiO2 films.

Automated summary

In this study, a high 2P(r) value of 44.4 mu C/cm(2) and a notable TER ratio of 11.6 were observed for 6-nm thick hafnia films with 1-nm thick TiO2 films, demonstrating the potential for enhanced ferroelectricity in FTJ operations.