Ferroelectricity of Hf0.5Zr0.5O2 Thin Films Free From the Influence of Electrodes by Using Al2O3 Capping Layers

Ferroelectricity of Hf0.5Zr0.5O2 thin films prepared by plasma-enhanced atomic layer deposition (PEALD) with andwithout TiN electrodes was demonstrated. Excellent ferroelectricity of Hf0.5Zr0.5O2 thin films was confirmed by both polarization versus voltage (P-V) and piezoresponse force microscopy (PFM) hysteresis loops. The 2P(r) value can reach as high as 53 mu C/cm(2) under a sweep voltage of 8 V with TiN top and bottom electrodes. By introducing Al2O3 capping layer (AOCL), the 2P(r) value of the sample can reach 47 mu C/cm(2) that is less sensitive to the annealing temperatures and electrode materials. At the same time, the leakage current is also significantly reduced. The typical P-V loops can always be observed for samples with different electrode materials or annealing temperatures. These results are beneficial to practical applications in nonvolatile memories and synaptic devices.

Automated summary

Ferroelectricity of Hf0.5Zr0.5O2 thin films prepared by PEALD was demonstrated. The introduction of an Al2O3 capping layer improved the stability of ferroelectricity and significantly reduced leakage current. These results are beneficial for the application in nonvolatile memories and synaptic devices.