Enhancement of ferroelectricity and homogeneity of orthorhombic phase in Hf 0.5 Zr 0.5 O 2 thin films

Abstract By adoption of a high permittivity ZrO 2 capping layer (ZOCL), enhanced ferroelectric properties were achieved in the Hf 0.5 Zr 0.5 O 2 (HZO) thin films. For HZO thin film with 10 Å ZOCL, the 2 P r value can reach as high as ∼43.1 μ C cm −2 under a sweep electric field of 3 MV cm −1 . In addition, a reduced coercive field of 1.5 MV cm −1 was observed, which is comparable to that of HZO with metallic CL. Furthermore, the homogeneity of ferroelectric orthorhombic phase in HZO films was observed to be clearly increased, as evidenced by nanoscale piezoelectric force microscopy measurements. These results demonstrate that ZOCL is very favorable for high performance ferroelectric HZO films and their future device applications.