Effect of Al2O3 insertion layer on ferroelectricity in HfO2/ZrO2 nanolaminates

Ferroelectric HfO2 with excellent scaling capability and good complementary-metal-oxide-semiconductor (CMOS) technology compatibility has triggered the interest in nonvolatile memories. Here, (HfO2-ZrO2)3/mAl2O3/ (HfO2-ZrO2)3 (m donate the Al2O3 (AO) thickness) nanolaminates with different AO thicknesses were fabricated using atomic layer deposition method. Ferroelectricity and reliability were investigated by varying AO thickness in the deposition process. The highest remnant polarization (Pr) of 23.87 mu C/cm2 is obtained in (HZO)3/1AO/(HZO)3 nanolaminate with 1 nm-thick AO dielectric layer. The leakage current can be decreased by 2-3 orders of magnitude with the increase of AO thickness. The performance enhancement is ascribed to the interfacial polarization because of the dielectric mismatch between AO and HfO2-ZrO2 (HZO) and high breakdown strength of AO. The insertion of lower-permittivity AO can effectively modulate the distribution of electric field in nanolaminates and achieves a significant improvement in reliability. Improved ferroelectricity and reliability in ferroelectric/dielectric/ferroelectric structure a new for the of HfO2-based ferroelectric memories with broader thickness