Capacitance Boosting of Antiferroelectric‐Hf0.2Zr0.8O2/Al2O3 Blocking Layer Using Y2O3 Interfacial Layer for Charge Trap Flash Memory

A Y 2 O 3 interfacial layer is introduced to enhance the capacitance of the blocking layer stacked with antiferroelectric (AFE)‐Hf 0.2 Zr 0.8 O 2 (HZO) and Al 2 O 3 films in charge trap flash (CTF) memories. The ultrathin Y 2 O 3 film, with a target thickness of 2 nm, intermixes with the HZO film during the atomic layer deposition (250 °C) of HZO and promotes stabilization of the AFE tetragonal phase during postmetallization annealing (600 °C). Significant increases in the spontaneous polarization and maximum dielectric constant are achieved in the AFE‐HZO/Y 2 O 3 structure compared with the single‐layer AFE‐HZO structure. When Si 3 N 4 ‐based CTF devices are fabricated with an AFE‐HZO/Al 2 O 3 blocking layer utilizing the capacitance‐boosting effect, the introduction of a Y 2 O 3 interfacial layer results in performance enhancement in terms of memory window and programming efficiency. These improvements are attributed to the enhanced negative capacitance effect, which stems from the increased spontaneous polarization in the AFE‐HZO film due to Y 2 O 3 doping.