Low-Damage Processed and High-Pressure Annealed High-k Hafnium Zirconium Oxide Capacitors near Morphotropic Phase Boundary with Record-Low EOT of 2.4Å & high-k of 70 for DRAM Technology

Abstract

We present record-low equivalent oxide thickness (EOT) of 2.4 Å with a remarkable dielectric constant (K) of 64 at 4.1nm-thick hafnium-based films with no wake-up characteristics. In comparison to conventional HZO films, our remarkable achievement stems from the high-quality crystalline structure with less oxygen vacancies formed by a low-damage process, as evidenced by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) images and electron energy-loss spectroscopy (EELS) analysis. In addition, with high-pressure annealing (HP A), we were able to reduce the annealing temperature to 450°C leading to a decrease in leakage current (1. 5 order). Further, increasing the measurement temperature from 298K to 389K results in the high-K from 66 to 70, which is the theoretical limit of the K value of t-phase.