Super High-k Dielectric via Composition-Dependent Hafnium Zirconium Oxide Superlattice for Si Nanosheet Gate-All-Around Field-Effect Transistors with NH Plasma-Optimized Interfaces.

This paper presents an advanced dielectric engineering approach utilizing a composition-dependent hafnium zirconium oxide (HfZrO) superlattice (SL) structure for Si nanosheet gate-all-around field-effect transistors (Si NSGAAFETs). The dielectric (DE) properties of solid solution (SS) and SL HfZrO capacitors were systematically characterized through capacitance-voltage (C-V) and polarization-voltage (P-V) measurements under varying annealing conditions. A high dielectric constant (k-value) of 59 was achieved in SL-HfZrO, leading to a substantial reduction in equivalent oxide thickness (EOT). Furthermore, the SL-HfZrO dielectric was integrated into Si NSGAAFETs, with the interfacial layer (IL) further optimized via NH plasma treatment. The resulting devices exhibited superior electrical performance, including an enhanced ON-OFF current ratio (I/I) reaching 10, an increased drive current, and significantly reduced gate leakage. These results highlight the potential of SL-HfZrO as a high-k dielectric solution for overcoming EOT scaling challenges in advanced CMOS technology and enabling further innovation in next-generation logic applications.