Low-Field Ferroelectricity in 10 nm AlBScN Thin Films

Abstract

Ferroelectric aluminum scandium nitride (Al1-xScxN, AlScN) offers CMOS-compatible integration but suffers from high coercive fields and leakage currents that hinder thickness scaling. Further reduction in thickness is essential for low-voltage embedded nonvolatile memory applications. Boron incorporation into AlScN (AlBScN) suppresses leakage current in films down to 40 nm, yet its ferroelectric characteristics in ultrathin films remains unexplored. This letter demonstrates robust ferroelectric switching in 10 nm sputtered AlBScN capacitors with a low coercive field and approximately two orders of magnitude lower leakage than AlScN. Notably, ferroelectric switching was observed at 2.2 MV/cm in capacitance-voltage measurements, and symmetric polarization reversal occurred near 4.6 MV/cm in positive-up-negative-down (PUND) measurements using 2 μs pulses. Moreover, Weibull analysis revealed a breakdown-to-coercive-field ratio (EBD/Ec) of ~2.2. These findings demonstrated AlBScN as a promising candidate for CMOS back-end-of-line (BEOL) compatible ferroelectric applications with improved energy consumption and reduced leakage current.

References in corpus (4)

• Ultrathin AlScN for low-voltage driven ferroelectric-based devices
• Al0.68Sc0.32N/SiC based metal-ferroelectric-semiconductor capacitors operating up to 1000 °C
• Toward accurate polarization estimation in nanoscopic systems
• Leakage Suppression Across Temperature in Al1-xScxN Thin Film Ferroelectric Capacitors through Boron Incorporation