Enhanced ferroelectric endurance in ScAlN by interfacial oxide reconstruction

Scandium-alloyed aluminum nitride (ScAlN) has emerged as a promising ferroelectric material for next-generation electronics, optoelectronics, photonics, and acoustics due to its high remanent polarization (Pr), tunable coercive field (Ec), and compatibility with GaN, Si, and complementary metal–oxide–semiconductor technologies. However, ScAlN devices have been limited by large Ec and poor endurance. In this work, we report a Ti-assisted surface oxide layer reconstruction approach to enhance the performance of ferroelectric ScAlN. Ti/ScAlN/GaN capacitors were fabricated and subsequently annealed to promote oxygen migration from the native ScAlON into the Ti electrode, forming an insulating TiOx interfacial layer. This reconstruction reduced the polarization switching field and improved device reliability. At an optimized annealing temperature of 400 °C, the capacitors exhibited endurance up to 6 × 108 cycles with Pr exceeding 60 μC/cm2. These results demonstrate a viable strategy for improving the endurance of ferroelectric ScAlN and underscore the importance of interfacial engineering for nonvolatile memory and neuromorphic computing applications.