Aluminum Scandium Nitride (AlScN) for Advanced Devices: Physical Mechanisms and Emerging Applications.

AlScN is an emerging semiconductor material that exhibits pronounced ferroelectric switching and enhanced piezoelectric responses through the incorporation of scandium (Sc) into aluminum nitride (AlN). These properties make AlScN a promising candidate for next-generation ferroelectric in-memory computing architecture and radio-frequency circuits. However, challenges arise when preparing high-quality epitaxial films with high Sc content, including insufficient ferroelectric endurance, interface instability, and leakage current, which collectively compromise device performance and reliability. This review provides a systematic overview of the ferroelectric and piezoelectric properties of AlScN with underlying physical mechanisms, highlights the challenges in material growth and device integration, and summarizes recent advances of emerging applications in piezoelectric devices, optoelectronic devices, ferroelectric memories, and high-electron-mobility transistors (HEMTs). Finally, perspectives are presented on future research directions, focusing on overcoming key barriers to device implementation. With ongoing advances in material optimization and system-level integration, AlScN presents broad prospects for energy-efficient computing and sensing hardware, accelerating the development of artificial intelligence (AI).