A groundbreaking collaboration between the Kurt J. Lesker Company, Penn State University, MIT, and the Army Research Laboratory has successfully demonstrated ferroelectric switching in aluminum scandium nitride (AlScN) thin films using plasma-enhanced atomic layer deposition (PEALD).
This ferroelectric material combines the superior piezoelectric properties of AlN with ferroelectric behavior through scandium doping, showing breakthrough potential for nonvolatile memory, energy harvesting, MEMS, RF filters, and optical devices. The research demonstrates how eliminating oxygen and carbon contaminants—which traditionally exceed 1,000 ppm in metallic scandium sputtering targets—dramatically improves ferroelectric performance with sharper hysteresis loops and higher remnant polarization compared to conventional PVD processes.
The innovative supercycle approach alternates AlN and ScN subcycles with intermittent plasma processing to build highly stoichiometric, crystalline films with angstrom-level precision. This achievement is the result of a collaboration among experts in atomic layer deposition (ALD) from academia, industry, and a government research center. They utilized an advanced thin film deposition system, the Kurt J. Lesker ALD 150LX, that combines high- and ultra-high-vacuum design principles with advanced gas purification technologies, minimizing background impurities during the growth of films. This advanced platform enabled the team to achieve extremely low contamination levels, demonstrating the critical importance of ultra-high purity ALD capabilities for advancing ferroelectric materials and multicomponent nitrides. The breakthrough opens doors for next-generation 3D architectures and extreme aspect ratio devices essential for future electronics.
The Nanofabrication Lab at PSU offers access to ultra-high purity systems like those used in this collaborative research, providing an exceptional environment for materials innovation. These advanced plasma-enhanced ALD platforms enable conformal deposition on complex 3D structures with atomic-layer precision, positioning the facility as a premier resource for developing ferroelectric materials, multicomponent nitrides, and emerging thin film technologies. Those interested in accessing these world-class ALD capabilities can reach out to Dr. Bangzhi Liu (bul2@psu.edu) for guidance on process development, equipment access, and collaboration opportunities.