Kinetic Monte Carlo Simulations of AlScN Sputter Deposition

Their high coercive field and stable remanent polarization, coupled with their compatibility with complementary metal-oxide-semiconductor and proven industrial fabrication process, make AlScN thin films attractive for novel neuromorphic computing and memory devices, such as ferroelectric field-effect transistors and ferroelectric tunnel junctions.<br/> <br/>However, ultrathin ferroelectric layers needed for more storage in miniaturized devices often have low remanent polarization, or even no ferroelectricity. While a solution to this problem is urgently sought, the reason behind the phenomenon is still poorly understood.<br/> <br/>To determine if this issue has any microstructural underpinnings that can be addressed, we do kinetic Monte Carlo simulations of AlScN film deposition to check for any deviations from bulk microstructure that could account for film property degradation at low thickness. By varying simulation conditions, we also search for processing conditions minimizing such microstructural variation with the potential to preserve ferroelectric properties in ultrathin films.<br/> <br/>Our approach can be more generally applied to other materials to suppress any similar property degradation in the ultrathin regime.