The Effect of Molybdenum Grain Characteristics on Ferroelectric Al0.7Sc0.3N Film Properties

Owing to the high coercive field of ferroelectric AlScN films, ultrathin (< 10 nm) is required for ferroelectric AlScN memory applications. High quality ultrathin film growth depends on the deposition parameters and the surface condition of the bottom electrode. In this work we fabricated Al 0.7 Sc 0.3 N film on Mo electrode and found that the large and flat Mo (110) facet promoted heterogeneous nucleation of AlScN (0002) grains. On contrast, misaligned AlScN grains initialized in Mo grain boundary trench area. Our findings demonstrated the substrate impact on the AlScN film quality. Through bottom electrode texture and surface topography optimization, high quality ultrathin AlScN films can be obtained.