Metal-ferroelectric-metal (MFM) capacitors with ferroelectric AlScN films were prepared by reactive sputtering using Ar/H₂/N₂ mixed gas. A reduction in dielectric constant, suppressed leakage current, and improvement in the breakdown field were obtained. Besides its higher coercive field (E_c), better reliability was obtained. The results indicate residual oxygen atom profiling is effective in designing a reliable AlScN film with reduced E_c.