Abstract: Hafnium oxide based ferroelectric thin films have excellent ferroelectric properties and perfect compatibility with CMOS processes, which receive widespread attention in recent years.HZO interface with Ar plasma treatment can effectively improve ferroelectric performance, but they have a problem of low polarization intensity (~30 μC/cm²).In this study, we research the ferroelectric properties of TiN/HZO/TiN/W structured devices which are the TiN/HZO interface treatment by Ar plasma with different powers (50W, 100W, 150W, 200W).When applying 150W plasma to treat the bottom electrode TiN, the ferroelectric performance of the device is optimalas.It can increase the twice remnant polarization(2Pr) from ~27 μC/cm² to ~44 μC/cm², and also reduce the electric field from ~1.7 MV/cm to ~1.37 MV/cm.Then, we find that Ar plasma treatment not only that inhibits the growth of monoclinic phase, but also increases the proportion of orthogonal phase (from ~66% to ~88%), which can improve the ferroelectric performance.In addition, the C-V curve of the Ar plasma treatment device shows a“butterfly” shape, and its relative dielectric constant increases to around 55, which greatly improves the device performance.