Ferroelectric Properties of HZO Ferroelectric Capacitors with Various Capping Electrodes and Annealing Conditions

HZO has drawn a lot of attention because they are CMOS compatible and possess promising ferroelectric properties. It was reported that the ferroelectric properties of HZO have strong dependence on the selection of electrode materials [1]. It has been exhibited that HZO with W and Mo electrodes showed enhanced polarization [2]. On the other hand, TiN and TaN electrodes are highly interested in the CMOS compatible fabrication process. In this study, we fabricated ferroelectric HZO Metal-Ferroelectric-Metal (MFM) structures with the four electrode materials including TiN, W, Mo, TaN (i.e. MFM=TiN/HZO/TiN, W/HZO/W, Mo/HZO/Mo, TaN/HZO/TaN). We demonstrated the ferroelectric properties of these MFM structures at annealing temperature of 300℃, 400℃, 500℃, and 600℃. The orthorhombic phase of samples with different electrodes and annealing temperature were investigated by GIXRD. The trends in remanent polarization and the coercive field were compared by the P-E measurement. The DC leakage was also revealed and compared by the I-V test. Detailed microstructure analysis for the MFM capacitors were also conducted using SEM and AFM.