Improved Ferroelectric Properties in Hf_0.5Zr_0.5O₂ Thin Films by Microwave Annealing

In the doped hafnia(HfO₂)-based films, crystallization annealing is indispensable in forming ferroelectric phases. In this paper, we investigate the annealing effects of TiN/Hf_0.5Zr_0.5O₂/TiN metal-ferroelectric-metal (MFM) capacitors by comparing microwave annealing (MWA) and rapid thermal annealing (RTA) at the same wafer temperature of 500 °C. The twofold remanent polarization (2Pr) of the MWA device is 63 µC/cm², surpassing that of the RTA device (40 µC/cm²). Furthermore, the wake-up effect is substantially inhibited in the MWA device. The orthorhombic crystalline phase is observed in the annealed HZO films in the MWA and RTA devices, with a reduced TiN and HZO interdiffusion in MWA devices. Moreover, the MFM capacitors subjected to MWA treatment exhibit a lower leakage current, indicating a decreased defect density. This investigation shows the potential of MWA for application in ferroelectric technology due to the improvement in remanent polarization, wake-up effect, and leakage current.