Influence of Stack Design on The Electrical Performance of HfZrO₂ Ferroelectric

Hafnium-zirconium oxide (HZO) ferroelectrics have been attracting growing interest in different memory applications owing to their complementary metal oxide semiconductor (CMOS) compatibility and scaling capability [1]. Unlike their perovskite and wurtzite ferroelectric counterparts, HZO retains an excellent leakage and decent ferroelectric response at very low thicknesses [2]. This work highlights the role of bottom and top electrodes on the electrical performance of thin film HZO such as remnant polarization, endurance, and leakage. Crystallinity, thickness, and roughness of the electrodes are found to play critical roles in improving the film quality, reducing the thermal budget, and ultimately improving the electrical response of HZO films. Wake-up free sub 100 Å thick HZO films with back-end-of-line compatible annealing conditions exhibiting high remnant polarization (2Pr ≈ 54 μC/cm²) and low leakage (10^-5 A/cm² at 1 MV/cm) are achieved. The trade-off between polarization and the coercive field is also discussed for achieving the desired ferroelectric performance for different memory applications.