Energy-Efficient Annealing Process of Ferroelectric Hf_0.5Zr_0.5O₂ Capacitor Using Ultraviolet-LED for Green Manufacturing

Thermal annealing process plays an important role in the formation of ferroelectric phase in Hf0.5Zr0.5O2 (HZO) thin films. In this study, the annealing process of the HZO capacitors is demonstrated using ultraviolet (UV)-LED, for the first time. Since the absorptance of the HZO films with TiN electrodes is highest in UV region, the UV-LED annealing process is promising to achieve a much more energy-efficient annealing process than a conventional halogen lamp RTA method. It was experimentally confirmed that UV-LED annealing reduces the energy consumption by nearly half compared to the conventional method. The ferroelectric characteristics obtained by this method are comparable to those achieved by the halogen lamp RTA process at 400-450(degrees)C. Grazing incidence X-ray diffraction (GIXRD) pattern shows that no monoclinic phase is formed and only the tetragonal and orthorhombic phases are confirmed. It is also confirmed that there is the in-plane tensile stress remaining after the UV-LED annealing process, which is necessary for the formation of the ferroelectric orthorhombic phase.