In this work, hafnium oxide (HfO2) thin films are deposited on p-type Si substrates by remote plasma atomic layer deposition on p-type Si at 250 °C, followed by a rapid thermal annealing in nitrogen. Effect of post-annealing temperature on the crystallization of HfO2 films and HfO2/Si interfaces is investigated. The crystallization of the HfO2 films and HfO2/Si interface is studied by field emission transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and atomic force microscopy. The experimental results show that during annealing, the oxygen diffuse from HfO2 to Si interface. For annealing temperature below 400 °C, the HfO2 film and interfacial layer are amorphous, and the latter consists of HfO2 and silicon dioxide (SiO2). At annealing temperature of 450-550 °C, the HfO2 film become multiphase polycrystalline, and a crystalline SiO2 is found at the interface. Finally, at annealing temperature beyond 550 °C, the HfO2 film is dominated by single-phase polycrystalline, and the interfacial layer is completely transformed to crystalline SiO2.

In this study, aluminum-doped zinc oxide (Al:ZnO) thin films were grown by high-speed atmospheric atomic layer deposition (AALD), and the effects of air annealing on film properties are investigated. The experimental results show that the thermal annealing can significantly reduce the amount of oxygen vacancies defects as evidenced by X-ray photoelectron spectroscopy spectra due to the in-diffusion of oxygen from air to the films. As shown by X-ray diffraction, the annealing repairs the crystalline structure and releases the stress. The absorption coefficient of the films increases with the annealing temperature due to the increased density. The annealing temperature reaching 600 °C leads to relatively significant changes in grain size and band gap. From the results of band gap and Hall-effect measurements, the annealing temperature lower than 600 °C reduces the oxygen vacancies defects acting as shallow donors, while it is suspected that the annealing temperature higher than 600 °C can further remove the oxygen defects introduced mid-gap states.

Zinc oxide (ZnO) has drawn much attention due to its excellent optical and electrical properties. In this study, ZnO film was prepared by a high-deposition-rate spatial atomic layer deposition (ALD) and subjected to a post-annealing process to suppress the intrinsic defects and improve the crystallinity and film properties. The results show that the film thickness increases with annealing temperature owing to the increment of oxide layer caused by the suppression of oxygen vacancy defects as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra. The film transmittance is seldom influenced by annealing. The refractive index increases with annealing temperature at 300–700 °C, possibly due to higher density and crystallinity of the film. The band gap decreases after annealing, which should be ascribed to the decrease in carrier concentration according to Burstein–Moss model. The carrier concentration decreases with increasing annealing temperature at 300–700 °C since the oxygen vacancy defects are suppressed, then it increases at 800 °C possibly due to the out-diffusion of oxygen atoms from the film. Meanwhile, the carrier mobility increases with temperature due to higher crystallinity and larger crystallite size. The film resistivity increases at 300–700 °C then decreases at 800 °C, which should be ascribed primarily to the variation of carrier concentration.