Layer structure variations of ultra-thin HfO2 films induced by post-deposition annealing

► Thermal annealing induces sizeable layer structure variation on 3 nm ALD HfO2 films. ► Crystallizes are monoclinic and orthorhombic at low annealing temperatures. ► Annealing causes films to crystallize into monoclinic phase at higher temperatures. ► XPS results showed formation of Hf silicate with increasing annealing temperatures. ► The existence of Hf silicate increases interfacial layer thickness in GIXRR analysis.