Structure and thermal stability of (Zr0.6Al0.4)O1.8 thin film on strained SiGe layer

Zr0.6Al0.4O1.8 dielectric films were deposited directly on strained SiGe substrates at room temperature by ultra-high vacuum electron-beam evaporation (UHV-EBE) and then annealed in N2 under various temperatures. X-ray diffraction (XRD) reveals that the onset crystallization temperature of the Zr0.6Al0.4O1.8 film is about 900 °C, 400 °C higher than that of pure ZrO2. The amorphous Zr0.6Al0.4O1.8 film with a physical thickness of ∼12 nm and an amorphous interfacial layer (IL) with a physical thickness of ∼3 nm have been observed by high-resolution transmission electron microscopy (HRTEM). In addition, it is demonstrated there is no undesirable amorphous phase separation during annealing at temperatures below and equal to 800 °C in the Zr0.6Al0.4O1.8 film. The chemical composition of the Zr0.6Al0.4O1.8 film has been studied using secondary ion mass spectroscopy (SIMS).