The chemistry and thermal stability of HfTaO/Si interface by x‐ray photoelectron spectroscopy

Abstract

The chemistry and thermal stability of HfTaO/Si interface as a function of annealing temperature have been investigated by x-ray photoelectron spectroscopy. For the as-deposited sample, the formation of Hf-silicate bond is observed on Hf 4f corelevel spectra, which contributes to bulk HfO 2 and SiO 2 . Besides, the suboxide of tantalum (Ta +1 ) is formed at the interface at room temperature because of oxygen-deficient conditions. HfSi 2 , Hf x Si y O 4, and HfO 2 coexists in interfacial region at 850 C, meanwhile, an evidence for transforming from the Ta 1+ to tantalum oxide (Ta 5+ ) is verified.