Investigation of HfO<inf>2</inf> high-k dielectrics electronic structure on SiO<inf>2</inf>/Si substrate by x-ray photoelectron spectroscopy

Abstract

In this Letter, x-ray photoelectron spectroscopy (XPS) was used to investigate electronic structures of HfO2 with various thicknesses on SiO2/Si substrate prepared by atomic layer deposition with post deposition annealing of 600 C, which is compatible with a gate last process in the fabrication of complementary metal oxide semiconductor. The hafnium silicate formed between HfO2 and SiO2 interface plays a key role in generating an internal electric field. This can be attributed to the presence of oxygen vacancies (Vo) at the interface. The XPS binding energy shifts of O 1s, Si 2p, and Hf 4f spectra with increasing HfO 2 thicknesses can be explained by the presence of the internal field and differential charging effects. Electrical measurements of capacitor structures support the XPS result. © 2011 American Institute of Physics.