Low-energy electron-excited nanoscale luminescence spectroscopy and secondary ion mass spectrometry were used to probe the defect states and chemical composition in as-deposited relatively thick (~100nm) HfO2 films and in SiO2/HfO2/SiO2/Si (5nm/15nm/5nm) heterojunction stacks grown by plasma enhanced chemical vapor deposition including as well changes in bonding and defects after high temperature (900C) annealing. Low-energy electron-excited nanoscale measurements of optical transitions in the thicker HfO2 films were attributed to defect-associated radiative transitions centered at approximately 2.7, 3.4, 4.2 and 5.5eV. These spectra exhibited significant changes in as-deposited films (300C) and after a 900C anneal in forming gas (N2/H2). Qualitative differences in low-energy electron-excited nanoscale spectra of stacked films were correlated with (i) formation of Hf silicate during deposition of the HfO2 film onto the SiO2 substrates in the as-deposited films, and (ii) a chemical phase separation of these Hf silicates into a heterogeneous mixture SiO2 and HfO2 nanocrystallites after the 900C anneal.

Low Energy Electron-Excited Nanoscale Luminescence Spectroscopy Studies of Intrinsic Defects in HfO2 and SiO2–HfO2–SiO2–Si Stacks. Y.M.Strzhemechny, M.Bataiev, S.P.Tumakha, S.H.Goss, C.L.Hinkle, C.C.Fulton, G.Lucovsky, L.J.Brillson: Journal of Vacuum Science & Technology B, 2008, 26[1], 232-43