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DS: Dünne Schichten
DS 3: Schichteigenschaften I
DS 3.4: Talk
Monday, March 26, 2001, 11:45–12:00, S 5.1
AES and XPS study of thermally activated inter-diffusion in high K dielectric Pr2O3 deposited on Si — •Andriy Goryachko1,2, Jinping Liu1, Dietmar Krüger1, Jörg Osten1, Eberhard Bugiel1, and Rainer Kurps1 — 1IHP, Im Technologiepark 25, D-15234 Frankfurt (Oder), Germany — 2National Taras Schevchenko University of Kyiv, Volodymyrska 64, 01033 Kyiv, Ukraine
We have investigated the thermal stability of Pr2O3 films on Si substrate by means of Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). We show that Si starts to diffuse into the film between 600C and 700C and a mixture of Pr2O3 and SiO2 is formed. New dielectric materials with sufficiently high permittivity are neccessary for usage as future insulators in the gates of sub - 100 nm field-effect transistors (FETs) or dynamic random access memory (DRAM) capacitors. Pr2O3 is a promising candidate for such a high K dielectric with a dielectric constant of the crystalline material equal to 30. We have investigated the effect of thermal annealing up to 900C in high vacuum on a 12 nm thick Pr2O3 film on Si(100) substrate using AES and XPS. Our results demonstrate that no significant Si diffusion into the film takes place up to 600C. Diffusion only starts in the temperature range between 600C and 700C. The diffused Si forms SiO2 with O, which diffuses from the surface. The O is supplied from the sample residual environment. The Pr2O3 stochiometry stays intact and a mixture of the two oxides forms. We observe that the saturated Si concentration is approximately 10%. The mixture of the two oxides is stable at least up to 900C.