Surface and sub-surface thermal oxidation of ruthenium thin films

Research output: Contribution to conferencePoster

Abstract

For next generation Extreme UV photolithography, multilayer coatings may require protective capping layers against surface contamination. Ruthenium, as a low-oxidation metal, is often used as a reference material. The oxidation behaviour of Ru thin films has been studied using X-ray reflectometry (XRR) and Atomic force microscopy (AFM). XRR is sensitive to the in-depth electron density distribution and as such to the formation of ruthenium oxides. In-situ XRR during atmospheric oxidation reveals formation of a low density RuOX layer near the surface, followed by sub-surface formation of a high density RuOX layer. Surprisingly, the ratio between RuOX formation and Ru consumption is only 1.2, in contrast to the value of 2.3 reported in literature. AFM studies show that the “missing” RuOX is found in surface agglomerates that grow with increasing oxidation temperature and duration. These agglomerates appear around 200˚C, consistent with RuO2 nucleation and growth reported in literature.
Original languageEnglish
Pages-
Publication statusPublished - 21 Jan 2014
EventPhysics@FOM Veldhoven 2014 - Veldhoven, Netherlands
Duration: 21 Jan 201422 Jan 2014

Conference

ConferencePhysics@FOM Veldhoven 2014
CountryNetherlands
CityVeldhoven
Period21/01/1422/01/14

Keywords

  • METIS-303765

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    Coloma Ribera, R., van de Kruijs, R. W. E., Zoethout, E., Yakshin, A., & Bijkerk, F. (2014). Surface and sub-surface thermal oxidation of ruthenium thin films. -. Poster session presented at Physics@FOM Veldhoven 2014, Veldhoven, Netherlands.