Optical characterization of HfO(2) thin films

0365941 - ÚPT 2012 RIV CH eng J - Journal Article
Franta, D. - Ohlídal, I. - Nečas, D. - Vižďa, F. - Caha, O. - Hasoň, M. - Pokorný, Pavel
Optical characterization of HfO(2) thin films.
Thin Solid Films. Roč. 519, č. 18 (2011), s. 6085-6091. ISSN 0040-6090. E-ISSN 1879-2731
Institutional research plan: CEZ:AV0Z20650511
Keywords : optical properties * ellipsometry * spectrophotometry * hafnium oxide * transition-metal oxide * Urbach tail
Subject RIV: JK - Corrosion ; Surface Treatment of Materials
Impact factor: 1.890, year: 2011

Hafnia films prepared onto silicon wafers at three substrate temperatures of 40, 160 and 280 degrees C are optically characterized utilizing the multi-sample method. The characterization uses the combination of variable angle spectroscopic ellipsometry and spectroscopic reflectometry within the spectral region 1.24-6.5 eV (190-1000 nm). The structural model of the HfO(2) films includes boundary nanometric roughness, thickness non-uniformity and refractive index profile. Spectral dependences of the film optical constants are expressed using a recently developed parametrized joint density of states model describing the dielectric response of both interband transitions and excitations of localized states below the band gap. It is shown that the observed weak absorption below the band gap does not correspond to the Urbach tail.
Permanent Link: http://hdl.handle.net/11104/0201067