Optical properties and band gap characterization of high dielectric constant oxides

详细信息	查看全文 | 推荐本文 |

• 作者：O. Fursenko ; ^{fursenko@ihp-microelectronics.com} ; J. Bauer ; G. Lupina ; P. Dudek ; M. Lukosius ; Ch. Wenger ; P. Zaumseil
• 关键词：Band gap ; Spectroscopic ellipsometry ; Reflectometry ; Dielectric constants ; High-魏 dielectrics ; Urbach energy ; Critical points
• 刊名：Thin Solid Films
• 出版年：2012
• 期刊代码：78_00406090
• 类别：ph
• 出版时间：1 May, 2012
• 卷：520
• 期：14
• 页码：4532-4535
• 文件大小：438 K

摘要

The optical characterization of amorphous and crystalline HfO₂, SrHfO₃, BaZrO₃, BaHfO₃, BaHf₀.₅Ti₀.₅O₃, SrTiO₃, Sr₂Ta₂O₇ and Ta₃Ti₂O_x high dielectric constant thin (15-50 nm) films was performed using a combination of spectroscopic ellipsometry and reflectometry in the photon-energy range 1.5-6.8 eV. The optical dielectric function, absorption coefficient, optical band gap energies E_g, Urbach energy E_u and 3D interband critical point energies were obtained from these studies. The E_g as well as the E_u of the dielectric materials are important for device performance. Indirect E_g was obtained for all materials investigated. Lower E_g tends to result in higher value of permittivity 魏. The results obtained deliver the necessary information for the selection of alternative high-魏 dielectrics with adequate E_u, E_g and 魏 values and additionally provide optical metrology for such films.