TY - JOUR A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Männ, Marion T1 - Ellipsometry and Standardization: Validation of Models - Key Issue for Reference Coatings and Non-ideal Samples N2 - Standardisation of ellipsometry is mainly based on three documents: pioneering work at NIST [1] on film standards, a publicly available specification and stan-dard testing procedure [2] for real-world samples by BAM and a standard specification for integrated metrology by SEMI [3]. Other activities refer to inter-laboratory comparisons for selected layer/substrate systems and analytical methods including ellipsometry [4] and the development of combined standards for thickness d and step height h [5]. Generally, precision of ellipsmetry in terms of raw data Ψ and Δ meets the major demands for all ellipsometric principles (RPE, RAE, PME, RCE, NE). As a result, fingerprint capabilty is al-most perfect for various layer/substrate systems. However, this is not true for accuracy in terms of physical quantities such as thickness d, optical (n, k) and dielectric constans (ε1, ε2,) as modelling is required. Hence, the layer/substrate and material dependent validation of models is nowadays a key issue. In contrast to the sub-nanometer sensi-tivity in vertical direction, the effective lateral resolution of almost all ellipso-metric principles except for imaging null ellipsometry is rather poor, usually be-yond 100 µm. Hence, nanometer-scaled homogeneity testing and the measurement of micro- and nanopatterned structures is not feasible by standard configurations. KW - Ellipsometry KW - Standardisation KW - Reference Coatings KW - Non-ideal samples KW - Validation of models PY - 2008 IS - 2 SP - 6 EP - 7 AN - OPUS4-18673 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Hannes A1 - Kemnitz, E. A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Transparent MgF2-films by sol-gel coating: Synthesis and optical properties N2 - Dielectric, anti-reflective or high reflective systems consist of low and high refractive index layers. Common systems are oxides. The preparation of low refractive index MgF2-films of optical quality by means of an anhydrous low temperature sol–gel synthesis is presented. The MgF2-sol is prepared by spin-coating on silicon and glass substrates. Various film thicknesses between 20 nm and 435 nm have been deposited. It has been shown that the thickness increase is proportional to the number of coating steps. The deposited MgF2-films consist of 10 nm to 20 nm large nanoparticles and have smooth surfaces with an average roughness (Ra) of (1.7 ± 0.3) nm. The optical constants n and k of the films are in agreement with the literature data of bulk-MgF2. KW - Sol-gel KW - Nano-MgF2 KW - Spin coating KW - Optical properties KW - Nanoparticles PY - 2008 DO - https://doi.org/10.1016/j.tsf.2007.10.126 SN - 0040-6090 VL - 516 IS - 12 SP - 4175 EP - 4177 PB - Elsevier CY - Amsterdam AN - OPUS4-17375 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rybachuk, Maksym A1 - Hertwig, Andreas A1 - Weise, Matthias A1 - Sahre, Mario A1 - Männ, Marion A1 - Beck, Uwe A1 - Bell, J. M. T1 - Near infrared optical materials from polymeric amorphous carbon synthesized by collisional plasma process N2 - The synthesis of polymerlike amorphous carbon (a-C:H) thin-films by microwave excited collisional hydrocarbon plasma process is reported. Stable and highly aromatic a-C:H were obtained containing significant inclusions of poly(p-phenylene vinylene) (PPV). PPV confers universal optoelectronic properties to the synthesized material. That is a-C:H with tailor-made refractive index are capable of becoming absorption-free in visible (red)-near infrared wavelength range. Production of large aromatic hydrocarbon including phenyl clusters and/or particles is attributed to enhanced coagulation of elemental plasma species under collisional plasma conditions. Detailed structural and morphological changes that occur in a-C:H during the plasma synthesis are also described. KW - Kohlenstoffschichten KW - Plasmachemie KW - PA-CVD KW - Amorphous state KW - Carbon KW - Coagulation KW - Hydrogen KW - Optical materials KW - Plasma collision processes KW - Plasma deposition KW - Refractive index KW - Thin films PY - 2010 DO - https://doi.org/10.1063/1.3431292 SN - 0003-6951 SN - 1077-3118 VL - 96 IS - 21 SP - 211909-1 - 211909-3 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-21365 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Hannes A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Kemnitz, E. T1 - Low temperature sol-gel metal oxide and fluoride layer stacks for optical applications N2 - MgF2 and TiO2 single layers and layer stacks were produced by a spin-coating sol-gel process. The final temperature treatment was carried out at 100 °C. The layers were deposited onto silicon and fused silica substrates and were analysed by means of atomic force microscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, ellipsometry, and UV-vis transmission spectroscopy. MgF2 and TiO2 single layers have morphological and optical properties comparable with physical vapour deposited layers. By using spectroscopic mapping ellipsometry, a good inter- and intra-sample homogeneity was confirmed. Multiple deposition steps result in a linear increase of layer thickness. Various films were deposited with thicknesses between 25 nm and 350 nm. It was shown that the low temperature sol-gel process results in films of optical quality. Anti-reflective and high reflective layer stacks consisting of MgF2 and TiO2 were designed and can be produced now by a sol-gel process, whereas the MgF2 layers in the layer stacks contains also traces of MgF2-2xOx. KW - Magnesium fluoride KW - Titanium oxide KW - Sol-gel KW - Spin-coating KW - Optical properties KW - Optical layer stacks KW - MgF2 KW - TiO2 PY - 2010 DO - https://doi.org/10.1016/j.tsf.2010.06.025 SN - 0040-6090 VL - 518 IS - 21 SP - 6080 EP - 6086 PB - Elsevier CY - Amsterdam AN - OPUS4-21516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas T1 - Reference coatings for thin film technology - beyond the state of the art T2 - 6th Workshop Ellipsometry CY - Berlin, Germany DA - 2011-02-02 PY - 2011 AN - OPUS4-23064 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Hannes A1 - Kemnitz, E. A1 - Hertwig, Andreas A1 - Beck, Uwe T1 - Moderate temperature sol-gel deposition of magnesium fluoride films for optical UV-applications: A study on homogeneity using spectroscopic ellipsometry N2 - Thin films of MgF2 have been deposited on silicon wafers in optical quality with a novel sol-gel deposition process at temperatures as low as 100 °C. The properties of the fluoride layers are compared to bulk MgF2 with respect to the optical constants. By employing spectroscopic mapping ellipsometry, the uniformity of the thickness of fluoride layers is confirmed to be within acceptable limits for optical applications. The optical constants are close to the bulk data. High-quality low-index films of suitable and homogeneous thickness have already been produced on a laboratory scale. KW - 78.20.-e KW - 78.66.Li KW - 78.68.+m KW - 81.20.Fw PY - 2008 DO - https://doi.org/10.1002/pssa.200777856 SN - 1862-6300 SN - 0031-8965 VL - 205 IS - 4 SP - 821 EP - 824 PB - Wiley-VCH CY - Berlin AN - OPUS4-17330 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas T1 - Optical vs. mivroscopic properties of ECR and RF bias generated amoephous hydrogenated carbon films T2 - PSE CY - Garmisch-Partenkirchen, Germany DA - 2010-09-13 PY - 2010 AN - OPUS4-20869 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Koter, Robert A1 - Weise, Matthias A1 - Hertwig, Andreas A1 - Beck, Uwe A1 - Krüger, Jörg T1 - Influence of film thickness and optical constants on femtosecond laser-induced ablation of hydrogenated amorphous carbon films N2 - Hydrogenated amorphous carbon layers were deposited on BK7 glass in a plasma-assisted chemical vapor deposition process. Low and high refracting films with thicknesses d ranging from 11 nm to 5.8 µm were produced having refractive indices n between 1.68 and 2.41 and linear absorption coefficients of α~100 cm-1 and α~20000 cm-1 at 800 nm wavelength as a result of different plasma modes. Laser ablation thresholds Fth in dependence on d were determined using 30-fs laser pulses. Low absorbing layers show a constant Fth while Fth increases with rising d up to the optical penetration depth of light α-1 for high absorbing films. KW - Physical radiation damage (61.80.-x) KW - Laser-beam impact phenomena (79.20.Ds) KW - Radiation treatment (81.40.Wx) KW - Carbon (81.05.Uw) KW - Optical constants (78.20.Ci) PY - 2010 SN - 1454-4164 VL - 12 IS - 3 SP - 663 EP - 667 PB - INOE & INFM CY - Bucharest AN - OPUS4-21084 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas T1 - Optische Messtechnik an Mikrotopografien T2 - OptecBB Veranstaltungsreihe MPK CY - Potsdam, Germany DA - 2010-05-19 PY - 2010 AN - OPUS4-21275 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hönig, D. A1 - Schneider, S. A1 - Domnick, R. A1 - Belzner, M. A1 - Beck, Uwe A1 - Hertwig, Andreas A1 - Stephanowitz, Ralph A1 - Weise, Matthias ED - Uhlmann, E. T1 - Ellipsometrische Codierung & Fabry-Perot Schichtsysteme mit offenen, versteckten und forensischen Merkmalen zur Produkt-Authentifizierung T2 - 3. Internationaler Kongress - Sichere Identität CY - Berlin, Deutschland DA - 2011-04-05 KW - Ellipsometric encoding KW - Fabry-Perot layer stacks KW - Product authentification PY - 2011 SP - 1 EP - 4(?) CY - Berlin AN - OPUS4-23306 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hertwig, Andreas T1 - Blistering and layer modification of hydrogenated amorphous carbon layers induced by femtosecond laser pulse irration T2 - Bunsentagung 2011 CY - Berlin, Germany DA - 2011-06-02 PY - 2011 AN - OPUS4-23361 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schalk, O. A1 - Yang, J.-P. A1 - Hertwig, Andreas A1 - Hippler, H. A1 - Unterreiner, A.N. T1 - Vibrational cooling in the liquid phase studied by ultrafast investigations of cycloheptatriene N2 - Solvent-mediated vibrational relaxation in UV pump-probe experiments has been studied using cycloheptatriene (CHT) and its perdeuterated counterpart (CHTd8) as model systems. Transient spectra containing absolute e(t) values are obtained by a modified Sulzer-Wieland ansatz and a global fit function for vibrational relaxation is proposed. KW - Vibrational cooling KW - Ultrafast dynamics KW - Cycloheptatriene KW - Internal conversion KW - Sulzer-Wieland model PY - 2009 DO - https://doi.org/10.1080/00268970903193010 SN - 0026-8976 SN - 1362-3028 VL - 107 IS - 20 SP - 2159 EP - 2167 PB - Taylor & Francis CY - London AN - OPUS4-20654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -