Hybrid deposition of sputtered and evaporated multilayer thin films

• Published in: Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures 2003-07, Vol.21 (4), p.1384-1390
• Main Authors: Martin, P. M., Olsen, L. C., Johnston, J. W., Depoy, D. M.
• Format: Article
• Language: English
• ISSN: 0734-211X; 1071-1023; 1520-8567
• DOI: 10.1116/1.1591745

Si:H/CaF 2 and Si:H/HfF 4 high reflectors with as many as 27 layers were deposited by a hybrid process that combined reactive magnetron sputtering and electron beam evaporation. The ultimate goal of this work was to deposit interference filters with low near-infrared (NIR) and LWIR absorption for use in thermophotovoltaic systems. The high index Si:H layers were deposited by reactive magnetron sputtering in mixtures of Ar + H 2 . Electron beam evaporation was the preferred deposition method for the CaF 2 layers. The multilayer hybrid coatings were deposited in the same chamber by sequentially rotating the substrate over the Si sputtering target and the CaF 2 evaporation source. The deposition rate of the evaporated CaF 2 was 18.3 Å/s, compared to 0.42 Å/s for sputtered CaF 2 . The deposition rate of the Si:H layers was 1 Å/s. The refractive index of the SiH at NIR wavelengths was 3.45, with extinction coefficient