Surface Passivated Porous Silicon-Based Antireflective Coating
Conference: MikroSystemTechnik Kongress 2023 - Kongress
10/23/2023 - 10/25/2023 at Dresden, Deutschland
Proceedings: MikroSystemTechnik Kongress 2023
Pages: 5Language: englishTyp: PDF
Authors:
Keshavarzi, S. (X-FAB MEMS Foundry Itzehoe GmbH, Electroplating Department, Itzehoe, Germany)
Kovacs, A. (Furtwangen University of Applied Scienec, Department of Medical and Mechanical Engineering, Institute for Microsys-tems Technology, Furtwangen, Germany)
Mescheder, U. (Furtwangen University of Applied Scienec, Department of Medical and Mechanical Engineering, Institute for Microsys-tems Technology, Furtwangen, Germany & University of Freiburg, Faculty of Engineering, Freiburg, Germany)
Abstract:
This paper reports a surface passivated porous silicon-based technique for realization of ultra-band infrared optical components applicable in thermal imaging and infrared spectroscopy. The functionalized Si-surface consists of light-trapping (islet-like) structures and a porous silicon (PSi) multilayer structure forming λ/4 layers underneath. The combined macro- and nanostructures are created by electrochemical etching processes with different etchant concentrations, current densities, and etching times in which the nanostructures are created in a self-organized process at suitable anodization conditions. The long-term stability of the manufactured optical component is obtained by an effective 2-step-oxidation surface stabilization process. The influence of this stabilisation process on the optical performance is almost negligible. The surface stability is proven by additional thermal annealing steps up to 1000deg C and 10 h. The samples maintained the almost perfect black body characteristic in a wavelength range from 1.5 µm to about 20 µm (MIR).