Thickness and tensile stress determination of black silicon layers by spectral reflectance and Raman scattering

• Published in: Journal of Electrical Engineering Vol. 70; no. 7; pp. 51 - 57
• Main Authors: Králik, Martin, Jurečka, Stanislav, Pinčík, Emil
• Format: Journal Article
• Language: English
• Published: Bratislava Sciendo 01.12.2019; De Gruyter Poland
• Subjects: anodic etching; Axial stress; black silicon; Crystal lattices; Effective medium theory; electrochemical etching; Etching; Hydrofluoric acid; Mathematical models; Optical properties; Parameters; porous silicon; Raman scattering; Raman spectra; Reflectance; SCOUT; Silicon substrates; Spectral reflectance; Spectrometers; Tensile stress; Thickness
• ISSN: 1339-309X; 1335-3632; 1339-309X
• DOI: 10.2478/jee-2019-0041

In this work black silicon (b-Si) samples were prepared by anodic (electrochemical) etching of p-type silicon substrate in solution of hydrofluoric acid (HF). We studied influence of anodic etching conditions (etching time, electrical potential and current) on the spectral reflectance and Raman scattering spectra. Optical properties of b-Si structures were experimentally studied by UV-VIS (AvaSpec-2048) and Raman (Thermo DXR Raman) spectrometers. B-Si layer thickness of formed substrate were determined by using SCOUT software. Effective medium approximation theory (Looyenga) was used in construction of the reflectance model. Influence of the deformation of crystal lattice introduced during the substrate etching was studied by Raman scattering method. Teoretical model of the 1 order Raman scattering profile was constructed by using pseudo-Voigt function and the profile parameters were extracted. The values of biaxial tensile stress were estimated by using optimized Raman profile parameters.