Details

Autor(en) / Beteiligte

• Zhang, Yu
• Kong, Charlie
• Davidsen, Rasmus Schmidt
• Scardera, Giuseppe
• Duan, Leiping
• Khoo, Kean Thong
• Payne, David N.R.
• Hoex, Bram
• Abbott, Malcolm

Titel

3D characterisation using plasma FIB-SEM: A large-area tomography technique for complex surfaces like black silicon

Ist Teil von

• Ultramicroscopy, 2020-11, Vol.218, p.113084-113084, Article 113084

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• •We investigated the surface topography of black silicon (BSi) with under-etching resulted overhanging structures by Xe+ Plasma FIB-SEM dual beam tomography.•Durcupan resin has been employed to fully infiltrate the needle like BSi surface and protect the top-surface from potential PFIB artifacts.•Rocking milling process and single-crystal sacrificial mask has been employed to minimize the susceptible PFIB artifacts.•Xe+ Plasma FIB-SEM tomography technology enables large area representative data (320 μm2) to be investigated with a controlled slice thickness of 10 nm.•Plasma FIB-SEM generated surface topography data offers a comparable resolution to traditional AFM but can be used for higher aspect ratio or overhanging features. This paper demonstrates an improved method to accurately extract the surface morphology of black silicon (BSi). The method is based on an automated Xe+ plasma focused ion beam (PFIB) and scanning electron microscope (SEM) tomography technique. A comprehensive new sample preparation method is described and shown to minimize the PFIB artifacts induced by both the top surface sample-PFIB interaction and the non-uniform material density. An optimized post-image processing procedure is also described that ensures the accuracy of the reconstructed 3D surface model. The application of these new methods is demonstrated by applying them to extract the surface topography of BSi formed by reactive ion etching (RIE) consisting of 2 µm tall needles. An area of 320 µm2 is investigated with a controlled slice thickness of 10 nm. The reconstructed 3D model allows the extraction of critical roughness characteristics, such as height distribution, correlation length, and surface enhancement ratio. Furthermore, it is demonstrated that the particular surface studied contains regions in which under-etching has resulted in overhanging structures, which would not have been identified with other surface topography techniques. Such overhanging structures can be present in a broad range of BSi surfaces, including BSi surfaces formed by RIE and metal catalyst chemical etching (MCCE). Without proper measurement, the un-detected overhangs would result in the underestimation of many critical surface characteristics, such as absolute surface area, electrochemical reactivity and light-trapping.