Electrochemical deposition of indium into oxidized and unoxidized porous silicon

• Published in: Thin solid films 2021-09, Vol.734, p.138860, Article 138860
• Main Authors: Grevtsov, Nikita, Chubenko, Eugene, Bondarenko, Vitaly, Gavrilin, Ilya, Dronov, Alexey, Gavrilov, Sergey
• Format: Article
• Language: English
• Subjects: Electrochemical deposition; Fusible metals; Indium; Oxidation; Porous silicon
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2021.138860

•Indium nucleates at defects inside pore channels, forming cylindrical structures.•Porous silicon oxidation helps localize metal deposition deeper inside the pores.•Thermal annealing leads to indium redistribution throughout the porous layer. Various cases of electrochemical deposition of indium into oxidized and unoxidized mesoporous silicon were investigated and subsequently compared. The results would suggest that both thermal and chemical oxidation of porous silicon cause the metal particles being deposited into its pores to shift deeper along the pore channels due to the latter's topmost areas being oxidized the most and therefore becoming significantly less conductive and more easily wettable by both the deposition solution and indium itself upon its subsequent thermal processing. However, oxidation becomes less effective as the thickness of the porous layer is increased due to the gradually escalating effect of reduced conductivity at the pore tips. Potentially, porous silicon layers with indium particles localized in the bottommost parts of the pore channels could be used to form germanium nanostructures inside the pores, allowing subsequent creation of Ge-Si alloys by utilizing the electrochemical liquid-liquid-solid approach.