Photoetching of Porous Silicon Nanostructures in Hydrofluoric Acid Using Monochromatic Light. (1st January 2018)

• Record Type: Journal Article
• Authors: Gelloz, B.; Fuwa, H.; Kondoh, E.; Jin, L.
• Is Part Of: ECS journal of solid state science and technology. Volume 7:Number 12(2018)
• Page Start: P730
• Page End: P735
• Publication Date: 2018-01-01
• Subjects: Semiconductors - Silicon -- photoetching -- porous silicon; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0121812jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : Photo-assisted etching of porous silicon (PSi) in hydrofluoric acid (HF) solution has been, so far, not well controlled and characterized. In this paper, the progress of photoetching of PSi formed from lightly-doped p-type silicon in ethanolic HF solutions was monitored using an in situ photoconduction technique. A model was proposed to explain the results. Two regimes were characterized, one in which the photoetch rate is limited by the supply of photo-generated holes at the Si surface, and another one where it is limited by the rate R0 of the chemical reactions after initial hole capture, for illumination powers greater than a threshold value. This value was about 1 mW/cm 2 when using a wavelength of 450 nm for a porosity of 62%. R0 was evaluated as about 0.06 Å/min. The model was used to calculate porosity profiles during photoetching. The effect of illumination wavelengths is discussed. A signature of quantum confinement in high-porosity PSi was observed.