In situ photoacoustic characterization for porous silicon growing: Detection principles
- Posgrado en Ciencia e Ingeniería de Materiales, Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México Campus Juriquilla, C.P. 76230 Querétaro, Qro. (Mexico)
- Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, México Distrito Federal, C. P. 04510 (Mexico)
There are a few methodologies for monitoring the in-situ formation of Porous Silicon (PS). One of the methodologies is photoacoustic. Previous works that reported the use of photoacoustic to study the PS formation do not provide the physical explanation of the origin of the signal. In this paper, a physical explanation of the origin of the photoacoustic signal during the PS etching is provided. The incident modulated radiation and changes in the reflectance are taken as thermal sources. In this paper, a useful methodology is proposed to determine the etching rate, porosity, and refractive index of a PS film by the determination of the sample thickness, using scanning electron microscopy images. This method was developed by carrying out two different experiments using the same anodization conditions. The first experiment consisted of growth of the samples with different etching times to prove the periodicity of the photoacoustic signal, while the second one considered the growth samples using three different wavelengths that are correlated with the period of the photoacoustic signal. The last experiment showed that the period of the photoacoustic signal is proportional to the laser wavelength.
- OSTI ID:
- 22596969
- Journal Information:
- Journal of Applied Physics, Vol. 119, Issue 18; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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