Porous Silicon Formation by Metal-Assisted Chemical Etching

M. Lipinski a, J. Cichoszewski b, R.P. Socha c and T. Piotrowski d a Institute of Metallurgy and Materials Science, PAS, W.S. Reymonta 25, 30-059 Cracow, Poland b Institute of Physical Electronics, University of Stuttgart, Pfaffenwaldring 47, 70569 Stuttgart, Germany c Institute of Catalysis and Surface Chemistry PAS, Niezapominajek 8, 30-239 Cracow, Poland d Institute of Electron Technology, al. Lotników 32/46, 02-668 Warsaw, Poland

Full Text PDF

The method of metal-assisted chemical etching produces a porous silicon layer. Palladium particles are deposited on both: multi-crystalline and Czochralski grown mono-crystalline Si wafers by immersing them in PdCl2 solution for 1 to 3 min. X-ray photoelectron spectroscopy analysis of Pd clusters shows a decrease in Pd metal fraction by prolonged immersion time t from FPd = 71.2% for t = 1 min to FPd = 61.4% for t = 3 min due to Pd oxidation process. Porous silicon forms by metal-assisted chemical etching in a HF:H2O2 solution for 1 to 3 min. Photoluminescence of metal-assisted chemical etched samples exhibits the peak with a maximum of t at λ=650 nm independent of the etching time. Simultaneously, the intensity of the photoluminescence spectra strongly decreases for extended etching time t = 3 min. This behavior is attributed to increasing layer macroporosity, which strongly reduces amount of light emitting nanocrystallites.

DOI: 10.12693/APhysPolA.116.S-117 PACS numbers: 81.16.Rf, 81.05.Rm, 78.55.Mb, 61.43.Gt, 78.67.Bf