Spectroscopic investigations of the stability of porous silicon structure obtained by etching Si(100) in aqueous ammonium fluoride solution

The structure of porous silicon (por-Si) obtained by electrochemical etching of Si(100) single crystal wafers in an aqueous ammonium fluoride solution with isopropyl alcohol additions has been studied using X-ray reflection spectroscopy, X-ray photoelectron spectroscopy, and external X-ray quantum yield measurements. It is established that por-Si layers obtained by the nontraditional technology (not involving hydrofluoric acid) possess a partly amorphized structure and bear a stable surface oxide film with a thickness not exceeding 5 nm.