Damage creation in porous silicon irradiated by swift heavy ions

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:327

Article

Canut, B.¹  Massoud, M.¹  Newby, P.²  Lysenko, V.¹  Frechette, L.²  Bluet, J. M.¹  Monnet, I.³ 

[1] Univ Lyon, Inst Nanotechnol Lyon, INL IMR5270, CNRS,INSA Lyon, F-69621 Villeurbanne, France

[2] Univ Sherbrooke, Ctr Rech Nanofabricat & Nanocaracterisat CNR2, Sherbrooke, PQ J1K 2R1, Canada

[3] Univ Caen, CEA CNRS ENSICAEN, Ctr Rech Ions Mat & Photon CIMAP CIRIL, F-14070 Caen 5, France

关键词: Irradiation;    High energy;    Porous silicon;    Damage;   

DOI  :  10.1016/j.nimb.2013.09.047

来源: Elsevier

【 摘 要 】

Mesoporous silicon (PS) samples were processed by anodising p(+) Si wafers in (1:1) HF-ethanol solution. Different current densities were used to obtain three different porosities (41%, 56% and 75%). In all cases the morphology of the PS layer is columnar with a mean crystallite size between 12 nm (75% porosity) and 19 nm (41% porosity). These targets were irradiated at the GANIL accelerator, using different projectiles (Xe-130 ions of 91 MeV and 29 MeV, U-238 ions of 110 MeV and 850 MeV) in order to vary the incident electronic stopping power S-e. The fluences ranged between 10(11) and 7 x 10(13) cm(-2). Raman spectroscopy and cross sectional SEM observations evidenced damage creation in the irradiated nanocrystallites, without any degradation of the PS layer morphology at fluences below 3 x 10(12) cm(-2). For higher doses, the columnar morphology transforms into a spongy-like structure. The damage cross sections, extracted from Raman results, increase with the electronic stopping power and with the sample porosity. At the highest S-e (>10 keV nm(-1)) and the highest porosity (75%), the track diameter coincides with the crystallite diameter, indicating that a single projectile impact induces the crystallite amorphization along the major part of the ion path. These results were interpreted in the framework of the thermal spike model, taking into account the low thermal conductivity of the PS samples in comparison with that of bulk silicon. (C) 2014 Elsevier B.V. All rights reserved.

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