Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 33: Nanostructures at Surfaces III
O 33.5: Vortrag
Dienstag, 12. März 2013, 11:30–11:45, H45
A new route for the electroless fabrication of mesoporous silicon — •Xiaopeng Li1, 2, Stefan L. Schweizer2, Alexander Sprafke2, and Ralf B. Wehrspohn2, 3 — 1Max-Planck Institute of Microstructure Physics, Halle D-06120, Germany — 2Martin-Luther-University Halle-Wittenberg, Germany — 3Fraunhofer Institute for Mechanics of Materials, Halle D-06120, Germany
Recently, mesoporous silicon (meso-PSi) has demonstrated considerable potential for bio-medical applications regarding biocompatibility and biodegradability, due to its large internal surface area and its mechanical stability. In photovoltaics, meso-PSi has been utilized for antireflective layers, and as sacrificial layers for layer-transfer processes. Until now, electrochemical etching (ECE) is considered as the only method to achieve controlled fabrication of meso-PSi. However, ECE is cost-inefficient on full wafer-scale, additionally, its process stability for high-throughput, in-line processes is critical on wafer-scale. Here, we present a new route for the fabrication of meso-PSi using Pt nanoparticle-assisted chemical etching (PaCE) without applying any external potential. Si wafers were firstly loaded with Pt nanoparitcles (PtNPs), and then immersed in solution containing HF and H2O2. PtNPs drill nanopores deep into the Si substrate; meanwhile, meso-PSi is created. The obtained mesoporous silicon films show surprisingly good uniformity in which the porosity and thickness can be tuned well via adjusting the etching conditions. To qualitatively explain the observed phenomenon, we propose a new model based on the Pt-Si nano-Schottky contact.