The Influence of Preparation Parameters on Structural and Optical Properties of N-Type Porous Silicon

Abstract

In this paper, we describe the formation of macroporous silicon (MPS) formed anodically polarized on n type Si (100) substrates at a constant current density under front side illumination using two electrolytes, HF/Ethanol and HF/Ethanol/H2O2. The effect of adding H2O2 in the solution on the resulting pores were investigated by scanning electron microscopy (SEM), infrared spectroscopy (FTIR), contact angle measurements and UV-vis spectrophotometry. The results showed that for the anodization conditions the MPS formed in peroxide based (H2O2)/HF/Ethanol solution exhibited structures with larger pore size and different pore morphologies depending on the etching time than those formed in HF/Ethanol. The pore density and the pore size of the MPS samples increased with the etching time. The infrared absorption spectrum (FTIR) carried out on the freshly prepared sample indicates that the MPS contains Si-Hx bonds which decrease with increasing the etching time. Finally, measurements of contact angle indicate that the formed MPS samples are highly hydrophobic.

Fabrication of Ordered Macropore Arrays in n-Type Silicon Wafer by Anodic Etching Using Double-Tank Electrochemical Cell

“…Since the macropore fabricated on n-type silicon was first reported in 1970's [1], it has attracted great attention for many applications, such as photonic crystals [2][3][4][5][6], field effect transistors (FETs) [7,8], high-density silicon capacitors [9][10][11][12][13][14], templates [15], through silicon vias [16,17], microneedles [18][19][20][21], microfluidics [22,23], heat sinks [24], neutron detectors [25,26], and so on. Among all of them, the crucial problem is to fabricate controllable and homogeneous macropore arrays, especially for high-aspect-ratio ordered macropores.…”