Photoelectrochemical etching, silicon

An initially flat silicon electrode surface will develop a surface topography if the photocurrent varies locally. This variation can be caused by a lateral variation of the recombination rate or by a lateral variation of the illumination intensity. The photoelectrochemical etching of a silicon electrode is related to the etch-stop techniques discussed in Chapter 3. While different etching rates for different areas of the electrode may be obtained by electrical insulation or by a different doping density, the etch rate may also be altered by a difference in illumination intensity. Basically four photoelectrochemical etching modes are possible for homogeneously doped substrates ... 

C. L. Clement, A. Lagoubi, and M. Tomkiewicz, Morphology of porous n-type silicon obtained by photoelectrochemical etching, J. Electrochem. Soc. 141, 958, 1994. 

C. Levy-Clement, A. Lagoubi, R. Tenne, and M. Neumann-Spallart, Photoelectrochemical etching of silicon, Electrochim. Acta 31(5), 877, 1992. 

J.-L. Maurice, A. Riviere, A. Alapini, and C. Levy-Clement, Electron beam irradiation ofn-type porous silicon obtained by photoelectrochemical etching, Appl Phys. Lett. 66(13), 1665, 1995. 

Excitation with photons can also create valence band holes, which initiate etching. This type of photoelectrochemical etching is commonly performed within an electrochemical cell on n-type Si since photoexcitation is required to make free carriers available for conduction at low voltages. However, connection to a counter electrode is not essential for this process to occur and the formation of porous silicon (por-Si) on freestanding crystals is well documented (Noguchi and Suemune 1993,1994 Koker and Kolasinski 2000,2001). This technique is also reviewed elsewhere in this handbook (chapter Porous Silicon Formation by Photoetching ). 

Kelly JJ, Xia XH, Ashruf CM A, French PJ (2001) Galvanic cell formation a review of approaches to silicon etching for sensor fabrication. IEEE Sensors J 1 127-142 Koker L, Kolasinski KW (2000) Photoelectrochemical etching of Si and porous Si in aqueous HF. Phys Chem Chem Phys 2 277-281... 

Barillaro G, Nannini A, Pieri F (2002a) Dimensional constraints on high aspect ratio silicon microstructures fabricated by HF photoelectrochemical etching. J Electrochem Soc 149 C180-C185... 

D photonic crystals can be fabricated by means of focused-ion-beam drilling of macroporous silicon. Yablonovite-like structure was formed by three sets of drilled holes (Wang et al. 2000,2003 Chelnokov et al. 2000 Fig. 10). Authors of paper (Schilling et al. 2005) obtained 3D photonic crystal of orthorhombic structure with large photonic band gap by utilization of only one orthogonal set of FIB-drilled holes interpenetrating with photoelectrochemically etched macropores. 

Astrova EV, Tolmachev VA, Zharova YA, Fedulova GV, Baldycheva AV, Perova TS (2010a) Silicon periodic structures and their liquid crystal composites. Solid State Phenom 156-158 547-554 Astrova EV, Fedulova GV, Guschina EV (2010b) Formation of 2D photonic crystal bars by simultaneous photoelectrochemical etching of trenches and macropores in silicon. Semiconductors 44 1617-1623... 

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