Metal-assisted etching of silicon molds for electroforming

Abstract

Articles you may be interested inVertical directionality-controlled metal-assisted chemical etching for ultrahigh aspect ratio nanoscale structures J. Vac. Sci. Technol. B 32, 06FI01 (2014); 10.1116/1.4898199 Influence of catalytic gold and silver metal nanoparticles on structural, optical, and vibrational properties of silicon nanowires synthesized by metal-assisted chemical etching J. Appl. Phys. 112, 073509 (2012); 10.1063/1.4757009Nanofabrication of x-ray zone plates using ultrananocrystalline diamond molds and electroforming Integration of benzocyclobutene polymers and silicon micromachined structures using anisotropic wet etchingIn-plane control of morphology and tunable photoluminescence in porous silicon produced by metal-assisted electroless chemical etching Ordered arrays of high-aspect-ratio micro/nanostructures in semiconductors stirred a huge scientific interest due to their unique one-dimensional physical morphology and the associated electrical, mechanical, chemical, optoelectronic, and thermal properties. Metal-assisted chemical etching enables fabrication of such high aspect ratio Si nanostructures with controlled diameter, shape, length, and packing density, but suffers from structure deformation and shape inconsistency due to uncontrolled migration of noble metal structures during etching. Hereby the authors prove that a Ti adhesion layer helps in stabilizing gold structures, preventing their migration on the wafer surface while not impeding the etching. Based on this finding, the authors demonstrate that the method can be used to fabricate linear Fresnel zone plates.

Fabrication of high aspect ratio structures in silicon independent of crystal orientation using metal assisted etching

“…Increasing the HF concentration further, however, showed a loss of verticality of the etch (due to the irregular catalyst motion mentioned above) as well as increased incidence of delamination of the Au layer (figure 6). This is a typical etch outcome for HF concentrations >4 M. This pattern has been observed elsewhere [10,19] and demonstrates that there is a balance to be maintained in the etching parameters in order to maintain a high aspect ratio etch with an acceptable Si surface quality. An option for reducing porous Si formation may be to conduct the MacEtch under an electric bias [20] which suppresses excessive etching and which may be investigated in future studies.…”

Effect of a metal interlayer under Au catalyst for the preparation of microscale holes in Si substrate by metal-assisted chemical etching

“…[18][19][20] A Ti interlayer between Au catalyst layer and Si substrate was previously introduced as a conventional adhesion layer, and these paper reported that the Ti interlayer helped to eliminate the unnecessary lateral Si etching during MacEtch. 21,22) However, the detail of role for Ti interlayer in MacEtch process has not been fully understood. Therefore, in this study, the usefulness of a metal interlayer interposed between the metal catalyst and Si is demonstrated for the formation of vertical microscale holes in a Si(100) substrate by MacEtch, and the effect of the interlayer is investigated and discussed.…”

Metal‐assisted chemical etching for realisation of deep silicon microstructures

“…[8]. Some of these problems have been overcome, for example by post‐partum sonication treatment [16], etchant formulation control [8, 16, 18], changing etch bath [16], using by‐layer catalyst [16, 19], and controlling deposition rate and thickness of catalyst [17].…”