Site-controlled fabrication of silicon nanotips by indentation-induced selective etching

Abstract

The indentation-induced selective etching approach is proposed to fabricate site-controlled pyramidal nanotips on monocrystalline silicon surface.  The height and radius of the pyramidal nanotips increase with the indentation force or etching time within the etching time of 20 min.  Various tip arrays on silicon surface can be produced by selective etching of the site-controlled indent patterns, and the maximum height difference of these tips is less than 10 nm.

Surface Structure Dependence of Mechanochemical Etching: Scanning Probe-Based Nanolithography Study on Si(100), Si(110), and Si(111)

“…In addition to the etch rate, the etch pattern is also different from chemical etching. For example, the side wall of the etch pit produced on Si(100) in base solutions is the (111) facet which is exactly at 54.7° with respect to the (100) surface. − On the Si(111) surface, the chemical etching proceeds faster in the lateral direction than the depth direction. , The cross-sectional topography profiles of the mechanochemically produced nanochannels are shown in Figure . The side wall angle of the nanochannel with respect to the top surface is measured to be 2.7 ± 0.4° on Si(100), 3.6 ± 0.5° on Si(110), and 9.2 ± 0.7° on Si(111), regardless of the scan direction.…”

“…14−16 On the Si(111) surface, the chemical etching proceeds faster in the lateral direction than the depth direction. 17,18 The crosssectional topography profiles of the mechanochemically produced nanochannels are shown in Figure 1. The side wall angle of the nanochannel with respect to the top surface is measured to be 2.7 ± 0.4°on Si(100), 3.6 ± 0.5°on Si(110), and 9.2 ± 0.7°on Si(111), regardless of the scan direction.…”

Friction-induced selective etching on silicon by TMAH solution

“…This can be ascribed to the fact that (111) crystal plane has a very low etching rate, which is comparable to the crystal deformation mask created by scratching. 28 During the etching, (111) plane played a role in preventing the etching, resulting in an inclined plane with an angle of 54.74°.…”

A review on fabrication of blazed gratings

“…Figure 10 schematically displays the etching process for an off-cut (111) silicon surface with resisting masks, where the dotted line represents the (111) crystal planes [98]. Given that the etching rate of the ( 111) silicon plane is significantly lower than that of other crystal planes, such as the ( 100) and ( 110) planes [99], a blazed surface can be formed on the (111) crystal planes after etching. Moreover, it should be noted that redundant edges or nubs are generated because the mask is not etched off, as shown in figure 11(a), which can degrade the performance of the fabricated gratings [100,101].…”