Temperature-Dependent Nanofabrication on Silicon by Friction-Induced Selective Etching

Abstract

Friction-induced selective etching provides a convenient and practical way for fabricating protrusive nanostructures. A further understanding of this method is very important for establishing a controllable nanofabrication process. In this study, the effect of etching temperature on the formation of protrusive hillocks and surface properties of the etched silicon surface was investigated. It is found that the height of the hillock produced by selective etching increases with the etching temperature before the collapse of the hillock. The temperature-dependent selective etching rate can be fitted well by the Arrhenius equation. The etching at higher temperature can cause rougher silicon surface with a little lower elastic modulus and hardness. The contact angle of the etched silicon surface decreases with the etching temperature. It is also noted that no obvious contamination can be detected on silicon surface after etching at different temperatures. As a result, the optimized condition for the selective etching was addressed. The present study provides a new insight into the control and application of friction-induced selective nanofabrication.

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

“…In the friction-induced selective etching process, the residual amorphous and deformed silicon layer produced by tip scratching can be directly used as an etching mask in KOH solution to fabricate protrusive nanostructures [24,25]. The amorphous and crystal transformation were also founded beneath the indented area [29].…”

“…When the indentation-induced selective etching method is used, long etching time in KOH aqueous solution could cause the roughness of Si surface [25]. For a tip array production, it is necessary to ensure that the tip is quite higher than the asperities around.…”

“…An alternative SPM-based nanofabrication can be realized by friction-induced selective etching, and protrusive structures or deep grooves can be produced by post etching of a scratch on material surface, such as silicon, quartz, glass and so on [21][22][23]. For producing protrusive nanostructures, the amorphous layer and/or deformed crystal layer beneath the scratched area can act as an etching mask in KOH aqueous solution [24][25][26]. In contrast, the scratched area after tribochemical removal of surface oxide can promote the chemical attack from the etching solutions and result in deep groove [27].…”

Friction-induced selective etching on silicon by TMAH solution

“…The commonly used etchants include potassium hydroxide (KOH), tetramethyl ammonium hydroxide (TMAH) and ethylenediamine-pyrocatechol (EDP). [7][8][9] However, during the etching process, KOH can introduce metal ions onto the fabrication surface, 10,11 while EDP is highly toxic and is not conducive to experimental operation. Compared with other etching agents, TMAH is stable and does not decompose at temperatures below 130 C. Thus, it is a commonly used etching agent in the MEMS process.…”

Revealing silicon crystal defects by conductive atomic force microscope

“…15,16 These crystal defects can lead to the change in physical and chemical performances, such as transmission of infrared light and selective etching in alkali-based solutions. [17][18][19] The change in the conductivity was also detected on the indented area on the Si(100) surface, and it was speculated that high current sites corresponded directly to Si-III and/or Si-XII phases toward the indent edge. 20,21 Owing to the combination of shear and stress in scratching, a significant difference is noticed in damage formation between the indentation and scratch tests.…”