Localized fabrication of Si nanostructures by focused ion beam implantation

Abstract

Si nanostructures have been fabricated by focused ion beam implantation (FIB) followed by etching in KOH/IPA. The FIB implantation into Si at a sufficiently high dose (≥1015/cm2) renders the local Si region much less susceptible to chemical etching. This effect has been observed for FIB implantation with Ga, Au, and Si ions. After etching, the implanted layer forms a cantilever structure whose thickness is a function of the implantation energy. At low energies (<30 keV) nanometer-scale Si structures can be formed using this technique.

Silicon micro/nanomechanical device fabrication based on focused ion beam surface modification and KOH etching

“…Underetched structures have been fabricated by appropriately oriented patterns [1,3]. Their structural thickness is determined by the penetration depth of the ions, which amounts to typically 30 nm for Ga + ions at an acceleration voltage of 30 kV [2]. Interestingly, when milling a hole into the Si by continued FIB exposure, the remaining sidewalls become equally doped due to back scattered ions and hence become also etch resistant.…”

“…Recently, a technique using the combination of local surface implantation by Ga + ions using a focused ion beam (FIB) and wet chemical etching has attracted much interest [1][2][3]. It is well known that a high impurity concentration in Si renders the implanted region relatively immune to subsequent etching with certain chemicals, such as potassium hydroxide (KOH) [4,5].…”

Three-Dimensional Lithography Using Combination of Nanoscale Processing and Wet Chemical Etching

“…This phenomenon is not dependent on the species of the irradiated ions and has been reported after irradiating Ga [47][48][49][50][51][52][53], Si [49,51,[54][55][56], Au [49], BF 2 [56], Ni [57], and P [56,58] ions. The "etch stop" effect of the ion-irradiated area is caused by the formation of an amorphous phase due to ion irradiation [55].…”

“…A silicon surface irradiated with ion beams resists some etchants such as KOH [47][48][49][50][51][52][53][54][55], tetramethylammonium hydroxide [58], sodium hydroxide [50], and hydrazine [56,57], so that protruding structures can be fabricated via etching. This phenomenon is not dependent on the species of the irradiated ions and has been reported after irradiating Ga [47][48][49][50][51][52][53], Si [49,51,[54][55][56], Au [49], BF 2 [56], Ni [57], and P [56,58] ions.…”

Fabrication of visibly photoluminescent Si microstructures by focused ion beam implantation and wet etching

“…This sequence proved to be essential to the success of selective PoSi formation by stain etching as described below. After cleaning, the samples were immersed in a solution of HF:HNO 3 formation in the implanted area is much shorter than that of the substrate 4 and therefore porous Si is selectively formed in implanted areas.…”