Vapor-Phase Chemical Etching of Silicon Assisted by Graphene Oxide for Microfabrication and Microcontact Printing

Abstract

Chemical etching of silicon assisted by a number of catalysts is attracting increasing attention in the fabrication of silicon micro–nanostructures. In practical applications, metal-free catalysts, including carbon materials, have been focused on as alternative materials for the assisted etching of silicon. Although this anisotropic etching process is suitable for the fabrication of silicon micro–nanostructures due to its simplicity and cost effectiveness, a number of challenges remain, such as the formation of a porous layer and peeling of the catalyst by the gases produced during the etching process. We herein report vapor-phase etching assisted by graphene oxide and its mechanism in terms of reaction kinetics. By optimizing etching conditions, graphene oxide enhances the etching reaction in the vapor phase without the formation of a porous layer. We also demonstrated the formation of micrometer-sized pores in the desired areas by combining the microcontact printing of graphene oxide with silicon etching in the vapor phase.

MoS2-assisted chemical etching of silicon in an HF/H2O vapor

“…The mechanism of MoS 2 -assisted chemical etching is discussed here. Previous studies have reported a vapor-phase etching using noble metals 21,29,30) and other materials 7,10,22) as a catalyst. Our study using MoS 2 flakes showed preferential etching under the MoS 2 flakes.…”

“…The details are reported in the previous literature. 22) Briefly, we sealed the MoS 2 -loaded silicon substrate and a small PFA container with an etching solution in a large PFA container. The etching solution was HF (50 wt%, for the semiconductor industry, Morita Chemical Industry).…”

“…An advantage of this method is the prevention of floating and delamination of the catalyst in the etching solution. 10,13,22) This study demonstrated assisted chemical etching using MoS 2 as a catalyst in an HF/H 2 O vapor. The etched hollows were formed on the silicon substrate under the MoS 2 flakes after the etching.…”

Quantum Dot Transfer from the Organic Phase to Acrylic Monomers for the Controlled Integration of Single-Photon Sources by Photopolymerization

“…In the past years, microfabrication techniques have enabled the development of advanced devices with unprecedented precision and functionality. − Between the different techniques, two-photon polymerization (TPP) of photosensitive resins has emerged as a powerful tool to create complex 3D polymeric nano- and microstructures, with a resolution below the diffraction limit. − Briefly, a femtosecond laser is focused on the photosensitive resin and triggers the polymerization of monomers due to multiphoton absorption. With two-photon absorption being a nonlinear optical process, photopolymerization occurs only inside the focus of the laser (volume pixel, voxel). − By sweeping the laser in the material, 3D objects can be created.…”

Chemical etching of InP assisted by graphene oxide

“…12) We reported that graphene oxide (GO), a 2D carbon material that contains oxygen functional groups, is one of the candidates for the catalyst of the semiconductor etching reaction, and we achieved the GO-assisted silicon etching in the optimized etching conditions. [13][14][15] Moreover, it was reported that GO and its derivatives were utilized as the catalyst for the Ge etching reaction. [16][17][18] In this report, we applied GO to the catalyst for the InP etching reaction.…”