Metal-assisted chemical etching of high throughput, high aspect ratio critical-angle transmission gratings with vertical and smooth sidewalls

Abstract

This paper reports the development of a critical-angle transmission (CAT) grating fabrication process based on metal-assisted chemical etching (MACE), from which grating prototypes with a period of 1 μm were fabricated. The prototype was composed of four 5 mm × 5 mm membrane cells, each of which comprising freestanding grating lines and a large-period cross-support structure. The support structure had a 60 μm period and a 4.5 μm line width. The grating line width was about 200 nm, the duty cycle was about 0.2, and the aspect ratio was up to 50. The effective open grating area reached 92.5%, and the grating sidewall had a roughness less than 0.8 nm and a perpendicularity reaching 89.2°. For the MACE process, the influence of etching solution ratio on the grating sidewall roughness and perpendicularity was explored on a 〈100〉 silicon wafer.

Fabrication of High‐Aspect Ratio Nanogratings for Phase‐Based X‐Ray Imaging

“…[28] Both can be corrected by fine-tuning oxidant/etchant ratio and more efficient temperature control by mixing (see Experimental Section), respectively. [42,43] Likewise the excess intensity between diffracted orders can be attributed to residual grating imperfections and especially to X-ray scattering, notably by air considering there was a 3.3 m grating-todetector distance in the used setup, without an evacuated tube.…”

Metal-Assisted Etching of n-Type and p-Type Silicon Using Patterned Platinum Films: Spatial Distribution of Mesoporous Layer and Open Circuit Potential of Silicon

“…In this context, the deposition of patterned metal films is reasonable way to control the interval between catalysts. Various kinds of Si structures have been fabricated by using patterned metal films, 23,26,27,30,[32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47] but many reports have focused on the formation of high-aspect ratio structures.…”