Faraday cage angled-etching of nanostructures in bulk dielectrics

Abstract

For many emerging optoelectronic materials, heteroepitaxial growth techniques do not offer the same high material quality afforded by bulk, single-crystal growth. However, the need for optical, electrical, or mechanical isolation at the nanoscale level often necessitates the use of a dissimilar substrate, upon which the active device layer stands. Faraday cage angled-etching (FCAE) obviates the need for these planar, thin-film technologies by enabling in-situ device release and isolation through an angled-etching process. By placing a Faraday cage around the sample during inductivelycoupled plasma reactive ion etching (ICP-RIE), the etching plasma develops an equipotential at the cage surface, directing ions normal to its face. In this Article, the effects Faraday cage angle, mesh size, and sample placement have on etch angle, uniformity, and mask selectivity are investigated within a silicon etching platform. Simulation results qualitatively confirm experiments and help to clarify the physical mechanisms at work. These results will help guide FCAE process design across a wide range of material platforms.

Tipping solutions: emerging 3D nano-fabrication/ -imaging technologies

“…This method was used to produce free-standing cantilievers, ring resonators [103], and other photonic nanostructures [104] in silicon [102,103], diamond [104] or even quartz [103]; thus, FCAE should work virtually on any material that can be etched by RIE. A schematic representation of FCAE setup and several nano-fabrication examples are shown in Figure 11. …”

Strongly Cavity-Enhanced Spontaneous Emission from Silicon-Vacancy Centers in Diamond

“…Nanophotonic cavities were fabricated in this silicon rich diamond using electron beam lithography (EBL) followed by angled-etching [34][35][36] of the bulk single-crystal diamond, with details given elsewhere 27 Optical characterization of fabricated devices was performed in a home built confocal microscope setup at cryogenic temperatures (~ 5 K). A low temperature photoluminescence (PL) spectrum from a representative device under 720 nm laser excitation is shown in Figure 1(d).…”

Fiber-Coupled Diamond Quantum Nanophotonic Interface

“…Recently, angled-etching nanofabrication [27][28][29][30] has emerged as a scalable method for realizing nanophotonic devices from bulk single-crystal diamond substrates. Using this approach, we have demonstrated high Q-factor (> 10 5 ) diamond photonic crystal cavities (PCCs) [31] operating over a wide wavelength range (visible to telecom).…”

“…Our work will ultimately enable new possibilities for realizing quantum networks that interface multiple emitters, both on-chip and separated by long distances. Figure 1 displays a series of SEM images revealing diamond nanophotonic structures realized by angled-etching nanofabrication [27,28] (see Supplementary Material for more details [45]). The nanophotonic systems consist of four key components: (1) freestanding diamond waveguides, (2) waveguide-coupled diamond nanobeam photonic crystal cavities (PCCs, Figure 1 (b)), (3) vertical waveguide support structures (Figure 1 (c)), and lastly, (4) freestanding diamond waveguide tapers (DWTs, Figure 1 (d) and (e)).…”