Specific Process Knowledge/Etch/DRIE-Pegasus/Pegasus-2/Si Nano etching

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The CORE sequence (meaning Clear, Oxidize, Remove and Etch) is a fluorocarbon-free directional plasma etch procedure that enables a higher selectivity, creates pattern independence of etching profiles and works excellent at room temperature. The CORE process resembles the well-known SF6-based Bosch process, but the usual C4F8 inhibitor is replaced by O2 oxidation with self-limiting characteristics. Therefore the CORE result is similar to Bosch, however has the advantage of preventing the pile-up of fluorocarbon deposits at the topside of deep-etched or nano-sized features. At the same time, process drift is minimized as the reactor wall is staying perfectly clean. The CORE process has shown an excellent performance in high aspect ratio (3D) nanoscale structures with an accurate and controllable etch rate between 1 and 50 nm min−1 (and SiO2-selectivity of ca. 35) using the etch-tool in the RIE-mode. By adding the ICP source (DRIE-mode), a directional etch rate up to 1 μm min−1 (at 50 sccm SF6 flow) and selectivity >200 for SiO2 is possible.

• 1. 3D silicon photonic crystal membranes.
  1. 3D silicon photonic crystal membranes.