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Photo by Mohammad Bereyhi, EPFL - LPQM

Results (5)


Critical point drying of suspended structures after wet etch

In this report I monitor a full successful cycle of critical point drying (CPD) run for drying MEMS sensors after wet release using KOH etching. The pressure and temperature of the CPD tool (Tousimis) is monitored during the process and plotted in a P-T diagram with \mathrm{CO_2} critical point. A few notes for higher yield in the drying process are mentioned in this report as well.



Bulk and Sleeve Electron Beam Lithography for Silicon Nitride Photonic Crystals

This is a method to improve the quality of lithography - in particular electron beam lithography (EBL). During an EBL exposure the electrons undergo different scattering processes. One scattering process that plays an important role is the back scattering of the electrons from the substrate or different stacks of thin film present in the exposure stack. As a result the actual dose that the resist sees is quite different that the original exposure dose. This ...


Fabrication of high-aspect ratio Si_3N_4 nanobeam resonators

We describe the fabrication of high-stress Si_3N_4 nanobeam resonators with high aspect ratios exceeding lengths of 3.5mm. The lowest order out-of-plane modes of these nanobeams have quality factors of Q\geq 10^6 with fundamental mode frequencies lying in the range of 80-500kHz. The beams are fabricated from high-stress, 20-50nm-thick films of Si_3N_4 deposited via LPCVD on standard silicon wafers. The beams are patterned via electron beam lithography and deep reactive ion etching. The underlying silicon is ...


Effect of LPCVD \mathrm{Si_3N_4} deposition on \mathrm{Al_2O_3} etch-stop films

Alumina (\mathrm{Al_2O_3}) films are widely used in photonics and superconducting circuits as an etch stop or passivation layer. In silicon nitride (\mathrm{Si_3N_4}) fabrication, a widely used etching recipe is dry etching using a mixture of \mathrm{SF_6/CHF_3} gasses. In case of multi-stacked materials, one might be interested to etch the \mathrm{Si_3N_4} layer with an stop layer to protect the rest of the stack from the etching step. \mathrm{Al_2O_3} is a great etch stop layer for \mathrm{Si_3N_4} ...