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Photo by Julien Dorsaz, EPFL - CMi

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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.

Version
Version 1.0
Date
1 year, 2 months ago
Lab
EPFL - LPQM
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7
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1606
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479
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2

High aspect ratio \mathrm{Si_3N_4} nanomembranes

A fabrication method for large-area, high-stress LPCVD \mathrm{Si_3N_4} membranes is presented. These devices can be used as mechanical resonators with very low dissipation, exploiting dissipation dilution. A phononic crystal pattern allows to work with a high-order localized mode, shielded from acoustic radiation in the substrate. The procedure is amenable to most research clean rooms, requiring conventional lithography techniques and wet etching in KOH for device undercut.

Version
Version 1.0
Date
1 year, 3 months ago
Lab
EPFL - LPQM
Comments
0
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753
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449
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1

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} ...

Version
Version 1.0
Date
1 year, 3 months ago
Lab
EPFL - LPQM
Comments
0
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563
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303
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1

UV light from ambient environment increases the \mathrm{Si_3N_4} etch rate in \mathrm{XeF_2} etching

Releasing mechanical structures is a fundamental step in MEMS processing. Given the wide usage of silicon nitride ( \mathrm{Si_3N_4} ) on silicon (Si) carrier due to high stress and high mechanical Q factors, high etching selectivity between \mathrm{Si_3N_4} and Si is very crucial for the release process. Here we demonstrate that UV light from ambient light sources in a cleanroom environment (EPFL - CMi) can increase the etch rate of \mathrm{Si_3N_4} ...

Version
Version 1.0
Date
1 year, 3 months ago
Lab
EPFL - LPQM
Comments
0
Viewed
567
Downloads
335
Liked
1