This phenomenon commonly occurs due to (*) capillary 9 forces after the sacrificial layer in a surface-micromachined structure is wet etched.
For silicon substrates, self-assembled monolayers based on octa-decyl-trichloro-silane, ODTS, and per- fluoro-decyl-trichloro-silane, FDTS, have been used to negate this phenomenon. An innovative method 3 for avoiding this phenomenon involves displacing an etchant with water, which is then displaced with methanol, which is then displaced by liquid CO2 in a pressure chamber, where the liquid CO2 is transformed to its supercritical phase and then to gaseous CO2. In working devices, this phenomenon 6 commonly appears as a result of electrostatic forces or acceleration due to shock. This phenomenoncan be negated by etching dimples into a sacrificial layer, so that the final structure also has dimples,which limits its contact area with the substrate. This phenomenon commonly occurs due to (*) capillary 9 forces after the sacrificial layer in a surface-micromachined structure is wet etched. For 10 points, name thismajor mode of failure for MEMS devices that occurs when the MEMS structure adheres to the substrate.
For silicon substrates, self-assembled monolayers based on octa-decyl-trichloro-silane, ODTS, and per- fluoro-decyl-trichloro-silane, FDTS, have been used to negate this phenomenon.
stiction [prompt on: Van der Waals forces, electrostatic forces, capillary forces, hydrogen bridging]