Fully Integrated MEMS Resonator in Unmodified Standard CMOS process
- Detailed Technology Description
- A new method has been developed for fabricating MEMS and NEMS devices alongside active and passive electronic elements using a standard CMOS foundry process without modification.
- Others
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Patent Application: PCT/US09/48835
- *Abstract
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A new method has been developed for fabricating MEMS and NEMS devices alongside active and passive electronic elements using a standard CMOS foundry process without modification. This means that now many MEMS can be manufactured at a lower cost in standard CMOS foundries rather than in foundries specializing in MEMS.
The key to this new method is appropriate design of the sacrificial material layer under the devices (the field oxide or local-oxidation-of-silicon layer) which facilitates out-of-plane buckling away from the substrate as stress is relieved when the devices are released. Devices like resonators can be manufactured in a polysilicon-silicon dioxide-polysilicon layer stack, and MHz frequency devices are achievable with quality factors in the thousands.
This design feature increases post-release yields of MEMS devices, and protects regions of the chip in the vicinity of the resonator during the post-processing release setup. The ability to design in out-of-plane buckling also facilitates resonator formation from the upper polysilicon layer using the inter-laying silicon oxide as a sacrificial layer. Without the forced out-of-plane buckling, the inter-layer spacing is insufficient to allow resonators in the upper polysilicon layer to be released without sticking to the bottom polysilicon layer. With the designed out-of-plane buckling, the upper polysilicon layer can be used as a resonator with a very large capacitance with respect to the lower polysilicon layer since the effective capacitor plate spacing is very small (a few nanometers up to perhaps twenty nanometers).
Potential Applications- MEMS and NEMS production
Advantages
- Enables MEMS and NEMS production in standard CMOS foundries
- *Licensing
- Martin Teschlmt439@cornell.edu(607) 254-4454
- Country/Region
- USA
