Examples of SiC Sensor R&D Activities
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Transcript of Examples of SiC Sensor R&D Activities
h t t p : / / m i n o l a b . c a s e . e d u /
Examples of SiC Sensor R&D Activities
Mehran Mehregany and Srihari Rajgopal
NATO RTO, Granada, Spain, October 6, 2005
C A S E S C H O O L O F E N G I N E E R I N
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Current SiC Sensor Device Research
Pressure sensors• On-demand production by Kulite• R&D by FLX Micro, STMicroelectronics, Sienna Tech.• Various govt. and academic (NASA, Case, TU Berlin, TU
Delft)Accelerometer
• Various academic (Case, NASA, TU Delft)Gas sensors
• Research by AppliedSensor (S) for automotive exhaust gas and various academic
• Availability >> 5 yearsUV sensors (market < $500K)
• Two devices (sglux, IFW) available, based on Cree chips• Small area limits applications
Radiation sensors• Prototype by Westinghouse (Siemens)
Gas sensor from Boston Microelectronics
UV sensor from IFW
Pressure sensor from KuliteSource: www.wtc-consult.de September
12, 2005
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Example: Micromachined Fuel Atomizers Achieve precise geometries through micromachining Reduce cost through batch fabrication
Si Fuel Atomizers
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Point of highest wear occursat the edge of the exit orifice.The rest of the swirl chamberfloor is largely unaffected.
SEM photo of edge after erosion
Si Fuel Atomizers Fail
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Fabricate a mold by DRIE of a Si wafer Fill with SiC, polish and etch the Si
SiC Fuel Atomizers
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Pressure Sensor – Bulk micromachining
Kulite/NASA example:
– Suspended membrane with piezoresistive elements
– Anisotropic reactive ion etch of 6H-SiC substrate
Source: Leadless sensor packaging for high temperature applicationsMasheeb, F.; et al.,MEMS, 2002
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Accelerometer – Bulk micromachining
NASA example:
– Suspended membrane with piezoresistive elements
– Anisotropic reactive ion etch of 6H-SiC substrate
Source: Ken Bradley 48th Annual NDIA Fuze Conferece, NC April 28, 2004
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Accelerometer – Test Results
Source: Ken Bradley 48th Annual NDIA Fuze Conferece, NC April 28, 2004
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Gas Sensors
MISiCFET (MI – metal insuator
•Gas molecules or reaction species diffuse to the metal-insulator interface and form a polarized layer
•This acts as an applied potential to the gate region
•Variations in the composition of the gas shift the sensor voltage to a higher or lower value
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Packaging
• Thermal conductivity• Minimize thermal resistance in packaging components
• Thermomechanical compatibility• Minimize difference in coefficient of thermal expansion between
components during assembly and operation• Thermal shock resistance
• Ability to withstand sudden thermal excursions during service• Chemical compatibility
• Inhibit electromigration in conductors and metallization reaction with the SiC semiconductor
• Hermiticity• Hermetic seal
• Simplicity, size and weight• Preferably light-weight with small form factor