polysilicon passivation tungsten - Fraunhofer
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tungsten polysilicon passivation n+ area buried oxide field oxide p+ area tungsten polysilicon passivation n+ area buried oxide field oxide p+ area The IMS developed an absolute pressure sensor with full scale pressures from ambient pressure to 70 bar. • Precise pressure measurements at temperatures up to 250 °C • Compact size and low mass • High overload pressure • Internal amplification • Low power consumption SOI CMOS pressure sensor A MEMS pressure sensor option has been integrated into the Fraunhofer IMS 1µm High-Temperature SOI CMOS process. The pressure sensing element consists of a polysilicon diaphragm over a conducting active area forming a capacitor whose capacitance depends on the deflection of FRAUNHOFER INSTITUTE FOR MICROELECTRONIC CIRCUITS AND SYSTEMS IMS 2 1 HIGH TEMPERATURE CAPACITIVE PRESSURE SENSOR • Operating temperature +250°C • On-Chip signal COnditiOning • sOi CmOs 1 Integrated SOI CMOS pressure sensor 2 SOI implementation of sensing element Fraunhofer Institute for Microelectronic Circuits and Systems IMS Finkenstr. 61 D - 47057 Duisburg phone +49 203 37 83-0 fax +49 203 37 83-266 www.ims.fraunhofer.de contact Michael Bollerott phone +49 203 37 83-227 [email protected] the diaphragm which is proportional to the applied input pressure. The monolithic integration of the sensor with signal condi- tioning circuits on a single chip reduces the influence of external noise sources on the sensor output signal and allows a variety of output options. Applications The small size, the low power consumption and the high temperature capability allows for high quality pressure measurements in locations where other sensors will not work. The sensor can be used for uninter- rupted, long lasting pressure monitoring in high temperature applications like geo- thermal wells, offshore drilling, automotive, aerospace and nuclear power applications with temperatures up to 250 °C.
Transcript of polysilicon passivation tungsten - Fraunhofer
tungsten
polysilicon passivation
n+ area buried oxide field oxide p+ area
tungsten
polysilicon passivation
n+ area buried oxide field oxide p+ area
The IMS developed an absolute pressure
sensor with full scale pressures from
ambient pressure to 70 bar.
• Precisepressuremeasurementsat
temperatures up to 250 °C
• Compactsizeandlowmass
• Highoverloadpressure
• Internalamplification
• Lowpowerconsumption
SOI CMOS pressure sensor
A MEMS pressure sensor option has been
integratedintotheFraunhoferIMS1µm
High-TemperatureSOICMOSprocess.The
pressuresensingelementconsistsofa
polysilicondiaphragmoveraconducting
activeareaformingacapacitorwhose
capacitancedependsonthedeflectionof
F R A U N H O F E R I N S t I t U t E F O R M I C R O E l E C t R O N I C C I R C U I t S A N d S y S t E M S I M S
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HIGH TEMPERATURE CAPACITIVE PRESSURE SENSOR• Operatingtemperature+250°C
• On-ChipsignalCOnditiOning
• sOiCmOs
1 Integrated SOI CMOS pressure sensor
2 SOI implementation of sensing element
Fraunhofer Institute for
Microelectronic Circuits
and Systems IMS
Finkenstr.61
D-47057Duisburg
phone+492033783-0
fax+492033783-266
www.ims.fraunhofer.de
contact
Michael Bollerott
phone+492033783-227
thediaphragmwhichisproportionalto
the applied input pressure. The monolithic
integrationofthesensorwithsignalcondi-
tioningcircuitsonasinglechipreducesthe
influenceofexternalnoisesourcesonthe
sensoroutputsignalandallowsavarietyof
output options.
Applications
Thesmallsize,thelowpowerconsumption
andthehightemperaturecapabilityallows
forhighqualitypressuremeasurements
in locations where other sensors will not
work.Thesensorcanbeusedforuninter-
rupted,longlastingpressuremonitoring
inhightemperatureapplicationslikegeo-
thermalwells,offshoredrilling,automotive,
aerospace and nuclear power applications
with temperatures up to 250 °C.
Sensor characteristics
Figure4showsthetemperatureand
pressuredependenceofthehightempe-
rature pressure sensor. The table below
summarizesthespecificationsofthesensor
system. The characteristics listed here
are derived from a basic MEMS pressure
sensorchipwithnoonboardlinearization
or temperature compensation. In this case
linearizationhasbeendonebysoftware
witha4thorderpolynomialforthe
pressure and 2nd order for the temperature
dependence. The advanced MEMS pressure
sensor chip provides a calibration table for
programmablelinearizationandtempera-
ture compensation.
High temperature packaging
Whendealingwithhightemperature
electronicspackagingisanotherissue
asstandardpolymer-basedtechniques
fail. IMS has developed a novel reliable
andcosteffectivetechniqueallowingdie
bondingandglobtoppingwithoutthe
needforexpensivevacuumpackages.
IMS services
ThecompetencesofFraunhoferIMSinthe
fieldofhightemperaturesensorsystems
arethedevelopmentandseries-production
ofMEMSincludingtheimplementation
offurtheron-chipfunctionalitieslike
programmablelinearization,temperature
compensation,combinedwithEEPROMfor
theon-chipstorageofcalibrationdataby
themonolithicintegrationofelectroniccir-
cuit components in addition to the pressure
sensorcellsononesinglechip.Amodern
8’’fabworkingatfourshiftsensuresthe
production of the microchips.
PressureSensorType Capacitive
Measuringranges Bar Designcontrolled,fullscalefrom
ambient pressureto70Bar(higher
pressurerangesonrequest)
Overload Bar 3xofmaximumofmeasuringrange
(higheroverloadonrequest)
SupplyVoltage VDC 4,5…5,5
PowerConsumption mW <1,5
OutputSignal V Analogordigital,adaptabletonearly
anystandardoutputrangebydesign
Min./Max.Temperature °C -40/250(tested35-250°C)
Hysteresis(35-250°C) %FSO <0,7
Thermalzeroshift(35-250°C) %FSO <0,5
1σ-Noise(35-250°C) %FSO <0,5
MeasurementError(35-250°C) %FSO <0,6
ResponseTime <300µs
Weight g 0,01
0,5
0,55
0,6
0,65
0,7
0,75
0,8
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Reference Pressure [Bar]
Mea
sure
d Vo
ltage
[V]
35°C50°C75°C100°C125°C150°C175°C200°C225°C250°C
3 High temperature application
4 Sample of sensor output
5 Table of sensor characteristics
