Languages
Pages
Legal
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
21
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
Top Related