Slide 1OverviewTeam MembersTeam ResponsibilitiesCurrent TechnologyKey SpecificationsSi vs. SiC ComparisonSi Plot of Resistance vs. TemperaturePrototype LayoutSiC Preliminary TestingSystem ComponentsTest SpecificationCost AnalysisDevice ImplementationFuture IntegrationSlide 16Silicon CarbideTemperature Sensorfor Harsh EnvironmentsOverviewNo reliable way to detect temperature changes in extreme environments using typical semiconductor material (Si)Space travel involves extreme temperaturesSiC has the ability to operate in and withstand extreme temperatures (>500 °C)Problem detection = Problem prevention! Spacecraft problems have proven fatalChris Rice Jason WallaceMichael Jackson Jovan BjelobrkADVISORDr. Stephen Saddow“a hot project…a cool advisor”Team MembersTeam ResponsibilitiesJovan BjelobrkJason WallaceMichael JacksonChris RiceProject Planning/CoordinationSensor DesignFabricationSensor DesignDocumentationSoftware/Web DesignDocumentationDevice Controller DesignCurrent Technology Thermocouples Silicon Chips Infrared Sensing RTD (resistive temperature device) ThermistorLimited RangeFragileLeast sensitiveRequires reference temperatureLimited RangeHigh Initial CostAccuracy affected by background radiationExpensive (made from Pt)Self-HeatingLess rugged than mostKey Specifications Increased Sensing Range0 ° C to 500 ° C Increased Operation Range0 ° C to 1000 ° C Increased ReliabilityPerforms equally well in temperature extremes without need for calibrationSi vs. SiC ComparisonSi SiCOperating Region170 °Cn/Ndn/Nd = (Nd + ni) / Ndni = (NcNv)1/2exp[-Eg/2kT]Si Plot of Resistance vs. TemperatureR vs. Temp.0204060801001201401600 50 100 150 200 250Temperature (oC)Resistance (k ohms)LWL1 = 400 μm L=1200μm t = 500 μm W=3400μmR=*L / A ; A=t*WL11000μmPrototype LayoutSI -SiC n+ or p+n+ or p+Metal ContactsSI-SiC ~ 1x1015 -cmSiC Preliminary TestingSample produced in EMRLApplied voltage and measured current to determine resistanceResistance obtained was too lowHigh resistivity sample needed!System Components•Temp. Sensing•Voltage Output•A/D Conversion•Serial Interface•Temp. Display•Advanced FunctionsVoutTest SpecificationDesign ConstraintPSPICE HEATING CHAMBERPERFORMANCE TESTINGSOFTWARE LASI 6Temperature RangeOperating TemperatureToleranceMask LayoutOperating VoltageA/D ConversionSoftware InterfaceReliability**** Denotes post-fabrication testCost AnalysisApproximately $2000 per substrate (35mm diameter wafer)Approximately $600 for whole-wafer EPI GrowthApproximately $400 for Fabrication RunProducing 25 devices per wafer, and assuming overall yield of process of 72%, produces 18 usable devices at approximately $167 eachControl board estimated at $30Total cost for working unit: $197Device ImplementationControl Board / PCSensorIncorporate onboard A/D as an integral part of the device designOnboard calculation of actual temperature valueDesign will be later incorporated into a single MEMS device for determining temperature, pressure, and vibration from a single point on a space vehicleFuture IntegrationSilicon CarbideTemperature Sensorfor Harsh
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