Materials · 2012 · 14 citations · 20 references
EngineeringElectrical EngineeringMaterials ScienceMicroelectromechanical SystemsMicroelectronicsSemiconductor DevicesMems CharacterizationMems SensorsMicroelectromechanical SensorsSemiconductor Device MaterialsSemiconductor HeterostructuresStrain SensorsElectron MobilityHigh-electron-mobility TransistorsPiezoresistive MaterialsPiezoresistive SensingRaman ScatteringSensor ApplicationsSiliconSilicon Wafers
Resonant Tunneling Diodes (RTD) and High Electron Mobility Transistor (HEMT) based on GaAs, as the piezoresistive sensing element, exhibit extremely high sensitivity in the MEMS sensors based on GaAs. To further expand their applications to the fields of MEMS sensors based on Si, we have studied the optimization of the GaAs epitaxy layers on Si wafers. Matching superlattice and strain superlattice were used, and the surface defect density can be improved by two orders of magnitude. Combing with the Raman spectrum, the residual stress was characterized, and it can be concluded from the experimental results that the residual stress can be reduced by 50%, in comparison with the original substrate. This method gives us a solution to optimize the epitaxy GaAs layers on Si substrate, which will also optimize our future process of integration RTD and HEMT based on GaAs on Si substrate for the MEMS sensor applications.
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Raman scattering and lattice defects in nanocrystalline CeO2 thin films
Igor Kosacki, Toshio Suzuki, Harlan U. Anderson et al. · Solid State Ionics · 2002 · 561 citations