简介：InordertoaccomplishreliablemechanicaldesignofMEMS,theinfluencesofsurfaceroughnessandoctadecyltrichlorosilane(OTS)self-assembledmonolayers(SAMs)onthemechanicalpropertiesofmicromachinedpolysiliconfilmsforMEMSareinvestigated.Surfaceeffectonthefracturepropertiesofmicromachinedpolysiliconfilmsisevaluatedwithanewmicrotensiletestingmethodusingamagnet-coilforceactuator.Statisticalanalysisofthesurfaceroughnesseffectsonthetensilestrengthpredicatedthesurfaceroughnesscharacterizationofpolysiliconfilmsbeingtestedandthedirectrelationofthemechanicalpropertieswiththesurfaceroughnessfeatures.Thefracturestrengthdecreaseswiththeincreaseofthesurfaceroughness.Theoctadecyltrichlorosilaneself-assembledmonolayerscoatingleadstoanincreaseoftheaveragefracturestrengthupto32.46%.SurfaceroughnessandthehydrophobicpropertiesofspecimenwhencoatedwithOTSfilmsarethetwomainfactorsinfluencingthetensilestrengthofmicromachinedpolysiliconfilmsforMEMS.

简介：Thebendingstrengthofmicrofabricatedpolysiliconbeamswasmeasuredbybeambendingusingananoindenter.Also,thetensilestrengthofmicrofabricatedpolysiliconthinfilmswasmeasuredbytensiletestingwithanewmicrotensiletestdevice.Itwasfoundthatthebendingstrengthandtensilestrengthofpolysiliconmicrostructuresexertssizeeffectonthesizeofthespecimens.Insuchcases,thesizeeffectcanbetracedbacktotheratioofsurfaceareatovolumeasthegoverningparameter.Astatisticalanalysisofthebendingstrengthforvariousspecimensizesshowsthattheaveragebendingstrengthofpolysiliconmicrocantileverbeamsis2.885±0.408GPa.ThemeasuredaveragevalueofYoung'smodulus,164±1.2GPa,fallswithinthetheoreticalbounds.Theaveragefracturetensilestrengthis1.36GPawithastandarddeviationof0.14GPa,andtheWeibullmodulusis10.4-11.7,respectively.Thetensiletestingof40specimensonfailureresultsinarecommendationfordesignthatthenominalstrainbemaintainedbelow0.0057.