简介：Alargediamondcrystalupto500μmindiameterwithasmooth(100)facetatitstophasbeensynthesizedonMosubstratethroughmicrowaveplasmachemicalvapordeposition(MPCVD).Itsmorphologyandqualitywerecharacterizedbyscanningelectronmicroscopy(SEM),andthegrowthmechanismwasroughlyillustratedfrombothmacroscopicandmicroscopicviewpoints.Itwasfoundthatmorphologicalinstabilitiesareamajorfactorresultinginsynthesisoflargediamondcrystals,moreover,highmicrowavepowerdensity(MPD),highCH4concentrations,highpressure,highsubstratesurfacetemperatureandtheadditionofasmallamountofO2werealsonecessaryforthesynthesisoflargediamondcrystals.

简介：Influenceoftheparametersofplasmaenhancedchemicalvapordeposition(PECVD)onthesurfacemorphologyofhydrogenatedamorphoussilicon(α-Si:H)filmwasinvestigated.Theroot-mean-square(RMS)roughnessofthefilmwasmeasuredbyatomicforcemicroscope(AFM)andtherelevantresultswereanalyzedusingthesurfacesmoothingmechanismoffilmdeposition.Itisshownthatanα-Si:HfilmwithsmoothsurfacemorphologycanbeobtainedbyincreasingthePH_3/N_2gasflow-ratefor10%inahighfrequency(HF)mode.Forhighpower,however,thesurfacemorphologyofthefilmwilldeterioratewhentheSiH_4gasflowrateincreases.Furthermore,optimizedparametersofPECVDforgrowingthefilmwithsmoothsurfacewereobtainedtobeSiH_4:25sccm(standardcubiccentimetersperminute),Ar:275sccm,10%PH_3/N_2:2sccm,HFpower:15W,pressure:0.9Torrandtemperature:350℃.Inaddition,forinthickfilmdepositiononsiliconsubstrate,aN_2OandNH_3preprocessingmethodisproposedtosuppresstheformationofgasbubbles.