Epitaxial Process Of Graphene On SiC Substrate And Raman Characterization

Obtaining large and high quality epitaxial graphene is a challenging job. Besides,identifying and characterizing graphene is of importance. In this paper, fabricationprocess of epitaxial graphene is presented, and the influence of process parameterssuch as temperature and process step is explored with the tool of Raman spectroscopy.This paper firstly illustrates basic characteristics of energy band structure ofgraphene, as well as the sources and features of its Raman spectroscopy. The positionand shape of G band (¹580cm^-1)and2D(²700cm^-1) are the main features of graphene.The strain effect and electronic band structure cause the position of G band and2Dband shift up in epitaxial graphene. With the increasing of graphene layers on SiC,2Dband becomes broader and upper.Secondly, mechanisms of epitaxial graphene on the two face of SiC are furtherresearched. On the Si face of SiC, growth is the reconstitution of buffer layer,and new graphene is stacked on buffer layer. On the C face of SiC, this bufferlayer doesn’t exist, and the epitaxial graphene are rotational disorder.Thirdly, the fabrication process of epitaxial graphene is investigated. Hydrogenetching can not only remove the scratches on the SiC surface,but also can producenanoscale step, which contributes to the epitaxial growth. With the increase of growthpressure（from UHV, high vaccum and Ar atmosphere）, the quality and size of graphenetends to be higher and larger.Finally, utilizing the VP508high reactor system, several experiments are done.With the increase of growth temperature, the epitaxial graphene on the Si face of4H-SiC doesn’t show the tendency of quality improvement.2D band of the samplewhich is growth under1300has a sharp and strong shape. Epitaxial graphene on theC face of Shanda6H-SiC（000-1） has the strong trend that high temperature yields highquality. With the addition of fabrication process which role is to remove the oxide afterH-etch,1m wide step-like graphene which covers the substrate has been successfullygrowth on the11cm²Si face of8off-cut Cree4H-SiC, which2720cm-12D band isbroad.