Large-area uniform epitaxial graphene on SiC by optimizing temperature field

Large-area uniform monolayer epitaxial graphene (EG) was prepared by the thermal decomposition of 4H-SiC in optimized temperature field. With the increase of substrate diameter, the radial temperature fluctuation also becomes more drastic. The convex and flat temperature fields with different growth system configurations were obtained by VR-PVT software. The EG surface morphology was characterized by atomic force microscopy (AFM). The graphene thickness uniformity was identified by Raman spectroscopy and scanning Kelvin probe microscopy (SKPM). After graphitization in convex temperature field with large axial and radial temperature gradients, the layer of graphene near the edge of the sample was about 1–2 layers thicker than that near the center. At the same time, many messy small steps splitting from big steps reduced the uniformity. By optimizing the temperature filed distribution the ratio of monolayer epitaxial graphene coverage increased from 65% to 94%. Furthermore, growth temperature dependence of the EG layer number and uniformity was investigated. The statistic results indicated that 1700°C was the most suitable growth temperature fabricating high quality and uniformity of EG.