A Study Of The Growth Process Of Epitaxial Graphene On The C Face Of SiC

Graphene has a very high research value and a broad application prospect, with many very excellent propreitys. However there is currently no proven method to get high-quality and large-area graphene films in low-cost. Epitaxial graphene grown on Si C is a method for the preparation of graphene which can compatible with the existing semiconductor technology.In order to research the growth mechanism of epitaxial graphene grown on Si C substrate, we have done a lot of experiments in epitaxial graphene on 0°angle 4H-Si C substrate in high- temperature under a low degree of vacuum(1~2Pa) condition, then done characterization of epitaxial results by instruments such as Raman spectroscopy, Atomic Force Microscopy, Scanning Electron Microscopy and Optical Microscope.After the reading and studying of a lot of references, we determine the starting point of this paper as follow: 1)The graphene forming temperature on the C surface of 4H-Si C under the low vacuum(1~2Pa) condition should be higher than 1400℃,the structural changes of the C surface of 4H-Si C substrate should be(1×1)Si Câ†'(3×3)Si Câ†'(2×2)Si Câ†'(1×1)g in the epitaxial growth process; 2)There should be more defects in the epitaxial graphene without a Si flux in the growth process; 3)Hydrogen etching process is conducive to the formation and expansion of graphene on the Si C substrate surface. In reference to the experiment of domestic and foreign and in view of the existing condition of our laboratory, we determine our own program, broadly divided into substrate cleaning, hydrogen eching, remove compounds and epitaxial growth.Through a comparative study of characterization test results, we reached the following conclusions: 1) We can approximately conclude that in the range of 1075 ℃ ~ 1200 ℃, the structure of C face of 4H-Si C is gradually transformed from(1×1) into(3 × 3) structure; In the range of 1200 ℃ ~ 1400 ℃, the structure of C face of 4H-Si C is gradually transformed from(3×3) into(2 × 2) structure; In the range of 1400 ℃ ~ 1500 ℃, the structure of C face of 4H-Si C is gradually transformed from(2×2) into(1 × 1) structure of graphene. The highest quality graphene is obtained in 1580℃ by keeping 10 min, and the number of layers of graphene will increase rapidly with the increase of keeping time. 2)The heating rate has a great effect in epitaxial graphene.I n general, the lower the heating rate, the higher the quality graphene growth. 3) The Si flux can effectively reduce the defects of epitaxial graphene and make graphene a better ording.4)Hydrogen etching process can remove the scratches and defects of the surface and be conducive to the formation and expansion of graphene on 4H-Si C substrate.Research of this paper is limited to the grown procedure of epitaxial graphene on C face of 4H-Si C substrate,so it has many limitations.Being a promising method of proparing of graphene,epitaxial graphene grown on Si C has many points worth exploring.