Effects of substrate on the domains and electrical properties of epitaxial graphene formed on on-axis C-face 4H-SiC

Abstract

The effect of substrate surface preparation on the quality of epitaxial graphene grown on on-axis C-face 4H-SiC has been investigated. Structural epitaxial graphene has been achieved using a graphite enclosure. The homogeneity and domain size of epitaxial graphene on different pretreated substrates were studied using Raman spectroscopy, field emission scanning electron microscopy and hall measurements. The etching of C-face SiC substrate using C3H8/H2 is shown to have a pronounced effect on the domain size and hall mobility of multilayer epitaxial graphene. From Raman measurements, it is found that the pretreatment of substrate has a great influence on the domain size of epitaxial graphene. From hall results, it is found that the effect of substrate pretreatment on carrier mobility follows the same tendency reflected in the results of Raman spectra. It is concluded that the pretreatment of substrate surface, mainly the etching for generating high density, regular and periodic step structure with flatter terrace, would allow the growth of graphene with significantly large area and high mobility, even on large on-axis C-face 4H-SiC wafer.