Epitaxial Graphene on SiC Surface: Growth and Device Applications

Abstract

Thanks to its superior electron and hole mobilities, graphene has been considered to be a promising candidate material for ultra-fast electronic devices operating up to THz frequency regime. Since the first successful isolation of graphene achieved by mechanically exfoliating highly oriented pyrolytic graphite (HOPG), there has been an enormous amount of research activities for synthesizing large-scale graphene by utilizing several different experimental techniques such as chemical vapor deposition (CVD), solid source deposition, and surface graphitation of SiC. Among these experimental techniques, the surface graphitation of a single crystalline SiC by thermal annealing in ultra high vacuum (UHV) or Ar environment at high temperature (> 1300 °C) has been of particular interest with the possibility of achieving wafer-scale uniform graphene. In this talk, unique material properties of graphene, especially relevant for electronic device applications, will be first introduced. And several types of graphene electronic devices will be introduced in terms of their structures and operational characteristics with a particular emphasis on high-frequency device applications. Then, the epitaxial graphene (EG) grown on hexagonal SiC surface will be discussed in terms of its growth methods and electrical properties. Two newly developed growth methods enabling the growth of high-quality EG at significantly reduced temperature in comparison with the conventional high-temperature annealing method will be introduced mainly. One method is to grow an EG film on a hexagonal SiC substrate by irradiating electron beam directly on the surface with no need to heat the entire substrate to high temperature over 1300 °C. The other method is to grow a very high-quality uniform EG film on a hexagonal SiC substrate by capping the SiC surface with a Molybdenum plate during UHV annealing process. As an important factor determining the quality of EG film, the surface structure of a hexagonal SiC substrate before growth and its preparation methods will be also discussed. Finally, the prospect of EG grown on SiC surface for future electronic device applications will be examined.