Effect of Residual Gas Composition on Epitaxial Growth of Graphene on SiC

Abstract

In recent years, graphene growth optimization has been one of the key routes towards large-scale, high-quality graphene production. We have measured in-situ residual gas content during epitaxial graphene growth on silicon carbide (SiC) to find detrimental factors of epitaxial graphene growth. The growth conditions in high vacuum and purified argon are compared. The grown epitaxial graphene is studied by Raman scattering mapping and mechanical strain, charge density, number of graphene layers and graphene grain size are evaluated. Charge density and carrier mobility has been studied by Hall effect measurements in van der Pauw configuration. We have identified a major role of chemical reaction of carbon and residual water. The rate of the reaction is lowered when purified argon is used. We also show, that according to time varying gas content, it is preferable to grow graphene at higher temperatures and shorter times. Other sources of growth environment contamination are also discussed. The reaction of water and carbon is discussed to be one of the factors increasing number of defects in graphene. The importance of purified argon and its sufficient flow rate is concluded to be important for high-quality graphene growth as it reduces the rate of undesired chemical reactions and provides more stable and defined growth ambient.

Hydrogen intercalation of epitaxial graphene and buffer layer probed by mid-infrared absorption and Raman spectroscopy

“…The conducting nitrogen doped SiC wafers have 28 Annealing in hydrogen is performed in the range of temperatures from 790 • to 1650 • C. The hydrogen pressure and flow rate are kept at 1000 mbar and 10 SLPH, respectively. The graphite crucible for hydrogen intercalation is 40 mm long isostatically pressed graphite cylinder with 10 mm diameter.…”

ZO phonon of a buffer layer and Raman mapping of hydrogenated buffer on SiC(0001)

“…The sample of single‐layer graphene (SLG) was grown at 1650 °C for 5 min at argon flow 30 SLPH() for comparison with the hydrogen intercalated samples.…”

Intercalation of hydrogen in the SiC/epitaxial graphene interface

“…The epitaxial graphene is grown in inductively heated furnace 22 at 1600 • C for 5 minutes in argon atmosphere and argon flow 30 standard liters per hour (SLPH). More details about the growth conditions can be found in our previous work 23 . Annealing in hydrogen is performed in the range of temperatures from 790 • to 1650 • C. The hydrogen pres- sure and flow are kept at 1000 mbar and 30 SLPH, respectively.…”