Why graphene growth is very different on the C face than on the Si face of SiC: Insights from surface equilibria and the(3×3)−3C−SiC(1¯1¯

Abstract

We address the stability of the surface phases that occur on the C side of 3C-SiC(111) at the onset of graphene formation. In this growth range, experimental reports reveal a coexistence of several surface phases. This coexistence can be explained by a Si-rich model for the unknown (3 × 3) reconstruction, the known (2 × 2) C adatom phase, and the graphene-covered (2 × 2) C phase. By constructing an ab initio surface phase diagram using a van der Waals corrected density functional, we show that the formation of a well defined interface structure like the "buffer layer" on the Si side is blocked by Si-rich surface reconstructions.

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

“…The SiC step bunching, as another issue reducing graphene mobility on SiC, has been solved by amorphous carbon step pinning [14]. The thermodynamics of stable phases that gov- * Electronic address: kunc@karlov.mff.cuni.cz erns the onset of graphene formation [5], oxidation [15] and other chemical reactions [16] has been discussed, too. However, there is a little or no experimental evidence of graphene growth conditions and composition of a residual gas inside a graphene furnace [17].…”

“…Among novel devices, the growth technique, together with SiC wafer preparation, stands at the beginning of whole manufacturing process. It is therefore a key to understand conditions under which reproducible high quality graphene can be reached [4,5]. The growth mechanisms has been studied both theoretically and experimentally.…”

Controllable Synthesis of Few-Layer Graphene on β-SiC(001)

“…Then, a number of works demonstrating the feasibility of graphene synthesis on β-SiC/Si wafers of different orientations have been published . Mostly, these studies have been conducted on β-SiC (111) thin films [51][52][53][54][55][56][57][58][59][60][61][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81] and single-crystalline SiC (111) wafers [62][63][64]. However, some studies have been carried out on β-SiC(001) [50, 61, 82-93, 101, 102] and even on polycrystalline β-SiC substrates [94].…”

Order and disorder at the C-face of SiC: A hybrid surface reconstruction

“…Indeed, in addition to the three previously discussed STM conditions, the low formation energy FE condition should also be fulfilled for a model to be a reasonable candidate to explain this reconstruction. As demonstrated by previously published models, [3][4][5][6][7] that also have failed to reproduce one or the other condition, meeting all the constraints in a model is a challenge.…”

“…3 This system shows a clear distinction between STM features at occupied states (stm o ) and unoccupied states (stm u ). Several attempts [3][4][5][6][7] to explain these observations with an atomic model of the surface were unsuccessful since the exact composition of the surface as well as the affected number of layers cannot be attained from the experimental data. The difficulty of determining the composition of the bare 3×3 is increased as this surface undergoes an evolution by increasing the temperature, with the subsequent formation of graphene on it.…”