Structural consequences of hydrogen intercalation of epitaxial graphene on SiC(0001)

Emery, Jonathan D.; Wheeler, Virginia H.; Johns, James E.; McBriarty, Martin E.; Detlefs, Blanka; Hersam, Mark C.; Gaskill, D. Kurt; Bedzyk, Michael J.

doi:10.1063/1.4899142

Cited by 52 publications

(38 citation statements)

References 33 publications

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“…However, the ZL plays an important role in passivating the dangling bonds of the SiC(0001) substrate, so that the overlying graphene layer exhibits truly delocalized π orbitals. An elegant way to remove the undesirable influence of the ZL on the overlying graphene is to prepare so-called quasi-free-standing epitaxial graphene (EG) through decoupling the ZL from the substrate [2] by the intercalation of various elements such as H [5,[10][11][12][13][14][15][16][17], Li [18], Na [19], O [20][21][22], F [2,23], Au [9,24], Cu [25], Fe [26,27], Yb [28], Al [29], Pt [30], Ge [7,31,32] and Si [33][34][35]. Among them, semiconducting elements in group IV, like Si and Ge, turn out to be easily intercalated by deposition at room temperature (RT) and…”

Section: Introductionmentioning

confidence: 99%

Bifunctional effects of the ordered Si atoms intercalated between quasi-free-standing epitaxial graphene and SiC(0001): graphene doping and substrate band bending

et al. 2015

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Section: Introductionmentioning

confidence: 99%

Bifunctional effects of the ordered Si atoms intercalated between quasi-free-standing epitaxial graphene and SiC(0001): graphene doping and substrate band bending

et al. 2015

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“…34,35 Thermally generated atomic hydrogen (H) is also one of the few known etchants for SiC (Refs. [41][42][43][44][45] Therefore, we have conducted a combined temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) investigation of the thermal desorption of molecular hydrogen (H 2 ) and various C, O, and F related surface species from ex-situ aqueous hydrogen fluoride (HF) and in-situ remote H-plasma cleaned 6H-SiC (0001) surfaces. 39 and 40) as well as producing quasifree standing graphene on SiC (0001) surfaces via hydrogen intercaltion.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen desorption from hydrogen fluoride and remote hydrogen plasma cleaned silicon carbide (0001) surfaces

King¹,

Tanaka²,

Davis³

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Articles you may be interested inDilute hydrogen plasma cleaning of boron from silicon after etching of Hf O 2 films in B Cl 3 plasmas: Substrate temperature dependence Structural, microstructural, and electrical properties of gold films and Schottky contacts on remote plasmacleaned, n -type ZnO{0001} surfaces Enhancement of secondary electron emission by annealing and microwave hydrogen plasma treatment of ionbeam-damaged diamond films Due to the extreme chemical inertness of silicon carbide (SiC), in-situ thermal desorption is commonly utilized as a means to remove surface contamination prior to initiating critical semiconductor processing steps such as epitaxy, gate dielectric formation, and contact metallization. In-situ thermal desorption and silicon sublimation has also recently become a popular method for epitaxial growth of mono and few layer graphene. Accordingly, numerous thermal desorption experiments of various processed silicon carbide surfaces have been performed, but have ignored the presence of hydrogen, which is ubiquitous throughout semiconductor processing. In this regard, the authors have performed a combined temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) investigation of the desorption of molecular hydrogen (H 2 ) and various other oxygen, carbon, and fluorine related species from ex-situ aqueous hydrogen fluoride (HF) and in-situ remote hydrogen plasma cleaned 6H-SiC (0001) surfaces. Using XPS, the authors observed that temperatures on the order of 700-1000 C are needed to fully desorb C-H, C-O and Si-O species from these surfaces. However, using TPD, the authors observed H 2 desorption at both lower temperatures (200-550 C) as well as higher temperatures (>700 C). The low temperature H 2 desorption was deconvoluted into multiple desorption states that, based on similarities to H 2 desorption from Si (111), were attributed to silicon mono, di, and trihydride surface species as well as hydrogen trapped by subsurface defects, steps, or dopants. The higher temperature H 2 desorption was similarly attributed to H 2 evolved from surface O-H groups at $750 C as well as the liberation of H 2 during Si-O desorption at temperatures >800 C. These results indicate that while ex-situ aqueous HF processed 6H-SiC (0001) surfaces annealed at <700 C remain terminated by some surface C-O and Si-O bonding, they may still exhibit significant chemical reactivity due to the creation of surface dangling bonds resulting from H 2 desorption from previously undetected silicon hydride and surface hydroxide species.

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“…They showed that by intercalating hydrogen between the SiC and the buffer layer, the buffer layer transforms reversibly to a normal graphene layer ( Figure 8c). This newly formed graphene layer is simply vertically displaced by 2.1Å along with the other graphene layers on top, if there are any, as shown by high-resolution X-ray reflectivity [102]. Moreover, when the hydrogen is intercalated in a monolayer graphene film, the monolayer graphene electronic structure transforms into that of an AB-stacked bilayer ( Figure 8d).…”

Section: Buffer Layermentioning

confidence: 99%

Silicon carbide and epitaxial graphene on silicon carbide

Berger

Conrad

Heer

2018

Physics of Solid Surfaces

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Graphene was defined [7] by H-P Boehm in 1986, and the nomenclature was officially adopted [23] by the International Union of Pure and Applied Chemistry (IUPAC) in 1994. It reads as follows:"Graphene is a single carbon layer of the graphite structure, describing its nature by analogy to a polycyclic aromatic hydrocarbon of quasi infinite size. Previously, descriptions such as graphite layers, carbon layers or carbon sheets, graphite monolayers have been used for the term graphene. Because graphite designates that modification of the chemical element carbon, in which planar sheets of carbon atoms, each atom bound to three neighbors in a honeycomb-like structure, are stacked in a three-dimensional regular order, it is not correct to use for a single layer a term which includes the term graphite, which would imply a three-dimensional structure. The term graphene should be used only when the reactions, structural relations or other properties of individual layers are discussed." Consistent with this definition, "graphite" should be used when graphene layers are stacked in the graphitic (Bernal) structure (see Figure 1), so that "few layer graphene" is incorrect and should be referred to as "thin graphite".In practice, graphene (including transferred graphene) is usually supported on a substrate. The term "freestanding graphene" is often used to suggest the absence of substrate-induced perturbations. Some even have suggested [24] to redefine graphene accordingly: "Graphene is a single atomic plane of graphite, which-and this is essential-is sufficiently isolated from its environment to be considered freestanding".However in practice graphene on a substrate is never freestanding. Substrates always affect the properties and quite significantly so in graphene transferred on SiO2 using the "Scotch tape" method, making this alternative definition ineffective. It makes more sense to adhere to the IUPAC definition of graphene and to apply "quasifreestanding" relative to a property. For electronic properties, quasi-freestanding implies that the electronic properties are essentially identical to those of an ideal graphene sheet. A recent publication in the authoritative journal Carbon suggests the usage of more precise definitions [25].The adhesion of graphene to many substrates involving van der Waals forces and/or electrostatic forces usually minimally affects its chemical and electronic properties (see below). But the adhesion to the substrate can be strong, involving significant chemical bonding of the carbon atoms in the graphene layer to the substrate. In these cases the electronic structure (as well as planarity) will be significantly modified. Finally, graphene can also be functionalized, in which cases atoms or molecules are chemically bound to graphene carbon atoms, whereby the electronic structure is typically significantly modified. Consequently chemical functionalization and chemical bonding to a substrate are closely related. Below, examples of all three forms of graphene are presented in the context of epitaxial...

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Structural consequences of hydrogen intercalation of epitaxial graphene on SiC(0001)

Cited by 52 publications

References 33 publications

Bifunctional effects of the ordered Si atoms intercalated between quasi-free-standing epitaxial graphene and SiC(0001): graphene doping and substrate band bending

Bifunctional effects of the ordered Si atoms intercalated between quasi-free-standing epitaxial graphene and SiC(0001): graphene doping and substrate band bending

Hydrogen desorption from hydrogen fluoride and remote hydrogen plasma cleaned silicon carbide (0001) surfaces

Silicon carbide and epitaxial graphene on silicon carbide

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