Controlled and Selective Area Growth of Monolayer Graphene on 4H-SiC Substrate by Electron-Beam-Assisted Rapid Heating

Abstract

A facile method for direct and selective area conversion of 4H-SiC substrates into homogeneous epitaxial graphene is demonstrated by the irradiation of a low energy (5 keV) electron beam (e-beam). The localized interactions like scattering, excitation, and ionization between the primary electrons and the SiC surface result in Si−C bond breaking, and the excess kinetic energy of electrons is dissipated as heat that results in the selective sublimation of the Si ion favoring the formation of epitaxial graphene. The thickness of the graphene layer is precisely controlled by varying the e-beam energy and the irradiation time. The number of graphene layers increases with irradiation due to thermally induced Si sublimation over the depth of a few atomic layers depending on the incident energy of the e-beam. The Hall mobility of large area single layer graphene formed on the Si-face is ∼6450 cm 2 V −1 s −1 with a surface carrier density (n-type) of 1.5 × 10 13 cm −2 . Our results demonstrate that the e-beam irradiation technique is a viable route to define wafer scalable selective area graphene structures directly on semi-insulating 4H-SiC substrates for electronic applications.

Optimized growth of graphene on SiC: from the dynamic flip mechanism

“…(i) The growth temperature can be significantly reduced provided that breaking of Si-C and Si-Si bonds during Si sublimation can be assisted by other mechanisms, such as energetic electron or laser beam irradiation instead of thermal excitation. [21][22][23][24] Moreover, other nanofabrication and patterning technologies which can cause the sputtering of substrate atoms with a high spatial resolution, such as a focused ion beam (FIB) and plasma etching, are alternatives. FIB offers both high-resolution imaging and flexible micromachining in a single platform.…”

“…21 Furthermore, Dharmaraj et al demonstrated the possibility of precise control of an E-beam over the SiC substrate for uniform graphene growth. 22 Meanwhile, Lee et al were able to synthesize graphene for the first time by heating only the SiC surface and keeping the substrate at room temperature using a KrF excimer laser. 23 Later, Yannopoulos et al reported the growth of low-strain graphene films on the SiC substrate using an infrared CO 2 laser as the surface heating source which promotes cleavage of Si-C bonds and evaporation of Si atoms from the SiC surface.…”

Selective-area growth and controlled substrate coupling of transition metal dichalcogenides

“…Selective-area growth has been a goal for many semiconductor materials and can be achieved in traditional group-III nitride semiconductor nanostructures [22] and 1D-nanowires [23,24] via templating of crystallographic growth substrates. Furthermore, selective Selective-area growth and controlled substrate coupling of transition metal dichalcogenides growth of graphene is possible via electron beam irradiation [25], crystallographic confinement [6,26], or using a PMMA-seeded approach [27,28]. In more recent years, there have been several reports of 'selective-area growth' of MoS 2 , however these techniques either rely on placing masks in contact with the substrate during growth [29], deposition and lithographic patterning of seeded areas [30] or templating (via direct etching) of the substrate [31].…”

Effect of ion-beam irradiation on the epitaxial growth of graphene via the SiC surface decomposition method

“…Strupinski et al 11) showed that high-quality graphene layers were deposited onto SiC substrates via CVD, and other authors [12][13][14][15] have attempted to form graphene by irradiating an SiC substrate using an electron beam or pulsed laser. For example, Go et al 12) prepared epitaxial graphene on a 6H-SiC substrate using a low-energy electron beam at an acceleration voltage of 8 kV under high-vacuum conditions.…”