Growth of 3C-SiC(111) on AlN/off-axis Si(110) hetero-structure and formation of epitaxial graphene thereon

Abstract

A cubic silicon carbide (3C-SiC) film was fabricated by pulsed laser deposition on an aluminum nitride layer grown on an off-axis Si(110) substrate. This is the first report about the use of off-axis Si(110) substrates for manufacturing SiC/AlN/Si multilayers. A high-quality epitaxial 3C-SiC(111) film without rotation domains or twins, as evidenced by reflection high-energy electron diffraction (RHEED) measurements, was successfully obtained by using a wurtzite AlN(0001)/off-axis Si(110) substrate. On this 3C-SiC film, graphene was formed through annealing in ultrahigh vacuum at 1200 °C and its structure and chemical bonding were investigated via in situ RHEED and X-ray photoelectron spectroscopy; the full width at half maximum of the C 1s core level peak and the root-mean-square surface roughness were 0.60 eV and 0.14 nm, respectively, which were substantially lower than those (0.73 eV and 1.44 nm) previously reported for a graphene sample with similar thickness but formed on a SiC/AlN/onaxis Si(110) substrate.

CVD Elaboration of 3C-SiC on AlN/Si Heterostructures: Structural Trends and Evolution during Growth

“…In the present case, it must be highlighted that the use of off axis AlN/Si(111) templates did not reduce the relative contribution of a given domain (see Figure 2b,c). Our results differ noticeably from those of [4], where a single-domain SiC film was obtained using the off axis AlN/Si(110) substrates. Discrepancies between this observation and our results can be related to the very different growth conditions between our work and those of [4].…”

“…These epitaxial relationships are similar to those already reported for SiC growth at a low temperature using the PLD technique both for AlN and SiC formation [4] on Si(110) substrates. According to the almost equivalent diffraction intensities of different domains, we can conclude that the statistical occurrence of both domains is equivalent.…”

“…The 3C-SiC/AlN heterostructure grown on silicon substrates offers advantages for different fields of investigation, from pseudo-substrate for 2D material growth to research on hybrid material-based microelectromechanical systems (MEMS). It has been attractive in the past decades due to its potential use as a base template for the fabrication of graphene on silicon wafer (GOS) samples [1][2][3][4] because of the presence of oriented 3C-SiC(111), which allows for the formation of high-quality graphene films by thermal treatment. From this perspective, the underlying AlN film, according to its very large bandgap, could permit the electrical insulation of the graphene from the substrate and could be used as a back electrode for transistor fabrication.…”

Understanding of impact of carbon doping on background carrier conduction in GaN*

“…The C N acceptors with a negative-to-neutral charge state (−/0) (0.9 eV above valence band) and a 0/+ level (0.4 eV above valence band) [25,26] are theoretically calculated which interpret the YL and BL luminescence, respectively. It is also recognized that these deep energy levels are difficult to be electrically ionized [27][28][29][30][31] and the compensation of background carrier is associated with the Fermi level pinning effect at around C N acceptor energy level. [28][29][30][31] While the pinning effect occurs when the acceptor trap density is much higher than that of donor trap density, the fermi energy levels and background carrier concentration remain constant as C concentration increases.…”

“…It is also recognized that these deep energy levels are difficult to be electrically ionized [27][28][29][30][31] and the compensation of background carrier is associated with the Fermi level pinning effect at around C N acceptor energy level. [28][29][30][31] While the pinning effect occurs when the acceptor trap density is much higher than that of donor trap density, the fermi energy levels and background carrier concentration remain constant as C concentration increases. In this work the background concentration generally varies with the carbon doping concentration.…”