Epitaxially Grown Hexagonal Boron Nitride Films on Sapphire and Silicon Substrates

Abstract

Hexagonal boron nitride (hBN) films were epitaxially grown on (100)-Oriented silicon and c-plane sapphire (α-Al2O3) substrates via a low-pressure chemical vapor deposition (LPCVD) method with boron trichloride (BCl3) and ammonia (NH3) as the boron source and nitrogen source. Crystalline quality differences between hBN films grown on different substrates are studied and discussed by XPS, Raman spectroscopy, XRD and SEM characterizations. All the characterization results indicate that the sapphire substrate is more suitable for epitaxial growth of hBN films than silicon substrates.

Influence of sapphire substrate with miscut angles on hexagonal boron nitride films grown by halide vapor phase epitaxy

“…5(a) and (b) indicating B and N atoms in the films are sp 2 -hybridized. 7 As shown in Fig. 5(a), the B 1S peak at 190.2 eV corresponds to the B–N bond.…”

“…45 All the grown h-BN films have higher phonon frequency than 1366 cm −1 , indicating that there is residual compressive stress in the films. 7,46 Fig. 3(e) shows the plots of E 2g FWHM and E 2g Raman shift versus m -miscut angle of sapphire.…”

“…4 Besides, it possesses excellent physical and chemical characteristics, such as great temperature stability, low dielectric constant, and outstanding mechanical properties. 5–7 Moreover, h-BN can be doped into p-type or n-type materials for deep ultraviolet optoelectronic and high-power electronic devices. 8,9 Furthermore, solid-state neutron detectors could be fabricated from large-size h-BN single crystals and be widely used in fission material sensing, medical imaging, neutron therapy, protein structure detection, and other applications.…”

“…Consequently, single-crystal h-BN thick films (≥1 μm) grown on large-size (≥2 inches) substrates, including sapphire, silicon carbide, and some metals, have become a viable option to supplant bulk single crystals. 7,15–17…”

“…Currently, chemical vapor deposition (CVD), metalorganic vapor phase epitaxy (MOVPE), and molecular beam epitaxy (MBE) are common methods to grow nanoscale h-BN thin films. 7,16,31–35 Although these methods have achieved some progress, the low growth rate and high cost limit further applications on the fabrication of h-BN thick films. In contrast, halide vapor phase epitaxy (HVPE) possesses a higher growth rate (≥1 μm h −1 ), 36 simple equipment requirements, and low cost, thus it is suitable for manufacturing large-size single-crystal thick films.…”