Synthesis of hexagonal boron nitride films on silicon and sapphire substrates by low-pressure chemical vapor deposition

Hexagonal boron nitride (hBN) films are synthesized on silicon (100) and c-sapphire substrates by low-pressure chemical vapor deposition at 1100 degrees C. Ammonia borane is used as a single-source precursor. hBN films are characterized by Raman, UV-vis, and x-ray photoelectron spectroscopies, and the surface morphology is studied by scanning electron microscopy. This study shows a direct method to synthesize and characterize hBN films on the most extensively used substrates in the semiconductor industry, eliminating the need for a transfer method used when the films are grown on metallic substrates. The synthesized hBN films have an approximate crystallize size of 6.37 nm on silicon and 6.13 nm on sapphire. The B:N ratio is found in agreement with the theoretical stoichiometric values of 1:1 for film growth on both substrates. The deposited films have a granular nature, and films grown on silicon have a high pinhole density. The measured optical band gaps of hBN grown on silicon and sapphire are 4.46 eV and 5.76 eV, respectively.

Automated summary

Hexagonal boron nitride (hBN) films were successfully synthesized on silicon and sapphire substrates using low-pressure chemical vapor deposition, demonstrating a direct method for film synthesis and characterization. The films grown on silicon exhibit large crystallize size and pinhole density, while the films grown on sapphire have larger optical band gaps.