Growth of hexagonal boron nitride on sapphire substrate by pulsed-mode metalorganic vapor phase epitaxy.

Hexagonal boron nitride (h-BN) was directly grown on sapphire substrate using alternating ammonia (NH 3 ) and triethylboron (TEB) supply (pulsed mode) in metalorganic vapor phase epitaxy. The best condition is when just enough NH 3 is supplied to fully convert the TEB within one cycle. Excess NH 3 caused islands on h-BN film surface while a lack of NH 3 does not form h-BN at all. The epitaxial relationship between grown h-BN layer and c -plane sapphire was confirmed to be [0001] h-BN ∥[0001] sapphire and [10-10] h-BN ∥[11-20] sapphire . It is known that, compared to AlN, BN requires higher V/III ratios for good crystallinity, which due to severe gas-phase reactions is difficult to achieve using continuous supply. Thus using pulsed mode the FWHM of the symmetric (0002) diffraction was almost halved and the growth rate was several times faster. [ABSTRACT FROM AUTHOR]