EFFECT OF LASER-ASSISTED RESONANT EXCITATION ON THE GROWTH OF GaN FILMS

Gallium nitride (GaN) films were grown using laserassisted metal organic chemical vapor deposition (LMOCVD). The vibrational mode (1084.63 cm-1) of ammonia (NH3) molecules was resonantly excited using a wavelength-tunable CO2 laser at a laser wavelength of 9.219 μm due to its high absorption cross-section. Through wavelength-matched resonant excitation of the NH3 molecules, highly c-axis oriented GaN films were successfully deposited on sapphire (α-Al2O3) substrates at low temperatures (250 to 600 oC). The strong (0001) GaN peak in Xray diffraction spectra confirmed the good crystalline quality of GaN films. Additionally, the resonant vibrational excitation of NH3 in LMOCVD promoted the GaN growth rate considerably compared to that synthesized by MOCVD without resonant vibrational excitation of NH3 molecules.