Effect of Ar addition in N2 discharge by ion bombardment of liquid Ga surface using plasma-sputter source

Abstract

The effect of plasma ion bombardment on liquid Ga had been investigated using a multi-cusp plasma sputter ion source. The use of pure N₂ plasma enhanced the reaction of N₂ with liquid Ga to produce bulk and thin film GaN. Optical emission spectra of the plasma near the Ga surface show the most intense peak in the second positive region of excited N₂ molecules at 391 nm wavelength. As the nitrogen line spectra dominate, the Ga peaks cannot be distinguished in a pure N₂ plasma. Using Ar, the sputtering of Ga has been confirmed and with the mixture of N₂, the peaks of N₂, Ar and Ga are observed. Produced bulk and thin film GaN are characterized using X-ray diffraction. The bulk crystals exhibit good crystalline and texture quality with peaks at angles corresponding to (002) and (004) GaN reflections. The produced GaN films also show preferred orientation at (002) reflection of GaN.