Lateral epitaxial overgrowth of GaN using diethyl gallium chloride in metal organic vapor phase epitaxy

Abstract

Diethyl gallium chloride (DEGaCl) was studied as an alternative gallium source for the lateral epitaxial overgrowth (LEO) of GaN by metal organic vapor phase epitaxy. The decomposition of DEGaCl to GaCl produces growth conditions similar to those found in the hydride vapor phase epitaxy technique near the growth front producing increased lateral growth rates. Controlled vertical and sloped facets were produced through the choice of the reactor operating conditions. X-ray diffraction was used to determine the LEO tilting angles that were found to decrease with decreasing lateral-to-vertical growth rate ratio. LEO GaN using DEGaCl source has shown a smaller kink density along the growing facets under the conditions required for rapid and smooth coalescence. The increased lateral growth rates and smoother sidewall facets within DEGaCl based growth were attributed to the ‘nearer-to-equilibrium’ conditions at the growth front that can result from the presence of HCl-related etching reactions.