Journal of Crystal Growth, Vol.464, 105-111, 2017
Growth by MOCVD of In(Ga)AIN alloys, and a study of gallium contamination in these layers under nitrogen and hydrogen carrier gas
We have studied the growth of In(Ga)AIN under nitrogen and hydrogen, changing the precursor flows, temperature and growth rate to examine the effect of these parameters on the indium incorporation and layer morphology. Under hydrogen carrier gas, we successfully incorporated indium into the layers by reducing the temperature below 620 degrees C. We have also studied the gallium contamination in In(Ga)AIN layers, finding a linear correlation between tri-methyl indium (TMIn) flow and tri-methyl gallium (TMGa) effective flow coming from the pollution source, thought to be due to desorption from the chamber. By performing a chamber cleaning process between the GaN pseudo-substrate and the InAlN layer, we have both eliminated the gallium contamination and increased the indium content in our layers, reaching indium levels of up to 11% under hydrogen. Finally, we achieved a sheet resistance of 250 Omega/sq on wafers with a clean between the GaN and the InAlN layers, showing the potential for using this technique to produce high performance devices.
Keywords:Metalorganic chemical vapor deposition;Semiconducting ternary compounds;Semiconducting indium compounds;Semiconducting quarternary alloys;Nitrides;Atomic force microscopy