The influence of GaN growth temperature on parasitic masking in SA-MOVPE using PECVD SiO2 mask

The paper reports a phenomenon of parasitic substrate masking during selective area metalorganic vapour phase epitaxy (SA-MOVPE) of gallium nitride (GaN), using silicon dioxide (SiO2) masks deposited by plasma enhanced chemical vapour deposition (PECVD), at variable temperature conditions. Selective GaN deposition was conducted in the mass-transport limited growth regime at increased pressure (350 hPa and 800 hPa) using hydrogen as a carrier gas, and trimethylgallium (TMGa) and ammonia (NH3) as epitaxial growth precursors. The discussion on the influence of temperature on surface morphology and SiO2 mask nitridation depth in ammonia-rich atmosphere is followed by the presentation of the experimental work results focused on the investigation of the relationship between the parasitic masking effect and susceptor temperature during MOVPE process. The average activation energy of the parasitic masking layer formation at 800 hPa was calculated at 6.7 eV. Analysis of the surface morphology was conducted using scanning electron microscopy (SEM).