Mask interference effect in GaN SA-MOVPE: Predicting the growth of isolated structures

Abstract

The material aggregation during selective area metalorganic vapor phase epitaxy (SA-MOVPE) of gallium nitride (GaN) structure arrays, using silicon dioxide (SiO₂) masking layer deposited by plasma enhanced chemical vapor deposition (PECVD) was investigated by optical profilometry measurements. Selective GaN deposition was performed at two pressure levels (50 hPa and 150 hPa) using hydrogen as the carrier gas and trimethylgallium and ammonia as epitaxial growth precursors. The relationship between the structure growth rate enhancement and the structure array density was analyzed. Sudo’s effective mask model was applied to estimate that the mask interference constant is in the range $[0.60;0.83]$ for the GaN epitaxy performed at 50 hPa and $[0.29;0.45]$ for the epitaxy performed at 150 hPa. A new method for the prediction of the growth rate of isolated structures was proposed based on profile measurements of the structure array.