Quaternary In0.12Al0.29Ga0.59N and In0.10Al0.02Ga0.88N layers some 200nm thick were grown onto (00•1) GaN/sapphire using metalorganic chemical vapor deposition. They were studied using transmission electron microscopy. These results indicated that the quaternary layers contained high-density stacking faults. Weak-beam dark-field analysis coupled with high-resolution electron microscopy revealed that stacking faults had zinc-blende structures bounded by Shockley partials. Compared with In0.10Ga0.90N layers, the stacking fault density increased substantially in an In0.10Al0.02Ga0.88N layer with only 2% additional Al. Z-contrast annular dark-field images showed that stacking faults were Al-rich in the In0.12Al0.29Ga0.59N layer, but not in the In0.10Al0.02Ga0.88N layer. Two reference AlxGa1−xN layers were grown using identical conditions, except for the carrier gases. Using H carrier gas resulted in an approximately 400nm-thick Al0.45Ga0.55N layer with no stacking faults. Using N carrier gas resulted in a roughly 250nm-thick Al0.25Ga0.75N layer with stacking faults. It was suggested that a low surface mobility of (CH3)2Al:NH2 species in the N environment led to stacking fault formation.

Stacking Faults in Quaternary InxAlyGa1-x-yN Layers. F.Y.Meng, M.Rao, N.Newman, R.Carpenter, S.Mahajan: Acta Materialia, 2008, 56[15], 4036-45