Migration enhanced metal organic chemical vapor deposition of AlN/GaN/InN-based heterostructures

This article has described a new Migration Metal Organic Chemical Vapour Deposition (MEMO-CVD) epitaxial technique for growth of AlN/GaN/InN films and heterostructure layers. MEMO-CVD is an improved Pulsed Atomic Layer Epitaxy (PALE), which deposits quaternary Al_xIn_yGa_1-xyN layers by repeats of a unit cell grown by sequential metal organic precursor pulses of Al-, In-, Ga- and NH₃. Since MEMO-CVD combines a fairly high growth rate for buffer layers with reduced growth temperature and improved quality for active layers, this new technique achieved a better mobility of pre-cursor species on the surface and thus, better atomic incorporation and improved surface coverage. MEMO-CVD also enabled scale up of our epitaxial technology to four inch and allowed for precise growth of strain and energy band engineered structures resulting in elimination of aging effects in AlGaN/GaN heterostructures grown on large area substrates.