The formation of crystalline defects and crystal growth mechanism in InxGa1-xN/GaN heterostructure grown by metalorganic vapor phase epitaxy

The composition pulling effect at the initial growth stage of InxGa1-xN grown on a GaN epitaxial layer is studied in relation to the lattice mismatch between InxGa1-xN and the GaN epitaxial layer. TEM observation of the InxGa1-xN/GaN heterostructure reveals that the degradation of the InxGa1-xN layer is caused by pit formation, which is converted from the edge dislocations penetrating to the InxGa1-xN layer from the GaN layer. By increasing the layer thickness. the crystalline quality becomes worse, and InxGa1-xN consists of two types of regions: a homogeneous: good crystalline quality layer and a bad crystalline quality layer. Crystalline quality of InxGa1-xN is good near the interface of InxGa1-xN/GaN, and EDX composition analysis shows that the composition of InxGa1-xN near the interface is close to that of GaN. (C) 1998 Elsevier Science B.V. All rights reserved.