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

Abstract

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.