Behavior of misfit dislocations in semipolar InGaN/GaN grown by MOVPE



A microstructure in an InGaN/GaN layer grown at the semipolar direction was observed in detail by means of transmission electron microscopy (TEM) in order to analyze the behaviour of dislocations. A (11equation image2) GaN layer was first deposited on a maskless r (1equation image02)-plane patterned-substrate, and then an Inx Ga1-xN (x =0.10, 0.24) was overgrown to be about 1 μm in thickness. Dislocations near the interface of InGaN/GaN are classified into several types: 1 Threading dislocations lying on (0001).

2. Misfit dislocations lying on the interface of InGaN/GaN. 3. Dislocations along [1equation image00] at a certain distance from the interface. 4. Dislocations newly formed at the interface and developing along [11equation image0] on (0001). 5. Partial dislocations accompanied with a stacking fault on (0001).

It was found that the misfit dislocations are arrayed in pairs at the direction along [1equation image00] on the interface of (11equation image2). Burgers vector of the misfit dislocations was found to be B = <2equation imageequation image3>/3. In case of B = [equation imageequation image23]/3, they are edge dislocations. The densities of dislocations and stacking faults increase with the In-content in InGaN. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)