Effects of interlayers in threading dislocation reduction of step-graded InGaN heteroepitaxy

This paper investigates the effects of interlayers to reduce the threading dislocation density at the top surface of the epilayer in step-graded InGaN heteroepitaxy. The reaction kinetic coefficients are considered as key parameter in the dislocation reduction and calculated analytically. The reaction model has been solved numerically with different number of interlayer. A significant improvement of epilayer quality with extremely low threading dislocation densities have been evaluated with increasing the interlayer up to 4 where 8% In composition difference used for each step-graded interlayers.