Suppression of V-pits formation in InGaN layer by stepped growth with annealing interval

An epitaxial method of stepped growth with additional annealing interval is proposed to suppress the V-pit formation in InGaN layer. Detailed investigation on the influences of annealing condition indicates that more cycles in an annealing interval, relatively higher annealing temperature or longer annealing time can better reduce the density and size of V-pits in InGaN, and finally obtain a InGaN layer with much less V-pits. Micro-photoluminescence mapping measurements present a better spatial distribution and a smaller full width half maximum of luminescence peaks, providing more information about the advantage of stepped growth with annealing interval. Moreover, an experiment for thick InGaN layer growth with a relatively higher indium content also proves that such stepped growth could suppress the V-pits effectively.