Effect of lateral vapor phase diffusion during the selective growth of InGaN/GaN MQW on semipolar and nonpolar GaN stripes

We investigated the InGaN/GaN multiple quantum well (MQW) thickness and cathode luminescence (CL) distribution on nonpolar (11–20)GaN, semipolar (11–22)GaN, and (1–101)GaN microstripes grown by selective metal‐organic vapor phase epitaxy (MOVPE) on patterned Si substrates. All samples exhibited ridge growth. To clarify the effect of vapor phase diffusion, the two‐dimensional diffusion equation was solved. The results were in good agreement with the thickness distribution on the (11–20)GaN stripe when we assumed D/k0 to be 1 µm. However, the results were not in agreement for the semipolar case. On the semipolar face, the surface migration length might be greater, thus increasing the thickness nonuniformity. CL analysis indicated a uniform indium composition on the (11–20) and (11–22) faces. On the (1–101)GaN stripe, the indium composition decreased near the (0001) edge. Excess Ga is considered to affect the compositional nonuniformity on the (1–101) facet.