Planar selective re-growth around a dry-etched mesa along the [11~0] direction by addition of HCl during MOCVD growth

We have investigated the selective MOCVD re-growth of InP around mesa-stripes along [11¯0] direction formed with reactive ion etching by the addition of HCl gas during MOCVD growth. It is shown that the large overgrowth on the SiO₂ mask in the conventional growth condition is remarkably reduced by the addition of the HCl gas. The mechanism of this effect is analyzed experimentally. It is found that the growth rate on (110) plane (mesa side wall) decreases more remarkably than that on the (001) plane (mesa base) with increasing HCl flow rate. Therefore the growth rate on the side wall can be effectively reduced by the addition of adequate amount of HCl. The reduction of the growth rate on the (110) plane suppress the formation of (111)A plane, which is the cause of the large overgrowth near the mask edge of the mesa stripes. Using these results, we have successfully achieved planar embedded re-growth of InP around dry-etched mesa along [11¯0] direction. This technique is very useful in the application of selective MOCVD growth to the photonic integrated circuits