Metalorganic vapor-phase epitaxial regrowth of InP on reactive ion-etched mesa structures for p-substrate buried heterostructure laser application

Growth behavior of sulfur-doped n-InP around reactive ion-etched (RIE) mesas has been investigated for realization of p-substrate buried heterostructure laser utilizing metalorganic vapor phase epitaxy. It is found that the growth of n-InP layer on the sidewall of the mesa ((1 1̄ 0) plane) is significantly suppressed, as the flow rate of hydrogen sulfide (H2S) which is used for n-type doping, increased. This phenomenon of growth suppression was also observed for growth of highly S-doped n-InP on narrow (0 0 1) facets. Taking account of both, these phenomena can be explained by migration enhancement of indium atoms on sulfur-terminated surfaces caused by excess H2S supply. Consequently, the shape of the regrown embedding layer was found to be exactly controlled by the H2S flow rate. Using this technique, a p-substrate 1.3 μm buried heterostructure laser with pnp current-blocking structure has been successfully fabricated around the RIE mesa and excellent lasing characteristics with high reliability has been realized for the first time.