Fabricating disk cavities for semiconductor lasers based on InAs(Sb)/InAsSbP heterostructures

Electrochemical etching in an HClO$_4$-CH$_3$COOH mixture has been used for the formation of disk cavities intended for a whispering-gallery-mode semiconductor laser. The isotropic etching of layers in a heterostructure based on InAs and a related InAsSb$_{0.14}$P$_{0.3}$ quaternary solid solution allowed us to obtain perfect round mesas with diameters from 275 to 50 $\mu$m. At a total etching depth reaching 15 $\mu$m, the vertical part of the side surface was about 7 $\mu$m.