Passivation scheme for oxide vertical cavity surface-emitting laser

A method for forming an oxide VCSEL (vertical cavity surface-emitting laser) includes forming a VCSEL structure, forming an oxidation cavity partially through the VCSEL structure, oxidizing a layer in the VCSEL structure, forming a first passivation layer over a surface of the oxidation cavity, and forming a second passivation layer over the first passivation layer. An oxide VCSEL structure includes a bottom mirror region, an active region atop the bottom mirror region, a top mirror region atop the active region, an oxidation cavity partially through the top mirror region, a first passivation layer covering a surface of the oxidation cavity, and a second passivation layer covering the first passivation layer. In both the method and the structure, the first passivation layer can be made of silicon nitride (SiN) while the second passivation layer can be made of silicon oxynitride (SiON).