Preparation method of GaN-based porous DBR

The invention discloses a preparation method of a GaN-based porous DBR. The method comprises the following steps of (1) sequentially growing a buffer layer, an n-type GaN conductive layer, n-type high-doped layers and non-doped layers on a substrate, wherein the n-type high-doped layers and the non-doped layers are alternately stacked to form a multi-period nitride epitaxial structure; (2) depositing an insulating dielectric layer on the upper surface of the nitride epitaxial structure; (3) forming an electrode window in one side of the upper surface of the insulated dielectric layer through photolithography and corrosion, and forming a groove in the area except for an electrode window; (4) etching the electrode window downwards by adopting a dry etching technology to form an electrode table and etching a groove downwards to expose the side wall of the nitride epitaxial structure to form a corrosion groove; and (5) carrying out electrochemical corrosion on the nitride epitaxial structure of which the side wall is exposed to form a periodical porous DBR; and (6) removing the insulated dielectric layer by employing wet corrosion and completing preparation.