A fabrication method of a vertical light-emitting diode, such as an infrared light-emitting diode, includes heating the reaction chamber during growth of the reflective layer to pre-diffuse the metal molecules of the reflective layer into the epitaxial layer. As a result, the diffusion of the metal molecules in the reflective layer into the epitaxial layer during high-temperature fusion of the reflective layer and the epitaxial layer slows down, and the blackness level of conventional ohm contact holes is reduced.