PHOTO-ASSISTED METHOD FOR WET ROUGHENING A RED LIGHT LED GALLIUM PHOSPHIDE WINDOW LAYER

摘要

A photo-assisted method for wet roughening a red light LED gallium phosphide layer (3). The method uses a mixed solution of hydrofluoric acid and an oxidant as the etching solution (4); the red light LED gallium phosphide layer can be surface-roughened through irradiation by the light from a light source (1) without the need of using a mask. The dimension and height of the roughened structures resulting from etch roughening are controlled via controlling the etching time and the concentration of the etching solution (4). The method solves the difficult problem of roughening the red light LED gallium phosphide layer, thus enabling the light extraction efficiency of an LED chip to increase by more than two-fold, and has the characteristics of low cost and fast speed.