Method for preparing inverted trapezoidal gallium-nitride-based light emitting diode

The invention relates to a method for preparing an inverted trapezoidal gallium-nitride-based light emitting diode. The method comprises the following steps of: preparing a transparent conductive electrode on an epitaxial structure; partially etching one side of the epitaxial structure to form a table-board; preparing an upper metal electrode on the transparent conductive electrode, and preparing a lower metal electrode on the table-board; thinning and polishing; preparing a silicon dioxide protection layer; performing laser scribing on the back face of a sapphire substrate with the silicon dioxide protection layer, so that two V-shaped deep grooves are retained on two sides of the back face of the sapphire substrate; performing ultrasonic washing; etching off the outer side parts of the two V-shaped deep grooves, and thus obtaining inclined sapphire side walls; and removing the silicon dioxide protection layer. According to the light emitting diode obtained by the method for preparing the inverted trapezoidal gallium-nitride-based light emitting diode, the luminous efficiency of a device can be improved.