Method of fabricating gallium nitride substrate using ion implantation
The present invention relates to technology for fabricating a gallium nitride substrate using an ion implantation process to which a self-separation technique is applied. According to the present invention, a method of fabricating a gallium nitride substrate may include a step of forming a first gallium nitride layer on a substrate, a step of implanting hydrogen ions into the first gallium nitride layer to form a separation layer, a step of grinding the edges of the substrate, the first gallium nitride layer, and the separation layer, a step of forming a second gallium nitride layer on the first gallium nitride layer having a ground edge, and a step of self-separating the second gallium nitride layer from the first gallium nitride layer having a ground edge.
1. A method of fabricating a gallium nitride substrate, comprising:
a step of forming a first gallium nitride layer on a substrate;
a step of implanting hydrogen ions into the first gallium nitride layer to form a separation layer;
a step of grinding edges of the substrate, the first gallium nitride layer, and the separation layer;
a step of forming a second gallium nitride layer on the first gallium nitride layer having a ground edge; and
a step of separating the second gallium nitride layer from the first gallium nitride layer having the ground edge,
wherein the step of implanting hydrogen ions into the first gallium nitride layer to form the separation layer comprises a step of implanting hydrogen ions at a dose of 1.75 E17 H + /cm 2 to 2.0 E17 H + /cm 2 into the first gallium nitride layer and then performing heat treatment at a temperature of about 500° C. for about 30 minutes, to form the separation layer and to form a plurality of cavities inside the separation layer,
the step of forming a second gallium nitride layer comprises a step of growing the second gallium nitride layer of about 800 μm on the first gallium nitride layer having the ground edge using the first gallium nitride layer having the ground edge as a seed layer,
the step of separating the second gallium nitride layer comprises a step of separating the second gallium nitride layer at room temperature based on the cavities,
the step of implanting is performed under the conditions where implantation of hydrogen ions is carried out at an implantation energy of about 70 keV, and a projection range is about 270 nm, and
the second gallium nitride layer, under the conditions of 1.75E17 H + /cm 2 and 2.0E17 H + /cm 2 , is separated, with 95% or more of the area.
2. The method according to claim 1 , wherein the step of forming the first gallium nitride layer on the substrate comprises a step of forming the first gallium nitride layer using a metal-organic chemical vapor deposition (MOCVD) process.
3. The method according to claim 1 , wherein the step of grinding edges of the substrate, the first gallium nitride layer, and the separation layer comprises a step of grinding edges of the first gallium nitride layer and the substrate to suppress growth of polycrystalline gallium nitride from the edges of the first gallium nitride layer and the substrate or to weaken adhesion between the polycrystalline gallium nitride and the substrate.
4. The method according to claim 1 , wherein the substrate is formed using at least one of sapphire, gallium arsenide (GaAs), spinel, silicon (Si), indium phosphide (InP), and silicon carbide (SiC).
5. The method according to claim 1 , wherein the step of forming the second gallium nitride layer on the first gallium nitride layer having the ground edge comprises a step of forming the second gallium nitride layer using a hydride vapor phase epitaxy (HVPE) process.