Method of fabricating semiconductor substrate and method of fabricating light emitting device

1. A method of fabricating a light emitting device, the method comprising:

forming a plurality of compound semiconductor layers on a first substrate, the compound semiconductor layers comprising a first semiconductor layer;

disposing a second substrate on the compound semiconductor layers;

separating the first substrate from the compound semiconductor layers,

wherein forming the plurality of compound semiconductor layers comprises:

forming a plurality of voids in the first compound semiconductor layer; and

increasing a volume of the voids,

wherein separating the first substrate comprises:

etching a portion of the first semiconductor layer.

2. The method of claim 1 , further comprising:

forming an additional layer on the first semiconductor layer.

3. The method of claim 2 , wherein the voids are formed below the additional layer.

4. The method of claim 3 , wherein the additional layer comprises a metallic material layer.

5. The method of claim 1 , wherein the voids are extended to the first substrate before disposing the second substrate on the compound semiconductor layers.

6. The method of claim 5 , wherein etching a portion of the first semiconductor layer comprises introducing a chemical solution to an interface between the first substrate and the first semiconductor layer via the voids.

7. The method of claim 1 , wherein the first semiconductor layer comprises a GaN-based layer.

8. A method of fabricating a light emitting device, the method comprising:

forming a plurality of compound semiconductor layers on a first substrate, the compound semiconductor layers comprising a first semiconductor layer and a second semiconductor layer contacting the first semiconductor layer;

disposing a second substrate on the compound semiconductor layers;

separating the first substrate from the second semiconductor layer,

wherein forming the plurality of compound semiconductor layers comprises:

forming a plurality of voids in the first compound semiconductor layer; and

increasing a volume of the voids, and

wherein separating the first substrate from the second semiconductor layer comprises twisting the first substrate away from the first semiconductor layer.

9. A method of fabricating a light emitting device, the method comprising:

forming a plurality of compound semiconductor layers on a first substrate, the compound semiconductor layers comprising a first semiconductor layer and a second semiconductor layer contacting the first semiconductor layer;

disposing a second substrate on the compound semiconductor layers;

separating the first substrate from the second semiconductor layer,

wherein forming the plurality of compound semiconductor layers comprises:

forming a plurality of voids in the first compound semiconductor layer; and

increasing a volume of the voids, and

wherein separating the first substrate from the second semiconductor layer comprises heating the first substrate such that the voids weaken a coupling force between the first substrate and the first semiconductor layer.

10. The method of claim 1 , wherein the second substrate is a silicon-based substrate, and the silicon-based substrate is disposed on the compound semiconductor layers before separating the first substrate from the compound semiconductor layers.

11. The method of claim 4 , wherein the plurality of compound semiconductor layers further comprises a second semiconductor layer contacting the first semiconductor layer, the first semiconductor layer and the second semiconductor layer comprising GaN, and the metallic material layer comprises Ta.

12. The method of claim 11 , wherein the metallic material layer is about 5-100 nm thick.