Method of manufacturing nitride semiconductor device
A method of manufacturing a nitride semiconductor device includes the steps of; forming a stripping layer including In on a substrate; forming a nitride semiconductor layer on the stripping layer; causing a decomposition of the stripping layer by increasing a temperature of the stripping layer; irradiating the stripping layer with laser light; and separating the nitride semiconductor layer from the substrate.
1. A method of manufacturing a nitride semiconductor device, comprising the steps of:
forming a stripping layer on a substrate, wherein the stripping layer comprises InGaN having an In composition ratio equal to or more than 18 mol %;
forming a nitride semiconductor layer on the stripping layer;
decomposing the stripping layer by increasing a temperature of the stripping layer;
irradiating the decomposed stripping layer with laser light; and
separating the nitride semiconductor layer from the substrate wherein, the decomposed stripping layer reduces a band gap-energy of the stripping layer; and,
a photon energy of the laser light is smaller than the band-gap energy of the stripping layer before decomposition and is larger than a band-gap energy of the stripping layer after decomposition.
2. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein a photon energy of the laser light is lower than the band-gap energy of the substrate.
3. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein a photon energy of the laser light is lower than the band-gap energy of respective layers forming the nitride semiconductor layer.
4. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein
the step of forming the nitride semiconductor layer on the stripping layer comprises forming an active layer; and
the step of forming the active layer is performed after decomposing the stripping layer.
5. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein the stripping layer includes InAlN or InGaAlN.
6. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein the stripping layer has an In composition ratio of less than or equal to 30 mol %.
7. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein the stripping layer comprises a superlattice structure formed by superposing a layer in a composition ratio relatively rich in In, and a layer which contains no In, or which is in a composition ratio relatively low in In.
8. The method of manufacturing the nitride semiconductor device according to claim 1 , comprising a step of:
forming a layer having a superlattice structure formed of AlGaN and GaN between the stripping layer and the nitride semiconductor layer.
9. The method of manufacturing the nitride semiconductor device according to claim 1 , wherein the substrate separated from the nitride semiconductor layer is reused as the substrate on which the stripping layer is formed.
10. A method of manufacturing a nitride semiconductor device comprising the steps of:
forming a stripping layer including In on a substrate;
forming a nitride semiconductor layer on the stripping layer, wherein the stripping layer has an In composition ratio of equal to or more than 18 mol %;
decreasing a band-gap of the stripping layer by increasing a temperature of the stripping layer;
irradiating the decreased band-gap stripping layer with laser light;
separating the semiconductor layer from the substrate, wherein a photon energy of the laser light is smaller than the band-gap energy of the stripping layer before decreasing the band-gap, and is larger than the a band-gap energy of the stripping layer after the band-gap energy is decreased.
11. The method of manufacturing the nitride semiconductor device of claim 10 , wherein a photon energy of the laser light is lower than the band-gap energy of the substrate.
12. The method of manufacturing the nitride semiconductor device of claim 10 , wherein a photon energy of the laser light is lower than the band-gap energy of respective layers forming the nitride semiconductor layer.
13. The method of manufacturing the nitride semiconductor device of claim 10 , wherein the step of forming the nitride semiconductor layer on the stripping layer comprises a step of forming an active layer; and
the step of forming the active layer is performed after decreasing the band-gap of the stripping layer.
14. The method of manufacturing the nitride semiconductor device of claim 10 , wherein the stripping layer has an In composition ratio of less than or equal to 30%.
15. The method of manufacturing the nitride semiconductor device according to claim 10 , wherein the stripping layer includes InAlN, or InGaAlN.
16. The method of manufacturing the nitride semiconductor device according to claim 10 , wherein the stripping layer has a superlattice structure formed by superposing a layer in a composition ratio relatively rich in In, and a layer which contains no In, or which is in a composition ratio relatively low in In.
17. The method of manufacturing the nitride layer semiconductor device according to claim 10 , comprising a step of:
forming a layer having a superlattice structure formed of AlGaN and GaN between the stripping layer and the nitride semiconductor layer.
18. The method of manufacturing the nitride semiconductor device according to claim 10 , wherein the substrate separated from the nitride semiconductor layer is reused as the substrate on which the stripping layer is formed.