Semiconductor substrate and method of forming
A method of forming a semiconductive substrate material for an electronic device including forming a plurality of semiconductive layers on a substrate during a continuous growth process in a reaction chamber, wherein during the continuous growth process, a release layer is formed between a base layer and an epitaxial layer by altering at least one growth process parameter during the continuous growth process. The method also including separating the plurality of semiconductive layers from the substrate.
1. A method of forming a semiconductive substrate material for an electronic device comprising:
forming a base layer comprising a Group III-V material overlying a substrate in a reaction chamber, wherein forming the base layer comprises a hydride vapor phase epitaxy (HVPE) process and alternating a 3D growth mode and a 2D growth mode more than one time;
continuing to grow the Group III-V material and introducing a first dopant material into the reaction chamber to form a first release layer overlying the base layer, wherein formation of the release layer includes forming the release layer in a 2D growth mode or a 3D growth mode;
continuing to grow the Group III-V material and removing the dopant from the reaction chamber to form a first epitaxial layer portion overlying the first release layer;
continuing to grow the Group III-V material and introducing a second dopant material into the reaction chamber to form a second release layer overlying the first epitaxial layer portion, wherein the second release layer has a different absorption coefficient compared to the first release layer, wherein the first release layer is configured to absorb greater than 50% of radiation of a first wavelength and the second release layer is configured to transmit substantially all of the radiation of the first wavelength; and
separating the first epitaxial layer portion from the base layer at the first release layer using radiation of the first wavelength impinging on the first release layer.
2. The method of claim 1 , wherein the second dopant material of the second release layer comprises an element different than a first dopant material within the first release layer.
3. The method of claim 1 , wherein the first release layer has a first dopant concentration, and the second release layer has a second dopant concentration, the first dopant concentration being different than the second dopant concentration.
4. The method of claim 1 , wherein the second release layer is configured to absorb greater than 50% of radiation of a second wavelength different than the first wavelength, and the first release layer is configured to transmit substantially all of the radiation of the second wavelength.
5. The method of claim 1 , further comprising continuing to grow the Group III-V material and removing the second dopant material from the reaction chamber to form a second epitaxial layer portion overlying the second release layer before separating the first epitaxial layer portion from the base layer.
6. The method of claim 5 , further comprising selectively separating the second epitaxial layer after separating the first epitaxial layer by impinging radiation of a second wavelength on the second release layer.
7. The method of claim 1 , wherein the base layer comprises gallium nitride.
8. The method of claim 1 , wherein the base layer comprises an absorption coefficient of not greater than about 50 cm −1 for radiation within the visible spectrum.
9. The method of claim 1 , wherein the base layer comprises an absorption coefficient of at least about 0.1 cm −1 for radiation within the visible spectrum.
10. The method of claim 1 , wherein the first release layer comprises a dopant concentration of at least about 2×10 18 cm −3 .
11. The method of claim 1 , wherein the first release layer comprises an absorption coefficient of at least about 500 cm −1 for radiation within the visible spectrum.
12. The method of claim 1 , wherein the first dopant material comprises C, Mg, Zn, Si, Sn, Fe, O, Ge, and a combination thereof.
13. The method of claim 1 , wherein the second release layer comprises a dopant concentration of at least about 2×10 18 cm −3 .
14. The method of claim 1 , wherein the second release layer comprises a dopant concentration of not greater than about 1×10 21 cm −3 .
15. The method of claim 1 , wherein the second release layer comprises an absorption coefficient of at least about 500 cm −1 for radiation within the visible spectrum.
16. The method of claim 1 , wherein the second dopant material comprises C, Mg, Zn, Si, Sn, Fe, O, Ge, and a combination thereof.
17. The method of claim 1 , wherein the first epitaxial layer comprises an absorption coefficient less than an absorption coefficient of the first release layer for radiation within the visible spectrum.
18. The method of claim 1 , wherein the first epitaxial layer comprises gallium nitride.
19. The method of claim 1 , wherein the first epitaxial layer comprises a dislocation density of not greater than about 1×10 8 dislocations/cm 2 as measured at an upper surface.
20. The method of claim 1 , wherein separating includes decomposing a portion of the first release layer via radiation.