Wafer composite and method for producing a semiconductor component
A wafer composite is provided which includes an auxiliary substrate, a donor substrate and a sacrificial layer formed between the auxiliary substrate and the donor substrate. Functional elements of the semiconductor component are formed in a component layer, including at least one partial layer of the donor substrate. The auxiliary substrate is then separated from the component layer by heat input into the sacrificial layer.
1. A method for producing a semiconductor component, comprising:
providing a wafer composite comprising an auxiliary substrate, a donor substrate and a sacrificial layer formed between the donor substrate and the auxiliary substrate;
forming functional elements of the semiconductor component in a component layer, comprising at least one partial layer of the donor substrate; and
separating the auxiliary substrate from the component layer by heat input into the sacrificial layer.
2. The method of claim 1 , wherein providing the wafer composite comprises:
forming a layer structure, which comprises at least one part of the sacrificial layer, on at least one of a first substrate surface of the donor substrate and a main surface of the auxiliary substrate; and
connecting the donor substrate to the auxiliary substrate,
wherein the layer structure is arranged between the donor substrate and the auxiliary substrate.
3. The method of claim 2 , wherein forming the layer structure comprises applying a first layer structure on the substrate surface of the donor substrate.
4. The method of claim 3 , wherein the first layer structure comprises the sacrificial layer.
5. The method of claim 2 , wherein the first layer structure comprises a first auxiliary layer which is applied directly on the first substrate surface.
6. The method of claim 5 , wherein a material of the first auxiliary layer has a higher specific heat capacity and/or a lower specific thermal conductivity than a material of the donor substrate.
7. The method of claim 5 , wherein the first auxiliary layer is a metallic layer.
8. The method of claim 2 , wherein forming the layer structure comprises applying a second layer structure comprising the sacrificial layer on the main surface of the auxiliary substrate.
9. The method of claim 8 , wherein the first layer structure comprises a first partial sacrificial layer of the sacrificial layer.
10. The method of claim 9 , wherein forming the layer structure comprises applying the second layer structure comprising a second partial sacrificial layer of the sacrificial layer on the main surface of the auxiliary substrate.
11. The method of claim 1 , wherein the sacrificial layer melts or decomposes with emission of gaseous decomposition products as a result of the heat input.
12. The method of claim 1 , wherein the heat input is provided by a laser beam that focuses in the sacrificial layer.
13. The method of claim 1 , furthermore comprising:
splitting, before the separating, the donor substrate along a plane parallel to the sacrificial layer,
wherein the component layer remains connected to the auxiliary substrate and a main part of the donor substrate which is separated off from the wafer composite.
14. The method of claim 13 , wherein before the splitting, a planar disturbance of a crystal structure of the donor substrate is formed in the plane parallel to the sacrificial layer.
15. The method of claim 13 , wherein before the splitting, a defect layer is formed by implantation of light ions in the donor substrate, and wherein before the splitting, a mechanical stability of the defect layer is reduced by thermal treatment.
16. The method of claim 1 , wherein before forming the functional elements, a layer thickness of the component layer is increased.
17. The method of claim 1 , wherein channels are formed in the sacrificial layer, the channels being open at an outer edge of the sacrificial layer.
18. The method of claim 1 , wherein the donor substrate comprises a first crystalline semiconductor material and the auxiliary substrate comprises a second crystalline semiconductor material comprising the same elements.
19. The method of claim 18 , wherein the first and second semiconductor materials differ from one another in a doping and/or a crystal shape.
20. The method of claim 1 , wherein the donor substrate and the auxiliary substrate comprise crystalline silicon carbide, wherein the sacrificial layer is thermally stable and solid up to at least 1700° C., and wherein the sacrificial layer is decomposable into gaseous decomposition products at a temperature of between 1700° C. and 2000° C.
21. The method of claim 1 , wherein the sacrificial layer contains silicon nitride.
22. The method of claim 1 , wherein the donor substrate comprises crystalline gallium nitride, gallium arsenide, silicon or germanium, and wherein the sacrificial layer is thermally stable and solid up to at least 1200° C.
23. The method of claim 22 , wherein the sacrificial layer comprises silicon oxide.