Methods and structures for bonding elements
View Patent ↗Embodiments of the invention relate to methods and structures for fabricating semiconductor structures that include at least one bonding layer for attaching two or more elements to one another. The at least one bonding layer may be at least substantially comprised of zinc, silicon and oxygen.
1. A method for fabricating a semiconductor structure comprising:
providing a bonding layer at least substantially comprised of zinc, silicon and oxygen on a surface of at least one of a first element and a second element, each of the first element and the second element comprising crystalline semiconductor material, the bonding layer being electrically conductive and transparent to light;
formulating a percentage concentration of silicon in the bonding layer to increase proximate to an exposed surface thereof such that a composition of the bonding layer is at least substantially comprised of silicon oxide within a distance adjacent to the exposed surface thereof, the distance being sufficiently small to at least substantially preserve electrical conductivity of the bonding layer through the silicon oxide;
disposing the bonding layer between the first element and the second element; and
attaching the first element and the second element to one another at a bonding interface using the bonding layer disposed between the first element and the second element such that the first element and the second element are optically and electrically coupled to one another through the bonding layer.
2. The method of claim 1 , further comprising selecting each of the first element and the second element to comprise at least one of a device structure, a bonded structure and a layer structure.
3. The method of claim 1 , wherein providing the bonding layer on the surface of at least one of a first element and a second element comprises:
forming a first bonding layer on a surface of the first element;
forming a second bonding layer on a surface of the second element; and
bonding the first bonding layer to the second bonding layer.
4. The method of claim 1 , wherein attaching the first element and the second element to one another comprises attaching the first element and the second element to one another by molecular adhesion.
5. The method of claim 1 , further comprising thinning at least one of the first element and the second element to form a thinned element by at least one of an ionic implantation process, a laser lift-off process, a mechanical thinning process and a chemical thinning process.
6. The method of claim 5 , further comprising forming another layer structure on the thinned element.
7. A semiconductor structure, comprising:
a first element and a second element, each of the first element and the second element comprising crystalline semiconductor material, and
at least one bonding layer disposed between and bonding together the first element and the second element, the at least one bonding layer at least substantially comprised of zinc, silicon and oxygen, the at least one bonding layer being electrically conductive and transparent to light, the first element and the second element being optically and electrically coupled to one another through the at least one bonding layer, a percentage concentration of silicon in the at least one bonding layer increasing proximate to a bonding interface between the at least one bonding layer and at least one of the first element and the second element such that a composition of the at least one bonding layer is at least substantially comprised of silicon oxide within a distance adjacent to the bonding interface, the distance being sufficiently small to at least substantially preserve electrical conductivity of the at least one bonding layer through the silicon oxide.
8. The semiconductor structure of claim 7 , wherein each of the first element and the second element comprises at least one of a device structure, a bonded structure and a layer structure.
9. The semiconductor structure of claim 8 , wherein at least one of the first element and the second element comprises a bonded structure including at least one additional bonding layer at least substantially comprised of zinc, silicon and oxygen.
10. The semiconductor structure of claim 7 , wherein at least one of the first element and the second element comprises a semiconductor layer having an average layer thickness of less than about 100 μm.
11. The semiconductor structure of claim 7 , wherein at least one of the first element and the second element comprises a photovoltaic subcell or a light-emitting element.
12. The semiconductor structure of claim 7 , wherein the semiconductor structure comprises a multijunction photovoltaic solar cell or a light-emitting structure.
13. The semiconductor structure of claim 7 , wherein the distance is about five nanometers (5 nm) or less.
14. The semiconductor structure of claim 13 , wherein the distance is about one nanometer (1 nm) or less.
15. The semiconductor structure of claim 14 , wherein the distance is about one-half of a nanometer (0.5 nm) or less.
16. The semiconductor structure of claim 7 , wherein a percentage concentration of zinc in the at least one bonding layer decreases proximate to the bonding interface.
17. The semiconductor structure of claim 7 , wherein each of the first element and the second element comprises a III-V semiconductor material.
18. The semiconductor structure of claim 7 , wherein the at least one bonding layer comprises a first bonding layer disposed on the first element and a second bonding layer disposed on the second element, the bonding interface disposed between the first bonding layer and the second bonding layer, and wherein each of the first bonding layer and the second bonding layer is at least substantially comprised of zinc, silicon and oxygen, and wherein a percentage concentration of silicon in each of the first bonding layer and the second bonding layer increases proximate to the bonding interface and a percentage concentration of zinc in each of the first bonding layer and the second bonding layer decreases proximate to the bonding interface.
19. A semiconductor structure, comprising:
a first element and a second element, each of the first element and the second element comprising crystalline semiconductor material, and
at least one bonding layer disposed between and physically, optically, and electrically coupling the first element and the second element, the at least one bonding layer formed by molecularly bonding the first element with the second element, and being electrically conductive and transparent to light, and at least substantially comprising zinc, silicon, and oxygen, a percentage concentration of silicon in the at least one bonding layer increasing proximate to a bonding interface between the at least one bonding layer and at least one of the first element and the second element such that a composition of the at least one bonding layer is at least substantially comprised of silicon oxide within a distance adjacent to the bonding interface, the distance being sufficiently small to at least substantially preserve electrical conductivity of the at least one bonding layer through the silicon oxide.