Optically transparent adhesion layer to connect noble metals to oxides
A reflective layer for use in lighting devices and methods of forming the reflective layer are provided. The reflective layer may include a dielectric layer including one or more insulating materials. An intermediate layer may be formed on the dielectric layer. The intermediate layer may include one or more materials having a higher enthalpy of reaction than the one or more insulating materials. Because of the higher enthalpy of reaction, atoms of the one or more materials in the intermediate layer may form bonds with atoms of the one or more insulating materials. A metal layer may be formed on the intermediate layer to reflect light emitted from an active region of a light emitting diode (LED).
1. A light emitting device comprising:
a semiconductor diode structure including a light emitting layer; and
a reflective layer disposed on a surface of the semiconductor diode structure, the reflective layer comprising:
a dielectric layer disposed on the surface of the semiconductor diode structure and comprising an oxide of a first element, the first element having an enthalpy of oxidation less than an enthalpy of oxidation of aluminum;
an intermediate layer disposed on the dielectric layer and substantially transparent to light emitted by the light emitting layer, comprising unoxidized aluminum as well as an oxide of aluminum, without comprising zinc nor nitrogen;
a reflective metal layer disposed on the intermediate layer and comprising a first stack of a first metal and a second stack of silver below the first stack in direct contact with the unoxidized aluminum or the oxide of aluminum of the intermediate layer.
2. The light emitting device of claim 1 , wherein the light emitting device comprises a pure silver p-contact.
3. The light emitting device of claim 1 , wherein the intermediate layer has a thickness of 1 angstrom to 50 angstroms perpendicular to the dielectric layer.
4. The light emitting device of claim 3 , wherein the intermediate layer has a thickness of 5 angstroms to 20 angstroms perpendicular to the dielectric layer.
5. The light emitting device of claim 1 , wherein the first metal comprises silver.
6. The light emitting device of claim 1 , wherein a top surface of the reflective metal layer facing away from the semiconductor diode structure is not in direct contact with dielectric material.
7. The light emitting device of claim 1 , wherein the reflective metal layer has a thickness of 50 nm to 1000 nm.
8. The light emitting device of claim 1 , wherein the semiconductor diode structure comprises a III-V semiconductor diode structure.
9. The light emitting device of claim 1 , wherein the unoxidized aluminum is elemental aluminum.
10. The light emitting device of claim 9 , wherein the intermediate layer consists of the elemental aluminum and the oxide of aluminum.
11. The light emitting device of claim 1 , wherein the first element is silicon.
12. The light emitting device of claim 11 , wherein the intermediate layer has a thickness of 1 angstrom to 50 angstroms perpendicular to the dielectric layer.
13. The light emitting device of claim 11 , wherein the semiconductor diode structure comprises a III-Nitride semiconductor diode structure.