Diffusion barrier for increased mirror reflectivity in reflective solderable contacts on high power led chip
First Claim
1. A method of fabricating a light-emitting apparatus comprising:
- depositing a layer of reflective material on a surface of a light-generating device;
forming a diffusion barrier on said layer of reflective material such that said layer of reflective material is positioned between said diffusion barrier and said light-generating device, said diffusion barrier being a single layer of uniform material composition;
depositing a layer of soldering material on said diffusion barrier so that said layer of reflective material and said layer of soldering material are physically separated by said diffusion barrier;
placing said light-generating device with said layer of reflective material, said diffusion layer and said layer of soldering material on a mounting surface such that said layer of soldering material is in contact with said mounting surface; and
melting said layer of solder material to attach said light-generating device to said mounting surface.
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Accused Products
Abstract
A solderable light-emitting diode (LED) chip and a method of fabricating an LED lamp embodying the LED chip utilize a diffusion barrier that appreciably blocks molecular migration between two different layers of the LED chip during high temperature processes. In the preferred embodiment, the two different layers of the LED chip are a back reflector and a solder layer. The prevention of intermixing of the materials in the back reflector and the solder layer impedes degradation of the back reflector with respect to its ability to reflect light emitted by the LED. The LED chip includes a high power AlInGaP LED or other type of LED, a back reflector, a diffusion barrier and a solder layer. Preferably, the back reflector is composed of silver (Ag) or Ag alloy and the solder layer is made of indium (In), lead (Pb), gold (Au), tin (Sn), or their alloy and eutectics. In a first embodiment, the diffusion layer is made of nickel (Ni) or nickel-vanadium (NiV). In a second embodiment of the invention, the diffusion barrier is made of titanium-tungsten-nitride (TiW:N). In addition to preventing the intermixing of the In of the solder layer with the Ag of the back reflector, the diffusion layer prevents degradation of the Ag reflective properties in the back reflector upon exposure to air. In an alternative embodiment, the diffusion layer is made of a non-conductive material.
132 Citations
11 Claims
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1. A method of fabricating a light-emitting apparatus comprising:
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depositing a layer of reflective material on a surface of a light-generating device;
forming a diffusion barrier on said layer of reflective material such that said layer of reflective material is positioned between said diffusion barrier and said light-generating device, said diffusion barrier being a single layer of uniform material composition;
depositing a layer of soldering material on said diffusion barrier so that said layer of reflective material and said layer of soldering material are physically separated by said diffusion barrier;
placing said light-generating device with said layer of reflective material, said diffusion layer and said layer of soldering material on a mounting surface such that said layer of soldering material is in contact with said mounting surface; and
melting said layer of solder material to attach said light-generating device to said mounting surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification