Diffusion barrier for increased mirror reflectivity in reflective solderable contacts on high power LED chip
US6222207A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 24, 1999 |
| Grant date | Apr 24, 2001 |
| Priority date | — |
| Expiry date | May 24, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10H20/835
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 …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.