Cheng Peter Lee

US Patent:

7683380, Mar 23, 2010

Filed:

Jul 13, 2007

Appl. No.:

11/777987

Inventors:

Cheng Tsin Lee - Richmond CA, US
Qinghong Du - Hercules CA, US
Jean-Yves Naulin - Richmond CA, US

Assignee:

Dicon Fiberoptics, Inc. - Richmond CA

International Classification:

H01L 27/15
H01L 29/26
H01L 31/12
H01L 33/00
H01L 29/22
H01L 29/227
H01L 29/06
H01L 31/0328
H01L 31/0336
H01L 31/072
H01L 31/109

US Classification:

257 79, 257 13, 257 98, 257 99, 257E25028, 257E25032, 257E33001, 257E33002

Abstract:

In one embodiment of an epitaxial LED device, a buffer layer (e. g. dielectric layer) between the current spreading layer and the substitute substrate includes a plurality of vias and has a refractive index that is below that of the current spreading layer. A reflective metal layer between the buffer layer and the substitute substrate is connected to the current spreading layer through the vias in the buffer layer. The buffer layer separates the current spreading layer from the reflective metal layer. In yet another embodiment, stress management is provided by causing or preserving stress, such as compressive stress, in the LED so that stress in the LED is reduced when it experiences thermal cycles. In one implementation of this embodiment, a layer is attached to the LED and reflective metal layer, and causes or preserves stress in the LED along one or more directions parallel to an interface between the LED epitaxial layers so that stress in the LED is reduced in said one or more directions when temperature of the structure is increased.

US Patent:

7919780, Apr 5, 2011

Filed:

Aug 5, 2008

Appl. No.:

12/186165

Inventors:

Cheng Tsin Lee - Richmond CA, US

Assignee:

DiCon Fiberoptics, Inc. - Richmond CA

International Classification:

H01L 29/26
H01L 31/00
H01L 29/18
H01L 33/00

US Classification:

257 79, 257 13, 257 88, 257 94, 257E33001, 257E33057

Abstract:

In one embodiment of the invention, a bonding material is used to bond a substitute substrate to the LED, wherein the bonding material does not including gold or tin. The bonding material preferably includes gallium (Ga), such as a combination of Ga and Al or Cu. This bonding material has high thermal conductivity, high strength, high temperature stability and is low cost. In another embodiment of the invention, the substitute substrate is first thinned before it is bonded to the LED structure, so that the substitute substrate is flexible and conforms to the shape of the LED structure. In yet another embodiment of the invention, an apparatus is used for bonding a substitute substrate to a LED which includes a plurality of semiconductor epitaxial layers, said semiconductor epitaxial layers having been grown on the growth substrate so that said semiconductor epitaxial layers are curved in shape. The apparatus includes a conduit for evacuating a region near the substitute substrate on a side of the substitute substrate that is opposite to that of said semiconductor epitaxial layers. Gas pressure is applied on the semiconductor epitaxial layers, and the substitute substrate conforms to the shape of said semiconductor epitaxial layers as a result of pressure applied.