Highly reflective contacts for light emitting semiconductor devices
First Claim
1. A reflective contact for a light emitting semiconductor device, the light emitting semiconductor device having a top and bottom surface, the reflective contact comprising:
- a reflective metal layer adjacent and abutting a predetermined portion of at least one of the top and bottom surface of the light emitting semiconductor device; and
a plurality of alloyed metal-semiconductor zones, each zone having a perimeter that is adjacent and abuts the reflective metal layer, formed from the reflective metal layer and the at least one of the top and bottom surfaces of the light emitting semiconductor device, the alloyed metal-semiconductor zones comprising by area no more than 10% of the total area of the reflective metal layer and the alloyed metal-semiconductor zones combined, the alloyed metal-semiconductor zones forming an ohmic, low resistance contact with the at least one of the the top and bottom surfaces of the light emitting semiconductor device.
8 Assignments
0 Petitions
Accused Products
Abstract
Light emitting diodes with highly reflective contacts and methods for fabricating them are described. In a first preferred embodiment of the present invention, LEDs with reflective contacts are formed using a laser to create small alloyed dots in a highly reflective metal evaporated on the top and bottom surface of the LED chip. Using this technique, most of the bottom surface remains highly reflective, and only those portions of the bottom surface where the laser struck become absorbing. Typically, only 1% of the bottom surface is formed into contacts, leaving 99% of the bottom surface to serve as a reflecting surface. The 1% of the surface, however, provides an adequate low resistance ohmic contact. LEDs fabricated with this technique allow photons to bounce off the rear surface more than 20 times before there is a 50% chance of absorption. In a second embodiment of the present invention, an application of compound semiconductor wafer bonding techniques permits the fabrication of LEDs with a plurality of these small, micro-alloyed contacts without the use of a laser.
159 Citations
6 Claims
-
1. A reflective contact for a light emitting semiconductor device, the light emitting semiconductor device having a top and bottom surface, the reflective contact comprising:
-
a reflective metal layer adjacent and abutting a predetermined portion of at least one of the top and bottom surface of the light emitting semiconductor device; and a plurality of alloyed metal-semiconductor zones, each zone having a perimeter that is adjacent and abuts the reflective metal layer, formed from the reflective metal layer and the at least one of the top and bottom surfaces of the light emitting semiconductor device, the alloyed metal-semiconductor zones comprising by area no more than 10% of the total area of the reflective metal layer and the alloyed metal-semiconductor zones combined, the alloyed metal-semiconductor zones forming an ohmic, low resistance contact with the at least one of the the top and bottom surfaces of the light emitting semiconductor device. - View Dependent Claims (2, 3, 4, 5, 6)
-
Specification