CN-122003973-A - High voltage LED emitter

Abstract

A high power LED array driven at greater than about 6V for vehicle applications and a method of manufacturing the LED array are described. The mirror is disposed on the n-semiconductor layer and the p-semiconductor layer. A dielectric spacer is disposed between the p-semiconductor and the mirror. A hard mask is deposited over the dielectric spacer and has openings with conductors to the mirror. A dielectric layer is deposited over the hard mask. A bonding layer formed on the dielectric layer is connected to the semiconductor. The trench extends through the semiconductor to form a series connected pixel. A dielectric spacer stack is disposed on the sidewalls of the trench to form a bragg reflector. A Redistribution Dielectric (RDL) layer is disposed on the bonding layer. An Under Bump Metallization (UBM) pad deposited on the RDL layer is coupled to the bonding layers of the first and last pixels via an opening in the RDL layer.

Inventors

• R. J. Bonner
• E.W.Yang
• F. G. munsjie
• A. Lopez, Julia

Assignees

• 亮锐有限责任公司

Dates

Publication Date

20260508

Application Date

20240517

Priority Date

20230531

Claims (20)

1. 1. A high power Light Emitting Diode (LED) array comprising: An n-semiconductor layer and a p-semiconductor layer formed on the substrate, an active region between the n-semiconductor layer and the p-semiconductor layer configured to emit light of the LED array; a mirror structure disposed on the n-semiconductor layer and the p-semiconductor layer, the mirror structure configured to reflect light from the active region back to the active region; a dielectric layer disposed on the mirror structure; an n-bonding layer and a p-bonding layer disposed on the dielectric layer and coupled to the n-semiconductor layer and the p-semiconductor layer, respectively, and A trench extending through the entire n-semiconductor layer and p-semiconductor layer to the substrate to form a pixel, the sidewalls of the trench being substantially parallel to the growth direction of the n-semiconductor layer and p-semiconductor layer.
2. 2. The high power LED array of claim 1, further comprising: a Transparent Conductive Oxide (TCO) layer disposed between the p-semiconductor layer and the mirror structure, and A dielectric spacer disposed between the TCO layer and the mirror structure, the dielectric spacer including an e-via electrically coupling the TCO layer and the mirror structure.
3. 3. The high power LED array of claim 2, further comprising a hard mask spacer disposed on said mirror structure, said hard mask spacer comprising an opening filled with a conductive material for current injection from the p-bonding layer to the mirror structure.
4. 4. The high power LED array of claim 3, wherein the openings are uniformly distributed on one side of the hard mask spacer of each pixel.
5. 5. The high power LED array of claim 4, wherein said openings are formed on alternating sides of a hard mask spacer of each pixel in each row of pixels.
6. 6. The high power LED array of any one of claims 1-5, further comprising a multi-layer dielectric spacer layer stack disposed on sidewalls of the trench, the dielectric spacer layer stack forming a photon bragg reflector.
7. 7. The high power LED array of claim 6, wherein at least some layers of the multi-layer dielectric spacer layer stack are disposed on at least one of an n-bonding layer and a p-bonding layer, and at least other layers of the multi-layer dielectric spacer layer stack are disposed between at least one of the n-bonding layer and the p-bonding layer.
8. 8. The high power LED array of any one of claims 1-7, further comprising an n-via disposed in the center of each pixel to provide electrical contact to the n-semiconductor layer.
9. 9. The high power LED array of any one of claims 1-7, wherein the pixels are coupled in series using an n-bonding layer and a p-bonding layer.
10. 10. The high power LED array of claim 9, further comprising a redistribution dielectric layer disposed over the n-bonding layer and the p-bonding layer, the redistribution dielectric layer having a first opening to the n-bonding layer of a first one of the series-coupled pixels and a second opening to the p-bonding layer of a last one of the series-coupled pixels.
11. 11. The high power LED array of claim 10, further comprising an n-Under Bump Metallization (UBM) pad and a p-UBM pad deposited or otherwise formed on the redistribution dielectric layer, the n-UBM pad electrically coupled to the n-bonding layer of a first pixel via the first opening, the p-UBM pad electrically coupled to the p-bonding layer of a last pixel via the first opening.
12. 12. The high power LED array of any one of claims 1-11, wherein: Each of the trenches has a width of at most about 5 microns, The mirror structure is an Ag mirror, and The substrate is patterned sapphire.
13. 13. A method of forming a high power Light Emitting Diode (LED) array, the method comprising: forming an n-semiconductor layer and a p-semiconductor layer on a substrate, an active region between the n-semiconductor layer and the p-semiconductor layer configured to emit light of the LED array; Forming a mirror structure on the n-semiconductor layer and the p-semiconductor layer, the mirror structure configured to reflect light from the active region back to the active region; Forming a hard mask spacer over the mirror structure; forming a dielectric layer on the hard mask spacers; forming an n-bonding layer and a p-bonding layer on the dielectric layer, the n-bonding layer and the p-bonding layer being coupled to the n-semiconductor layer and the p-semiconductor layer, respectively, and Trenches extending substantially vertically through the entire n-semiconductor layer and p-semiconductor layer are etched to form pixels, the sidewalls of the trenches being substantially parallel to the growth direction of the n-semiconductor layer and p-semiconductor layer.
14. 14. The method of claim 13, further comprising: Forming a dielectric spacer on the p-semiconductor layer, a mirror structure being formed on the dielectric spacer; Forming an e-via in the dielectric spacer, and An opening is formed in the hard mask spacer and filled with a conductive material for current injection from the p-junction layer to the mirror structure.
15. 15. The method of claim 13 or 14, further comprising forming a multi-layer dielectric spacer layer stack on sidewalls of the trench, the dielectric spacer layer stack forming a photon bragg reflector, wherein: at least some of the layers of the multi-layer dielectric spacer layer stack are disposed on at least one of the n-bonding layer and the p-bonding layer, and At least one other layer of the multi-layer dielectric spacer layer stack is disposed between at least one of the n-bonding layer and the p-bonding layer.
16. 16. The method of any of claims 13-15, further comprising: using the n-bonding layer and the p-bonding layer to couple pixels in series; forming a redistribution dielectric layer on the n-bonding layer and the p-bonding layer; Forming a first opening in the redistribution dielectric layer to an n-bonding layer of a first one of the series-coupled pixels and a second opening to a p-bonding layer of a last one of the series-coupled pixels, and An n-Under Bump Metallization (UBM) pad electrically coupled to the n-bonding layer of the first pixel via the first opening and a p-UBM pad electrically coupled to the p-bonding layer of the last pixel via the first opening are formed on the redistribution dielectric layer.
17. 17. A vehicle headlamp comprising: A high power Light Emitting Diode (LED) array comprising: An n-semiconductor layer and a p-semiconductor layer formed on the substrate, and an active region between the n-semiconductor layer and the p-semiconductor layer configured to emit light of the LED array; a mirror structure disposed on the n-semiconductor layer and the p-semiconductor layer and configured to reflect light from the active region back to the active region; a dielectric layer on the mirror structure; an n-bonding layer and a p-bonding layer formed on the dielectric layer and coupled to the n-semiconductor layer and the p-semiconductor layer, respectively, and A trench extending through the entire n-semiconductor layer and p-semiconductor layer to the substrate to form a pixel, a sidewall of the trench being substantially parallel to a growth direction of the n-semiconductor layer and p-semiconductor layer, and A driver configured to drive the high power LED array at a voltage greater than about 6V.
18. 18. The vehicle headlamp of claim 17, further comprising: a Transparent Conductive Oxide (TCO) layer disposed between the p-semiconductor layer and the mirror structure; a dielectric spacer disposed between the TCO layer and the mirror structure, the dielectric spacer including an e-via electrically coupling the TCO layer and the mirror structure, and A hard mask spacer disposed over the mirror structure, the hard mask spacer including an opening filled with a conductive material for current injection from the p-bonding layer to the mirror structure.
19. 19. The vehicle headlamp of claim 17 or 18, further comprising a multi-layer dielectric spacer layer stack disposed on a sidewall of the trench, the dielectric spacer layer stack forming a photon bragg reflector, wherein at least some layers of the multi-layer dielectric spacer layer stack are disposed on at least one of an n-bonding layer and a p-bonding layer, and at least other layers of the multi-layer dielectric spacer layer stack are disposed between at least one of an n-bonding layer and a p-bonding layer.
20. 20. The vehicle headlamp of any of claims 17-19, further comprising: an n-via disposed in the center of each pixel to provide electrical contact to the n-semiconductor layer, the pixels being coupled in series using an n-bonding layer and a p-bonding layer; A redistribution dielectric layer disposed over the n-bonding layer and the p-bonding layer, the redistribution dielectric layer having a first opening to the n-bonding layer of a first one of the series-coupled pixels and a second opening to the p-bonding layer of a last one of the series-coupled pixels, and An n-Under Bump Metallization (UBM) pad and a p-UBM pad formed on the redistribution dielectric layer, the n-UBM pad being electrically coupled to the n-bonding layer of the first pixel via the first opening, the p-UBM pad being electrically coupled to the p-bonding layer of the last pixel via the first opening.

Description

High voltage LED emitter Priority statement The present application claims the benefit of priority from U.S. provisional patent application Ser. No.63/469981 filed on 31, 5, 2023, which is incorporated herein by reference in its entirety. Technical Field The present disclosure relates to Light Emitting Diode (LED) arrays. In particular, embodiments are directed to driving an LED array. Background The driver architecture of the LED array may enable LEDs to be relatively efficient, but at a cost of price. However, in some circumstances, improving efficiency is not as desirable as greatly reducing costs. Drawings Fig. 1 shows an example of a driver architecture. Fig. 2 illustrates an LED array according to some examples. Fig. 3 illustrates isolated pixels according to some examples. Fig. 4A illustrates a cross section of an LED array during fabrication according to some examples. Fig. 4B illustrates another cross-section of the LED array during fabrication subsequent to fig. 4A, according to some examples. Fig. 4C illustrates another cross-section of the LED array during fabrication subsequent to fig. 4B, according to some examples. Fig. 4D illustrates another cross-section of the LED array during fabrication subsequent to fig. 4C, according to some examples. Fig. 5A illustrates a top view of a high voltage LED array during fabrication according to some examples. Fig. 5B illustrates a top view of the high voltage LED array during fabrication after fig. 5A, according to some examples. Fig. 5C illustrates a top view of the high voltage LED array during fabrication after fig. 5B, according to some examples. Fig. 5D illustrates a top view of the high voltage LED array during fabrication after fig. 5C, according to some examples. Fig. 5E illustrates a top view of the high voltage LED array during fabrication after fig. 5D, according to some examples. Fig. 5F illustrates a top view of the high voltage LED array during fabrication after fig. 5E, according to some examples. Fig. 5G illustrates a top view of the high voltage LED array during fabrication after fig. 5F, according to some examples. Fig. 6 illustrates an example of a generic device according to some embodiments. Fig. 7 illustrates an example lighting system according to some embodiments. Fig. 8 illustrates an example hardware arrangement for implementing the disclosed subject matter described above, in accordance with some embodiments. Fig. 9 illustrates an example method of making a lighting device according to some embodiments. Fig. 10 illustrates another driver architecture according to some examples. FIG. 11 is a schematic diagram of an example vehicle headlamp system. Detailed Description Existing LED driver architectures include various components, some of which are too expensive for the driver and the system in which the LED array is to be located. In some systems, particularly (but not exclusively) in-vehicle systems, cost is one of the parameters used to determine whether a particular LED system is attractive for a particular application. LED arrays can be used in many applications including, for example, both automotive interior and exterior lighting. In particular, the use of LED arrays in motor vehicle headlamps is gaining attention because it allows to selectively illuminate the whole road or only selected parts of the road, the latter being able to be used to reduce problems associated with glare or blinding of an oncoming driver if combined with individual driving. In this case, an infrared camera in the head lamp or elsewhere in the vehicle may be used as a sensor, the LED array activating only those pixels for illuminating the road, while disabling pixels that may dazzle the driver of a pedestrian or an oncoming vehicle. In addition, pedestrians, animals, or logos outside the roadway may be selectively illuminated, for example, to increase the driver's environmental awareness. For pixels of a spectrally distinct LED array, the color temperature of the light may be adjusted according to, for example, ambient lighting conditions (such as daytime, dusk, or nighttime conditions). Depending on the matrix or display size and pixel-per-inch requirements of the matrix or display size, such an adaptive high beam (ADB) system may be formed from individual light emitting sources with areas of several square millimeters (mini-LEDs) down to several square micrometers (micro-LEDs). Each LED may be coupled with primary optics (such as a collimator array) and secondary optics. Other common applications supported by LED arrays include video lighting, building and area lighting, street lighting, and information display. One consideration associated with ADB systems that use high power LED arrays is the cost of the electronics used to control each pixel. Matrix drivers (also known as matrix controllers) for individually controlling each LED in an array are relatively expensive. For example, the cost of a matrix driver for an m×n LED array exceeds 1/3 of the