Laser lift-off on isolated III-nitride light islands for inter-substrate LED transfer
View Patent ↗A laser liftoff process is provided. A device layer can be provided on a transfer substrate. Channels can be formed through the device layer such that devices comprising remaining portions of the device layer are laterally isolated from one another by the channels. The transfer substrate can be bonded to a target substrate through an adhesion layer. Surface portions of the devices can be removed from an interface region between the transfer substrate and the devices by irradiating a laser beam through the transfer substrate onto the devices. The laser irradiation decomposes the III-V compound semiconductor material. The channels provide escape paths for the gaseous products (such as nitrogen gas) that are generated by the laser irradiation. The transfer substrate is separated from a bonded assembly including the target substrate and remaining portions of the devices. The devices can include a III-V compound semiconductor material.
1. A device assembly comprising:
a substrate;
an adhesion layer including a plurality of laterally spaced adhesion material portions that are located on a surface of the substrate; and
an array of devices located on the adhesion layer, comprising at least one light emitting device, and laterally spaced from one another by channels,
wherein at least one of the adhesion material portions comprises a horizontal step that provides a lateral offset between a sidewall of an upper region thereof and a sidewall of a lower region thereof; and
wherein the upper region and the lower region have a same lateral dimension for each of the at least one of the adhesion material portions.
2. The device assembly of claim 1 , wherein each of the at least one of the adhesion material portions comprises another horizontal step located at an opposite side of the horizontal step, having a same lateral dimension as the horizontal step, and facing an opposite direction with respect to the horizontal step.
3. The device assembly of claim 1 , wherein areas of upper regions of the adhesion layer have a pattern that is congruent with a pattern of areas of lower regions of the adhesion layer, and are laterally translated with respect to the areas of the lower regions of the adhesion layer.
4. The device assembly of claim 1 , wherein areas of upper regions of the adhesion layer are congruent with, and overlap with, areas of the array of devices.
5. The device assembly of claim 1 , wherein the adhesion layer comprises a material selected from a dielectric material and a metal.
6. The device assembly of claim 1 , wherein the devices comprise a III-V compound semiconductor material.
7. The device assembly of claim 1 , further comprising an array of Group III metal portions located on surfaces of the devices and spaced from the adhesion layer by the devices.
8. The device assembly of claim 1 , wherein the device assembly comprises a direct view display panel containing red, green, and blue wavelength light emitting diodes and sensors as the devices, the devices being bonded to the substrate through the adhesion layer.
9. The device assembly of claim 1 , wherein:
the devices comprise a rectangular array of light emitting devices; and
the channels form a rectangular grid by which the light emitting devices in the rectangular array are laterally spaced from one another.
10. A device assembly comprising:
a substrate;
an adhesion layer including a plurality of laterally spaced adhesion material portions that are located on a surface of the substrate; and
an array of devices located on the adhesion layer, comprising at least one light emitting device, and laterally spaced from one another by channels,
wherein at least one of the adhesion material portions comprises a horizontal step that provides a lateral offset between a sidewall of an upper region thereof and a sidewall of a lower region thereof; and
wherein areas of upper regions of the adhesion layer are congruent with, and overlap with, areas of the array of devices.
11. The device assembly of claim 10 , wherein each of the at least one of the adhesion material portions comprises another horizontal step located at an opposite side of the horizontal step, having a same lateral dimension as the horizontal step, and facing an opposite direction with respect to the horizontal step.
12. The device assembly of claim 10 , wherein areas of upper regions of the adhesion layer have a pattern that is congruent with a pattern of areas of lower regions of the adhesion layer, and are laterally translated with respect to the areas of the lower regions of the adhesion layer.
13. The device assembly of claim 10 , wherein the adhesion layer comprises a material selected from a dielectric material and a metal.
14. The device assembly of claim 10 , wherein the devices comprise a III-V compound semiconductor material.
15. The device assembly of claim 10 , further comprising an array of Group III metal portions located on surfaces of the devices and spaced from the adhesion layer by the devices.
16. The device assembly of claim 10 , wherein the device assembly comprises a direct view display panel containing red, green, and blue wavelength light emitting diodes and sensors as the devices, the devices being bonded to the substrate through the adhesion layer.
17. The device assembly of claim 10 , wherein:
the devices comprise a rectangular array of light emitting devices; and
the channels form a rectangular grid by which the light emitting devices in the rectangular array are laterally spaced from one another.