Light emitting device including shaped substrate
View Patent ↗Embodiments of the invention include a semiconductor structure ( 23 ) including a light emitting layer. A substrate ( 10 ) comprising lithium is attached to the semiconductor structure ( 23 ). A surface of the substrate ( 10 ) forms an angle with a major plane of the semiconductor structure ( 23 ) that is between 60° and 75°.
1. A device comprising: a substrate comprising lithium, the substrate having a first surface and a second surface opposite the first surface; and a semiconductor structure comprising a light emitting layer, the semiconductor structure having a first surface and a second surface opposite the first surface, the first surface of the semiconductor structure disposed adjacent the first surface of the substrate, at least a portion of the second surface of the substrate is shaped into at least one truncated pyramid, each truncated pyramid including four outer walls, each of the four outer walls of each truncated pyramid being angled toward a center of the truncated pyramid and adjoining two adjacent side walls of the same truncated pyramid at respective edges, wherein an intersecting notch is formed in each of the respective edges, each intersecting notch having side walls that form an angle between 600 and 750 relative to the second surface of the semiconductor structure.
2. The device of claim 1 , wherein the substrate comprises lithium niobate tantalate (LiNb a Ta 1−a O 3 ) where 0≤a≤1.
3. The device of claim 1 , wherein the second surface of the substrate is part of a feature formed in the substrate, wherein a plurality of features are formed over a portion of the light emitting layer corresponding to a single light emitting device.
4. The device of claim 1 , further comprising a wavelength converting layer disposed over the second surface of the substrate.
5. A method comprising:
providing a substrate comprising lithium, the substrate having a first surface and a second surface opposite the first surface, wherein a semiconductor structure comprising a light emitting layer and having a first surface and a second surface opposite the first surface is disposed adjacent the first surface of the substrate; and
shaping the second surface of the substrate such that at least a portion of the second surface of the substrate is shaped into at least one truncated pyramid, each truncated pyramid including four outer walls, each of the four outer walls of each truncated pyramid being angled toward a center of the truncated pyramid and adjoining two adjacent side walls of the same truncated pyramid at respective edges, an intersecting notch is formed in each of the respective edges, each intersecting notch having side walls that form an angle between 60° and 75° relative to the second surface of the semiconductor structure.
6. The method of claim 5 , wherein the providing the substrate comprising lithium further comprises growing the semiconductor structure on the substrate comprising lithium.
7. The method of claim 5 , wherein the providing the substrate comprising lithium further comprises:
growing the semiconductor structure on a growth substrate; and
after the growing, bonding the semiconductor structure to the substrate comprising lithium.
8. The method of claim 5 , wherein the shaping comprises sawing.
9. The method of claim 5 , wherein the shaping comprises etching.
10. The method of claim 5 , wherein the shaping comprises forming at least one pyramid.
11. The method of claim 5 , wherein the substrate comprises one of lithium niobate tantalate (LiNb a Ta 1−a O 3 ) where 0≤a≤1, LiN b O 3 , LiTaO 3 , and LiVO 3 .
12. The method of claim 5 , further comprising disposing a wavelength converting layer over the substrate.
13. The device of claim 1 , wherein each of the four outer walls of each truncated pyramid forms an angle of between 60° and 75° with the second surface of the semiconductor structure.
14. The method of claim 5 , wherein each of the four outer walls of each truncated pyramid forms an angle of between 60° and 75° with the second surface of the semiconductor structure.
15. The device of claim 1 , wherein each truncated pyramid has an upper surface that is substantially parallel with the second surface of the semiconductor structure such that the intersecting notches form four regions atop the truncated pyramid that are substantially parallel with the second surface of the semiconductor structure and respectively adjoin each of the intersecting notches.
16. The method of claim 5 , wherein each truncated pyramid has an upper surface that is substantially parallel with the second surface of the semiconductor structure such that the intersecting notches form four regions atop the truncated pyramid that are substantially parallel with the second surface of the semiconductor structure and respectively adjoin each of the intersecting notches.