Laser Diode Orientation on Mis-Cut Substrates

• US 20080265379A1
• Filed: 06/27/2006
• Published: 10/30/2008
• Est. Priority Date: 07/11/2005
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Brandes, George R., Xu, Xueping, Vaudo, Robert P.
• Granted Patent: US 7,884,447 B2
• Time in Patent Office: Days
• US Class Current: 257/627
• CPC Class Codes: H01S 5/32341 blue laser based on GaN or GaP
• CPC Class Codes: Y10S 438/973 Substrate orientation

Abstract

A microelectronic assembly in which a semiconductor device structure is directionally positioned on an off-axis substrate (201). In an illustrative implementation, a laser diode is oriented on a GaN substrate (201) wherein the GaN substrate includes a GaN (0001) surface off-cut from the <0001> direction predominantly towards either the <1120> or the <11 00> family of directions. For a <11 20> off-cut substrate, a laser diode cavity (207) may be oriented along the <1 100> direction parallel to lattice surface steps (202) of the substrate (201) in order to have a cleaved laser facet that is orthogonal to the surface lattice steps. For <11 00> off-cut substrate, the laser diode cavity may be oriented along the <1 100> direction orthogonal to lattice surface steps (207) of the substrate (201) in order to provide a cleave laser facet that is aligned with the surface lattice steps.

Claims

1. An electronic device comprising a III-V nitride substrate having a III-V nitride (0001) surface off-cut from the <

0001>

direction predominantly towards the <

11 2 0>

direction.

2. The electronic device of claim 1 further comprising an off-cut surface angle from the (0001) surface that is in a range of from about 0.2 to about 10 degrees.

3. The electronic device of claim 1, wherein the surface off-cut from the <

0001>

direction predominantly towards the <

11 2 0>

direction has a tilt direction that is oriented to within ±

15 degrees of the <

11 2 0>

direction.

4. The electronic device of claim 1, wherein the surface off-cut from the <

0001>

direction predominantly towards the <

11 2 0>

direction has a tilt direction that is oriented to within ±

5 degrees of the <

11 2 0>

direction.

5. The electronic device of claim 1, further comprising a laser diode cavity on the substrate oriented parallel to the <

1 100>

direction

6. The electronic device of claim 1, further comprising a laser facet oriented on a cleavage plane orthogonal to the <

1 100>

direction.

7. The electronic device of claim 1, further comprising a laser diode cavity on the substrate, with a laser facet disposed orthogonal to the laser diode cavity.

8. The electronic device of claim 1, further comprising a facet oriented on a cleavage plane orthogonal to the <

1 100>

direction, wherein the substrate comprises a substrate flat having a flat tolerance of less than 5 degrees of azimuthal orientation

9. The electronic device of claim 8, wherein the substrate comprises a substrate flat having a flat tolerance of less than 1 degree of azimuthal orientation.

10. The electronic device of claim 1, including a substrate flat that is positioned to define the <

11 20>

direction of the cleavage plane.

11. The electronic device of claim 5, comprising a doped epitaxial film on the laser diode cavity.

12. The electronic device of claim 1, comprising epitaxial layers grown on said substrate.

13. The electronic device of claim 1, comprising any of an optoelectronic device, a microelectronic device, and a semiconductor device.

14. The electronic device of claim 1, comprising a laser diode.

15. The electronic device of claim 1, wherein the III-V nitride substrate is a GaN substrate.

16. The electronic device of claim 1, further comprising top contacts.

17. The electronic device of claim 1, comprising a vertical device.

18. An electronic device comprising a III-V nitride substrate, wherein the III-V nitride substrate includes a III-V nitride (0001) surface off-cut from the <

0001>

direction predominantly towards the <

1 100>

direction.

19. The electronic device of claim 18, wherein the off-cut surface is characterized by an off-cut angle in a range of from 0.2 to 10 degrees providing surface lattice steps parallel to the <

11 20>

direction.

20. The electronic device of claim 18, including a cavity formed on the off-cut substrate surface such that the cavity direction is oriented along the <

1 100>

direction orthogonal to lattice surface steps of the substrate.

21. The electronic device of claim 20, including a cleavage plane that is orthogonal to the <

1 100>

direction yielding a cleaved facet that contains the c-axis vector.

22. The electronic device of claim 18, comprising a laser diode.

23. An electronic device comprising:

a III-V nitride substrate having an (Al,Ga,In)N off-cut surface with a plurality of parallel steps, each step having a first step face and a second step face meeting along a crest, wherein each first step face and each second step face is orthogonal to a cleavage plane; and

a laser diode cavity disposed parallel to each first step face and each second step face.

24. The electronic device of claim 23, including epitaxial layers grown on said substrate.

25. The electronic device of claim 23, wherein the off-cut surface has an off-cut angle in a range of from 0.2 to 10 degrees.

26. The electronic device of claim 23, further comprising facets, wherein the laser diode cavity is substantially orthogonal to the facets.

27. The electronic device of claim 23, further comprising a substrate flat disposed substantially parallel to the cleavage plane.

28. The electronic device of claim 23, wherein the substrate is cleaved along the cleavage plane.

29. The electronic device of claim 23, comprising a laser diode.

30. A III-V nitride substrate including a III-V nitride (0001) surface off-cut from the <

0001>

direction predominantly towards the <

11 20>

direction and further comprising a substrate flat that defines a cleavage plane orthogonal to the <

1 100>

direction.