Orientation of electronic devices on mis-cut substrates

• US 8,378,463 B2
• Filed: 12/21/2010
• Issued: 02/19/2013
• Est. Priority Date: 07/11/2005
• Status: Active Grant

• Current Assignee: Creeled Incorporated
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Brandes, George R., Vaudo, Robert P., Xu, Xueping
• Primary Examiner(s): HO, TU TU V
• Application Number:
  US12/974,332
• Publication Number:
  US 20110089536A1
• Time in Patent Office: 791 Days
• Field of Search: 257/627, 257/628, 257/615, 257/E31.04, 438/973, 372/44.011, 372/45.01
• 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. In an illustrative implementation, a laser diode is oriented on a GaN substrate wherein the GaN substrate includes a GaN (0001) surface off-cut from the <0001>direction predominantly towards either the <11 20> or the <1 100> family of directions. For a <11 20> off-cut substrate, a laser diode cavity may be oriented along the <1 100> direction parallel to lattice surface steps of the substrate in order to have a cleaved laser facet that is orthogonal to the surface lattice steps. For a <1 100> off-cut substrate, the laser diode cavity may be oriented along the <1 100> direction orthogonal to lattice surface steps of the substrate in order to provide a cleaved laser facet that is aligned with the surface lattice steps.

Claims

1. A III-V nitride substrate having an (Al,Ga,In)N off-cut surface with a plurality of parallel steps, each step of the plurality of parallel steps 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 wherein the off-cut surface is off-cut from a <

0001>

direction and has a tilt direction oriented to within ±

15 degrees of the <

11 20>

direction.

2. The III-V nitride substrate of claim 1, wherein the <

11 20>

direction includes the [11 20] direction.

3. The III-V nitride substrate of claim 1, wherein the off-cut surface has an off-cut angle in a range of from 0.2 to 10 degrees.

4. The III-V nitride substrate of claim 1, wherein the substrate is cleaved along the cleavage plane.

5. The III-V nitride substrate of claim 1, comprising a substrate flat disposed substantially parallel to the cleavage plane.

6. The III-V nitride substrate of claim 1, comprising a substrate flat having a flat tolerance of less than 5 degrees of azimuthal orientation.

7. The III-V nitride substrate of claim 1, comprising a facet oriented on the cleavage plane.

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

9. The III-V nitride substrate of claim 1, comprising a laser diode cavity disposed parallel to each first step face and each second step face.

10. The III-V nitride substrate of claim 9, further comprising at least one facet, wherein the laser diode cavity is substantially orthogonal to the at least one facet.

11. An electronic device comprising the III-V nitride substrate of claim 1, comprising any of an optoelectronic device, a microelectronic device, and a semiconductor device.

12. The electronic device of claim 11, further comprising epitaxial layers grown on or over at least a portion of the III-V nitride substrate.

13. The electronic device of claim 11, comprising a vertical device.

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

0001>

direction predominantly towards a <

11 20>

direction and including a substrate flat, wherein the substrate flat has a flat tolerance of less than 5 degrees of azimuthal orientation.

15. The III-V nitride substrate of claim 14, wherein the <

11 20>

direction includes the [11 20] direction.

16. The III-V nitride substrate of claim 14, wherein the substrate flat has a flat tolerance of less than 1 degree of azimuthal orientation.

17. The III-V nitride substrate of claim 14, wherein the substrate flat defines a cleavage plane.

18. The III-V nitride substrate of claim 14, wherein the surface off-cut from the <

0001>

direction predominantly towards the <

11 20>

direction has an off-cut surface angle in a range of from about 0.2 to about 10 degrees.

19. The III-V nitride substrate of claim 14, wherein the surface off-cut from the <

0001>

direction predominantly towards the <

11 20>

direction has a tilt direction that is oriented to within ±

15 degrees of the <

11 20>

direction.

20. The III-V nitride substrate of claim 14, wherein the surface off-cut from the <

0001>

direction predominantly towards the <

11 20>

direction has a tilt direction that is oriented to within ±

5 degrees of the <

11 20>

direction.

21. The III-V nitride substrate of claim 14, wherein the III-V nitride substrate is a GaN substrate.

22. An electronic device comprising the III-V nitride substrate of claim 14, comprising any of an optoelectronic device, a microelectronic device, and a semiconductor device.

23. The electronic device of claim 22, further comprising epitaxial layers grown on or over at least a portion of the III-V nitride substrate.

24. The electronic device of claim 22, wherein the substrate flat is disposed substantially parallel to a cleavage plane of the substrate.

25. The electronic device of claim 22, wherein the substrate is cleaved along the cleavage plane.

26. The electronic device of claim 22, comprising a vertical device.

27. The electronic device of claim 22, comprising a facet oriented on the cleavage plane.

28. The electronic device of claim 22, comprising a laser diode cavity on the substrate oriented parallel to the <

1 100>

direction.

29. A III-V nitride substrate having an (Al,Ga,In)N off-cut surface with a plurality of parallel steps, each step of the plurality of parallel steps 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 wherein parallel steps of the plurality of parallel steps are disposed parallel to a <

11 20>

direction.