Structure for nitride based laser diode with growth substrate removed

• US 6,757,314 B2
• Filed: 03/26/1999
• Issued: 06/29/2004
• Est. Priority Date: 12/30/1998
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Kneissl, Michael A., Bour, David P., Romano, Linda T., Mei, Ping
• Primary Examiner(s): LEUNG, QUYEN PHAN
• Application Number:
  US09/276,913
• Publication Number:
  US 20040105471A1
• Time in Patent Office: 1,922 Days
• Field of Search: 372/45, 372/46, 372/38, 372/35, 372/50, 372/36
• US Class Current: 372/50.1
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/2007 Bonding of semiconductor wafers to insulating substrates or to semiconducting substrates using an intermediate insulating layer H01L21/2011 takes precedence; bonding of semiconductor wafers to semiconductor wafers for junction formation H01L21/187
• CPC Class Codes: H01L 21/6835 using temporarily an auxiliary support
• CPC Class Codes: H01L 2221/68359 used as a support during manufacture of interconnect decals or build up layers
• CPC Class Codes: H01L 2221/68368 used in a transfer process involving at least two transfer steps, i.e. including an intermediate handle substrate
• CPC Class Codes: H01L 2224/83192 wherein the layer connectors are disposed only on another item or body to be connected to the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/83895 between electrically conductive surfaces, e.g. copper-copper direct bonding, surface activated bonding
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01S 5/0217 Removal of the substrate
• CPC Class Codes: H01S 5/34333 with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence
• CPC Class Codes: H01S 5/4031 Edge-emitting structures

Abstract

A structure for nitride laser diode arrays attached to a thermally conducting substrate is described where the sapphire growth substrate has been removed. The thermally conducting substrate is attached to the side opposite of the sapphire growth substrate.

Claims

1. A structure for a nitride laser diode array comprising:

a semiconductor membrane comprising at least two active layers, said semiconductor membrane having a first crystal plane;

a thermally conducting substrate having a second crystal plane, said thermally conducting substrate supporting said semiconductor membrane and being attached to said semiconductor membrane to enhance thermal coupling between said thermally conducting substrate and said plurality of active layers;

a metal layer disposed between said semiconductor membrane and said thermally conducting substrate, the metal layer having a thickness of less than approximately 10 micro meters; and

three or more electrodes to electrically bias said laser diode array, the three or more electrodes to allow individual addressing of each active layer in the plurality of active layers.

2. The nitride laser diode array of claim 1 wherein said first crystal plane of said semiconductor membrane is aligned with said second crystal plane of said thermally conducting substrate.

3. The nitride laser diode array of claim 1 wherein at least one active layer of said at least three active layers is bounded on one side by a facet cleaved along said first crystal plane.

4. The nitride laser diode array of claim 1 wherein at least one active layer of said at least three active layers is bounded on one side by etched mirror facets.

5. The nitride laser diode array of claim 1 wherein said first crystal plane of said semiconductor membrane is the {1100} plane.

6. The nitride laser diode array of claim 1 wherein said second crystal plane of said thermally conducting substrate is the {111} plane.

7. The nitride laser diode array of claim 1 wherein said thermally conducting substrate is made of a material selected from the group consisting of silicon, silicon carbide, copper and diamond.

8. The nitride laser diode array of claim 1 wherein said semiconductor membrane is comprised of In, Ga, Al and N.

9. The nitride laser diode array of claim 1 wherein said nitride laser diode array is integrated onto an electronic driver chip.

10. The nitride laser diode array of claim 9 wherein said electronic driver chip comprises silicon.

11. The nitride laser diode array of claim 1 wherein the plurality of electrodes includes at least one electrode coupled to at least two active layers in the plurality of active layers such that said one electrode allows current flow through a first active layer to a second electrode, said one electrode also allows current flow through a second active layer to a third electrode.

12. The nitride diode laser array of claim 11 wherein each active layer in the plurality of active layers is in a common plane oriented parallel to other active layers in the plurality of active layers.

13. The nitride diode laser array of claim 12 wherein each active layer in the plurality of active layers is separated from an adjacent active layer by an air gap.

14. The nitride diode laser array of claim 1 wherein each active layer in the at least three active layers having a common composition and thickness such that when subject to excitation, each active layers outputs a common frequency of light.

15. The structure of claim 1 wherein said metal layer serves as a first one of the three or more electrodes and couples to at least two active layers in the plurality of active layers, each of the at least two active layers coupled to a corresponding other one of the three or more electrodes to allow individual addressing of each active layer.

16. The structure of claim 1 wherein at least one of said two active layers include a gallium nitride composition.

17. The structure of claim 1 wherein the individual addressing of each active layer allows different potentials to be applied to each active layer of the plurality of active layers.

18. The structure of claim 1 wherein the metal layer thickness is less than approximately 5 micrometers.

19. The structure of claim 1 wherein the semiconductor membrane comprises at least three active layers.

20. The structure of claim 1 wherein the thermally conducting substrate supporting said semiconductor membrane is attached to the semiconductor membrane by thermo-compression bonding.

21. The structure of claim 1 wherein the at least two active layers form the active layers in a nitride laser diode array.

22. The structure of claim 1 in which the plurality of electrodes includes three or more electrodes.

23. The structure of claim 1 in which said semiconductor membrane has a first surface toward said thermally conducting substrate and a second surface away from said thermally conducting substrate:

the structure further comprising;

a first layer structure bonding the first surface of said semiconductor membrane to said thermally conducting substrate;

the first layer structure thermally coupling said plurality of active layers with said thermally conducting substrate;

the first layer structure including said metal layer; and

a second layer structure on the second surface of said semiconductor membrane;

one of the first and second layer structures including a common electrical contact for said plurality of active layers and the other of the first and second layer structures including a respective separate electrical contact for each of said plurality of active layers;

said semiconductor membrane having been formed by deposition of nitrides on an insulating substrate, one of the first and second surfaces of said semiconductor membrane having been formed by a process that includes removing the insulating substrate at an interface on said semiconductor membrane and then preparing the interface for a layer structure.

24. A structure for a nitride laser diode array comprising:

a semiconductor membrane comprising a plurality of active layers, wherein each active layer in the plurality of active layers has a common composition and thickness such that when subject to excitation, each active layer outputs light of a common predetermined wavelength;

said semiconductor membrane having a first crystal plane;

a thermally conducting substrate having a second crystal plane, said thermally conducting substrate supporting said semiconductor membrane and being attached to said semiconductor membrane to enhance thermal coupling between said thermally conducting substrate and said plurality of active layers;

a metal layer disposed between said semiconductor membrane and said thermally conducting substrate, the metal layer having a thickness of less than approximately 10 micrometers; and

a plurality of electrodes to electrically bias said laser diode array, the plurality of electrodes to allow individual addressing of each active layer in the plurality of active layers.

25. The structure of claim 24 in which the plurality of electrodes includes three or more electrodes.

26. A structure for a nitride laser diode array comprising:

a semiconductor membrane comprising at least two regions in an active layer, each region electrically isolated from adjacent active regions, said semiconductor membrane having a first crystal plane;

a thermally conducting substrate having a second crystal plane, said thermally conducting substrate supporting said semiconductor membrane and being attached to said semiconductor membrane to enhance thermal coupling between said thermally conducting substrate and said plurality of active layers;

a metal layer disposed between said semiconductor membrane and said thermally conducting substrate, the metal layer having a thickness of less than approximately 10 micro meters; and

three or more electrodes to electrically bias said laser diode array, the three or more electrodes to allow individual addressing of each region in the active layer.

27. The structure of claim 26 in which the plurality of electrodes includes three or more electrodes.

28. A laser diode array comprising:

a thermally conducting substrate;

a nitride semiconductor membrane supported on the substrate;

the membrane comprising first and second active regions in an active layer, the first and second active regions being electrically isolated from each other, the membrane having a first surface toward the substrate and a second surface away from the substrate;

a first layer structure bonding the first surface of the membrane to the substrate;

the first layer structure thermally coupling the first and second active regions with the substrate; and

a second layer structure on the second surface of the membrane;

one of the first and second layer structures including a common electrical contact for the first and second active regions and the other of the first and second layer structures including first and second separate electrical contacts for the first and second active regions, respectively;

the membrane having been formed on an insulating substrate, one of the first and second surfaces of the membrane having been formed by a process that includes removing the insulating substrate at an interface on the membrane and then preparing the interface for a layer structure.

29. The laser diode array of claim 28 in which the semiconductor membrane has a first crystal plane resulting from its formation on the insulating substrate;

the thermally conducting substrate having a second crystal plane aligned to allow cleaving along the first crystal plane of the semiconductor membrane and the second crystal plane of the thermally conducting substrate;

the laser diode array further comprising;

a mirror at a facet cleaved along the first crystal plane of the semiconductor membrane and the second crystal plane of the thermally conducting substrate.

30. The laser diode array of claim 28 in which the thermally conducting substrate includes silicon, silicon carbide, diamond, or copper.

31. The laser diode array of claim 28 in which the nitride semiconductor membrane comprises a nitride layer that has a multi-quantum well structure.

32. The laser diode array of claim 28 in which the one of the first and second surfaces of the nitride semiconductor membrane has been formed by:

melting a metal nitride layer at the interface to remove the insulating substrate at the interface on the membrane;

removing residual metal and damaged film at the interface to prepare the interface for a layer structure.

33. The laser diode array of claim 32 in which the damaged film was removed by dry-etching, the one of the first and second surfaces having further been formed by:

ion sputtering to reduce surface damage caused by the dry-etching.

34. The laser diode array of claim 28 in which the first layer structure comprises a solder layer that joins the nitride semiconductor membrane to the thermally conducting substrate.

35. The laser diode array of claim 28 in which the first layer structure comprises an Au—

Au thermo-compression bond that joins the nitride semiconductor membrane to the thermally conducting substrate.

36. The laser diode array of claim 28 in which the first surface of the membrane has been formed by the process that includes removing the insulating substrate and then preparing the interface for a layer structure;

the first layer structure including the common electrical contact;

the second layer structure including the first and second separate electrical contacts.

37. The laser diode array of claim 28 in which the second surface of the membrane has been formed by the process that includes removing the insulating substrate and then preparing the interface for a layer structure;

the first layer structure including the common electrical contact;

the second layer structure including the first and second separate electrical contacts.

38. The laser diode array of claim 28 in which the second surface of the membrane has been formed by the process that includes removing the insulating substrate and then preparing the interface for a layer structure;

the first layer structure including the first and second separate electrical contacts;

the second layer structure including the common electrical contact.