Optoelectronic device containing at least one active device layer having a wurtzite crystal structure, and methods of making same

• US 8,859,412 B2
• Filed: 02/09/2012
• Issued: 10/14/2014
• Est. Priority Date: 04/06/2011
• Status: Active Grant

• Current Assignee: VerLASE Technologies, LLC
• Original Assignee: VerLASE Technologies, LLC
• Inventors: Jain, Ajaykumar R.
• Primary Examiner(s): Lee, Cheung
• Application Number:
  US14/007,168
• Publication Number:
  US 20140024159A1
• Time in Patent Office: 978 Days
• Field of Search: 438/77, 438/603, 438/607, 257/E21.543, 257/E21.603, 257/E21.606, 257/E21.607
• US Class Current: 438/603
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: H01L 21/0237 Materials
• CPC Class Codes: H01L 21/024 Group 12/16 materials
• CPC Class Codes: H01L 21/02417 Chalcogenide semiconducting materials not being oxides, e.g. ternary compounds
• CPC Class Codes: H01L 21/02521 Materials
• CPC Class Codes: H01L 21/02551 Group 12/16 materials
• CPC Class Codes: H01L 21/02557 Sulfides
• CPC Class Codes: H01L 21/02568 Chalcogenide semiconducting materials not being oxides, e.g. ternary compounds
• CPC Class Codes: H01L 31/02325 the optical elements not being integrated nor being directly associated with the device
• CPC Class Codes: H01L 31/0296 including, apart from doping material or other impurities, only AIIBVI compounds, e.g. CdS, ZnS, HgCdTe
• CPC Class Codes: H01L 31/032 including, apart from doping materials or other impurities, only compounds not provided for in groups H01L31/0272 - H01L31/0312
• CPC Class Codes: H01L 31/0324 comprising only AIVBVI or AIIBIVCVI chalcogenide compounds, e.g. Pb Sn Te
• CPC Class Codes: H01L 31/035236 Superlattices; Multiple quantum well structures
• CPC Class Codes: H01L 31/036 characterised by their crystalline structure or particular orientation of the crystalline planes
• CPC Class Codes: H01L 33/005 Processes
• CPC Class Codes: H01L 33/0083 for devices with an active region comprising only II-VI compounds
• CPC Class Codes: H01L 33/0087 with a substrate not being a II-VI compound
• CPC Class Codes: H01L 33/0093 Wafer bonding; Removal of the growth substrate
• CPC Class Codes: H01L 33/06 within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/18 within the light emitting region
• CPC Class Codes: H01L 33/26 : Materials of the light emitting region
• CPC Class Codes: H01L 33/28 : containing only elements of Group II and Group VI of the Periodic Table
• CPC Class Codes: H01L 33/32 : containing nitrogen
• CPC Class Codes: H01L 33/46 : Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01S 5/0206 : Substrates, e.g. growth, shape, material, removal or bonding; specific crystal orientation H01S5/3202
• CPC Class Codes: H01S 5/0217 : Removal of the substrate
• CPC Class Codes: H01S 5/125 : Distributed Bragg reflector [DBR] lasers
• CPC Class Codes: H01S 5/183 : having only vertical cavities, e.g. vertical cavity surface-emitting lasers [VCSEL]
• CPC Class Codes: H01S 5/187 : using Bragg reflection
• CPC Class Codes: H01S 5/327 : in AIIBVI compounds, e.g. ZnCdSe-laser
• CPC Class Codes: H01S 5/347 : in AIIBVI compounds, e.g. ZnCdSe- laser

Abstract

Optoelectronic devices, such as light-emitting diodes, laser diodes, image sensors, optical detectors, etc., made by depositing (growing) one or more epitaxial semiconductor layers on a monocrystalline lamellar/layered substrate so that each layer has a wurtzite crystal structure. In some embodiments, the layers are deposited and then one or more lamellas of the starting substrate are removed from the rest of the substrate. In one subset of such embodiments, the removed lamella(s) is/are partially or entirely removed. In other embodiments, one or more lamellas of the starting substrate are removed prior to depositing the one or more wurtzite-crystal-structure-containing layer(s).

Claims

1. A method of fabricating a light-generating optoelectronic device, the method comprising:

providing a starting substrate, wherein the starting substrate has a naturally lamellar single-crystal structure and is selected to induce a wurtzite crystal structure in a coating layer applied to the starting substrate, wherein the coating layer comprises a II-VI semiconductor;

forming a light-generating optoelectronic structure, wherein said forming the light-generating optoelectronic structure includes forming the coating layer as an epitaxial layer on the starting substrate so that the coating layer has the wurtzite crystal structure, wherein the coating layer has a base composition of a II-VI semiconductor base composition or a I-VI semiconductor base composition;

cleaving the starting substrate so as to provide a sliver of the starting substrate on which the coating layer is formed; and

providing a pair of electrodes in electrical communication with the light-generating optoelectronic structure so that when a current is supplied across the light-generating optoelectronic structure via the pair of electrodes the light-generating optoelectronic structure emits light.

2. A method according to claim 1, wherein said providing a starting substrate includes providing a substrate having a base selected from the group consisting of GaTe, WS₂, ZnIn₂S₄, SnS₂, Bi₂Se₃, Bi₂Te₃, GeSe, and PbI₂.

3. A method according to claim 2, wherein said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a II-VI semiconductor base composition selected from a group consisting of ZnS, ZnSSe, ZnSe, CdS, CdSSe, HgS, CdSe, ZnTe, HgSe, CdTe, and HgTe.

4. A method according to claim 3, wherein:

said providing a starting substrate includes providing a substrate having a base selected from the group consisting of WS₂ and ZnIn₂S₄; and

said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a II-VI semiconductor base composition selected from a group consisting of ZnS, ZnSSe, ZnSe.

5. A method according to claim 3, wherein:

said providing a starting substrate includes providing a substrate having a base selected from the group consisting of SnS₂, Bi₂Se₃, and GaTe; and

said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a II-VI semiconductor base composition selected from a group consisting of ZnSe, ZnSSe, CdS, CdSSe, and HgS.

6. A method according to claim 3, wherein:

said providing a starting substrate includes providing a substrate having a base selected from a group consisting of Bi₂Te₃ and GeSe; and

said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a II-VI semiconductor base composition selected from a group consisting of CdSe, CdSSe, ZnTe, and HgSe.

7. A method according to claim 3, wherein:

said providing a starting substrate includes providing a substrate having a base of PbI₂; and

said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a II-VI semiconductor base composition selected from a group consisting of CdTe and HgTe.

8. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base of GaSe; and

said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a II-VI semiconductor base composition selected from a group consisting of ZnS, ZnSSe, and ZnSe.

9. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base of GaSe; and

said forming a light-generating optoelectronic structure includes;

forming, on the starting substrate, a first ZnS coating layer having a wurtzite crystal structure and a doping of a first type;

forming, over the first ZnS coating layer, a CdSe quantum confining layer having a wurtzite crystal structure; and

forming, over the CdSe quantum confining layer, a second ZnS coating layer having a wurtzite crystal structure and a doping of a second doping type opposite the first doping type.

10. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base of GaSe; and

said forming a light-generating optoelectronic structure includes;

forming, on the starting substrate, a first ZnS coating layer having a wurtzite crystal structure and a doping of a first type;

forming, over the first ZnS coating layer, a CdS quantum confining layer having a wurtzite crystal structure; and

forming, over the CdS quantum confining layer, a second ZnS coating layer having a wurtzite crystal structure and a doping of a second doping type opposite the first doping type.

11. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base of GaSe; and

said forming a light-generating optoelectronic structure includes;

forming, on the starting substrate, a first ZnS coating layer having a wurtzite crystal structure and a doping of a first type;

forming, over the first ZnS coating layer, a HgS quantum confining layer having a wurtzite crystal structure; and

forming, over the HgS quantum confining layer, a second ZnS coating layer having a wurtzite crystal structure and a doping of a second doping type opposite the first doping type.

12. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base of GaSe; and

said forming a light-generating optoelectronic structure includes;

forming, on the starting substrate, a first ZnS coating layer having a wurtzite crystal structure and a doping of a first type;

forming, over the first ZnS coating layer, a Cu_xS quantum confining layer having a wurtzite crystal structure; and

forming, over the Cu_xS quantum confining layer, a second ZnS coating layer having a wurtzite crystal structure and a doping of a second doping type opposite the first doping type.

13. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base selected from a group consisting of Bi₂Te₃ and Bi₂Se₃; and

said forming a light-generating optoelectronic structure includes;

forming, on the starting substrate, a CdS coating layer having a wurtzite crystal structure and a doping of a first type;

forming, over the CdS coating layer, a quantum confining layer having a wurtzite crystal structure and a base composition selected from the group consisting of CdSe and HgS; and

forming, over the quantum confining layer, a ZnTe coating layer having a wurtzite crystal structure and a doping of a second doping type opposite the first doping type.

14. A method according to claim 1, wherein:

said providing a starting substrate includes providing a substrate having a base of GaSe; and

said forming a light-generating optoelectronic structure includes;

forming, on the starting substrate, a ZnSe coating layer having a wurtzite crystal structure and a doping of a first type;

forming, over the ZnSe coating layer, a Cu_xS quantum confining layer having a wurtzite crystal structure; and

forming, over the Cu_xS quantum confining layer, a Cu_xS coating layer having a wurtzite crystal structure and a doping of a second doping type opposite the first doping type.

15. A method according to claim 1, further comprising finishing fabricating the surface-emitting light-generating optoelectronic device so that at least a portion of the sliver of the starting substrate remains intact.

16. A method according to claim 1, further comprising removing the sliver of the starting substrate prior to finishing fabricating the surface-emitting light-generating optoelectronic device.

17. A method according to claim 1, wherein said providing a pair of electrodes includes providing the pair of electrodes on opposite sides of the coating layer.

18. A method according to claim 1, wherein said providing a pair of electrodes includes providing the pair of electrodes on the same side of the coating layer.

19. A method according to claim 1, wherein said cleaving the starting substrate includes cleaving the starting substrate after said forming the coating layer.

20. A method according to claim 1, wherein said cleaving the starting substrate includes cleaving the starting substrate before forming the coating layer.

21. A method according to claim 1, wherein said forming a coating layer as an epitaxial layer includes forming a coating layer wherein the coating layer has a I-VI semiconductor base composition.

22. A method according to claim 21, wherein said forming a coating layer having a I-VI semiconductor base composition includes forming a coating layer having a copper sulfide base composition.