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Technique for the growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices achieved

Foreign code F110003775
File No. E06722US2
Posted date Jul 4, 2011
Country United States of America
Application number 95302910
Gazette No. 20110062449
Gazette No. 8686466
Date of filing Nov 23, 2010
Gazette Date Mar 17, 2011
Gazette Date Apr 1, 2014
Priority data
  • 2005US-60686244 (Jun 1, 2005) US
  • 2006US-11444946 (Jun 1, 2006) US
Title Technique for the growth and fabrication of semipolar (Ga,Al,In,B)N thin films, heterostructures, and devices achieved
Abstract (US8686466)
A method for growth and fabrication of semipolar (Ga, Al, In, B)N thin films, heterostructures, and devices, comprising identifying desired material properties for a particular device application, selecting a semipolar growth orientation based on the desired material properties, selecting a suitable substrate for growth of the selected semipolar growth orientation, growing a planar semipolar (Ga, Al, In, B)N template or nucleation layer on the substrate, and growing the semipolar (Ga, Al, In, B)N thin films, heterostructures or devices on the planar semipolar (Ga, Al, In, B)N template or nucleation layer.
The method results in a large area of the semipolar (Ga, Al, In, B)N thin films, heterostructures, and devices being parallel to the substrate surface.
Scope of claims [claim1]
1. A light emitting device , comprising: a semipolar III-nitride film including a light emitting device structure, wherein: the light emitting device structure includes one or more semipolar III-nitride active layers grown on or above a surface of a substrate, and
one or more material properties of the semipolar III-nitride active layers are such that the device has an output power of at least 1.5 milliwatts at 250 milliamps drive current and at a current density of no more than 278 Amps per centimeter square.
[claim2]
2. The device of claim 1, wherein the semipolar III-nitrade active layers are grown on or above a semipolar surface of the substrate comprising a free-standing gallium nitride (GaN) substrate.
[claim3]
3. The device of claim 1, wherein the substrate is grown on a foreign material.
[claim4]
4. The device of claim 1, wherein the semipolar III-nitride active layers form a heterostructure and the device is a light emitting diode.
[claim5]
5. The device of claim 1, wherein the semipolar III-nitride emit light with reduced blue-shift in -a blue emission peak with increasing drive current density between at least 33 Amps per centimeter square and at least 222 Amps per centimeter square, as compared to polar III-nitride active layers operating in similar wavelength and drive current density ranges.
[claim6]
6. The device of claim 1, wherein the semipolar III-nitride active layers emit light with a reduced decrease in the external quantum efficiency (EQE) with increasing drive current density, as compared to polar III-nitride active layers operating in similar wavelength and drive current density ranges.
[claim7]
7. The device of claim 1, wherein the semipolar III-nitride active layers have reduced polarization effects and effective hole masses, as compared to polar III-nitride active layers operating in similar wavelength and drive current density ranges.
[claim8]
8. The device of claim 1, wherein the device structure comprises a blue light emitting semipolar Light Emitting Diode (LED).
[claim9]
9. The device of claim 1, wherein a top surface of the semipolar III-nitride active layers is planar, semipolar, and substantially parallel to a main surface of the substrate.
[claim10]
10. The device of claim 1, wherein: the light emitting device structure has a peak External Quantum Efficiency (EQE) at a current density of no more than 55 Amps per centimeter square; and a drop in the EQE is no more than 15% at a current density of at least 111 Amps per centimeter square, as compared to the peak EQE.
[claim11]
11. The device of claim 1, wherein the semipolar III-nitride active layers are grown on or above a semipolar surface of a gallium nitride (GaN) template having a thickness of at least 10 micrometers.
[claim12]
12. The device of claim 1, wherein the light emitting device structure has an emission peak at a blue wavelength at a current density in a range between at least 33 Amps per centimeter square and at least 222 Amps per centimeter square.
[claim13]
13. The device of claim 1, wherein the substrate is a nitride substrate.
[claim14]
14. A method for fabricating a device, comprising: growing a semipolar III-nitride film including a light emitting device structure, wherein: the light emitting device structure includes one or more semipolar III-nitride active layers grown on or above a surface of a nitride substrate, and
the semipolar III-nitride active layers have one or more material properties such that the device has an output power of at least 1.5 milliwatts at 250 milliamps drive current and at a current density of no more than 278 Amps per centimeter square.
[claim15]
15. The method of claim 14, wherein the semipolar III-nitride active layers are grown on or above the nitride substrate comprising a free-standing gallium nitride (GaN) substrate.
[claim16]
16. The method of claim 14, wherein the nitride substrate is grown on a foreign material.
[claim17]
17. The method of claim 14, wherein the semipolar III-nitride active layers form a heterostructure and the device is a light emitting diode.
[claim18]
18. The method of claim 14, wherein the semipolar III-nitride active layers emit light with a reduced blue-shift in a blue emission peak with increasing drive current density between at least 33 Amps per centimeter square and at least 222 Amps per centimeter square as compared to polar III-nitride active layers operating in similar wavelength and drive current density ranges.
[claim19]
19. The method of claim 14, wherein the semipolar III-nitride active layers emit light with a reduced decrease in the external quantum efficiency (EQE) with increasing drive current density, as compared to polar III-nitride active layers operating in similar wavelength and drive current density ranges.
[claim20]
20. The method of claim 14, wherein the semipolar III-nitride active layers have reduced polarization effects and effective hole masses, as compared to polar III-nitride active layers operating in similar wavelength and drive current density ranges.
[claim21]
21. The method of claim 14, wherein the light emitting device structure comprises a blue light emitting semipolar Light Emitting Diode (LED).
[claim22]
22. A device fabricated using the method of claim 14.
[claim23]
23. The method of claim 14, wherein: a top surface of the semipolar III-nitride active layers is planar, semipolar, and substantially parallel to a semipolar surface of the nitride substrate comprising a nitride template layer, and
the top surface has a surface area of at least 300 micrometers by 300 micrometers.
[claim24]
24. The method of claim 14, wherein the semipolar III-nitride active layers are grown on or above a semipolar surface of a gallium nitride (GaN) template having a thickness of at least 10 micrometers.
[claim25]
25. The method of claim 14, wherein a semipolar orientation and the one or more material properties of the semipolar III-nitride active layers are such that the light emitting device structure has a peak External Quantum Efficiency (EQE) at a current density of no more than 222 Amps per centimeter square and a drop in the EQE of no more than 51% at a current density of at least 278 Amps per centimeter square, as compared to the peak EQE.
[claim26]
26. A light emitting device, comprising: a semipolar III-nitride film including a light emitting device structure, wherein: the light emitting device structure includes one or more seimpolar III-nitride active lavers grown on or above a surface of a substrate,
one or more material properties of the semipolar III-nitride active layers are such that the device has an output power of at least 1.5 milliwatts at 250 milliamps drive current, and
a semipolar orientation and the one or more material properties of the semipolar III-nitride active layers are such that the light emitting device structure has a peak External Quantum Efficiency (EQE) at a current density of no more than 222 Amps per centimeter square and a drop in the EQE of no more than 51% at a current density of at least 278 Amps per centimeter square, as compared to the peak EQE.
  • Inventor, and Inventor/Applicant
  • FARRELL JR ROBERT M
  • BAKER TROY J
  • CHAKRABORTY ARPAN
  • HASKELL BENJAMIN A
  • PATTISON P MORGAN
  • SHARMA RAJAT
  • MISHRA UMESH K
  • DENBAARS STEVEN P
  • SPECK JAMES S
  • NAKAMURA SHUJI
  • JAPAN SCIENCE AND TECHNOLOGY AGENCY
  • UNIVERSITY OF CALIFORNIA
IPC(International Patent Classification)
Reference ( R and D project ) ERATO NAKAMURA Inhomogeneous Crystal AREA
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