Solid-state transducer devices with selective wavelength reflectors and associated systems and methods

Patent metadata

Field	Value
Publication number	US-10879428-B2
Application number	US-201213474658-A
Country	US
Kind code	B2
Filing date	May 17, 2012
Priority date	May 17, 2012
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

Solid state transducer (“SST”) devices with selective wavelength reflectors and associated systems and methods are disclosed herein. In several embodiments, for example, an SST device can include a first emitter configured to emit emissions having a first wavelength and a second emitter configured to emit emissions having a second wavelength different from the first wavelength. The first and second emitters can be SST structures and/or converter materials. The SST device can further include a selective wavelength reflector between the first and second emitters. The selective wavelength reflector can be configured to at least substantially transmit emissions having the first wavelength and at least substantially reflect emissions having the second wavelength.

First claim

We claim:

1. A solid-state transducer (SST) device having a front side from which emissions exit the SST device and a back side facing away from the front side, the SST device comprising:
a SST structure configured to emit emissions having a first wavelength and having a front surface facing the front side of the SST device and a back surface facing the back side of the SST device, the SST structure comprising:
a first semiconductor material at the back surface of the SST structure;
a second semiconductor material at the front surface of the SST structure; and
an active region between the first and second semiconductor materials;

a second emitter configured to emit emissions having a second wavelength different from the first wavelength, wherein a back surface of the second emitter includes a converter material;
a selective wavelength reflector having a front surface facing the front side of the SST device and a back surface facing the back side of the SST device, the selective wavelength reflector configured to at least substantially transmit emissions having the first wavelength and at least substantially reflect emissions having the second wavelength, wherein the selective wavelength reflector includes a multilayer stack of materials comprising layers of silicon dioxide (SiO 2 ), titanium dioxide (TiO 2 ), and alloys thereof, and wherein two neighboring TiO 2 layers of the multilayer stack are separated by a SiO 2 layer and one or more alloy layers; and
a first spacer and a second spacer, the first spacer disposed between the selective wavelength reflector back surface and the second semiconductor material of the SST structure, and the second spacer disposed between the selective wavelength reflector front surface and the back surface of the second emitter, wherein the second spacer comprises one or more air gaps or voids.

2. The SST device of claim 1 wherein:
the first semiconductor material comprises N-type gallium nitride (N—GaN), the second semiconductor material comprises a P-type gallium nitride (P—GaN), and the active region comprises indium gallium nitride (InGaN);
the SST structure is configured to emit blue light;
the second emitter converter material is configured to emit yellow light; and
the selective wavelength reflector is configured to at least substantially transmit blue light and at least substantially reflect yellow light.

3. The SST device of claim 1 wherein:
the first emitter is a first SST structure configured to emit red light;
the second emitter is a second SST structure configured to emit green light;
the selective wavelength reflector is a first selective wavelength reflector between the first SST structure and the second SST structure, the first selective wavelength reflector being configured to at least substantially transmit red light and at least substantially reflect green and blue light; and
the SST device further comprises—
a third SST structure proximate the front side of the SST device with respect to the second SST structure, the third SST structure being configured to transmit blue light; and
a second selective wavelength reflector between the second and third SST structures, wherein the second selective wavelength reflector is configured to at least substantially transmit green and red light and at least substantially reflect blue light toward the front side of the SST device.

4. The SST device of claim 1 wherein:
the SST structure is configured to emit blue light;
the converter material of the second emitter is a first converter material configured to emit red light;
the selective wavelength reflector is a first selective wavelength reflector configured to at least substantially transmit blue light and at least substantially reflect red light and green light toward the front side of the SST device; and
the SST device further comprises—
a second converter material proximate the front side of the SST device with respect to the first converter material, the second converter material being configured to emit green light; and
a second selective wavelength reflector between the first and second converter materials, wherein the second selective wavelength reflector is configured to at least substantially transmit blue and red light and at least substantially reflect green light toward the front side of the SST device.

5. The SST device of claim 1 wherein:
the SST structure is configured to produce emissions having a first energy; and
the second emitter is configured to produce emissions having a second energy less than the first energy.

6. The SST device of claim 1 wherein:
the first emitter is a first SST structure; and
the second emitter is a second SST structure.

7. The SST device of claim 6 wherein the emissions of the second SST structure have a shorter wavelength than the emissions of the first SST structure.

8. The SST device of claim 1 wherein:
the converter material of the second emitter is a second converter material.

9. The SST device of claim 8 wherein the first wavelength is shorter than the second wavelength.

10. The SST device of claim 1 wherein each layer of the multilayer stack of materials of the selective wavelength reflector has a thickness and a refractive index such that a combination of the materials in the multilayer stack at least substantially transmits emissions having the first wavelength and at least substantially reflects emissions having the second wavelength toward the front side of the SST device.

11. The SST device of claim 1 wherein the multilayer stack of materials of the selective wavelength reflector further includes fluoride glasses.

12. The SST device of claim 1 wherein:
the first spacer comprises one or more air gaps or voids.

13. The SST device of claim 1 wherein:
the first spacer and the second spacer each comprise a substantially transmissive nonconductive material.

14. The SST device of claim 1 wherein:
the active region of the SST structure includes a first dimension, across which the emissions having the first wavelength are emitted; and
the first spacer and the second spacer each include a second dimension that is substantially parallel to and same as the first dimension.

15. The SST device of claim 1 wherein the one or more alloy layers comprise an alloy layer including approximately 7% titanium dioxide.

16. The SST device of claim 1 wherein the one or more alloy layers comprise an alloy layer including approximately 54% titanium dioxide.

17. The SST device of claim 1 wherein the one or more alloy layers comprise:
a first alloy layer including approximately 7% titanium dioxide; and
a second alloy layer including approximately 54% titanium dioxide.

18. A solid-state transducer (SST) device, comprising:
an SST structure configured to emit emissions having a first wavelength and having a front surface facing a front side of the SST device and a back surface facing a back side of the SST device, the SST structure comprising:
a first semiconductor material at the back surface of the SST structure;
a second semiconductor material at the front surface of the SST structure; and
an active region between the first and second semiconductor materials;

a converter material structure configured to emit emissions having a second wavelength different from the first wavelength, wherein a back surface of the converter material structure includes a converter material;
a selective wavelength reflector disposed between the SST structure and the converter material structure, wherein the selective wavelength reflect

Assignees

• Schubert Martin F
• Odnoblyudov Vladimir
• Micron Technology Inc

Inventors

• Schubert Martin F
• Odnoblyudov Vladimir

Classifications

• H10H20/825

  containing nitrogen, e.g. GaN · CPC title

• H10H20/841

  Reflective coatings, e.g. dielectric Bragg reflectors · CPC title

• H10H20/851 Primary

  Wavelength conversion means · CPC title

• H01L33/32

  Electricity · mapped topic

• H01L33/46

  Electricity · mapped topic