# US 2019/0355702 A1 · Light emitting device with small size and large density

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- Number: US 2019/0355702 A1
- Document ID: US20190355702A1
- Status: Published application
- Kind: A1
- Application number: 15/984,370
- Filed: 2018-05-20
- Published: 2019-11-21
- Earliest claimed: 2018-05-20
- Assignees: Black Peak LLC
- Inventors: Scott Brad Herner
- Web page: https://patentgrep.com/patent/US20190355702A1

## CPC

- H10W 90/00: Package configurations
- H10D 64/0112: {using conductive layers comprising silicides}
- H10D 64/62: Electrodes ohmically coupled to a semiconductor
- H10D 84/0149: {Manufacturing their interconnections or electrodes, e.g. source or drain electrodes}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/83: of only insulated-gate FETs [IGFET]
- H10H 20/82: Roughened surfaces, e.g. at the interface between epitaxial layers
- H10H 20/824: comprising only Group III-V materials, e.g. GaP
- H10H 20/825: containing nitrogen, e.g. GaN
- H10H 20/833: Transparent materials
- H10H 20/8515: {not being in contact with the bodies}
- H10H 20/856: Reflecting means
- H10H 20/857: Interconnections, e.g. lead-frames, bond wires or solder balls
- H10W 20/023: {the interconnections being through-semiconductor vias}
- H10W 20/20: Interconnections within wafers or substrates, e.g. through-silicon vias [TSV]
- H10D 88/00: Three-dimensional [3D] integrated devices
- H10H 20/018: {Bonding of wafers}
- H10H 20/0361: {of wavelength conversion means}
- H10H 20/0363: {of optical field-shaping means}
- H10H 20/0364: {of interconnections}
- H10H 20/819: characterised by their shape, e.g. curved or truncated substrates
- H10H 20/851: Wavelength conversion means
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

This application describes a light emitting device, an assembly of light emitting devices, a display comprising assemblies of light emitting devices, and methods of fabricating same. The light emitting device comprises a transistor, an LED that at least partially overlies the transistor, a reflector layer disposed between the LED and transistor, and conductive wires that connect electrically the transistor to the LED. The assembly comprises a plurality of light emitting devices, and the display comprises a plurality of assemblies.

## Claims

### Claim 1

A light emitting device comprising:
a transistor substrate having a top surface and a bottom surface, wherein the top surface comprises a plurality of conductive regions;
a plurality of conductive wires, wherein each conductive wire of the plurality extends through the transistor substrate from one of the conductive regions of the plurality of conductive regions to the bottom surface of the transistor substrate;
a transistor, wherein the transistor is formed in the top surface of the transistor substrate;
an LED having a surface area, wherein the LED at least partially overlies the transistor; and
a reflector layer, wherein the reflector layer is disposed between the LED and the transistor.

### Claim 2 (depends on 1)

The light emitting device of claim 1, further comprising an interconnect, wherein the interconnect connects the LED to the transistor electrically.

### Claim 3 (depends on 2)

The light emitting device of claim 2, wherein at least a portion of the interconnect is substantially transparent to light of wavelength 450 to 730 nm.

### Claim 4 (depends on 1)

The light emitting device of claim 1, further comprising a wavelength-converting layer, wherein the wavelength-converting layer partially overlies the LED.

### Claim 5 (depends on 4)

The light emitting device of claim 4, wherein the wavelength-converting layer comprises phosphor particles or quantum dots.

### Claim 6 (depends on 1)

The light emitting device of claim 1, further comprising a backboard, wherein the backboard comprises a plurality of metal interconnects, and wherein at least one of the metal interconnects is connected electrically to the transistor.

### Claim 7 (depends on 6)

The light emitting device of claim 6, wherein the backboard is a printed circuit board or an interposer.

### Claim 8 (depends on 1)

The light emitting device of claim 1, wherein a transparent conductive layer is disposed on the LED.

### Claim 9 (depends on 8)

The light emitting device of claim 8, wherein the transparent conductive layer comprises indium tin oxide, fluorine tin oxide, or aluminum zinc oxide.

### Claim 10 (depends on 1)

The light emitting device of claim 1, wherein the transistor comprises single crystal silicon.

### Claim 11 (depends on 1)

The light emitting device of claim 1, wherein at least some of the conductive regions further comprise a silicide layer.

### Claim 12 (depends on 1)

The light emitting device of claim 1, wherein the transistor substrate further comprises an etch-stop layer.

### Claim 13 (depends on 1)

The light emitting device of claim 1, wherein the transistor substrate has a thickness, and wherein the thickness is less than 20 microns.

### Claim 14 (depends on 1)

The light emitting device of claim 1, wherein the LED comprises gallium nitride, indium gallium nitride, indium arsenide, aluminum gallium arsenide, gallium arsenide, gallium phosphide, gallium arsenide phosphide, or aluminum indium gallium phosphide.

### Claim 15 (depends on 1)

The light emitting device of claim 1, wherein the surface area of the LED is 40,000 square microns or less.

### Claim 16 (depends on 1)

The light emitting device of claim 1, wherein the surface area of the LED is 1,000 square microns or less.

### Claim 17 (depends on 1)

The light emitting device of claim 1, wherein the surface area of the LED is 100 square microns or less.

### Claim 18 (depends on 1)

The light emitting device of claim 1, wherein the reflector layer comprises a Bragg reflector.

### Claim 19 (depends on 1)

The light emitting device of claim 1, wherein the plurality of conductive wires comprises titanium, titanium nitride, tantalum, tantalum nitride, chrome, indium, tungsten, copper, or aluminum.

### Claim 20 (depends on 2)

The light emitting device of claim 2, wherein the interconnect comprises titanium, titanium nitride, tantalum, tantalum nitride, tungsten, copper, aluminum indium tin oxide, aluminum zinc oxide, or fluorine tin oxide.

### Claim 21

A light emitting assembly, comprising:
a transistor substrate having a top surface and a bottom surface, wherein the top surface comprises a plurality of conductive regions;
a plurality of conductive wires, wherein each conductive wire extends through the transistor substrate from a conductive region of the plurality of conductive regions to the bottom surface of the transistor substrate;
a plurality of transistors, wherein each transistor is formed in the top surface of the transistor substrate;
a plurality of LEDs, wherein each LED has a surface area and each LED at least partially overlies a transistor of the plurality of transistors; and
at least one reflector layer, wherein the at least one reflector layer is disposed between one LED of the plurality of LEDs and a transistor of the plurality of transistors.

### Claim 22 (depends on 21)

The light emitting assembly of claim 21, further comprising a plurality of interconnects, wherein each interconnect electrically connects an LED of the plurality of LEDS to a transistor of the plurality of transistors.

### Claim 23 (depends on 22)

The light emitting assembly of claim 22, wherein at least portions of the plurality of interconnects are substantially transparent to light of wavelength 450 to 730 nm.

### Claim 24 (depends on 21)

The light emitting assembly of claim 21, wherein a transparent conductive layer is disposed on the plurality of LEDs.

### Claim 25 (depends on 24)

The light emitting assembly of claim 24, wherein the transparent conductive layer comprises indium tin oxide, fluorine tin oxide, or aluminum zinc oxide.

### Claim 26 (depends on 21)

The light emitting assembly of claim 21, further comprising a plurality of wavelength-converting layers, wherein at least one of the wavelength-converting layers at least partially overlies one LED of the plurality of LEDs.

### Claim 27 (depends on 26)

The light emitting assembly of claim 26, wherein the plurality of wavelength-converting layers comprises phosphor particles or quantum dots.

### Claim 28 (depends on 26)

The light emitting assembly of claim 26, wherein the plurality of wavelength-converting layers comprises at least a first wavelength-converting layer that emits fight with a dominant wavelength between 500 and 550 nm and a second wavelength-converting layer that emits light with a dominant wavelength between 610 and 730 nm.

### Claim 29 (depends on 21)

The light emitting assembly of claim 21, further comprising side reflectors, wherein the side reflectors are disposed between adjacent LEDs of the plurality of LEDs and prevent light from neighboring light emitting devices from mutually interfering.

### Claim 30 (depends on 29)

The light emitting assembly of claim 29, wherein the side reflectors comprise aluminum, silver, or metal oxide.

### Claim 31 (depends on 21)

The light emitting assembly of claim 21, wherein the transistor substrate has a thickness, and wherein the thickness is less than 20 microns.

### Claim 32 (depends on 21)

The light emitting assembly of claim 21, wherein at least some of the conductive regions further comprise a silicide layer.

### Claim 33 (depends on 21)

The light emitting assembly of claim 21, wherein the light emitting assembly is attached to a backboard, the backboard comprising a plurality of metal interconnects, and wherein at least one of the metal interconnects is connected electrically to one of the transistors.

### Claim 34 (depends on 33)

The light emitting assembly of claim 33, wherein the backboard is printed circuit board or an interposer.

### Claim 35 (depends on 21)

The light emitting assembly of claim 21, wherein the plurality of transistors comprises single crystal silicon.

### Claim 36 (depends on 21)

The light emitting assembly of claim 21, wherein the transistor substrate further comprises an etch-stop layer.

### Claim 37 (depends on 21)

The light emitting assembly of claim 21, wherein the plurality of LEDs comprises gallium nitride, indium gallium nitride, indium arsenide, aluminum gallium arsenide, gallium arsenide, gallium phosphide, gallium arsenide phosphide, or aluminum indium gallium phosphide.

### Claim 38 (depends on 21)

The light emitting assembly of claim 21, wherein the surface area of at least one LED of the plurality of LEDs is 40,000 square microns or less.

### Claim 39 (depends on 21)

The light emitting assembly of claim 21, wherein the surface area of at least one LED of the plurality of LEDs is 1,000 square microns or less.

### Claim 40 (depends on 21)

The light emitting assembly of claim 21, wherein the surface area of at least one LED of the plurality of LEDs is 100 square microns or less.

### Claim 41 (depends on 21)

The light emitting assembly of claim 21, wherein the plurality of reflector layers comprises a Bragg reflector.

### Claim 42

A display apparatus comprising:
a plurality of light emitting assemblies, wherein each assembly comprises:
a transistor substrate having a top surface and a bottom surface, wherein the top surface comprises a plurality of conductive regions;
a plurality of conductive wires, wherein each conductive wire extends through the transistor substrate from a conductive region of the plurality of conductive regions to the bottom surface of the transistor substrate;
a plurality of transistors, wherein each transistor is formed in the top surface of the transistor substrate;
a plurality of LEDs, wherein each LED has a surface area, and wherein each LED is connected electrically to a transistor of the plurality of transistors;
at least one reflector layer, wherein the at least one reflector layer is disposed between one LED of the plurality of LEDs and a transistor of the plurality of transistors; and
a backboard, wherein the backboard comprises a plurality of metal interconnects, and wherein at least one of the metal interconnects is connected electrically to at least one of the transistors of the plurality of transistors.

### Claim 43 (depends on 42)

The display apparatus of claim 42 wherein at least some of the conductive regions further comprise a silicide layer.

### Claim 44 (depends on 42)

The display apparatus of claim 42 wherein the plurality of conductive wires comprises titanium, titanium nitride, tantalum, tantalum nitride, chrome, indium, tungsten, copper, or aluminum.

### Claim 45 (depends on 42)

The display apparatus of claim 42, further comprising a plurality of wavelength-converting layers, wherein at least one wavelength-converting layer overlies one LED of the plurality of LEDs.

### Claim 46 (depends on 45)

The display apparatus of claim 45, wherein the plurality of wavelength-converting layers comprises phosphor particles or quantum dots.

### Claim 47 (depends on 45)

The display apparatus of claim 45, wherein the plurality of wavelength-converting layers comprises at least a first wavelength-converting layer and a second wavelength-converting layer.

### Claim 48 (depends on 47)

The display apparatus of claim 47, wherein the first wavelength-converting layer emits light with a dominant wavelength between 500 and 550 nm and the second wavelength-converting layer emits light with a dominant wavelength between 610 and 730 nm.

### Claim 49 (depends on 42)

The display apparatus of claim 42, wherein the backboard is a printed circuit board or an interposer.

### Claim 50 (depends on 42)

The display apparatus of claim 42, wherein the transistor substrate has a thickness, and wherein the thickness is less than 20 microns.

### Claim 51 (depends on 42)

The display apparatus of claim 42, wherein the plurality of transistors comprises single crystal silicon.

### Claim 52 (depends on 42)

The display apparatus of claim 42, wherein the transistor substrate further comprises an etch-stop layer.

### Claim 53 (depends on 42)

The display apparatus of claim 42, further comprising side reflectors, wherein the side reflectors are disposed between adjacent LEDs of the plurality of light emitting devices and prevent light from neighboring light emitting devices from mutually interfering.

### Claim 54 (depends on 53)

The display apparatus of claim 53, where in the side reflectors comprise aluminum, silver, or metal oxide.

### Claim 55 (depends on 42)

The display apparatus of claim 42, wherein the plurality of LEDs comprises gallium nitride, indium gallium nitride, indium arsenide, aluminum gallium arsenide, gallium arsenide, gallium phosphide, gallium arsenide phosphide, or aluminum indium gallium phosphide.

### Claim 56 (depends on 42)

The display apparatus of claim 42, wherein the surface area of at least one LED of the plurality of LEDs is 40,000 square microns or less.

### Claim 57 (depends on 42)

The display apparatus of claim 42, wherein the surface area of at least one LED of the plurality of LEDs is 1,000 square microns or less.

### Claim 58 (depends on 42)

The display apparatus of claim 42, wherein the surface area of at least one LED of the plurality of LEDs is 100 square microns or less.

### Claim 59 (depends on 42)

The display apparatus of claim 42, wherein the reflector layers comprise a Bragg reflector.