# US 2022/0045236 A1 · Micro led laser release from silicon wafer

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- Number: US 2022/0045236 A1
- Document ID: US20220045236A1
- Status: Published application
- Kind: A1
- Application number: 17/485,398
- Filed: 2021-09-25
- Published: 2022-02-10
- Earliest claimed: 2021-09-25
- Inventors: Paul West; Khaled Ahmed
- Web page: https://patentgrep.com/patent/US20220045236A1

## CPC

- H10H 20/018: {Bonding of wafers}
- H10W 90/00: Package configurations
- H10H 20/01335: {the light-emitting regions comprising nitride materials}
- H10H 20/819: characterised by their shape, e.g. curved or truncated substrates
- H10H 20/856: Reflecting means
- H10H 20/0363: {of optical field-shaping means}
- H10H 20/821: of the light-emitting regions, e.g. non-planar junctions
- H10H 20/825: containing nitrogen, e.g. GaN
- H10H 20/835: {Reflective materials}
- H10H 20/84: Coatings, e.g. passivation layers or antireflective coatings
- H10H 29/142: {Two-dimensional arrangements, e.g. asymmetric LED layout}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Methods and systems for improving the yield of laser ablation of semiconductor devices, such as micro-LEDs, in a direct transfer method are described. In the disclosed embodiments, an ablation layer is used to mask a nucleation layer on a donor substrate, with an aperture provided to allow epitaxial growth of a semiconductor structure. The aperture size is selected as the minimum necessary to ensure proper epitaxial growth. Layers disposed above the ablation layer may have larger apertures to that a portion of the semiconductor structure stem overlies the ablation layer, allowing a greater force generated during the ablation process to be directed against the semiconductor structure, improving the likelihood of separation of the structure from the donor substrate. Other embodiments are described.

## Claims

### Claim 1

An apparatus, comprising:
a nucleation layer;
an ablation layer formed on the nucleation layer, the ablation layer comprising a plurality of apertures that expose the nucleation layer;
one or more dielectric layers formed on the ablation layer, the one or more dielectric layers comprising a plurality of apertures wherein individual of the dielectric layer apertures are disposed concentrically with individual of the ablation layer apertures and are at least as large as the individual ablation layer apertures; and
a plurality of micro-light emitting diodes (micro-LEDs), each of the micro-LEDs comprising a stem and a body, wherein the stem of individual micro-LEDs is formed through the individual ablation layer apertures and individual dielectric layer apertures, and the body extends past the dielectric layer of the one or more dielectric layers that is most proximate to the body.

### Claim 2 (depends on 1)

The apparatus of claim 1, further comprising a substrate, and wherein the nucleation layer is formed on the substrate.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the nucleation layer is comprised of Gallium and Nitrogen.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the ablation layer is comprised of a metal and Nitrogen.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the one or more dielectric layers are comprised of a compound that comprises Silicon, and Nitrogen or Oxygen.

### Claim 6 (depends on 1)

The apparatus of claim 1, further comprising:
an adhesion layer formed on the micro-LED;
a mirror layer formed on the adhesion layer; and
a contact layer formed on the mirror layer.

### Claim 7 (depends on 6)

The apparatus of claim 6, further comprising a recipient substrate adhered to the contact layer.

### Claim 8 (depends on 1)

The apparatus of claim 1, wherein the micro-LED is formed from a compound that comprises Gallium and Nitrogen.

### Claim 9 (depends on 1)

The apparatus of claim 1, wherein the bodies of the individual micro-LEDs comprise nano-pyramids.

### Claim 10 (depends on 1)

The apparatus of claim 1, wherein the apertures of the one or more dielectric layers are larger than the apertures of the ablation layer.

### Claim 11 (depends on 1)

The apparatus of claim 1, wherein the apertures of the dielectric layer that is most proximate to the ablation layer are the same size as the apertures of the ablation layer, and the apertures of the dielectric layer that is most proximate to the body are larger than the apertures of the ablation layer.

### Claim 12 (depends on 1)

The apparatus of claim 1, wherein the apertures of the one or more dielectric layers are the same size as the apertures of the ablation layer, and wherein the apertures of the ablation layer are sized to a minimum size necessary for formation of the micro-LED.

### Claim 13

A method, comprising:
forming, upon a substrate, a nucleation layer;
forming, upon the nucleation layer, an ablation layer, the ablation layer having an aperture that partially exposes the nucleation layer;
forming, upon the ablation layer, one or more dielectric layers including a top dielectric layer, individual one or more dielectric layers having an aperture that exposes the ablation layer aperture and that is least as large as the ablation layer aperture; and
forming a micro-light emitting diode (micro-LED) from the nucleation layer that comprises a stem that fills the ablation layer aperture, the dielectric layer apertures, and a body that extends past the aperture of the dielectric layer most proximate to the body.

### Claim 14 (depends on 13)

The method of claim 13, wherein the substrate is a donor substrate, and further comprising:
forming, on the micro-LED, a mirror layer;
forming, on the mirror layer, a contact layer; and
adhering, to the contact layer, a recipient substrate.

### Claim 15 (depends on 14)

The method of claim 14, further comprising releasing the micro-LED from the nucleation layer by applying a laser pulse to the ablation layer sufficient to cause the ablation layer to ablate.

### Claim 16 (depends on 14)

The method of claim 14, wherein at least a portion of the body of the micro-LED extends into the mirror layer.

### Claim 17 (depends on 14)

The method of claim 14, wherein the recipient substrate is a glass backplane.

### Claim 18 (depends on 14)

The method of claim 14, wherein the recipient substrate is a Silicon wafer.

### Claim 19

A system, comprising:
a micro-light emitting diode (micro-LED) comprised of a stem and a body;
a plurality of dielectric layers formed around the stem, such that the stem defines an aperture in individuals of the plurality of dielectric layers;
at least one oxide layer formed around the body;
a mirror layer formed on the at least one oxide layer, wherein the body at least partially extends into the mirror layer;
a contact layer formed on the mirror layer; and
a substrate adhered to the contact layer.

### Claim 20 (depends on 19)

The system of claim 19, wherein the aperture of the dielectric layer most distal from the body is smaller than the aperture of the dielectric layer most proximate to the body.

### Claim 21 (depends on 19)

The system of claim 19, wherein the apertures of the plurality of dielectric layers are of the same size, and are sized to a smallest size necessary for formation of the micro-LED.

### Claim 22 (depends on 19)

The system of claim 19, wherein the plurality of dielectric layers comprises a layer comprising Oxygen and a layer comprising Nitrogen.

### Claim 23 (depends on 19)

The system of claim 19, wherein the system is a display.

### Claim 24 (depends on 19)

The system of claim 19, wherein the system is an optical interconnect.