# US 12,216,243 B2 · Air-spaced encapsulated dielectric nanopillars for flat optical devices

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- Number: US 12,216,243 B2
- Document ID: US12216243B2
- Status: Granted
- Kind: B2
- Application number: 16/905,703
- Filed: 2020-06-18
- Published: 2020-12-24
- Granted: 2025-02-04
- Earliest claimed: 2019-06-18
- Assignees: Applied Materials, Inc.
- Applicants: Applied Materials, Inc.
- Inventors: Ludovic Godet; Tapashree Roy; Prerna Sonthalia Goradia; Srobona Sen; Robert Jan Visser; Nitin Deepak; Tapash Chakraborty
- Web page: https://patentgrep.com/patent/US12216243B2

## CPC

- G02B 1/06: made of fluids in transparent cells
- B32B 3/20: of hollow pieces, e.g. tubes; of pieces with channels or cavities
- G02B 1/002: {made of materials engineered to provide properties not available in nature, e.g. metamaterials}
- G02B 5/1809: {with pitch less than or comparable to the wavelength}
- G02B 5/1838: {for use with ultraviolet radiation or X-rays}
- G02B 2207/101: Nanooptics
- G02B 2207/109: Sols, gels, sol-gel materials
- G02F 1/13398: {Spacer materials; Spacer properties}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS

## Abstract

Embodiments described herein relate to flat optical devices and methods of forming flat optical devices. One embodiment includes a substrate having a first arrangement of a first plurality of pillars formed thereon. The first arrangement of the first plurality of pillars includes pillars having a height h and a lateral distance d, and a gap g corresponding to a distance between adjacent pillars of the first plurality of pillars. An aspect ratio of the gap g to the height h is between about 1:1 and about 1:20. A first encapsulation layer is disposed over the first arrangement of the first plurality of pillars. The first encapsulation layer has a refractive index of about 1.0 to about 1.5. The first encapsulation layer, the substrate, and each of the pillars of the first arrangement define a first space therebetween. The first space has a refractive index of about 1.0 to about 1.5.

## Claims

### Claim 1

A flat optical device, comprising:
a substrate, the substrate having a first arrangement of a first plurality of pillars formed thereon, the first arrangement of the first plurality of pillars comprising:
pillars having a height h and a lateral distance d;
a gap g corresponding to a distance between adjacent pillars of the first plurality of pillars, and
a silica-containing aerogel material having an absorption coefficient less than 0.001 only disposed in each gap g; and
a first encapsulation layer disposed on the first arrangement of the first plurality of pillars, the first encapsulation layer is disposed on a top surface of each pillar of the first plurality of pillars and on the silica-containing aerogel material disposed in each gap g, the first encapsulation layer having a refractive index of about 1.0 to about 1.5.

### Claim 2 (depends on 1)

The flat optical device of claim 1, wherein the silica-containing aerogel material has nanoscale porosities formed therein.

### Claim 3 (depends on 2)

The flat optical device of claim 2, wherein the silica-containing aerogel material and the first encapsulation layer consist of substantially the same materials.

### Claim 4 (depends on 1)

The flat optical device of claim 1, wherein the gap g has an air gap disposed in a center opening of the silica-containing aerogel material.

### Claim 5 (depends on 1)

The flat optical device of claim 1, wherein a liner is disposed over the pillars.

### Claim 6 (depends on 5)

The flat optical device of claim 5, wherein the liner has a thickness of about 1 nanometer (nm) to about 200 nm.

### Claim 7 (depends on 1)

The flat optical device of claim 1, further comprising:
a second arrangement of a second plurality of pillars formed over the first encapsulation layer, the second arrangement of the second plurality of pillars comprising:
pillars having the height h and the lateral distance d;
the gap g corresponding to the distance between adjacent pillars of the second plurality of pillars, and
a silica-containing aerogel material having an absorption coefficient less than 0.001 only disposed in each gap g; and
a second encapsulation layer disposed on the second arrangement of the second plurality of pillars, the second encapsulation layer is disposed on a top surface of each pillar of the second plurality of pillars and on the silica-containing aerogel material disposed in each gap g, the second encapsulation layer having the refractive index of about 1.0 to about 1.5 .

### Claim 8 (depends on 1)

The flat optical device of claim 1, wherein the pillars comprise one or more of titanium dioxide (TiO2), zinc oxide (ZnO), tin dioxide (SnO2), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO), cadmium stannate (tin oxide) (CTO), zinc stannate (tin oxide) (SnZnO3), or silicon containing materials.

### Claim 9 (depends on 1)

The flat optical device of claim 1, wherein the fist encapsulation material comprises a lower surface, wherein the lower surface is disposed on a top surface of each pillar of the first plurality of pillars and each gap, and wherein the lower surface is planar over the top surface.

### Claim 10

A flat optical device, comprising:
a substrate, the substrate having a first arrangement of a first plurality of pillars formed thereon, the first arrangement of the first plurality of pillars comprising:
pillars having a height h and a lateral distance d; and
a gap g corresponding to a distance between adjacent pillars of the first plurality of pillars, wherein each gap g is composed of only a silica-containing aerogel material with nanoscale porosities within the silica-containing material, the silica-containing aerogel material having:
an absorption coefficient less than 0.001; and
a first encapsulation layer disposed on the first arrangement of the first plurality of pillars, the first encapsulation layer is disposed on a top surface of each pillar of the first plurality of pillars and on the silica-containing aerogel material disposed in each gap g, the first encapsulation layer having a refractive index of about 1.0 to about 1.5.

### Claim 11 (depends on 10)

The flat optical device of claim 10, wherein the gap is less than 350 nanometers (nm).

### Claim 12 (depends on 10)

The flat optical device of claim 10, wherein the height h is about 1500 nm or less.

### Claim 13 (depends on 10)

The flat optical device of claim 10, wherein the first encapsulation layer has a thickness less than 50 micrometers (μm).

### Claim 14 (depends on 10)

The flat optical device of claim 10, further comprising:
a second arrangement of a second plurality of pillars formed over the first encapsulation layer, the second arrangement of the second plurality of pillars comprising:
pillars having the height h and the lateral distance d;
the gap g corresponding to the distance between adjacent pillars of the second plurality of pillars, and
a silica-containing aerogel material having an absorption coefficient less than 0.001 only disposed in each gap q; and
a second encapsulation layer disposed on the second arrangement of the second plurality of pillars, the second encapsulation layer is disposed over a top surface of each pillar of the second plurality of pillars and on the silica-containing aerogel material disposed in each gap g, the second encapsulation layer having the refractive index of about 1.0 to about 1.5 .

### Claim 15 (depends on 10)

The flat optical device of claim 10, wherein the pillars comprise one or more of titanium dioxide (TiO2), zinc oxide (ZnO), tin dioxide (SnO2), aluminum-doped zinc oxide (AZO), fluorine-doped tin oxide (FTO), cadmium stannate (tin oxide) (CTO), zinc stannate (tin oxide) (SnZnO3), or silicon containing materials.