# US 2024/0201556 A1 · Layered structure with high dielectric constant for use with active matrix backplanes

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- Number: US 2024/0201556 A1
- Document ID: US20240201556A1
- Status: Published application
- Kind: A1
- Application number: 18/428,968
- Filed: 2024-01-31
- Published: 2024-06-20
- Earliest claimed: 2019-05-03
- Assignees: Nuclera Ltd
- Applicants: Nuclera LTD
- Inventors: Cristina Visani
- Web page: https://patentgrep.com/patent/US20240201556A1

## CPC

- G02F 1/16756: Insulating layers
- C23C 14/083: {of refractory metals or yttrium}
- C23C 16/403: {of aluminium, magnesium or beryllium}
- C23C 16/405: {of refractory metals or yttrium}
- C23C 16/45525: {Atomic layer deposition [ALD]}
- C23C 28/042: {including a refractory ceramic layer, e.g. refractory metal oxides, ZrO2, rare earth oxides}
- G02F 1/1368: in which the switching element is a three-electrode device {(G02F1/136277 takes precedence)}
- G02F 1/167: by electrophoresis
- G02F 1/1676: Electrodes
- G02F 1/1685: Operation of cells; Circuit arrangements affecting the entire cell
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/69391: {the material containing aluminium, e.g. Al2O3}
- G02F 2001/1678: {characterised by the composition or particle type}
- 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
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Layered dielectric materials for use in controlling dielectric strength in microelectronic devices, especially as they relate to electrophoretic and electrowetting applications. Specifically, a combination of a first atomic layer deposition (ALD) step, a sputtering step, and a second ALD step result in a layer that is chemically robust and nearly pinhole free. The dielectric layer may be disposed on the transparent common electrode of an electrophoretic display or covering the pixelated backplane electrodes, or both.

## Claims

### Claim at position 1

-13. (canceled)

### Claim 14

An electrowetting on dielectric (EWoD) device having a plurality of active matrix electrodes disposed in an array where each electrode is associated with a thin film transistor (TFT), the device comprising:
a layered dielectric stack comprising multiple metal oxide layers, wherein the layers include:
a first layer of an aluminum oxide deposited by atomic layer deposition and having a thickness between 9 and 80 nm;
a second layer of a hafnium oxide, the second layer having a thickness between 40 nm and 250 nm;
a third layer of a hafnium oxide deposited by atomic layer deposition, the third layer having a thickness between 10 nm and 35 nm, wherein the second layer is disposed between the first and third layers; and
a hydrophobic layer deposited on the layered dielectric.

### Claim 15 (depends on 14)

The device of claim 14, wherein the first layer has a thickness between 20 to 40 nm.

### Claim 16 (depends on 14)

The device of claim 14, wherein the second layer has a thickness between 100 to 150 nm.

### Claim 17 (depends on 14)

The device of claim 14, wherein the dielectric layer has a dielectric constant greater than 5.

### Claim 18 (depends on 14)

The device of claim 14, wherein the electrowetting is performed with voltages in the range +/−10 to +/−50V.

### Claim 19 (depends on 14)

The device of claim 14, wherein the hydrophobic layer comprises a fluoropolymer.

### Claim 20 (depends on 14)

The device of claim 14, wherein the hydrophobic layer is between 10 and 50 nm thick.

### Claim 21 (depends on 14)

The device of claim 14, wherein the dielectric strength of the layered dielectric is greater than 6 MV/cm.

### Claim 22 (depends on 14)

The device of claim 14, wherein the thickness of the dielectric stack and hydrophobic layers is less than 600 nm.

### Claim 23 (depends on 14)

The device of claim 14, wherein the thickness of the layered dielectric stack and hydrophobic layers is less than 300 nm.

### Claim 24

A method of creating an electrowetting on dielectric (EWoD) device having a layered structure, the method comprising:
providing a substrate having a plurality of active matrix electrodes disposed in an array where each electrode is associated with a thin film transistor (TFT);
depositing a layered dielectric stack on the substrate by:
depositing a first layer of aluminum oxide using atomic layer deposition, the first layer having a thickness between 9 nm and 80 nm;
depositing a second layer of hafnium oxide, the second layer having a thickness between 40 nm and 250 nm; and
depositing a third layer of hafnium oxide using atomic layer deposition, the third layer having a thickness between 10 nm and 35 nm; and
depositing a hydrophobic layer on the layered dielectric.

### Claim 25 (depends on 24)

The method of claim 24, wherein the hydrophobic layer is coated onto the layered dielectric stack by spin coating.

### Claim 26 (depends on 24)

The method of claim 24, wherein the first layer has a thickness between 20 to 40 nm.

### Claim 27 (depends on 24)

The method of claim 24, wherein the second layer is 100 to 150 nm thick.

### Claim 28 (depends on 24)

The method of claim 24, wherein the electrowetting is performed with voltages in the range +/−10 to +/−50V.

### Claim 29 (depends on 24)

The method of claim 24, wherein the hydrophobic layer comprises a fluoropolymer.

### Claim 30 (depends on 24)

The method of claim 24, wherein the hydrophobic layer is between 10 and 50 nm thick.

### Claim 31 (depends on 24)

The method of claim 24, wherein the thickness of the layered dielectric stack and hydrophobic layers is less than 600 nm.

### Claim 32 (depends on 24)

The method of claim 24, wherein the thickness of the layered dielectric stack and hydrophobic layers is less than 300 nm.