# US 2023/0411522 A1 · Double gate ferroelectric field effect transistor devices and methods for forming the same

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- Number: US 2023/0411522 A1
- Document ID: US20230411522A1
- Status: Published application
- Kind: A1
- Application number: 18/366,826
- Filed: 2023-08-08
- Published: 2023-12-21
- Earliest claimed: 2021-04-27
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company Limited
- Inventors: Yen-Chieh HUANG; Song-Fu LIAO; Po-Ting LIN; Hai-Ching CHEN; Sai-Hooi YEONG; Yu-Ming LIN; Chung-Te LIN
- Web page: https://patentgrep.com/patent/US20230411522A1

## CPC

- H10D 30/701: {IGFETs having ferroelectric gate insulators, e.g. ferroelectric FETs}
- H10B 51/30: characterised by the memory core region
- H10D 30/0415: {of FETs having ferroelectric gate insulators}
- H10D 30/611: {having multiple independently-addressable gate electrodes influencing the same channel (FinFETs having multiple distinct gate electrodes H10D30/6215; multi-gate TFT H10D30/6733)}
- H10D 30/6734: {having gate electrodes arranged on both top and bottom sides of the channel, e.g. dual-gate TFTs}
- H10D 30/6739: {Conductor-insulator-semiconductor electrodes}
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 64/033: {comprising ferroelectric layers}
- H10D 64/258: {characterised by the relative positions of the source or drain electrodes with respect to the gate electrode}
- H10D 64/689: {having ferroelectric layers}
- H10D 64/691: {comprising metallic compounds, e.g. metal oxides or metal silicates (insulators comprising nitrogen H10D64/693)}
- H10D 99/00: Subject matter not provided for in other groups of this subclass
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A ferroelectric field effect transistor (FeFET) having a double-gate structure includes a first gate electrode, a first ferroelectric material layer over the first gate electrode, a semiconductor channel layer over the first ferroelectric material layer, source and drain electrodes contacting the semiconductor channel layer, a second ferroelectric material layer over the semiconductor channel layer, and a second gate electrode over the second ferroelectric material layer.

## Claims

### Claim 1

A semiconductor structure, comprising:
a first gate electrode;
a first ferroelectric material layer over the first gate electrode;
a seed layer over the first ferroelectric material layer;
a semiconductor channel layer over the seed layer;
source and drain electrodes contacting the semiconductor channel layer;
a second ferroelectric material layer over the semiconductor channel layer; and
a second gate electrode over the second ferroelectric material layer.

### Claim 2 (depends on 1)

The semiconductor structure of claim 1, wherein the source and drain electrodes comprise:
an upper source electrode that extends through the second ferroelectric material layer and contacts an upper surface of the semiconductor channel layer; and
an upper drain electrode that extends through the second ferroelectric material layer and contacts the upper surface of the semiconductor channel layer.

### Claim 3 (depends on 2)

The semiconductor structure of claim 2, wherein each of the upper source electrode and the upper drain electrode are laterally surrounded by a dielectric material spacer layer.

### Claim 4 (depends on 2)

The semiconductor structure of claim 2, further comprising:
a first dielectric material layer that underlies the first ferroelectric material layer and laterally surrounds the first gate electrode; and
a second dielectric material layer over the second ferroelectric material layer and laterally surrounding the second gate electrode, the upper source electrode and the upper drain electrode extending through the second dielectric material layer.

### Claim 5 (depends on 4)

The semiconductor structure of claim 4, wherein the source and drain electrodes further comprise:
a bottom source electrode that extends from the first dielectric material layer through the first ferroelectric material layer and the seed layer and contacts a bottom surface of the semiconductor channel layer; and
a bottom drain electrode that extends from the first dielectric material layer through the first ferroelectric material layer and the seed layer and contacts the bottom surface of the semiconductor channel layer.

### Claim 6 (depends on 5)

The semiconductor structure of claim 5, wherein each of the bottom source electrode and the bottom drain electrode are laterally surrounded by a dielectric material spacer layer.

### Claim 7 (depends on 1)

The semiconductor structure of claim 1, wherein the semiconductor channel layer comprises an oxide semiconductor material having a formula MxM′yZnzO where 0<(x, y, z)<1, M is a first metal selected from a group consisting of indium (In) and tin (Sn) and combinations thereof, M′ is a second metal selected from a group consisting of gallium (Ga), hafnium (Hf), zirconium (Zr), titanium (Ti), aluminum (Al), strontium (Sr), barium (Ba), scandium (Sc), magnesium (Mg), lanthanum (La), gadolinium (Gd), and combinations thereof.

### Claim 8 (depends on 1)

The semiconductor structure of claim 1, wherein the first ferroelectric material layer and the second ferroelectric material layer comprise hafnium oxide-based ferroelectric materials.

### Claim 9 (depends on 1)

The semiconductor structure of claim 1, wherein at least one of an additional seed layer and a stress layer are located between the first gate electrode and a bottom surface of the first ferroelectric material layer.

### Claim 10 (depends on 1)

The semiconductor structure of claim 1, wherein an insulating layer is located between an upper surface of the seed layer and a bottom surface of the semiconductor channel layer, and at least one of an insulating layer and an additional seed layer are located between an upper surface of the semiconductor channel layer and a bottom surface of the second ferroelectric material layer.

### Claim 11 (depends on 1)

The semiconductor structure of claim 1, further comprising an additional seed layer located between an upper surface of the second ferroelectric material layer and a bottom surface of the second gate electrode.

### Claim 12 (depends on 1)

The semiconductor structure of claim 1, wherein the seed layer comprises at least one of zirconium oxide (ZrO2), zirconium-yttrium oxide (ZrO2—Y2O3), hafnium oxide (HfO2), aluminum oxide (Al2O3), and hafnium zirconium oxide (HfxZr1-xO2, where 0≤x≤1).

### Claim 13 (depends on 12)

The semiconductor structure of claim 12, wherein the seed layer has a thickness of 5 nm or less.

### Claim 14

A semiconductor structure, comprising:
a gate electrode;
a semiconductor channel layer, wherein the semiconductor channel layer comprises:
a first alternating stack of first sublayers and second sublayers, the first sublayers having a different composition than the second sublayers,
a third sublayer over the first alternating stack of first and second sublayers, the third sublayer having a different composition than the first sublayers and the second sublayers, and
a second alternating stack of the first sublayers and the second sublayers over the third sublayer, wherein each of the first sublayers of the first alternating stack and the second alternating stack comprises a combination of a first metal oxide material, MOx, and a second metal oxide material, M′Ox, and each second sublayer of the first alternating stack and the second alternating stack comprises zinc oxide, and the third sublayer comprises a combination of a first metal oxide material, MOx, a second metal oxide material, M′Ox, and zinc oxide, and wherein M is a first metal selected from a group consisting of indium (In) and tin (Sn) and combinations thereof, and M′ is a second metal selected from a group consisting of gallium (Ga), hafnium (Hf), zirconium (Zr), titanium (Ti), aluminum (Al), strontium (Sr), barium (Ba), scandium (Sc), magnesium (Mg), lanthanum (La), gadolinium (Gd), and combinations thereof;
a ferroelectric material layer located between the gate electrode and a surface of the semiconductor channel layer;
a seed layer located between the ferroelectric material layer and the surface of the semiconductor channel layer; and
source and drain electrodes contacting the semiconductor channel layer.

### Claim 15 (depends on 14)

The semiconductor structure of claim 14, wherein a lowermost sublayer of the semiconductor channel layer is a first sublayer of the first alternating stack of first sublayers and second sublayers, and an uppermost sublayer of the semiconductor channel layer is a first sublayer of the second alternating stack of first sublayers and second sublayers, and wherein the third sublayer is contacted by a second sublayer of the second alternating stack of first sublayers and second sublayers on an upper surface of the third sublayer, and the third sublayer is contacted by a second sublayer of the first alternating stack of first sublayers and second sublayers on a bottom surface of the third sublayer.

### Claim 16 (depends on 14)

The semiconductor structure of claim 14, wherein the gate electrode comprises a first gate electrode and the ferroelectric material layer comprises a first ferroelectric material layer located between the first gate electrode and a first surface of the semiconductor channel layer, the semiconductor structure further comprising:
a second gate electrode; and
a second ferroelectric material layer located between the second gate electrode and a second surface of the semiconductor channel layer.

### Claim 17

A method of fabricating a semiconductor structure, comprising:
forming a first gate electrode;
forming a first ferroelectric material layer over the first gate electrode;
forming a seed layer over the first ferroelectric material layer;
forming a semiconductor channel layer over the seed layer;
forming source and drain electrodes contacting the semiconductor channel layer;
forming a second ferroelectric material layer over the semiconductor channel layer; and
forming a second gate electrode over the second ferroelectric material layer.

### Claim 18 (depends on 17)

The method of claim 17, wherein forming source and drain electrodes contacting the semiconductor channel layer comprises forming upper source and drain electrodes contacting an upper surface of the semiconductor channel layer, the method further comprising:
forming bottom source and drain electrodes contacting a bottom surface of the semiconductor channel layer.

### Claim 19 (depends on 18)

The method of claim 18, further comprising:
forming dielectric material spacer layers laterally surrounding at least one of the upper source and drain electrodes and the bottom source and drain electrodes.

### Claim 20 (depends on 17)

The method of claim 17, wherein forming the semiconductor channel layer comprises:
forming a first alternating stack of first and second sublayers including a set of first sublayers that each include a combination of a first metal oxide material, MOx, and a second metal oxide material, M′Ox, and a set of second sublayers including zinc oxide;
forming a third sublayer over the first alternating stack, wherein the third sublayer includes a combination of a first metal oxide material, MOx, a second metal oxide material, M′ Ox, and zinc oxide; and
forming a second alternating stack of first and second sublayers over the third sublayer including a set of first sublayers that each include a combination of a first metal oxide material, MOx, and a second metal oxide material, M′Ox, and a set of second sublayers including zinc oxide, wherein M is a first metal selected from a group consisting of indium (In) and tin (Sn) and combinations thereof, M′ is a second metal selected from a group consisting of gallium (Ga), hafnium (Hf), zirconium (Zr), titanium (Ti), aluminum (Al), strontium (Sr), barium (Ba), scandium (Sc), magnesium (Mg), lanthanum (La), gadolinium (Gd), and combinations thereof.