# US 2022/0045274 A1 · Ofets having organic semiconductor layer with high carrier mobility and in situ isolation

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- Number: US 2022/0045274 A1
- Document ID: US20220045274A1
- Status: Published application
- Kind: A1
- Application number: 17/098,492
- Filed: 2020-11-16
- Published: 2022-02-10
- Earliest claimed: 2020-08-06
- Assignees: Facebook Technologies, LLC
- Applicants: Facebook Technologies LLC
- Inventors: Tingling Rao; Lafe Purvis; Tanya Malhotra; Andrew John Ouderkirk
- Web page: https://patentgrep.com/patent/US20220045274A1

## CPC

- H10K 71/191: {characterised by provisions for the orientation or alignment of the layer to be deposited}
- H10K 10/466: {Lateral bottom-gate IGFETs comprising only a single gate}
- H10K 10/471: {the gate dielectric comprising only organic materials}
- H10K 10/484: {characterised by the channel regions}
- H10K 85/113: {Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene}
- H10K 85/615: {Polycyclic condensed aromatic hydrocarbons, e.g. anthracene}
- H10K 85/623: {containing five rings, e.g. pentacene}
- H10K 85/6576: {comprising only sulfur in the heteroaromatic polycondensed ring system, e.g. benzothiophene}
- Y02E 10/549: Organic PV cells
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

An organic field effect transistor includes a channel structure defining an active area located between a source and a drain. The channel structure includes a photoalignment layer and an organic semiconductor layer disposed directly over the photoalignment layer. The photoalignment layer is configured to influence an orientation of molecules within the organic semiconductor layer and hence impact the mobility of charge carriers both within the active area and adjacent to the active area.

## Claims

### Claim 1

An organic field effect transistor comprising:
a channel structure defining an active area located between a source and a drain, the channel structure comprising a photoalignment layer and an organic semiconductor layer disposed directly over the photoalignment layer.

### Claim 2 (depends on 1)

The organic field effect transistor of claim 1, wherein the photoalignment layer comprises a material selected from the group consisting of azo-compounds, polyimides, polysilanes, polystyrenes, polyesters, cinnamates, coumarins, chalconyls, tetrahydrophthalimides, and maleimides.

### Claim 3 (depends on 1)

The organic field effect transistor of claim 1, wherein the photoalignment layer is configured to influence an orientation of molecules within the organic semiconductor layer.

### Claim 4 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer comprises a polycrystalline layer or a single crystal layer.

### Claim 5 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer comprises a polycyclic aromatic hydrocarbon.

### Claim 6 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer comprises a molecule selected from the group consisting of naphthalene, anthracene, tetracene, pentacene, pyrene, polycene, fluoranthene, benzophenone, benzochromene, benzil, benzimidazole, benzene, hexachlorobenzene, nitropyridine-N-oxide, benzene-1, 4-dicarboxylic acid, diphenylacetylene, N-(4-nitrophenyl)-(s)-prolinal, 4,5-dicyanoimidazole, benzodithiophene, cyanopyridine, thienothiophene, stilbene, and azobenzene.

### Claim 7 (depends on 1)

The organic field effect transistor of claim 1, further comprising a gate structure located proximate to the channel structure, the gate structure configured to control the conductivity of the channel structure within the active area.

### Claim 8 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer is characterized by a charge carrier mobility of at least approximately 0.01 cm2V−1s−1 within the active area along a direction between the source and the drain.

### Claim 9 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer is characterized by a charge carrier mobility of at least approximately 1 cm2V−1s−1 within the active area along a direction between the source and the drain.

### Claim 10 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer comprises an isolation region adjacent to the active area.

### Claim 11 (depends on 1)

The organic field effect transistor of claim 1, wherein the organic semiconductor layer comprises an amorphous layer within the isolation region.

### Claim 12

A method comprising:
forming a photoalignment layer;
illuminating the photoalignment layer with polarized light to form an oriented photoalignment layer; and
forming an organic semiconductor layer directly over the oriented photoalignment layer.

### Claim 13 (depends on 12)

The method of claim 12, wherein the photoalignment layer comprises a material selected from the group consisting of azo-compounds, polyimides, polysilanes, polystyrenes, polyesters, cinnamates, coumarins, chalconyls, tetrahydrophthalimides, and maleimides.

### Claim 14 (depends on 12)

The method of claim 12, wherein the organic semiconductor layer comprises a polycyclic aromatic hydrocarbon.

### Claim 15 (depends on 12)

The method of claim 12, wherein the organic semiconductor layer comprises a molecule selected from the group consisting of naphthalene, anthracene, tetracene, pentacene, pyrene, polycene, fluoranthene, benzophenone, benzochromene, benzil, benzimidazole, benzene, hexachlorobenzene, nitropyridine-N-oxide, benzene-1, 4-dicarboxylic acid, diphenylacetylene, N-(4-nitrophenyl)-(s)-prolinal, 4,5-dicyanoimidazole, benzodithiophene, cyanopyridine, thienothiophene, stilbene, and azobenzene.

### Claim 16 (depends on 12)

The method of claim 12, further comprising:
forming a source adjacent to a first region of the organic semiconductor layer; and
forming a drain adjacent to a second region of the organic semiconductor layer, wherein a charge carrier mobility of the organic semiconductor layer within an active area between the source and the drain is greater than a charge carrier mobility of the organic semiconductor layer within an isolation region adjacent to the active area.

### Claim 17 (depends on 16)

The method of claim 16, wherein the photoalignment layer is illuminated with a first polarized light within the active area and the photoalignment layer is illuminated with a second polarized light within the isolation region.

### Claim 18 (depends on 16)

The method of claim 16, wherein the organic semiconductor layer is characterized by a charge carrier mobility of at least approximately 0.01 cm2V−1s−1 within the active area along a direction between the source and the drain.

### Claim 19

An organic field effect transistor comprising a photoalignment layer and an organic semiconductor layer disposed directly over the photoalignment layer, wherein a first region of the organic semiconductor layer is characterized by a first charge carrier mobility and a second region of the organic semiconductor layer is characterized by a second charge carrier mobility.

### Claim 20 (depends on 19)

The organic field effect transistor of claim 19, wherein the first region is located within an active area between a source and a drain and the second region comprises an isolation region located adjacent to the active area.