# US 7,608,857 B2 · Field effect transistor having a structure in which an organic semiconductor that forms a channel is made of a single crystal or a polycrystal of organic molecules

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- Number: US 7,608,857 B2
- Document ID: US7608857B2
- Status: Granted
- Kind: B2
- Application number: 11/602,404
- Filed: 2006-11-21
- Published: 2007-05-24
- Granted: 2009-10-27
- Earliest claimed: 2005-11-22
- Assignees: Hitachi, Ltd.
- Inventors: Masaaki Fujimori; Tomihiro Hashizume; Masahiko Ando
- Web page: https://patentgrep.com/patent/US7608857B2

## CPC

- H10K 71/12: using liquid deposition, e.g. spin coating
- 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: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

A TFT having a large mobility of carriers that are conducted through a channel as compared with a conventional organic TFT, and a method of manufacturing the TFT inexpensively and easily are provided. The channel is formed of a semiconductor organic molecular crystal thin film which is highly oriented, and a TFT that is large in the mobility of the carriers that are conducted through the channel, and a lyophilic TFT pattern that is surrounded by a lyophobic region on a substrate are formed, and the configuration of the pattern is featured, whereby a solution of the semiconductor organic molecules which is supplied to an appropriate region of a substrate surface including the channel is spontaneously dried in an anisotropic fashion, and highly oriented crystal is grown in the drying process.

## Claims

### Claim 1

A field effect transistor, comprising:
a substrate;
a lyophobic region formed over the substrate; and
lyophilic regions corresponding to source and drain electrodes and a channel that connects both of the source and drain electrodes to each other, said lyophilic regions being formed in the lyophobic region, said channel including a crystal having a grain size larger in a longitudinal direction of said channel than in a width direction of said channel,
wherein a width of said channel changes along the longitudinal direction of said channel, and said channel is sandwiched by the lyophobic region.

### Claim 2 (depends on 1)

The field effect transistor according to claim 1, wherein a plurality of channels are formed between said source electrode and said drain electrode, and each of the plurality of channels includes a crystal having a larger grain size in the longitudinal direction of each channel than in a width direction of each channel,
wherein a width of each channel changes along the longitudinal direction of each channel, and each channel is sandwiched by the lyophobic region.

### Claim 3

A field effect transistor, comprising:
an insulator;
a lyophobic region formed on the insulator; and
lyophilic regions corresponding to source and drain electrodes and a channel that connects both of the source and drain electrodes to each other, said lyophilic regions being formed in the lyophobic region, said channel including a crystal having a lager grain size in the longitudinal direction of said channel than in a width direction of said channel,
wherein a width of said channel changes along the longitudinal direction of said channel, and said channel is sandwiched by the lyophobic region.

### Claim 4 (depends on 3)

The field effect transistor according to claim 3, wherein a plurality of channels are formed between said source electrode and said and drain electrode, and each of the plurality of channels includes a crystal having a larger grain size in the longitudinal direction of each channel than in a width direction of each channel,
wherein a width of each channel changes along the longitudinal direction of each channel, and each channel is sandwiched by the lyophobic region.