# US 2014/0191224 A1 · Organic transistor and method for manufacturing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191224 A1 - Document ID: US20140191224A1 - Status: Published application - Kind: A1 - Application number: 14/237,055 - Filed: 2012-07-18 - Published: 2014-07-10 - Earliest claimed: 2011-08-04 - Assignees: Osaka University - Inventors: Junichi Takeya; Takafumi Uemura; Mayumi Uno - Web page: https://patentgrep.com/patent/US20140191224A1 ## CPC - H10K 10/466: {Lateral bottom-gate IGFETs comprising only a single gate} - H10K 10/468: {characterised by the gate dielectrics} - H10K 10/84: Ohmic electrodes, e.g. source or drain electrodes - H10D 30/47: having two-dimensional [2D] charge carrier gas channels, e.g. nanoribbon FETs or high electron mobility transistors [HEMT] - H10D 62/882: {Graphene} - H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract An organic transistor is provided with: an insulating substrate; a pair of insulating pedestals (2, 3) that are arranged spaced apart from each other on the substrate and that form respectively raised flat surfaces; a source electrode (4) provided on the raised flat surface formed on one of the pedestals; a drain electrode (5) provided on the raised flat surface formed on the other pedestal; a gate electrode (6) provided on the substrate between the pair of pedestals; and an organic semiconductor layer (7) arranged in contact with the upper surfaces of the source electrode and the drain electrode. The gate electrode and the lower surface of the organic semiconductor layer vertically oppose each other across a gap region (8), and the side surfaces of the pedestals facing the gap region are shaped such that the lower side edges recede apart from the gate electrode with respect to the upper side edges. A contact resistance between the source and drain electrodes and the organic semiconductor layer is reduced, high-speed response performance is enhanced by shortening the channel, and short-circuits between the source and drain electrodes and the gate electrode, which accompany shortening of the channel, can be avoided. ## Claims ### Claim 1 An organic transistor comprising: an insulating substrate; a pair of insulating pedestals arranged spaced apart from each other on the substrate and forming respectively raised flat surfaces; a source electrode provided on the raised flat surface formed on one of the pedestals; a drain electrode provided on the raised flat surface formed on the other pedestal; a gate electrode provided on the substrate between the pair of pedestals; and an organic semiconductor layer arranged in contact with the upper surface of the source electrode and the upper surface of the drain electrode, wherein the gate electrode and the lower surface of the organic semiconductor layer oppose each other vertically across a gap region, and the side surfaces of the pedestals facing the gap region are shaped such that the lower side edges recede apart from the gate electrode with respect to the upper side edges. ### Claim 2 (depends on 1) The organic transistor according to claim 1, wherein the side surfaces of the pedestals facing the gap region form reverse tapers from the lower side edges toward the upper side edges. ### Claim 3 (depends on 2) The organic transistor according to claim 2, wherein each of the pedestals has a shape of a reverse mesa in a channel direction cross section including a direction of a channel between the source electrode and the drain electrode. ### Claim 4 (depends on 1) The organic transistor according to claim 1, wherein the side surface of each of the pedestals facing the gap region has an area of a certain height on the lower edge side including a part opposing the gate electrode, which area recedes stepwise with respect to the upper edge side area, thereby forming a reverse staircase. ### Claim 5 (depends on 1) The organic transistor according to claim 1, comprising a semiconductor layer member constituted by forming the organic semiconductor layer on a support substrate, wherein the semiconductor layer member is mounted on the source electrode and the drain electrode, in a state where the surface of the organic semiconductor layer side opposes the source electrode and the drain electrode. ### Claim 6 (depends on 1) The organic transistor according to claim 1, wherein at least a part of the gap region is formed of an insulating solid, and the insulating solid has a permittivity greater than 1. ### Claim 7 (depends on 1) The organic transistor according to claim 1, wherein the gap region is entirely formed of an ionic liquid. ### Claim 8 (depends on 6) The organic transistor according to claim 6, wherein at least a part of the gap region to be in contact with the organic semiconductor layer is formed of the insulating solid, and the part other than the insulating solid is formed of an ionic liquid. ### Claim 9 (depends on 1) The organic transistor according to claim 1, wherein a channel length L as the distance between the source electrode and the drain electrode is 20 μm or less. ### Claim 10 (depends on 9) The organic transistor according to claim 9, wherein a height d of the pedestals satisfies a relationship of d≦L/2 μm with respect to the channel length L. ### Claim 11 A method for manufacturing an organic transistor, comprising: forming on an insulating substrate a pair of insulating pedestals that are spaced apart from each other and that form respectively raised flat surfaces; forming a source electrode on the raised flat surface formed on one of the pedestals and forming a drain electrode on the raised flat surface formed on the other pedestal, and forming a gate electrode on the substrate between the pair of pedestals; fabricating a semiconductor layer member having the organic semiconductor layer formed on a support substrate; and mounting the semiconductor layer member in contact with the upper surface of the source electrode and the upper surface of the drain electrode so that the surface of the organic semiconductor layer side opposes the source electrode and the drain electrode, thereby forming a gap region between the gate electrode and the lower surface of the organic semiconductor layer; wherein in the step of forming the pedestals, the side surfaces of the pedestals facing the gap region is shaped such that the lower side edges recede apart from the gate electrode with respect to the upper side edges. ### Claim 12 (depends on 11) The method for manufacturing an organic transistor according to claim 11, wherein the source electrode, the drain electrode and the gate electrode are formed simultaneously by a batch film formation on the pedestals and on the substrate.