CN1144301C - An organic thin film transistor switching device and manufacturing method thereof - Google Patents

Abstract

The invention belongs to an organic thin film transistor switching device and a manufacturing method. The source/drain electrode of the top electrode configuration device containing a light-shielding layer is placed on the organic semiconductor layer, wherein the gate electrode is on the substrate, and the insulating layer is on the gate electrode and On the substrate, the organic semiconductor layer is on the insulating layer, the low-dielectric organic photoresist island is on the organic layer, the source and drain electrodes are on the insulating layer and organic semiconductor layer, and the light-shielding layer is on the photoresist island; on the substrate A layer of metal is sputtered and photo-etched into the gate electrode; the organic semiconductor material is thermally evaporated in a vacuum as the active layer and photo-etched, and dry RIE reactive ion etching is used to shape it; photoresist is applied, and the gate is used as a mask with an ultraviolet light source. Backside exposure; development, vacuum thermal evaporation of a layer of metal to form source/drain electrodes, and a light-shielding layer above the channel at the same time. The introduction of self-alignment technology and lift-off technology into the manufacturing process of organic transistors makes the gate/source and gate/drain overlap areas of the device almost zero, thereby greatly reducing the gate/source and gate/drain parasitic capacitance of the device.

Description

An organic thin film transistor switching device and manufacturing method thereof

Technical Field: The present invention relates to an organic thin film transistor (hereinafter referred to as OTFT) switching device.

The invention also relates to a manufacturing method of the organic thin film transistor switch device.

Background technology: In recent years, the research on organic semiconductor materials is extremely active. The performance of OTFT has exceeded the level of amorphous silicon thin film transistor (a-Si: HTFT). In particular, the room temperature carrier mobility of some organic small molecule oligomers (such as Pentacene, Oligothiophene, Tetracene, etc.) has exceeded 1 (square centimeter per volt per second) [Y.Y.Lin et al IEEE Electron Device Lett.18, 606 (1997) , J.H. Schon et al Science 287, 1022 (2000), J.H. Schon et al Science 288, 2338 (2000)]. However, some chemical etching solutions commonly used in the processing of inorganic semiconductor devices have a considerable adverse effect on the properties of organic semiconductor materials, so it is difficult to process organic semiconductor devices using conventional inorganic semiconductor device processing techniques. Therefore, the application of the OTFT is limited. There are few reports on patents on the OTFT manufacturing process. Although the U.S. Patent No. US005854139A discloses a method for making an OTFT with oligothiophene and its derivatives as a semiconductor layer, it does not introduce a photolithography process, so the device size is very large (the channel width is 1 cm, the channel channel length is 100 μm). Moreover, shielding the photocurrent of the device and reducing the parasitic capacitance of the device are not considered, which will have an adverse effect on the performance of the device.

capacitance, these can adversely affect device performance.

Summary of the invention: One of the objectives of the present invention is to provide an organic thin film transistor switching device, the gate/source, gate/drain overlap area of the device is almost zero, thereby greatly reducing the gate/source, gate/drain parasitic capacitance of the device .

Another object of the present invention is to provide a method for manufacturing an organic thin film transistor switching device, which can simplify the manufacturing process and improve device performance, and at the same time form a light-shielding layer.

In order to achieve the above object, an organic thin film transistor switching device provided by the present invention has a structure of:

A top electrode configuration device containing a light-shielding layer, its source/drain electrodes are placed on the organic semiconductor layer, wherein the gate is on the substrate, the insulating layer is on the gate and the substrate, and the organic semiconductor layer is on the insulating layer. The dielectric organic photoresist island is on the organic layer, the source electrode and the drain electrode are on the insulating layer and the organic semiconductor layer, and the light shielding layer is on the photoresist island.

The method for making the above-mentioned device provided by the present invention, the main steps are as follows:

In the first step, a layer of metal is sputtered or evaporated on the substrate and photolithographically formed into a gate electrode;

In the second step, sputter or evaporate the gate insulating film or spin-coat high molecular polymer as _the gate insulating film; the insulating film is Ta _{2 O 5} , Al ₂ O ₃ , TiO ₂ Methyl methacrylate, polyimide, polyvinyl alcohol, polyvinylidene fluoride or any two of them;

The third step is to vacuum thermally evaporate the organic semiconductor material as the active layer and perform photolithography, and adopt the method of dry RIE reactive ion etching to shape;

The fourth step is to apply photoresist and use the grid as a mask to expose from the back with an ultraviolet light source;

The fifth step is development, so that the edge of the photoresist is in the shape of an eaves or a shape with a large top and a small bottom;

The sixth step is to evaporate a layer of metal Au, Ag, Mo, Al, or any two of them in vacuum to form source/drain electrodes, and to form a light-shielding layer above the channel at the same time;

Among the above manufacturing steps: the fourth step is the self-alignment technology, and the fifth step is the lift-off technology.

The advantage of the invention is that the source and drain electrodes can be made on the top of the organic semiconductor layer by applying the photolithography stripping technology, so that small-sized top electrode devices can be realized. The top electrode device is beneficial to carrier injection into organic semiconductors, which is beneficial to the improvement of device performance. In addition, through the application of back-exposure self-alignment technology, the gate/source and gate/drain overlap of the device becomes almost zero, thereby greatly eliminating the influence of gate/source and gate/drain parasitic capacitance, and improving the operating speed of the transistor. At the same time, the light-shielding layer eliminates the influence of photocurrent on the switching ratio of the transistor.

The method can be widely used in low-cost integrated circuits, active matrix displays and the like.

Description of drawings:

Fig. 1a-Fig. 1f are the production process flow diagrams of the present invention.

Detailed ways

Example

On the 7059 glass substrate or flexible plastic substrate 1, use radio frequency magnetron sputtering to coat a layer of metal Ta film with a thickness of 200 nanometers, and photoetch it into a grid shape 2; use DC magnetron sputtering on the grid Methods A layer of Ta ₂ O ₅ was reactively sputtered as a gate insulating layer 3 with a thickness of 100 nanometers; then an organic semiconductor layer was prepared by molecular vapor deposition with a thickness of about 40 nanometers, and was etched into an island shape by photolithography and RIE dry method 4 Then apply a layer of photoresist 5 with a thickness of 1 micron, develop after exposure from the back of the grid, so that the cross section of the photoresist layer becomes the shape of an eaves and a shape with a large top and a small bottom; finally, a layer of 100 nanometer Au layer is vacuum evaporated , the Au layer is naturally separated on both sides of the photoresist to form a source electrode 6 and a drain electrode 7, and a light shielding layer 8 is formed on the top of the channel.

Claims (6)

1, a kind of organic film transistor switch device is characterized in that, transistor arrangement is that source/drain electrode places the top electrode structure on the organic semiconductor layer, the light shield layer that and contains in the preparation source/form simultaneously during drain electrode.

2, a kind of manufacture method of organic film transistor switch device, its key step is:

The first step, sputter or evaporate layer of metal and be photo-etched into gate electrode on glass or plastic base;

In second step, sputter or evaporation gate insulating film or spin coating high molecular polymer are as gate insulating film; Dielectric film is Ta ₂O ₅, Al ₂O ₃, TiO ₂, high molecular polymer is polymethyl methacrylate, polyimides, polyvinyl alcohol or Kynoar;

In the 3rd step, the vacuum thermal evaporation organic semiconducting materials is as active layer, with photoetching and dry etching moulding;

The 4th step, the spin coating photoresist, with the grid be mask with ultraviolet source from back-exposure;

The 5th step, develop, make the photoresist edge be eaves shape or up big and down small shape;

In the 6th step, vacuum thermal evaporation layer of metal Au, Ag, Mo or Al form source/drain electrode, and form light shield layer above raceway groove simultaneously.

3, organic crystal tube device as claimed in claim 1 is characterized in that, gate insulating film is Ta ₂O ₅, Al ₂O ₃, TiO ₂, SiO ₂, SiN _x, polymethyl methacrylate, polyimides, polyvinyl alcohol, Kynoar or in them any two kinds, source/leak electricity is Au, Ag, Mo, Al or in them any two kinds very;

4, organic crystal tube device as claimed in claim 1 is characterized in that, organic semiconducting materials is CuPc, phthalein mountain valley with clumps of trees and bamboo nickel, Phthalocyanine Zinc, fluoro CuPc, fluoro phthalocyanine chromium, pentacene, five thiophene or six thiophene.

5, manufacture method as claimed in claim 2, it is characterized in that, introduce self-aligned technology and lift-off technology in the manufacturing process of organic transistor, make the grid/source of device, grid/leakage overlapping area almost nil, thereby reduce the living electric capacity in the grid/source, grid of device/omit greatly.

6, manufacture method as claimed in claim 2 is characterized in that, when making source, drain electrode, the light shield layer at raceway groove top forms synchronously.

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