JPS629672A - Semiconductor device and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a semiconductor device such as a field effect transistor formed on an insulating substrate such as a glass plate or a polymer film, and a method for manufacturing the same. The insulating material layer constituting a semiconductor element using a polymer film as a substrate can be reliably adhered to the polymer film substrate without peeling.

(Prior Art) In semiconductor devices such as field effect transistors, this type of semiconductor device (i.e., an insulating game whose constituent element is an insulating material layer directly adhered to an insulating material substrate) has conventionally been made using fused quartz or glass. A metal oxide film deposited directly on a heat-resistant insulating material substrate such as the above was used as an insulating component such as a gate insulating layer.

- Recently, there has been a demand for forming semiconductor elements of this type, such as field effect transistors, on flexible polymer films for use in driving flat liquid crystal display panels.

(Problems to be Solved by the Invention) However, if a polymer film is used as a substrate and a semiconductor element, such as a field effect transistor, is deposited thereon in the conventional manner.

Because the metal oxide layer deposited on the polymer film substrate as an insulating component tends to peel off or form pinholes, it is difficult to form field effect transistors that can be used and obtained stably and reliably. It was extremely difficult.

(Means for Solving the Problems) In order to solve the above-mentioned problems in 3 when manufacturing semiconductor devices such as field effect transistors using a polymer film as a substrate, the present invention provides gate insulation of field effect transistors. The insulating material layer itself, which is a component to be adhered directly to the polymer film substrate such as a layer, is made of a homogeneous polymer that has an affinity for the polymer film substrate, and the electric field is applied to the entire polymer film substrate. When manufacturing a semiconductor element such as an effect transistor, a polymer constituting an insulating material element such as a gate insulating layer is formed by plasma polymerization.

(Function) For example, the gate insulating film of conventional insulated gate field effect transistors was formed by thermal oxidation of metal, anodic oxidation, or thinning of the oxide itself. The metal oxide film being formed may peel off from the polymer film substrate, or
Although it was not possible to fabricate a field effect transistor due to pinholes appearing in the metal oxide film, the gate insulating film itself was made of the same polymer as the polymer film substrate, and was formed by plasma polymerization during the fabrication of the field effect transistor. By doing so, it is possible to obtain a gate insulating film that is stably and reliably adhered to a polymer film substrate, and it becomes possible to manufacture required semiconductor elements such as high-quality field effect transistors on a flexible insulating material substrate.

(Example) The present invention will be described in detail below with reference to the drawings.

As an example of the present invention, a field effect transistor t-g having the configuration shown in FIG. 1 was manufactured. After confirming the manufacturing method and performance of a field effect transistor using a polymer as the gate insulating film, we fabricated a thin film field effect transistor using the desired polymer film as a substrate using the same method as when using a glass substrate. The performance of the field effect transistor itself using a polymer gate insulating film and the compatibility between the polymer gate insulating film and the polymer film substrate were confirmed separately.

That is, the field effect transistor according to the present invention has a first
As shown in Figures (a) and (b), a gate electrode 1 is deposited on a substrate S, and a polymer insulating film 2'jk is deposited on the substrate S covering the gate electrode 1. A portion of the gate electrode 1 is left open on the polymer insulating film 2, and a source electrode 8 and a drain electrode 41 are formed! ″The electrodes 8 are deposited and formed.
．． 4 and the polymer insulating film 2 of the gate electrode 1 portion, and the semiconductor film 5 is formed in such a manner that the polymer insulating film 2t is sandwiched between the gate electrode 1 and the polymer insulating film 2t.

In the production of a field effect transistor with such a configuration, each component 1, 8, except the polymer gate insulating film 2 is
4.5 is fabricated by vacuum evaporation, and the polymer gate insulating film 2 is fabricated by plasma polymerization. That is, first, gold is vacuum-deposited on a substrate S as a gate electrode, and a polymer obtained by plasma polymerizing monomers such as acetonitrile and benzene is produced on the substrate S as a gate insulation film 2, covering the gate electrode 1 with gold. This plasma polymerization is carried out by creating a vacuum in the reaction vessel, introducing a monomer gas such as acetonitrile into the reaction vessel, and generating plasma in the reaction vessel by applying a high-frequency electric field using a parallel plate capacitive coupling method. was polymerized. Thereafter, metal nickel is deposited as the source electrode 8 and the drain electrode 47 by vacuum evaporation so that good ohmic contact can be obtained with the semiconductor tellurium which is the semiconductor film 5,
Finally, a semiconductor film 5 was formed by depositing semiconductor tellurium so that the electrodes 8 and 4 were in common contact with the gate insulating film 2.

As described above, a thin film field effect transistor fabricated using a gate insulating film formed by plasma polymerization of acetonitrile on a polymer film substrate exhibits excellent output characteristics as shown in Figure 2. ing. The output characteristics of an insulated gate field effect transistor are expressed by Weimer (P) as follows.

・K, Weimer)'s theoretical formula.

That is, the drain current of the field effect transistor has the following relationship with the drain voltage VD and the gate voltage VG.

Nine, Vp ((VG VT), Vo>
VT Here, L is the channel length, W is the channel width, μ is the carrier field effect mobility, C is the gate capacitance per unit area, and vT is the threshold voltage of the semiconductor film. When the pressure th and the initial charge density in the semiconductor film are no, it is given by: . Note that q is the charge of the electron.

As mentioned above, the drain current of a field effect transistor is
It can be controlled by applying drain voltage and gate voltage.

In the configuration example F shown in the first figure, a polymer insulating film 2 is deposited on an insulating substrate S to cover a gate electrode 1 deposited on an insulating material substrate S, and the polymer insulating film 2 is deposited on an insulating substrate S. [A field effect transistor according to the present invention is not limited to this example, but a field effect transistor according to the present invention may be constructed as follows. You can also do that.

That is, the polymer insulating film 2t formed on the insulating material substrate S covering the gate electrode 1t is removed by patterning, leaving only the portion in contact with the gate electrode 1, and the polymer insulating film 2t is deposited on the insulating material substrate S exposed by the removal. , a polymer insulating film 2' covering the gate electrode 1 and having an end in contact with the insulating substrate S.
A source electrode 3 and a drain electrode 4 are respectively deposited so as to partially cover the electrodes 8 and 4, and a semiconductor layer 5t is placed in common contact with the electrodes 8, 4 and the polymer film 2 exposed in the middle. - By depositing, it is possible to construct an insulated gate field effect transistor in which the gate electrode 1 is opposed to the semiconductor layer 5 connecting the source electrode 8 and the drain electrode 4 with the polymer insulating film 2 interposed therebetween. can.

Further, the semiconductor device of the present invention includes electrodes formed on a flexible insulating material substrate such as a thin polymer film, in the same manner as in the field effect transistor example 1 described above. A metal-insulator-metal (MIM) diode in which another electrode is deposited on a polymer insulating film overlying the insulating material substrate, or a semiconductor layer is deposited on the polymer insulating film. Metal-insulator-semiconductor (MIS) diodes, polymer insulating films ft
Other semiconductor elements used as constituent elements can also be manufactured reliably in the same manner as described above.

(Effects of the Invention) As is clear from the above description, according to the present invention, plasma-polymerized polymer thin films used, for example, as gate insulating films of field-effect transistors, generally have a highly cross-linked, next-cell structure, and are chemically Its advantage is that it is physically and mechanically stable, and almost no pinholes occur.
It has good adhesion to the polymer film used as the substrate.

L7'C means that a semiconductor device such as a field effect transistor, which has an insulating film as a constituent element, is made by depositing at least a portion of a plasma-polymerized polymer thin film on an insulating material substrate, even on a polymer film substrate. It can be manufactured reliably.

A field effect transistor formed on a flexible substrate made of such a polymer film is suitable for use, for example, in switching display elements in an active matrix drive type flat liquid crystal display panel. That is, in contrast to the polymer film jR liquid crystal display panel, which exhibits excellent characteristics in terms of brightness and viewing angle dependence by arranging display elements in a matrix on a polymer film, a switching element is provided for each display element for each pixel. It is possible to apply an active matrix drive method that drives the elements in a corresponding manner by using components on a polymer insulating film as described above, and it is possible to obtain a liquid crystal display panel with even higher resolution and higher contrast. Particular advantages are obtained with the invention.

Brief explanation of the front surface Figure 1 (8 and Φ) is a side sectional view and a top view showing an example of the configuration of a field effect transistor according to the present invention, respectively. Figure 2 is the same (the output characteristics of the field effect transistor). FIG. 3 is a characteristic curve diagram showing an example.

S... Insulating material substrate 1... Gate electrode 2... Gate insulating film a.
...Source electrode 4...Drain electrode 5...
Semiconductor layer Figure 2 Drain voltage VO (V)

Claims (1)

[Scope of Claims] 1. A semiconductor device comprising an insulating layer made of a thin polymer film deposited on an insulating base layer. 2. The semiconductor device according to claim 1, wherein the insulating material base layer is made of a polymer thin film. 3. The semiconductor device according to claim 1 or 2, wherein a field effect transistor is constructed using the insulating layer as a gate insulating layer. 4. A method for manufacturing a semiconductor device, which comprises forming a thin polymer film as an insulating layer of the semiconductor device by depositing it on an insulating material base layer by plasma polymerization. 5. The method of manufacturing a semiconductor device according to claim 4, wherein the insulating material base layer is formed of a polymer thin film. 6. The method of manufacturing a semiconductor device according to claim 4 or 5, wherein a field effect transistor is formed using the insulating layer as a gate insulating layer. 7. Form a conductor for a gate electrode on the insulating material base layer, cover the conductor for the gate electrode by depositing a polymer thin film for the gate insulating layer on the insulating material base layer by plasma polymerization, and form the gate insulating material. A conductor layer for a drain electrode and a source electrode is deposited on the polymer thin film for the layer or on the insulating material base layer, and a semiconductor layer is formed in contact with these conductor layers and the polymer thin film for the gate insulating layer, respectively. A semiconductor device manufacturing method according to claim 6, characterized in that: