JPS611059A - Manufacture of mis diode - Google Patents

Abstract

PURPOSE:To obtain stable performance and excellent durability by laminating insulating organic polymer layer formed by depositing a conductive layer, a semiconductor layer and a different annular polymer to become electrodes and a metal layer to become electrodes. CONSTITUTION:An Au electrode 14 is formed on a glass substrate 15 as an operating electrode. A poly N-methylpyrrole film 12 is formed on the electrode to obtain pi-conjugate polymer sample. Then, a poly P-phenylene-1,3,4-oxadiazole film 11 is formed by a depositing method as an insulating organic polymer layer on the sample. Further, an In layer 10 is formed thereon. A MIS diode obtained in this manner has high performance and stable performance with excellent durability.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This F! A relates to a method for manufacturing an MIS diode in which the insulating organic polymer layer is formed by vapor-depositing a heterocyclic polymer containing at least one of nitrogen and sulfur atoms.

[Prior art]

Figure 1 is a cross-sectional view of a typical MIS diode, (1)
, (6) is a lead wire, (2) is a metal layer that becomes an electrode, (3
) is an insulating layer, (4) is a semiconductor layer, and (5) is a conductive layer that becomes an electrode, and is constructed in the order of metal-insulator-semiconductor (MIS). 810
2-Those with a metal structure, ie, MOS diodes, have been put into practical use. In the figure, (7) tri 5io 2 layers,
(8) is a Si layer. In the past, it was said that deterioration occurred due to the SiO'2-8i structure, but now this problem has been clarified, MO8 structures close to the ideal have been created, and their practicality has increased. ing.

These manufacturing methods include the vapor phase growth method of Si with oxygen,
Alternatively, a gas containing oxygen such as CO2 or H2O may be introduced to
How to grow 5i02 on and SiH4 and 02
There is a method of forming 5102 into a film by reacting.

Recently, organic MIS diodes have also started to be made, as shown in the following publication by Miso et al.
These are made by depositing polyethylene (PE) or stearic acid on an organic semiconductor to a layer thickness of about 20 to 100X by vapor deposition, and then attaching a metal electrode to the layer (Publications, i.e., polymer Collected Papers, Volume 41, Page 183, 19
(Published in April 1984). Also known is a MIS diode in which an organic polymer layer is provided on an inorganic semiconductor by the above method.

However, when depositing PK and stearic acid layers using conventional vapor deposition methods, a uniform film cannot be formed, pinholes are easily formed, it is difficult to control the film thickness, and the film is sensitive to heat and easily comes into contact with the electrodes during vapor deposition. This method is not practical as a deposition method for an insulating layer of MIS diodes due to lack of durability. Also, 5i
When using 02, there was a drawback that the cost was high and the device was expensive.

[Summary of the invention]

This invention was made in order to eliminate the drawbacks of the conventional methods described above, and includes a conductive layer that serves as an electrode, a semiconductor layer, an insulating organic polymer layer formed by vapor depositing a heterocyclic polymer, and a metal that serves as an electrode. By stacking layers, MI can be easily created with high performance, stable performance, and excellent durability.
It is an object of the present invention to provide a method for manufacturing an S diode.

[Embodiments of the invention]

The conductive material used for the conductive layer serving as the electrode according to the present invention includes metals such as gold and platinum, carbon, etc., which are generally used for electrodes, and are used alone or in conjunction with various substrates.

Semiconductors used in the semiconductor layer according to the present invention include inorganic semiconductors such as 81 and organic semiconductors such as π-conjugated polymers. Here, the π-conjugated polymers include, for example, pyrrole, a copolymer of 5N-substituted pyrrole, a homopolymer of pyrrole, a homopolymer of N-substituted pyrrole, polythenylene, polyaniline, polyfuran, polyazulene, polyvinylpyridine, and polythiophene, At least one of the following is preferably used.

For example, in order to provide a semiconductor layer of the above-mentioned π-conjugated polymer on a conductive layer serving as an electrode, a monomer corresponding to the above-mentioned π-conjugated polymer and a supporting electrolyte are dissolved in an organic solvent to form a reaction solution, and the above-mentioned conductive layer is A desired π-conjugated polymer layer is deposited on the working electrode by electrolytic polymerization by passing a current between the working electrode and a counter electrode such as platinum, and the deposited π-conjugated polymer layer is thoroughly washed. , a method of drying in a nitrogen atmosphere is used. In this case, the deposited π-conjugated polymer layer is doped with the anion of the supporting electrolyte during the reaction and becomes a P-type semiconductor. On the other hand, by dedoping this P-type semiconductor and further doping with cations, it can be made into an n-type semiconductor. Here, the organic solvent is
Any material that dissolves the supporting electrolyte and the above-mentioned 7mers may be used, such as acetonitrile, nitromenthene, nitromethane, N,N-dimethylformamide (DMF),
dimethyl sulfoxide (DMSO), dichloromethane,
Polar solvents such as tetrahydro7rane, ethyl alcohol, and methyl alcohol may be used alone or as a mixed solvent of two or more. The supporting electrolyte is a substance that has a high oxidation potential and reduction potential, does not itself undergo an oxidation or reduction reaction during electrolytic polymerization, and can impart conductivity to a solution by dissolving it in a solvent. For example, Perchloric acid tetraalkylammonium salts, tetraalkylammonium, tetrafluoroborate salts, tetraalkylammonium, hexafluorophosphate salts, tetraalkylammonium, paratoluenesulfonate salts, sodium hydroxide, etc. are used, but of course two or more of them can be used in combination. I don't mind if you do.

The heterogeneous polymer used in the insulating organic polymer layer according to the present invention is an organic polymer containing at least one of a thiadiazole ring, a thiazolobenzthiazole ring, a triazole ring, an oxazole ring, and an oxadiazole ring in its molecular structure. A polymer compound is used, for example, polyP-7
Eco-1゜3.4-oxadiazole, poly m-phenylene-1,3,4-oxadiazole, poly P-phenylene-1,3,4-thiadiazole, poly m-phenylene-1,3,4-thiadiazole , poly-1,3,4
-thiazole-2,5-ylene vinylene-1,4-phenylene vinylene poly-1,3,4-diazole-2,5
-ylenevinylene-1,4-phenylenevinylene, polythiazolo[4,5-f]pensthiazole-2,6-ylenepynylene-1.4-7 22lenevinylene, poly-3
, 5-P-phenylene-4-phenyl-1,2,4-triazole, polypenzimi-1nobenzothiazole, poly-2,6-dianilitupenzobisthiazole, pyromeric dianhydride and 2°5-diamino- 1,
There is at least one type of polyimide synthesized from 3,4-thiadiazole, poly P-phenylene oxazole, and poly m-7 dinilene oxazole. It is used as a vapor deposited film by either the beam method or the ion class Scoobeam method.

When the semiconductor layer is P-type, the metal of the gold edge layer that becomes the electrode according to the present invention may be, for example, indicum (Indium gallium alloy containing Ga, aluminum (A), silver (Ag), When metals with small work functions such as tin (Sn) and glumanicum (Ge) are n-type, for example, gold (Au), platinum (pt), and copper (
Metals with large work functions such as Cu) are used, and vapor deposition,
Deposition is performed by methods such as sputtering, CVD growth, and coating.

Note that the electrical characteristics of the MIS diode obtained according to the present invention largely depend on the material used during vapor deposition. The inventors investigated various vapor-deposited films of W5#1 polymers mentioned above, and found that a vapor-deposited film of polyP-phenylene-1.3.4-oxadiazole is particularly effective as an insulating organic polymer layer. I found that. The MIS diode according to Kazuo's embodiment of the present invention using the above-mentioned vapor-deposited film has a small current when reverse voltage is applied, and has a significantly superior rectification ratio compared to those using other vapor-deposited films of heterogeneous polymers. Moreover, its durability is sufficient for practical use.

Examples of the present invention will be described in detail below.
This invention is not limited to these.

Example 1 A chromium layer with a thickness of 100A was provided by vacuum evaporation on a glass substrate of 3, 5 am was used as the working electrode (effective working electrode area is 2 x 3.5σ).

N-methylpyrrole (
o, sg), tetraethylammonicum barchlorei)
(0.7 g) was dissolved therein and used as a reaction solution.

Platinum (PT-an electrode) was used as the counter electrode, and 5CE (5CE) was used as the reference electrode.
A saturated calomel electrode) was immersed together with the working electrode in the reaction solution, and a constant current (0.15 mA) was passed between it and the counter electrode for 90 minutes with the working electrode as the anode in a nitrous gas atmosphere.
A π-conjugated polymer layer was deposited on the working electrode to a thickness of about 4 ooo×, washed with acetonitrile, and then dried in a nitrogen gas atmosphere to obtain a π-conjugated polymer sample (I).

Next, on the π-conjugated polymer sample (1,), a polym-phenylene-1゜3.4-oxadiazole layer was deposited as an insulating organic polymer layer to a thickness of 1OX by vacuum heating evaporation. Established by The vapor deposition conditions at this time were pressure 1. OXl 0
' Torr, heating temperature 350°C, amount of polyP-phenylene-1,3.4-oxadiazole charged 0, Ig
, the distance between the π-conjugated polymer sample (I) and the heating source is 10 (
! II+1 deposition time is 10 seconds. In this way π
- Obtain a conjugated polymer sample (b).

Furthermore, an MIS diode obtained by providing an indium (In) layer with a thickness of about 3001 on the π-conjugated polymer sample (II) by vacuum evaporation method was used as an MIS diode.
Let it be a diode sample (I).

Example 2 Using the π-conjugated polymer sample (I) obtained in Example 1, the same procedure as Example 1 was performed except that the vapor deposition time was 15 seconds.
Similarly, a π-conjugated polymer sample (III) was obtained by providing an insulating organic polymer layer with a thickness of 15X.

Furthermore, about 3 layers of nano-layers are added on top of the π-conjugated polymer sample (m).
ooooo! The MIS diode obtained by providing it with a thickness of 2 is referred to as MIS diode sample (2).

Example 3 Using the π-conjugated polymer sample CI obtained in Example 1, the same procedure as in Example 1 was applied, except that the evaporation time was 20 seconds.
Similarly, a π-conjugated polymer sample (ff) is obtained by providing an insulating organic polymer layer with a thickness of 20×. Furthermore, a π-conjugated polymer sample (approximately aooo In layer on top of the cup)
! The MIS diode obtained by providing a thickness of K is referred to as MIS diode sample (3).

Example 4 An insulating organic polymer sample (I) was prepared by providing an insulating organic polymer layer with a thickness of xoX in the same manner as in Example 1 on the working electrode obtained in Example 1. .

Next, the insulating organic polymer sample (I) is placed in a plasma CVD apparatus, and the pressure is reduced to 10'-''I'orr.

The insulating organic polymer sample (I) in the device was heated to 300°C, and a phosphine-monosilazie mixed gas containing 48.5% phosphine was added thereto at 40 ci/min a L.
, further hydrogen power so that the overall pressure becomes 0.4 Torr.

Run the stream. Once the atmospheric pressure stabilized, the atmospheric pressure was increased to 2 Torr, a 13.56 MHz plasma was generated at 25 W for 5 minutes, and a Kn-type amorphous silicon layer was formed on the insulating organic polymer sample (I). Obtain a sample (b). Furthermore, an insulating organic polymer sample (n
) was obtained by providing an In layer with a thickness of about 3oooX on top of the MIS diode sample (
ff).

Comparative Example 1 An organic Schottky diode obtained by providing an In layer with a thickness of about aoooX on the π-conjugated polymer sample (I) obtained in Example 1 was used as a comparative sample (I). do.

Comparative Example 2 A polyethylene (pa) layer was deposited on the π-conjugated polymer sample (I) obtained in Example 1 for 10 minutes using a vacuum heating evaporation method.
It was provided to have a thickness of X. The vapor deposition conditions at this time were pressure 1. OXl 0' Torr, heating temperature 250℃, P
Charge amount of E: 0.05 g, π-conjugated polymer sample (I)
The distance between the sample and the heating source was 7 mm, and the deposition time was 5 seconds. The sample thus obtained is referred to as a π-conjugated polymer sample (V).

Furthermore, MIS obtained by providing an In layer with a thickness of about 30001 on the π-conjugated polymer sample (V)
A diode is used as a comparison sample (2).

Figure 3 shows MIS diode samples (1) to (3).
FIG. 4 shows a cross-sectional view of the MIS diode sample (4), FIG. 5 shows a cross-sectional view of a comparative sample (1), and FIG. 6 shows a cross-sectional view of a comparative sample (2).

In the figure (9), (13), (16), (22)
is a lead wire, (10), (20) are In electrodes, (
11), (19) are P-phenylene-1,3,4-oxadiazole vapor deposited films, (12) are polyN-methylpyrrole films, (14), (17) are Au electrodes (15),
(21) is a glass substrate, (18) is an n-type silicon layer, (
23) is a PE vapor deposited film.

Figure 7 shows MIS diode samples (1) to (4).
and the voltage of comparative sample (1) and comparative sample (2) (
FIG. 3 is an IV characteristic diagram showing changes in current (I) due to V).

In the figure, (24) and (25) are the characteristics of comparative sample (1) and comparative sample (2), and (26) to (29] are the MIS
These are the characteristics of diode samples (1) to (4). Note that the positive voltage side is the forward direction, and the negative voltage side is the reverse direction. According to this, the MIS diode obtained according to the embodiment of the present invention has good rectifying characteristics, and also exhibits a specific change depending on the layer thickness of the insulating layer. It can be seen that a MIS diode with desired characteristics can be obtained.

Also, in terms of durability, comparative sample (1) and comparative sample (2)
However, the rectifying properties of the MIS diode deteriorated after about a week had passed after manufacture, but no change in the characteristics of the MIS diode obtained by the present invention was observed even after one month had passed.

In addition, in the above example, a case was described in which a polymer containing an oxadiazole ring in the molecular structure was used as the heterocyclic polymer used in the insulating organic polymer layer. Those containing at least one of a thiazolobenzthiazole ring, a triazole ring, and an oxazole ring exhibit similar effects.

〔Effect of the invention〕

As explained above, the present invention includes a conductive layer serving as an electrode,
By laminating a semiconductor layer, an insulating organic polymer layer formed by vapor-depositing a heterocyclic polymer, and a metal layer that serves as an electrode, it is possible to easily achieve high performance, stable performance, and durability. An excellent method for manufacturing MIS diodes can be obtained. In addition, in the present invention, the layer thickness of the insulating organic polymer layer can be easily controlled, and is useful for manufacturing various electronic components such as optical sensors and photoelectric conversion elements.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a general MIS diode, FIG. 2 is a sectional view of a conventional MOS diode, FIGS. 3 and 4 are sectional views of MIS diodes according to embodiments of the present invention, and FIG. 5 is a sectional view of a conventional MOS diode. A cross-sectional view of a general organic Schottky diode. FIG. 6 is a cross-sectional view of a conventional general organic MIS diode. FIG. 7 is a current (I)-voltage (V) characteristic diagram for comparing the MIS diode of the embodiment of the present invention, a general organic Schottky diode, and a conventional general organic MIS diode. In the figure, (1) + (6) are lead wires, (2) is a metal layer that becomes an electrode, (3) is an insulating layer, (4) is a semiconductor layer,
(5) is a conductive layer that becomes an electrode, (7) is a 5i02 layer, (8
) is a Si layer, (9). (13) is a lead wire, (10) is an engineered n-layer, (11) is a polyP-phenylene-1.3.4-oxadiazole vapor deposited film, (12) is a polyN-methylvirol film, (14)
#-1 Au electrode, (15) is glass substrate, (16),
(22) is a lead wire, (17) is an Au electrode, (18)
is an n-type silicon layer, (19) is a zopolyp-phenylene-1,3,4-oxacyaburu vapor deposited film, (20) is an In electrode, (21) is a glass substrate, (
23) is the PE deposited film, (24) and (25) are the characteristics of comparative sample (1) and comparative sample (2), respectively.
, (26), (27), and (28) are MIS diode samples (1) to (4) according to embodiments of the present invention, respectively.
). In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (4)

[Claims] (1) In an MIS diode in which a conductive layer serving as an electrode, a semiconductor layer, an insulating organic polymer layer, and a metal layer serving as an electrode are laminated, the insulating organic polymer layer is formed by vapor-depositing a heterocyclic polymer. MI characterized by being
Method of manufacturing S diode. (2) The heterocyclic polymer is an organic polymer compound containing at least one of a thiadiazole ring, a thiazolobenzthiazole ring, a triazole ring, an oxazole ring, and an oxadiazole ring in its molecular structure. A method for manufacturing an MIS diode according to claim 1. (3) Claim 1 or 2, characterized in that the vapor deposition is performed by any one of a heated vapor deposition method, high frequency sputtering, ion blating method, electron beam method, and ion cluster beam method. MI listed
Method of manufacturing S diode. (4) Heterocyclic polymer is polyP-phenylene-1,3
, 4-oxadiazole, the method for manufacturing an MIS diode according to claim 2.