JP3041092B2 - MIM element and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a first conductive layer (M) as a first electrode, an insulating layer (I), and a second electrode used as a switching element of an active matrix type liquid crystal display device. The present invention relates to a structure of an MIM element including a certain second conductive layer (M) and a method for manufacturing the MIM element.

[0002]

2. Description of the Related Art Liquid crystal display devices are widely applied as representatives of flat panel displays. In particular, the active matrix method, in which a switching element is provided for each pixel that constitutes a flat panel display and controls the liquid crystal of each pixel, enables completely independent switching of the liquid crystal, enabling large-capacity, high-quality display. Become. Typical active matrix switching elements include:
Examples include a thin film transistor (TFT) and an MIM element. Among them, particularly, the MIM element can realize a low-cost, low-defect, and high-quality liquid crystal display device because of its simple structure.

FIGS. 2 and 3 show typical M in the prior art.
1 shows a method for manufacturing an IM device and a MIM device structure.

First, as shown in FIG. 2A, a first conductive layer 1 serving as a first electrode is formed on the entire surface of a substrate 4.

Next, as shown in FIG. 2B, the first conductive layer 1 is patterned by a photoetching technique using a first photomask. FIG. 3A shows a planar pattern shape of the first conductive layer. The first conductive layer 5 has a wiring section 10 and an MIM element section 11.

Next, as shown in FIG. 2C, an insulating layer 2 is formed by anodizing the patterned first electrode layer 1. This insulating layer 2 is formed as shown in FIG.
As shown in (b), the first conductive layer 5 is formed on the upper surface and the side surface, and becomes the anodized portion 6.

[0007] Finally, as shown in FIG. 2 (d), a second conductive layer 3 is formed on the entire surface, and a second photomask is used.
The second conductive layer 3 is patterned by a photo etching technique. As shown in FIG. 3C, the second conductive layer 3 shown in FIG. 2D is formed on at least the MIM element section 11 and the pixel section 12. M
In the IM element section 11, the first conductive layer 5, the anodic oxidation section 6, and the second conductive layer 7 constitute an MIM element.

[0010] In the conventional example shown in FIG.
Is formed as a part of the conductive layer 7. However, it is more common that the pixel portion 12 is formed of a third conductive layer different from the second conductive layer 7.

The first conductive layer 1 serving as the first electrode is made of Ta.
(Tantalum), and the insulating layer 2 is Ta ₂ O ₅ (tantalum pentoxide) obtained by anodizing this Ta.

As shown in FIG. 3, when the MIM electrode of the MIM element section 11 and the display electrode of the pixel section 12 are used as the second conductive layer 3 serving as the second electrode, as shown in FIG.
A transparent conductive film such as O (indium tin oxide) is used. In this case, use two photomasks,
An MIM element is formed by two patterning steps. MI
When the M element section 11 and the pixel section 12 are formed of different conductive layers, the second conductive layer may be formed of Cr (chromium), Ta
Use a metal film such as At this time, an MIM element is formed in three patterning steps using three photomasks.

In any case, the MIM element can be formed in two or three patterning steps, and has a high yield and a low cost in active steps compared to a TFT requiring six or more patterning steps. A switching element for a matrix can be provided.

[0012]

When an asymmetric voltage is applied to the liquid crystal, flicker and image burn-in occur. In order to avoid these, it is preferable that the current-voltage characteristics of the MIM element have good symmetry with respect to the polarity of the applied voltage. However, the switching characteristics of a general MIM element are often asymmetric with respect to the polarity of the applied voltage.

In order to avoid this asymmetry, it is necessary to optimize the material of the second electrode layer and the control of the interface between the first conductive layer and the insulating film and the interface between the insulating film and the second conductive layer. . A typical currently used MIM element structure that can obtain a relatively symmetrical characteristic of current-voltage characteristic is T
is a-Ta ₂ O ₅ -Ta (or Cr).

FIG. 4 shows a current-voltage characteristic of a typical MIM element. The vertical axis shows the absolute value of the current on a logarithmic axis, and the horizontal axis shows the positive and negative voltages.

The current-voltage characteristics of the MIM element having the Ta—Ta ₂ O ₅ —Ta (or Cr) structure are as shown by a curve 51 on the plus side of the voltage and a curve 52 on the minus side.
Shows almost symmetric characteristics. However, this current-voltage characteristic has a small voltage threshold, and it is difficult to obtain high display quality, that is, good contrast. Furthermore, this Ta-T
In the a ₂ O ₅ -Ta (or Cr) structure, the display electrode portion of the pixel portion must be formed of a transparent electrode film such as ITO separately from the second conductive layer of Ta or Cr. Three patterning steps are required.

The curves 53 and 54 in FIG.
Current of the MIM element having a structure of Ta-Ta ₂ O ₅ -ITO - a voltage characteristic shows a very large asymmetry in the positive voltage side and the negative voltage side. But Ta-Ta ₂
The voltage threshold in the O ₅ -ITO structure is sufficiently large, and the display quality is equivalent to that of the TFT.

In the MIM element structure in which the MIM element part shown by the curves 51 and 52 and the display electrode part which is a pixel part are formed of the same transparent electrode film made of a conductive layer such as ITO, two patterning steps are performed. Thus, an MIM element can be formed, which is very attractive in terms of cost and yield. However, it is not impossible to use the MIM element having a large asymmetry in the current-voltage characteristic of the Ta—Ta ₂ O ₅ —ITO structure if the driving method is devised. Is difficult and problematic.

As a method for obtaining symmetrical characteristics using an MIM element having asymmetrical current-voltage characteristics, two MI
There is a so-called back-to-back structure in which M elements are connected in series in the opposite direction. This will be described with reference to the equivalent circuit diagram of FIG.

FIG. 5A shows a normal single MIM element, but as shown in FIG. 5B, a single first MIM element.
A structure in which two elements 58 and the second MIM element 59 are connected in series back to back is called a back-to-back structure.

In the back-to-back structure shown in FIG. 5B, a wiring electrode 55, an intermediate electrode 56, a pixel electrode 5
7 and three independent nodes.

When the insulating film is formed by using the anodic oxidation method, only the wiring electrode 55 can be connected to the outside.
For this reason, the second M between the intermediate electrode 56 and the pixel electrode 57
IM element 59 cannot be formed by anodizing. Therefore, back-to-
It is impossible to form an MIM element having a back structure.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and realize a back-to-back MIM device structure using an anodization method, a method of manufacturing the MIM device, and a method of manufacturing the same. Is to provide. This makes it possible to realize a MIM element having good display quality with a high voltage threshold and symmetric current-voltage characteristics in a simple manufacturing process.

[0023]

To achieve the above object, the present invention employs the following structure and manufacturing method.

According to the present invention, a first conductive layer and the first conductive layer are provided.
An insulating layer formed by anodizing the layer, a second conductive layer,
A MIM element comprising: a first conductive layer pattern;
The shape of the wiring part, the MIM element part, the wiring part and the M
A bottleneck portion provided between the bottleneck portion and the IM device portion;
Characterized in that the part is left insulated by oxidation
I do. In addition, the MIM element has a MIM element
-It is characterized by being connected to back. Ma
And at least a part of the wiring section and the MIM element section.
And the bottleneck is insulated by oxidation to expose the conductive layer.
There is no protrusion. A first conductive layer;
An insulating layer formed by anodizing the first conductive layer;
In the method for manufacturing the MIM element comprising the conductive layer of
Serial first pattern shape of the conductive layer, a wiring portion, possess a MIM element, and a narrow path portion provided between the wiring portion and the MIM device portion, sufficient first conductive layer of the narrow path portion Oxidize to
To insulate and separate the wiring section from the MIM element section.
Characterized by having a step of:

In the part of the first conductive layer which has been anodized,
Configuration in which a part of the pixel electrode overlaps the upper part of anodization
, And has an additional capacity.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, the structure of the MIM element according to the present invention will be described with reference to the plan view of FIG.

As shown in FIG. 1A, the first conductive layer 3
A bottleneck portion 26 is provided between the wiring portion 25 made of 0 and the MIM element portion 27. Bottleneck portion 2 made of first conductive layer 30
The width of 6 is about 1 to 3 microns. The MI that forms the MIM element by oxidizing the narrow passage portion 26 having the narrow width is formed.
The M element section 27 and the wiring section 25 are insulated and separated.

Next, a manufacturing process for manufacturing the structure of the above-described MIM element will be described with reference to FIGS. 1 and 6 are a plan view and a cross-sectional view for explaining a manufacturing process in a method for manufacturing an MIM element according to the present invention.

First, as shown in FIG. 6A, a metal layer such as Ta, which can be subjected to anodizing treatment, is used as the first conductive layer 15.
It is formed on the entire surface of the substrate.

Subsequently, as shown in FIG. 6B, an insulating layer 16 is formed on the upper surface of the first conductive layer 15. This insulating layer 1
6 is formed by performing anodic oxidation in a solution such as citric acid to form the insulating layer 16. The insulating layer 16 formed by the first anodic oxidation treatment becomes the insulating layer (I) of the MIM element.

Subsequently, as shown in FIG.
The insulating layer 16 and the first conductive layer 15 are etched using the resist 18 which is a photosensitive material formed on the mask 6 as a mask to form the wiring portion 21, the bottleneck portion 22, and the MIM element portion 23. As shown in FIG. 1A, these planar pattern shapes include a wiring portion 25 made of a first conductive layer 30 and
It has a shape having an IM element portion 27 and a bottleneck portion 26 connecting these wiring portions 25 and the MIM element portion 27. The resist 18 used in this patterning step is left without being peeled off, as shown in FIG.

Subsequently, as shown in FIG. 6D, a second anodic oxidation treatment is performed in a solution such as citric acid. In this citric acid solution, the first conductive layer 30 is anodized by applying a positive voltage through the wiring portion 25 shown in FIG. At this time, the upper surface of the first conductive layer 15 is covered with the resist 18. For this reason, the anodic oxidation proceeds from the side surface of the first conductive layer 15, the side surface oxidized portion 19 is formed on the side surface portion of the first conductive layer 15, and finally, the narrowest narrow channel portion 22 is completely oxidized. Is done.

As a result, as shown in FIG.
The intermediate electrode 35 of the M element part 27 and the first wiring electrode 36 of the wiring part 25 are formed by an anisotropic bottleneck part 26 formed by anodizing the first conductive layer 30, that is, the side oxidized part 3.
1 for isolation. At the stage where the first conductive layer 30 of the bottleneck portion 26 is completely oxidized, the MIM element portion 27
The second anodic oxidation treatment for performing side oxidation of the above is stopped.

Next, as shown in FIG. 6E, the resist 18 used as a mask for anodic oxidation is removed.

Finally, as shown in FIG. 6F, a second conductive layer 17 made of a transparent conductive film such as ITO is formed, and the second conductive layer 17 is patterned into a predetermined shape. Second
As shown in FIG. 1C, the planar pattern shape of the conductive layer 17 is a second wiring electrode 37 made of the second conductive layer 32.
And a pixel electrode 38. The second wiring electrode 37 and the intermediate electrode 35 form a first MIM element 33 with an insulating layer interposed therebetween. The pixel electrode 38 and the intermediate electrode 35 form an insulating layer. The second MIM element 34 is configured to sandwich the second MIM element 34 to realize a back-to-back structure as a whole.

In the first embodiment described with reference to FIGS. 1 and 6, the second conductive layer 17 is composed of a single layer of a transparent conductive film such as ITO. A multilayer film of a thin film metal film and ITO or another transparent conductive film may be used, and of course, the electrodes on the MIM element and the pixel electrodes may be made of different materials.

FIG. 7A is an equivalent circuit showing a pixel configuration used in the first embodiment. The unit pixel is a non-linear back-to-back configuration including a first MIM element 63 and a second MIM element 64 between a scanning line (or data line) 62 and a data line (or scanning line) 61. The switching element is configured to be connected to the liquid crystal 65.

On the other hand, a pixel configuration as shown in FIG. 7B is also possible. That is, the first MIM element 63 and the second MIM
A liquid crystal 68 and an additional capacitor 70 are connected to one end of a back-to-back non-linear switching element composed of the IM element 64. The other end of the back-to-back non-linear switching element is connected to the data line 6.
7, the other end of the additional capacitor 70 is connected to the scanning line 66, and the other end of the liquid crystal 68 is connected to the counter electrode 69.

The additional capacity 70 as shown in FIG.
The MIM type active matrix element having
Even a liquid crystal display device with a small pixel having a small capacity of 8 can be driven sufficiently. Further, there is an advantage that the influence of the voltage dependence of the capacity of the liquid crystal can be reduced. Further, it is advantageous that patterning on the counter substrate is unnecessary. In particular, in color display, there is no need for patterning on the color filter of the opposing substrate, which is a great advantage in manufacturing.

A method of manufacturing the pixel configuration shown in the equivalent circuit diagram of FIG. 8 and 9 show M of the present invention.
It is sectional drawing and a top view which show 2nd Example in IM element structure and manufacturing method.

First, the pixel configuration will be described with reference to FIG. 9C showing a completed pattern shape.

The scanning line 66 shown in FIG. 7B corresponds to the first wiring electrode 87 shown in FIG. 9, and similarly, the data line 67 is the second wiring electrode 92 and one electrode of the liquid crystal 68. Are the pixel electrode 93, the first MIM element 63 and the second MIM element 64 are the first MIM element 90 and the second MIM element 91,
The additional capacitors 70 correspond to the additional capacitors 89, respectively.

As in the first embodiment, the intermediate electrode 88 between the first MIM element 90 and the second MIM element 91 is separated from the first wiring electrode 87 by the bottleneck portion 83 insulated by side anodic oxidation. It is a separated isolated electrode pattern.

Further, the additional capacitance portion 89 is formed of a first wiring electrode 87, an insulating film on the first wiring electrode 87, and a pixel formed by projecting over the insulating film on the first wiring electrode 87. An electrode 93 is provided.

Here, the first MIM element 90 and the second
The M element 91 and the additional capacitance section 89 are the same MIM in which an insulating film is interposed between the first conductive layer and the second conductive layer.
Has a structure.

However, the first MIM element 90 and the second MIM element 90
Active matrix driving cannot be performed if the film quality and thickness of the insulating films in the MIM structure of the IM element 91 and the additional capacitance unit 89 are the same.

Here, the area, thickness, capacitance,
The amount of current is represented by S (MIM), d (MIM), and C, respectively.
(MIM) and I (MIM). Further, the area, thickness, capacity, and current amount of the additional capacitor are represented by S (C) and d, respectively.
(C), C (C), and I (C).

The MIM element is a switching element, and it is necessary to supply a current in the ON state, and the additional capacitance must not leak. Therefore, the following relationship is required. I (MIM)> I (C) (1)

If the relationship of the above formula (1) cannot be satisfied, the electric charge to be stored in the pixel electrode escapes through the additional capacitance, and there is a problem in driving the liquid crystal.

The following relationship is also required. C (MIM) <C (C) (2)

When the capacity of the additional capacitor is not larger than the capacity of the MIM element as in the above equation (2), the potential of the pixel electrode couples with the capacity of the MIM element and fluctuates in accordance with the potential fluctuation of the data line. This makes it impossible to apply a constant voltage to the liquid crystal.

The thickness of the insulating film between the MIM element and the additional capacitance,
When the film quality is equal, I (MIM) / S (MIM) = I (C) / S (C) (3) C (MIM) / S (MIM) = C (C) / S (C) (4) From the expressions (1) and (3), S (MIM)> S (C) (5) From the expressions (2) and (4), S (MIM) <S (C) (6) contradicts each other. Therefore, the thickness and the quality of the insulating films of the MIM element and the additional capacitor must not be the same.

When the conduction mechanism of the insulating film of the MIM element is Poole-Ferrenkel conduction, the current largely depends on the film thickness. If the thickness of the insulating film of the additional capacitance is several times the thickness of the insulating film of the MIM element, the current will be several orders of magnitude lower. Therefore, for example, if d (C) / d (MIM) = 2 to 5 (7) S (C) / S (MIM) = 10 to 100 (8), I (MIM) / I (C)> 1 to 1000 (9) C (C) / C (MIM)> 2 to 20 (10), and the relationship between the expressions (1) and (2) can be sufficiently satisfied. As described above, the thickness of the insulating film in the additional capacitance section is required to be several times the thickness of the insulating film in the MIM element section.

In this embodiment, in consideration of the above considerations, the first, second,
And a third three-stage anodic oxidation process. First
In the anodic oxidation step, an insulating film of the MIM element is formed.
The second anodic oxidation step is used for side oxidation for separating an intermediate electrode for realizing a back-to-back structure.
The third anodic oxidation step is used to increase the thickness of the insulating film for additional capacitance.

The pixel structure shown in FIG. 7B is realized by using only two photomasks by these three stages of the anodic oxidation process. This manufacturing process will be described with reference to the cross-sectional view of FIG. 8 and the plan view of FIG.

First, as shown in FIG. 8A, an anodically oxidizable metal layer such as Ta is formed as the first conductive layer 15 on the entire surface of the substrate.

Subsequently, as shown in FIG. 8B, a first anodic oxidation step for forming an insulating layer of the MIM element is performed, and an insulating layer 16 is formed on the upper surface of the first conductive layer 15.
This insulating layer 16 is formed by performing anodic oxidation in a solution such as citric acid to form the insulating layer 16. The insulating layer 16 formed in the first anodic oxidation step becomes the insulating layer (I) of the MIM element.

Subsequently, as shown in FIG.
The insulating layer 16 and the first conductive layer 15 are etched using the resist 18 formed on 6 as an etching mask to form a wiring portion 21, a bottleneck portion 22, and an MIM element portion 23. As shown in FIG. 9A, these planar pattern shapes include a wiring portion 82 made of a first conductive layer 81,
IM element section 84, wiring section 82 and MIM element section 84
Are patterned into a shape having a bottleneck portion 83 connecting the first and second conductive layers 81 and a backup wiring portion 85 separated and independent from the first conductive layer 81. The photoresist 18 used in the step of patterning the first conductive layer 81 is left without being peeled off, as shown in FIG.

Subsequently, as shown in FIG. 8D, a second anodic oxidation treatment for insulating and isolating the element is performed. Second
The anodic oxidation treatment is performed in a solution such as citric acid as shown in FIG.
The first conductive layer 81 is anodized by applying a positive voltage through the wiring section 82 shown in FIG. At this time, since the upper surface of the first conductive layer 15 is covered with the resist 18, the anodic oxidation proceeds from the side surface, and as shown in FIG. 8D, a side surface oxidized portion 19 is formed. The narrowest bottleneck 83 is completely oxidized.

As a result, as shown in FIG.
The intermediate electrode 88 of the M element part 84 and the first wiring electrode 87 of the wiring part 82 are insulated and separated by a bottleneck part 83 having an insulating property, that is, a side oxidized part 86. This second
In the anodic oxidation process step, the backup wiring portion 85 formed independently and separately from the first wiring electrode 87 is not supplied with electric current and remains on the metal surface without being anodized. At the stage where the first conductive layer 81 of the bottleneck portion 83 is completely oxidized, the second anodizing process for oxidizing the side surface of the MIM element portion 84 is stopped.

Thereafter, as shown in FIG. 8E, the resist 18 is peeled off. Next, the additional capacitance section 8 shown in FIG.
A third anodic oxidation step for forming No. 9 is performed. By applying a positive voltage in the citric acid solution through the first wiring electrode 87, only the upper part of the first wiring electrode 87 is anodized, and finally the upper surface oxidation sufficiently thicker than the insulating film of the MIM element. The part 20 is formed on the upper surface of the first conductive layer 15.

The additional capacitance section 89 shown in FIG. 9C also has the same MIM structure as the MIM element section 23 in structure.
As described above, when the insulating film is thin, a current flows and functions as a switching element rather than an additional capacitance. Therefore, it is important to suppress the leak current by the third anodizing process.

Finally, as shown in FIG. 8F, a second conductive layer 17 made of a transparent electrode film such as ITO is formed on the entire surface, and the second conductive layer 17 is patterned by using a photo-etching technique. .

The planar pattern shape of the second conductive layer 17 is
As shown in FIG. 9C, a second wiring electrode 92 made of a transparent conductive film such as ITO and a pixel electrode 93 are provided, and the second wiring electrode 92 and the intermediate electrode 88 sandwich an insulating layer. Thus, the first MIM element 90 is formed, and the pixel electrode 93 and the intermediate electrode 88 are connected to the second MIM element 90 with an insulating layer interposed therebetween.
The element 91 is configured to realize a back-to-back structure as a whole.

Further, since the second wiring electrode 92 is formed independently of the first wiring electrode 87, it is connected to the upper surface of the backup wiring portion 85 which is not anodized. Although not necessary, the backup wiring section 85 can reduce the wiring resistance and reduce the probability of disconnection defects.

Further, the pixel electrode 93 is patterned so as to overlap the first wiring electrode 87 via the insulating film formed in the first anodic oxidation step and the third anodic oxidation step. Is formed.

As described above, in the present invention in which a bottleneck portion is provided between the wiring portion and the MIM element portion, and the conductive layer in the bottleneck portion is completely oxidized to be insulated, the present invention provides a structure in which Can be insulated and separated. In addition, independent anodic oxidation of the wiring portion is possible, and an additional capacitance can be formed in the wiring portion. Further, the structure of the active matrix of the MIM element in which the additional capacitance section is formed can be realized with two photomasks.

[0068]

According to the present invention, the back-to-back structure of the MIM element using the anodic oxidation method, which has been difficult in the past, can be achieved by a very simple method of a patterning step using two photomasks. As a result, a switching element for an active matrix having a current-voltage characteristic symmetrical to a voltage threshold higher than that of the related art can be realized. As a result, the contrast and the viewing angle are improved, and problems such as flicker and image sticking are reduced.

Furthermore, the MI having the additional capacitance section
An M element active matrix can also be realized by a patterning process using two photomasks. As a result,
Sufficient characteristics can be obtained even in applications such as fine pattern pixels where the charge retention characteristics of liquid crystal pixels are insufficient.

[Brief description of the drawings]

FIG. 1 is a plan view showing a structure of a MIM element and a method of manufacturing the MIM element according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a manufacturing step in a conventional typical MIM element manufacturing method in the order of steps.

FIG. 3 is a plan view showing a structure of a conventional typical MIM element and a manufacturing method thereof.

FIG. 4 is a graph showing current-voltage characteristics of a typical MIM element.

FIG. 5 is an equivalent circuit diagram showing a single MIM element and a MIM element having a back-to-back structure.

FIG. 6 is a cross-sectional view illustrating a method of manufacturing the MIM element according to the first embodiment of the present invention in the order of manufacturing steps.

FIG. 7 is an equivalent circuit diagram showing a pixel configuration used in an embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a manufacturing process in a second embodiment of the MIM element manufacturing method of the present invention in the order of steps.

FIG. 9 is a plan view showing the structure of a MIM element and a method of manufacturing the MIM element according to a second embodiment of the present invention in the order of manufacturing steps.

[Explanation of symbols]

 Reference Signs List 15 first conductive layer 16 insulating layer 17 second conductive layer 21 wiring section 22 bottleneck section 23 MIM element section

Claims (5)

(57) [Claims] An M layer comprising a first conductive layer, an insulating layer formed by anodizing the first conductive layer, and a second conductive layer.
In the IM device, the pattern shape of the first conductive layer may be a wiring portion, an MIM
An MIM element comprising: an element portion; and a bottleneck portion provided between the wiring portion and the MIM device portion, wherein the bottleneck portion is left insulated by oxidation. 2. The MIM element according to claim 1, wherein MIM elements are connected to the MIM element section in a back-to-back manner. 3. The semiconductor device according to claim 1, wherein at least a part of said wiring portion and said M
The MIM element according to claim 1 or 2, wherein the IM element and the bottleneck are insulated by oxidation and have no exposed portion of the conductive layer. 4. An M layer comprising a first conductive layer, an insulating layer formed by anodizing the first conductive layer, and a second conductive layer.
In the method for manufacturing an IM device, the pattern shape of the first conductive layer may be a wiring portion, an MIM
An element portion, and a bottleneck portion provided between the wiring portion and the MIM device portion. The first conductive layer of the bottleneck portion is sufficiently oxidized to insulate the wiring portion and the MIM device portion. A method for manufacturing an MIM element, comprising a step of separating. 5. A method according to claim, characterized in that had additional capacity by forming a part overlapping configuration of the upper to the pixel electrode of the are anodized part of anodized said first conductive layer
The MIM element according to claim 1 or claim 2 or claim 3 .