JPH06275776A - Capacitor - Google Patents

Abstract

PURPOSE:To provide a capacitor wherein a Ta2O5 film is used as a capacitor insulating film which can reduce deterioration of leak current characteristics of the capacitor in comparison with a conventional one when thermal treatment is performed after completion of the capacitor. CONSTITUTION:In the title device, a silicon oxide film 13 is provided on a silicon substrate 11, an electrode 15a comprised of polysilicon which is doped with phosphorus is provided on the silicon oxide film 13 as a lower electrode, a lamination 33 wherein a silicon oxide film 21 and a tantalum oxide film 19 are laminated on the lower electrode 15a one by one from the side of the lower electrode 15a as a capacitor insulating film and an electrode 35 comprised of tungsten nitride is provided on the tantalum oxide film 19 as an upper electrode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor suitable as a capacitor for a semiconductor device, for example.

[0002]

2. Description of the Related Art With the high integration of LSIs, it has become necessary to miniaturize the capacitors built in the LSIs while maintaining the required capacitance. However, a silicon oxide film (SiO 2) that has been conventionally used as an insulating film for capacitors is used.
_{In the case of two} films), a silicon nitride film (SiN film), or a laminated film thereof, there is a limit in reducing the film thickness to secure a necessary capacity. Therefore, in recent years, research on a capacitor using a tantalum oxide (Ta ₂ O ₅ ) film as an insulating film for a capacitor has been activated. This is because the tantalum oxide film, the dielectric constant has several times the 22 and SiO ₂ film, and the withstand voltage was also because has advantages such higher SiO ₂ film.

A conventional capacitor using a tantalum oxide film and a method for manufacturing the same are described in, for example, Document I (IEDM Tech. Digest).
g.), (1991), pp. 827-830). The capacitor disclosed in Document I and the manufacturing method thereof will be described below according to the manufacturing procedure. 8 and 9 are diagrams used for the description. All are shown by the cross-sectional view of the sample. However, although an example of obtaining a cylindrical stacked capacitor is described in Document I, the technique of Document I is referred to as a stack type capacitor in the following description in the sense that it is sufficient to explain the principle of the technique disclosed in Document I. An example applied to formation of a capacitor is shown. Further, FIGS. 8 and 9 show an example in which two stacked capacitors are formed on a silicon substrate.

First, the SiO ₂ film 13 is formed on the silicon substrate 11 by the thermal oxidation method or the chemical vapor deposition method. Then, a polysilicon film 15 is formed on the SiO ₂ film 13 by a CVD method as a thin film for forming one electrode (hereinafter, also referred to as a lower electrode) of the capacitor electrode (see FIG. 8A. )).

Next, in order to reduce the electric resistance of the polysilicon film 15, phosphorus (P) is added to the polysilicon film 15.
Are introduced by an ion implantation method or by a method of thermally diffusing phosphorus by placing this sample in a POCl ₃ gas atmosphere. However, in the figure, the polysilicon film into which phosphorus is introduced is also shown as the polysilicon film 15 as it is. Next, a resist pattern (not shown) that serves as a mask when patterning the polysilicon film 15 into the shape of the lower electrode is formed on the polysilicon film 15. Then, an unnecessary portion of the polysilicon film 15 is etched by using this resist pattern as a mask to form an electrode 15a made of polysilicon as a lower electrode (FIG. 8B).

Next, this sample was subjected to instantaneous heat treatment (RTA: Ra).
Heat treatment is performed for 1 minute in an ammonia gas atmosphere using a pid thermal annealing device. As a result, the silicon nitride film 17 having a thickness of about 1.5 nm is formed on the surface of the electrode 15a made of polysilicon (FIG. 8C).

Next, a substrate temperature of 45 is applied to the entire surface of this sample.
At 0 ° C., pentaethoxy tantalum [T
a (OC ₂ H ₅ ) ₅ ] and C using oxygen (O ₂ ) gas
The Ta ₂ O ₅ film 19 is formed by the VD method (FIG. 9).
(A)).

After the Ta ₂ O ₅ film 19 is formed, the sample is subjected to a heat treatment for densifying the film and reducing the defect density. This heat treatment is performed for 1 minute at a temperature of 700 to 900 ° C. in an O ₂ atmosphere using an RTA apparatus. In this heat treatment, the portion of the electrode 15a made of polysilicon on the Ta ₂ O ₅ film 19 side is oxidized, so that the silicon oxide film 21 is formed in this portion (FIG. 9B). However, since the silicon nitride film 17 was previously provided on the surface of the electrode 15a made of polysilicon, Ta ₂ O for the electrode 15a made of polysilicon was formed.
_Since the effect of oxygen from the side of the _5th film 19 is reduced as compared with the case where both 15a and 15a are in direct contact, it is possible to prevent the thickness of the silicon oxide film 21 from increasing. Therefore, the decrease in the capacitance of the capacitor can be suppressed to a small level.

Next, a titanium nitride (TiN) film (not shown) is formed on this sample as a thin film for forming the other electrode of the capacitor electrode (hereinafter, also referred to as upper electrode) by the reactive sputtering method or It is formed by the CVD method. Next, a resist pattern (not shown) that serves as a mask when patterning the TiN film into the shape of the upper electrode is formed on the TiN film. Then, using this resist pattern as a mask, unnecessary portions of the TiN film are etched,
The upper electrode 23 made of an N film is formed. As a result, the silicon oxide film 21, the silicon nitride film 17 and the Ta ₂ O ₅ film are formed.
A laminated body 25 composed of a plurality of insulating films of the film 19 is used as a capacitor insulating film, and the laminated body 25 is composed of a lower electrode 15a made of polysilicon and an upper electrode 2 made of TiN.
A capacitor 27 having a structure sandwiched by 3 is obtained (FIG. 9).
(C)).

Further, in this document I, the Ta ₂ O ₅ film 19 is used.
When the capacitor electrode in contact with the capacitor is made of a tungsten (W) film which has been often used conventionally, and when it is made of a TiN film as described above, the results of investigating the leak current generation state in each capacitor are disclosed. There is. More specifically, a respective capacitor when configured in the case and TiN film constituting the capacitor electrode in contact with the Ta ₂ O ₅ film 19 in the W film, its the Ta ₂ O ₅ film 19 in the manufacture of these capacitors O ₂ for purposes such as densification
Regarding the generation state of the leakage current for each of the capacitors when the heat treatment is performed in the gas atmosphere by the RTA apparatus and when the heat treatment is not performed, the two capacitor electrodes 15a, 2
The results of the respective investigations are disclosed by using the biasing method between the three as a parameter. FIGS. 10A and 10B are characteristic diagrams showing this result. All are characteristic diagrams quoted from Document I. Here, FIG. 10A shows the voltage V _g (V) and the leak current density J (A / cm) when the voltage V _g is applied to the capacitor with the upper electrode 23 made of the TiN film or the W film being positive. ² ) Characteristic diagram showing the relationship with
FIG. 10B is a characteristic diagram when the lower electrode 15a made of polysilicon is positive. In both figures, the group with p is the characteristic when the heat treatment is performed on the Ta ₂ O ₅ film 19 in the O ₂ gas atmosphere by the RTA apparatus, and the group with q is the characteristic without the heat treatment. In addition, I is Ta ₂ O in each group of p and q.
₅ is a characteristic when the electrode in contact with the film 19 is made of a TiN film, and II is a characteristic when the electrode is made of a W film. In both figures, the vertical axis is actually a logarithmic scale, but the scale is not shown.

As is apparent from FIG. 10, it is understood that the leak current can be reduced when the Ta ₂ O ₅ film is annealed in the O ₂ gas atmosphere by the RTA apparatus as compared with the case where the heat treatment is not performed. Further, it can be seen that when the capacitor electrode in contact with the Ta ₂ O ₅ film 19 is made of a TiN film, the leak current can be reduced more than when it is made of a W film.

[0012]

However, Ta ₂
In the case where the capacitor electrode (the upper electrode 23 in the example of FIG. 9 (C)) in contact with the O ₅ film is formed of a TiN film, this heat treatment is performed when a high temperature (for example, 800 ° C. or higher) is applied to the completed capacitor. Even if the heat treatment is performed in an inert gas, the leak current characteristics are deteriorated (the leak current is increased) compared with before the heat treatment, which is revealed by the detailed study by the inventor of the present application. (See Comparative Examples and FIGS. 4 to 6 described later). The reason why such a phenomenon occurs is that the Ta ₂ O ₅ film and Ti
I think that it is because the N film reacts. Considering that various heat treatments (for example, heat treatment for densification of an intermediate insulating film formed after capacitor formation) are often performed even after capacitor formation in the manufacture of semiconductor devices, considering that Improvement of the phenomenon is desired.

The present invention has been made in view of the above points, and an object of the present invention is to provide a capacitor using a Ta ₂ O ₅ film as an insulating film for a capacitor.
It is an object of the present invention to provide a capacitor in which deterioration of leakage current characteristics of this capacitor when heat treatment is performed after completion of the capacitor is smaller than in the conventional case.

[0014]

In order to achieve this object, according to the present invention, a laminated body composed of a plurality of insulating films, at least one outermost layer of which is a tantalum oxide film. In a capacitor having a structure in which a laminated body is sandwiched between two electrodes, at least one of the two electrodes which is in contact with the tantalum oxide film is made of tungsten nitride.

In the present invention, the aforementioned laminated body composed of a plurality of insulating films means that one outermost layer, that is, the lowermost layer or the uppermost layer of the laminated body is composed of a tantalum oxide film and the remaining layers are silicon oxide. Not only a laminated body composed of one kind or two or more kinds of insulating films such as a film and a silicon nitride film, but also a tantalum oxide film as both the lowermost layer and the uppermost layer of the laminated body and an intermediate film other than the tantalum oxide film. The insulating film may be made of various materials, such as an insulating film, or an intermediate film containing a tantalum oxide film. However, when both the lowermost layer and the uppermost layer of the laminated body are made of tantalum oxide films, 2
Both electrodes will come into contact with tantalum oxide.
In this case, at least one of the two electrodes is made of tungsten nitride.

In implementing the present invention, when the present invention is applied to a semiconductor device, the above-mentioned capacitor, a semiconductor substrate, and a lower electrode directly or indirectly provided on the semiconductor substrate, A laminate comprising a plurality of insulating films provided on the lower electrode, the uppermost layer of which is a tantalum oxide film, and an upper electrode provided on the tantalum oxide film. It is preferable that the above-mentioned upper electrode is made of tungsten nitride as a capacitor. Incidentally, the semiconductor substrate referred to here is a semiconductor substrate itself such as a silicon substrate or a compound semiconductor substrate, a case where an epitaxial layer is provided on these substrates, a case where other elements are formed on these substrates, and the like. It refers to various semiconductor substrates in which capacitors are built.

Further, it is considered that the present invention can be applied to a capacitor having only a tantalum oxide film instead of the laminated body composed of a plurality of insulating films. However, in this case, both of the two electrodes are in contact with tantalum oxide. In this case, at least one of the two electrodes is made of tungsten nitride.

[0018]

According to the structure of the present invention, as will be apparent from the experimental results described below, the extent to which the leakage current increases when heat treatment is performed on the completed capacitor is the same as in the conventional case (the electrode in contact with the tantalum oxide film is It is less than the case of using a TiN film). The cause is not clear, but it is considered that tungsten nitride does not react with the tantalum oxide film.

[0019]

Embodiments of the capacitor of the present invention will be described below with reference to the drawings. However, the drawings used in the description merely show the dimensions, shapes, and positional relationships of the respective constituent components to the extent that the present invention can be understood. Further, in each of the drawings used for description, the same components as those in the related art are denoted by the same reference numerals.

1. Description of Structure and Method of Forming Capacitor of Embodiment FIG. 1 is a sectional view showing an example in which the present invention is applied to a stack capacitor. In this example, two capacitors 31 are shown.

The capacitor 31 of this embodiment is provided with a silicon oxide film 13 on a silicon substrate 11 as a semiconductor substrate, and on the silicon oxide film 13, a lower electrode 15a made of polysilicon and lean-doped. A silicon oxide film 21 and tantalum oxide (Ta ₂ O ₅ ) on the lower electrode 15a from the lower electrode 15a side.
A laminated body 33 in which the films 19 are laminated in this order is provided as an insulating film for capacitors, and an electrode 35 made of tungsten nitride (WN) is provided as an upper electrode on the tantalum oxide film 19. However, in the capacitor of this embodiment, the thickness of the tantalum oxide film 19 is about 11 nm. The film thickness of the stacked body 33 is 3.1 nm expressed by the silicon oxide film converted film thickness t _eff (the film thickness of the silicon oxide film 21 is about 1.3 nm). Further, the electrode 35 made of the tungsten nitride film is formed by the reactive sputtering method. Then, when forming the tungsten nitride for the upper electrode 35 by the reactive sputtering method, a plurality of samples are prepared by varying the flow rate ratio of the nitrogen gas used therein (for details, refer to the section of the forming method below). It should be understood that the silicon oxide film 13 is to electrically insulate the two capacitors and may be unnecessary depending on the design.

In the case of this embodiment, the capacitor described with reference to FIG. 1 was formed by the method described below. Figure 2
FIG. 3 is a process chart for the explanation. In each case, the state of the sample in the main steps is shown by a sectional view corresponding to FIG.

First, the SiO ₂ film 13 is formed on the silicon substrate 11 by the thermal oxidation method or the chemical vapor deposition method, and then polysilicon is formed as a thin film for forming the lower electrode 15a on the SiO ₂ film 13. The film 15 is formed by the CVD method (FIG. 2A).

Next, phosphorus (P) is added to the polysilicon film 15 in order to reduce the electric resistance of the polysilicon film 15.
Are introduced by an ion implantation method or by a method of thermally diffusing phosphorus by placing this sample in a POCl ₃ gas atmosphere. However, in the figure, the polysilicon film into which phosphorus is introduced is also shown as the polysilicon film 15 as it is. Next, a resist pattern (not shown) that serves as a mask when patterning this into the shape of the lower electrode is formed on the polysilicon film 15. Then, an unnecessary portion of the polysilicon film 15 is etched using this resist pattern as a mask to form an electrode 15a made of polysilicon as a lower electrode (FIG. 2B).

Next, on the entire surface of this sample, the substrate temperature was set to a predetermined temperature, and pentaethoxy tantalum [T
a (OC ₂ H ₅ ) ₅ ] and C using oxygen (O ₂ ) gas
The Ta ₂ O ₅ film 19 is formed by the VD method (FIG. 2).
(C)).

After the Ta ₂ O ₅ film 19 is formed, this sample is subjected to heat treatment in order to densify the film and reduce the defect density. This heat treatment is performed for 1 minute at a temperature of 800 ° C. in an O ₂ atmosphere using an RTA apparatus. In this heat treatment, Ta _{2 of the} electrode 15a made of polysilicon is
Since the portion on the O ₅ film 19 side is oxidized, the silicon oxide film 21 is formed in this portion (FIG. 3A).

Next, a tungsten nitride (WN) film (not shown) is formed on this sample as a thin film for forming the upper electrode which is the other electrode of the capacitor electrode by the reactive sputtering method. In the case of this embodiment, a flow rate ratio of argon (Ar) and nitrogen (N ₂ ) (N ₂ / (N ₂ + A
r)) is different from 0, 10, 20 and 30% to prepare a plurality of samples having WN films having different nitrogen compositions.
However, the pressure in the film formation chamber during film formation was 5 mTorr.
In addition, the DC power is set to 2 kW. When an X-ray diffraction analysis was performed on the tungsten film formed by the reactive sputtering method using such N ₂ gas, the (111) plane and (200) plane of W ₂ N and (2
The peaks on the 20) plane were detected. From this, it can be said that the tungsten (WN) film formed by the reactive sputtering method using N ₂ gas is tungsten nitride.

Next, a resist pattern (not shown) is formed on the WN film as a mask when patterning the WN film into the shape of the upper electrode. Then, using this resist pattern as a mask, unnecessary portions of the WN film are etched to form an electrode 23 made of the WN film (FIG. 3).
(B)). As a result, the capacitor shown in FIG. 1 is obtained.

2. Description of Comparative Example On the silicon substrate 11, the same procedure and conditions as those of the example described with reference to FIGS.
The formation up to the laminated body 33 is performed. Next, an upper electrode composed of a TiN film was formed by a reactive sputtering method and a known fine processing technique, and a capacitor of a comparative example having the same structure as that of the example except that the upper electrode was composed of a TiN film. obtain. The TiN film in the comparative example is a reactive sputtering method, and the flow rate ratio of argon (Ar) and nitrogen (N ₂ ) (N ₂ / (N ₂ + Ar)) is set to 26%, and the TiN film is formed. The film forming chamber pressure is set to 5 mTorr and DC power is set to 2K.
It is formed by the reactive sputtering method with W.

3. Description of Results of Characteristic Comparison between Example and Comparative Example 3-1. Leakage current characteristics before heat treatment In the capacitor of the embodiment, the flow rate ratio (N ₂ / (N ₂ + Ar)) of argon and nitrogen at the time of forming the upper electrode 35 is set to 2
Before performing any heat treatment on each of the capacitor formed as 0% and the capacitor of the comparative example formed by the procedure of the above item 2, a state in which the upper electrode is positive between the upper electrode and the lower electrode, The voltage V _g is applied in each state in which the side electrode is positive, and the leak current with respect to changes in the applied voltage V _g is measured. Figure 4 shows this measurement result on the horizontal axis as V
_g (V) is taken and the vertical axis shows the leakage current density J (A / cm ² ).
It is shown by taking. In FIG. 4, the group with a is the characteristic in which the voltage V _g is applied with the upper electrode 35 side being positive, and the group with b is the lower electrode 15a.
The characteristic is that the voltage V _g is applied with the side being positive. further,
In the group a of FIG. 4, the characteristic marked with Ia is that of the capacitor of the example, the characteristic marked with IIa is that of the capacitor of the comparative example, and in the group b of FIG. The above characteristics are those of the capacitor of the example, and the characteristics with IIb are those of the capacitor of the comparative example.

As is apparent from FIG. 4, it can be said that the capacitors of Examples and Comparative Examples exhibit substantially the same leakage current characteristics after the capacitor is completed and before any heat treatment is applied thereto.

3-2. Leakage current characteristics after heat treatment Next, the capacitors of the example and the comparative example, which obtained the characteristics of FIG. 4, are placed in a diffusion furnace in a nitrogen atmosphere having a temperature of 800 ° C. for 30 minutes for heat treatment. afterwards,
The leak current with respect to the change of the applied voltage V _g is measured by the same procedure as the above-mentioned item 3-1. FIG. 5 shows the measurement results in FIG.
It is a characteristic view shown by the notation method substantially similar to. However, in the group a of FIG. 5, the characteristics with Iax in FIG. 4 are those of the capacitor of the example, the characteristics with IIax are those of the capacitor of the comparative example, and
In group b of FIG. 5, the characteristic marked with Ibx is that of the capacitor of the example, and the characteristic marked with IIbx is that of the capacitor of the comparative example. Further, each characteristic shown in FIGS. 4 and 5 is collectively shown in FIG.

As can be seen from FIGS. 4 to 6, the capacitor of the example in which the upper electrode is made of tungsten nitride is heat-treated after completion of the capacitor as compared with the capacitor of the comparative example in which the upper electrode is made of a TiN film. It can be seen that the deterioration of the leakage current characteristic of this capacitor when performed is small.

4. Regarding the Relationship between the Composition of the Tungsten Nitride Film and the Leakage Current Characteristics Next, the relationship between the composition of the upper electrode 35 made of the tungsten nitride film and the degree of improvement of the leakage current characteristics will be described. However, since the composition of the upper electrode of the completed capacitor has not been analyzed, here, the nitrogen flow rate ratio (N ₂ / (N ₂ + Ar)), the relationship between the composition of the upper electrode 35 and the degree of improvement of the leakage current characteristic is investigated. Specifically, regarding the leakage current characteristics of each capacitor formed by setting the above flow rate ratio of nitrogen to 0, 10, 20 and 30%, and after the heat treatment of the above section 3-2, the leakage current characteristics of the upper electrode as the positive electrode When the voltage V _g was applied and when the lower electrode was used as the positive electrode and the voltage V _g was applied, the results were obtained, and the relationship between the composition of the upper electrode 35 and the degree of improvement of the leakage current property was examined from these characteristics. FIG. 7 is a characteristic diagram showing the results organized. That is, 1 μA / c in each capacitor formed with the above flow rate ratio of nitrogen of 0, 10, 20 and 30%.
The absolute value | V _B | (unit: Volt) of the voltage applied between the upper and lower electrodes when a leak current of m ² flows is plotted on the vertical axis, and the flow rate ratio (%) of nitrogen is plotted on the horizontal axis. FIG. However, in FIG. 7, a is the upper electrode 35.
The characteristic is obtained when a voltage V _g is applied between the upper and lower electrodes with the side being the positive electrode, and the characteristic b is obtained when the lower electrode 15a side is used as the positive electrode. In FIG. 7, a larger | V _B | means that the capacitor is less likely to cause a leak current.

As is apparent from FIG. 7, the flow rate ratio of nitrogen during reactive sputtering is the same when the voltage V _g is applied between the upper and lower electrodes with the upper electrode 35 side as the positive electrode and vice versa. It can be seen that when the value is increased, the deterioration of the leak current characteristic when the heat treatment is performed on the completed capacitor is reduced. In particular, when the lower electrode 15a is used as a positive electrode and the voltage V _g is applied between the upper and lower electrodes, it can be seen that the leakage current characteristic is significantly improved as compared with the reverse bias. Further, regardless of the polarity of V _g , the nitrogen flow rate ratio in the reactive sputtering for forming the tungsten nitride film is 20%.
It can be seen that the leakage current improving effect saturates as the amount increases.

Although the embodiment of the capacitor of the present invention has been described above, the present invention is not limited to the above embodiment.

For example, in the above embodiment, the stack capacitor formed on the silicon substrate has the capacitor insulating film from the substrate side to the silicon oxide film 21 and Ta ₂ O ₅ film.
The present invention has been applied to the stack capacitor composed of the film 19. However, the structure of the capacitor and the structure of the capacitor insulating film to which the present invention can be applied are not limited to this. For example, the present invention can be applied to other types of capacitors such as a trench type, and the capacitor insulating film is composed of, for example, a laminated body of a silicon oxide film, a silicon nitride film and a Ta ₂ O ₅ film (see FIG. 9C). It is also applicable to Further, the lower electrode is not limited to the polysilicon film and can be changed according to the design.

Further, although the tungsten nitride film is formed by the reactive sputtering method in the above-mentioned embodiments, it is considered that the same effect can be expected by other methods such as the CVD method and the MBE method in a nitrogen atmosphere. . Further, although the tantalum oxide film is formed by the CVD method in the embodiment,
This film formation is not limited to this method either. For example, the sputtering may be performed in a O ₂ atmosphere using a Ta target.

[0039]

As is apparent from the above description, according to the present invention, the electrode in contact with the tantalum oxide film in the capacitor using tantalum oxide as the capacitor insulating film is made of tungsten nitride. Ti
As compared with the case where the N film is used, the deterioration of the leak current characteristics when the heat treatment is performed after the capacitor is completed can be reduced. Therefore, a capacitor using tantalum oxide as an insulating film for a capacitor, which is superior in heat resistance to the conventional one, can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view provided for explaining a capacitor of an example.

FIG. 2 is a process chart for explaining an example of a method for forming a capacitor according to an example.

FIG. 3 is a process diagram following FIG. 2 for explaining an example of a method for forming a capacitor according to an example.

FIG. 4 is a diagram showing a leak current characteristic before heat treatment of each capacitor of Examples and Comparative Examples.

FIG. 5 is a diagram showing leakage current characteristics after heat treatment of each capacitor of Examples and Comparative Examples.

FIG. 6 is a diagram for explaining changes in leakage current characteristics before and after heat treatment of each capacitor of the example and the comparative example.

FIG. 7 is a diagram which is used for explaining an example, showing the flow rate ratio of nitrogen (N ₂ ) and the effect of improving the leakage current characteristic of a capacitor when forming tungsten nitride for forming an upper electrode by a reactive sputtering method. It is a characteristic view showing the relationship.

FIG. 8 is a process diagram for explaining a conventional capacitor and a method for forming the same.

FIG. 9 is a process diagram following FIG. 8 for explaining a conventional capacitor and a method for forming the same.

FIG. 10 is a diagram for explaining a conventional technique.

[Explanation of symbols]

11: Semiconductor Substrate (Silicon Substrate) 13: Silicon Oxide Film 15a: Lower Electrode (Electrode Made of Polysilicon) 19: Tantalum Oxide Film 21: Silicon Oxide Film 31: Capacitor of Example 33: Laminate (Insulation for Capacitor) Membrane) 35: Upper electrode (electrode composed of tungsten nitride)

Claims (3)

[Claims] 1. A capacitor having a structure in which two electrodes sandwich a laminate composed of a plurality of insulating films, and at least one outermost layer of which is a tantalum oxide film, A capacitor, wherein at least the electrode on the side in contact with the tantalum oxide film is made of tungsten nitride. 2. The capacitor according to claim 1, wherein the capacitor includes a semiconductor substrate, a lower electrode directly or indirectly provided on the semiconductor substrate, and a plurality of capacitors provided on the lower electrode. A capacitor comprising a laminated body formed of an insulating film, the uppermost layer of which is a tantalum oxide film, and an upper electrode provided on the tantalum oxide film, wherein the upper electrode is tungsten nitride. A capacitor characterized by being composed of. 3. The capacitor according to claim 1, wherein only a tantalum oxide film is provided in place of the laminated body composed of a plurality of insulating films (however, in this case, 2 At least one of the two electrodes is composed of tungsten nitride).