JP2002110931A - Ferrodielectric memory device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent hydrogen from infiltrating the capacitor part of a ferrodielectric memory device and causing malfunctions due to deterioration of the capacitor by hydrogen. SOLUTION: The ferrodielectric memory device is constituted by forming on a silicon substrate 11 a device isolating oxide film 12, interlayer insulating film 14 having a contact plug 13, ferrodielectric capacitor 15 which includes a lower electrode 15a and a capacitor insulating film 15b made of a ferrodielectric material and an upper electrode 15c, conductive hydrogen barrier film 16, interlayer insulating film 22 having a contact hole 23, and wiring layer 17 formed in the contact hole 23. The conductive hydrogen barrier film 16 is formed of a TiAl alloy or TiAl nitride or a partially oxidized material of these materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferroelectric memory device having a ferroelectric capacitor.

[0002]

2. Description of the Related Art In recent years, semiconductor devices such as Sr
Bi ₂ Ta ₂ O ₉ (hereinafter referred to as SBT) or Pb (Zr,
A ferroelectric memory which is a nonvolatile memory using a ferroelectric material having a hysteresis characteristic such as Ti) O ₃ (hereinafter referred to as PZT) for a capacitance insulating film has been developed.

Hereinafter, a conventional ferroelectric memory device will be described with reference to the drawings.

FIG. 7 is a sectional view showing the structure of a conventional ferroelectric memory device.

As shown in FIG. 7, a transistor 2 is formed on a semiconductor substrate 1 made of silicon, and an interlayer insulating film 3 deposited on the semiconductor substrate 1 has a lower electrode 4a made of a conductive thin film. A ferroelectric capacitor 4 having a capacitor insulating film 4b made of a ferroelectric thin film and an upper electrode 4c made of a conductive thin film is formed.

A first contact hole 5 for exposing the upper surface of semiconductor substrate 1 located between transistor 2 and ferroelectric capacitor 4 and an upper electrode 4c are formed in interlayer insulating film 3.
A second contact hole 6 exposing the upper surface of the semiconductor device 1 is formed, and a wiring layer made of a conductive film electrically connecting the semiconductor substrate 1 and the upper electrode 4c to the first contact hole 5 and the second contact hole 6 is formed. 7 are formed. A surface protection film 8 is formed over the entire surface of the interlayer insulating film 3 and the wiring layer 7.

[0007]

However, since ferroelectrics such as SBT and PZT used in such a ferroelectric memory device are oxides, they are ferroelectric when exposed to a reducing atmosphere, particularly hydrogen. It is known that the reduction of the body oxide causes the crystal composition to collapse, and the insulating properties and ferroelectric properties to be greatly degraded.

In particular, in recent years, the miniaturization of ferroelectric memory devices has been accompanied by the miniaturization of ferroelectric capacitors, so that the influence of hydrogen has further increased.

However, the atmosphere containing hydrogen is an LSI.
And so on in the manufacturing process of semiconductor devices. For example, after the Al wiring is formed, annealing is performed in an atmosphere containing hydrogen to secure the characteristics of the MOS transistor. Further, with the miniaturization of semiconductor devices, a CVD method is used for embedding W (tungsten) in a contact hole having a large aspect ratio, which is performed in a very strong reducing atmosphere containing hydrogen.

In the present invention, in consideration of the above, in order to prevent hydrogen from penetrating into the capacitor insulating film made of the ferroelectric material of the ferroelectric capacitor portion even in a hydrogen reducing atmosphere at the time of manufacturing the ferroelectric memory device. Accordingly, an object of the present invention is to provide a highly integrated ferroelectric memory device capable of preventing deterioration of a capacitance insulating film due to a reducing atmosphere.

[0011]

According to a first aspect of the present invention, there is provided a ferroelectric memory device comprising a lower electrode on a substrate and a ferroelectric material formed on the lower electrode. Forming a ferroelectric capacitor having a capacitance insulating film made of a material and an upper electrode formed on the capacitance insulating film, and on the upper electrode, or on the upper electrode and the side surfaces of the upper electrode and the capacitance insulating film Is covered with a film made of a TiAl alloy or a nitride of a TiAl alloy having a conductive hydrogen barrier property. Further, in the ferroelectric memory device according to claim 2 of the present invention, in the ferroelectric memory device according to claim 1, the film having the conductive hydrogen barrier property is made of TiAl alloy or TAl.
The film is characterized by being a film obtained by oxidizing a part of the nitride of the iAl alloy.

These TiAl-based materials are characterized by forming a structure composed of two types of phases (substances), making it difficult to form grain boundaries serving as paths for hydrogen gas, easily absorbing a large amount of hydrogen, and Temperature of releasing absorbed hydrogen is 600 ℃
Is an alloy of Ti and Al covalently bonded to hydrogen, so that a large amount of hydrogen can be occluded more stably.

Furthermore, when a TiAl alloy or its nitride is oxidized, a dense Al ₂ O ₃ phase is formed on the surface.
₂ O ₃ is well known as a material having a barrier property against hydrogen. Therefore, when the TiAl-based material is used as the hydrogen barrier film, even if the TiAl-based material is exposed to a hydrogen reducing atmosphere in the ferroelectric memory device manufacturing process, the TiAl-based material allows hydrogen to form a capacitive insulating film made of a ferroelectric material. Since the permeation can be prevented, deterioration of the characteristics of the ferroelectric capacitor in a hydrogen reducing atmosphere can be avoided.
In addition, since the TiAl-based material has conductivity, it is not necessary to provide an opening for an electrode outlet. Therefore, it is necessary to sufficiently protect the capacitor insulating film and at the same time make good contact with a wiring layer for drawing. Can be.

According to a third aspect of the present invention, there is provided a ferroelectric memory device having a lower electrode, a capacitor insulating film made of a ferroelectric material formed on the lower electrode, and a capacitor insulating film formed on the capacitor insulating film. And a ferroelectric capacitor having an upper electrode formed thereon, and the ferroelectric capacitor is covered with an amorphous structure Si film or SiC film having an insulating hydrogen barrier property.

As described above, the hydrogen barrier film is made of Si
When an amorphous structure film is used, since there is no grain boundary or the like which serves as a hydrogen gas path unlike a crystallized film, sufficient hydrogen gas barrier properties can be obtained, and amorphous silicon
Since dangling bonds of Si in the inside are easily bonded to hydrogen, it also has a hydrogen absorbing property. Furthermore, in amorphous SiC, C and C
And the bond energy between C and H is Si and H
, It is possible to more stably store hydrogen. Therefore, when Si or SiC having the amorphous structure is used as the hydrogen barrier film, even if the amorphous silicon or SiC is exposed to a hydrogen reducing atmosphere in the ferroelectric memory device manufacturing process, hydrogen is used as the capacitive insulating film made of a ferroelectric material due to the material. Therefore, it is possible to avoid deterioration of the characteristics of the ferroelectric capacitor in a hydrogen reducing atmosphere.

According to a fourth aspect of the present invention, there is provided a ferroelectric memory device, wherein a lower electrode, a capacitor insulating film made of a ferroelectric material formed on the lower electrode, and the capacitor insulating film are formed on the substrate. A ferroelectric capacitor having an upper electrode and a hydrogen barrier film formed so as to cover the ferroelectric capacitor and block the transmission of hydrogen has a laminated structure of a hydrogen diffusion reducing material and a hydrogen storage material. It is characterized by having.

In this configuration, it is possible to prevent hydrogen from penetrating into the capacitor insulating film made of a ferroelectric material by two mechanisms of a hydrogen diffusion reducing effect and a hydrogen absorbing effect. Deterioration of the characteristics of the capacitor can be avoided.

According to a fifth aspect of the present invention, in the ferroelectric memory device according to the fourth aspect, the hydrogen diffusion reducing material is made of SiON or Si ₃ N _4. Things. The ferroelectric memory device according to claim 6 of the present invention is the ferroelectric memory device according to claim 4, wherein the constituent element of the hydrogen storage material is Ti, Ta, V, Y, Zr, Nb or Hf. Characterized by comprising a material containing:

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

(Embodiment 1) FIG. 1 is a side sectional view of a ferroelectric memory device according to a first embodiment of the present invention.
As shown in FIG. 1, in this ferroelectric memory device, an element isolation oxide film 12, an interlayer insulating film 14 having a contact plug 13 on a silicon substrate 11, a lower electrode 15a and a capacitive insulating film made of a ferroelectric material. 15b and upper electrode 15c
Ferroelectric capacitor 15 and hydrogen barrier film 16 having
And the wiring layer 17 are formed in order, and the upper electrode 15c and the side surfaces of the upper electrode 15c and the capacitor insulating film 15b are formed of Ti.
It is covered with an Al-based hydrogen barrier film 16. A gate electrode 20 is formed on gate oxide film 19 between impurity diffusion regions 18 of silicon substrate 11.

Next, a method of manufacturing the ferroelectric memory device according to the first embodiment configured as described above will be described with reference to FIG.

First, as shown in FIG.
Between the impurity diffusion regions 18 on the silicon substrate 11 by the OS process (separated from the element isolation oxide film 12)
A transistor portion is formed by forming a gate electrode 20 on a gate oxide film 19 formed on the substrate. After that, a first interlayer insulating film 14 of a BPSG layer is formed,
As shown in FIG. 2A, a contact hole is formed by etching. 10 nm of Ti by sputtering and TiN by CVD on the side and bottom of the contact hole
Is deposited to a thickness of 10 nm, W is buried in the contact hole by the CVD method, and etched back by the CMP to form the contact plug 13.

Next, as shown in FIG.
5a is made of 40 nm TiN, 10
0 nm Ir, 100 nm IrO ₂ , 50 nm Pt
Are sequentially formed, and the lower electrode 15a is processed by etching. Then, an NSG film having a thickness of 500 nm is formed as the second interlayer insulating film 21 by the CVD method, and the upper surface of the lower electrode 15a and the upper surface of the second interlayer insulating film 21 are planarized by CMP.

Next, as shown in FIG.
A capacitance insulating film 15b made of a ferroelectric material such as an SBT film is formed on the Pt of 5a by spin coating to a thickness of 100 nm.
A 100 nm Pt film to be the upper electrode 15c is formed thereon by a sputtering method. Then, etching is performed so that the capacitance insulating film 15b and the upper electrode 15c remain larger than the area of the upper surface of the lower electrode 15a as shown in FIG.

Subsequently, a conductive hydrogen barrier film 16 is formed, and etching is performed so as to cover the upper surface of the upper electrode 15c and the side surfaces of the upper electrode 15c and the capacitor insulating film 15b. Here, as the hydrogen barrier film 16, a TiAl alloy or a nitride thereof formed by a sputtering method, or a film obtained by oxidizing a part of these materials, for example, a TiAl alloy or a nitride thereof is subjected to RTA treatment in oxygen. Is used, and the thickness of the hydrogen barrier film 16 is set to 100 nm.

Thereafter, as shown in FIG. 2D, N ₃ is formed on the entire surface by a non-reducing CVD method using O ₃ and TEOS (tetraethoxysilane) as the third interlayer insulating film 22.
After forming the SG film, a contact hole 23 is formed in the third interlayer insulating film 22 on the upper electrode 15c. Then, by depositing an Al alloy or the like and processing it into a predetermined shape, a wiring layer 17 connected to the upper electrode 15c via the contact hole 23 is formed, and a protective film is formed on the wiring layer 17. .

In the above embodiment, the upper electrode 15
c and the side surfaces of the upper electrode 15c and the capacitive insulating film 15b made of a ferroelectric material have a hydrogen barrier property.
Since the lower electrode 15a is covered with a TiN film having a hydrogen barrier property also at the lowermost layer, most of the ferroelectric capacitor 15 except for a part of the lower surface is covered with a film having a hydrogen barrier property. Will be Therefore, even in a process under a hydrogen reducing atmosphere after the formation of the ferroelectric capacitor, the capacitance insulating film 15b made of an oxide ferroelectric material can be used.
Since most of the hydrogen diffusing into the capacitor insulating film 15b can be prevented, the characteristics of the ferroelectric material forming the capacitive insulating film 15b are not deteriorated by the reduction. Therefore, a ferroelectric memory device having high reliability can be obtained, and a high yield can be realized.

In this embodiment, the lower electrode 15
If a TiAl alloy or its nitride is used instead of TiN in the lowermost layer of a, the effect can be further enhanced.

(Embodiment 2) FIG. 3 is a side sectional view of a ferroelectric memory device according to a second embodiment of the present invention.
In this ferroelectric memory device, an element isolation oxide film 32, an interlayer insulating film 34 having a contact plug 33, a first conductive hydrogen barrier film 35, a lower electrode 36a, and a ferroelectric material are formed on a silicon substrate 31. A ferroelectric capacitor 36 having a capacitive insulating film 36b and an upper electrode 36c;
Conductive hydrogen barrier film 37, insulating hydrogen barrier film 3
8 and the wiring layer 39 are formed in this order, and the peripheral portion of the ferroelectric capacitor 36 is covered with the hydrogen barrier film without any gap. Further, a gate electrode 42 is formed on the gate oxide film 41 between the impurity diffusion regions 40 of the silicon substrate 31.

Next, a method of manufacturing the ferroelectric memory device according to the second embodiment configured as described above will be described with reference to FIG.

First, as shown in FIG.
Between the impurity diffusion regions 40 on the silicon substrate 31 by the OS process (separated from the element isolation oxide film 32)
A transistor portion is formed by forming a gate electrode 42 on the gate oxide film 41 of FIG.

Thereafter, a first interlayer insulating film 34 of a BPSG layer is formed, and as shown in FIG. 4A, a contact hole is formed by etching. 10n of Ti on the side and bottom of contact hole by sputtering
After depositing 10 nm of TiN by the CVD method,
W is buried in the contact hole by a method and etched back by CMP to form a contact plug 33.

Next, as shown in FIG. 4B, the first conductive hydrogen barrier film 35 of Ti is formed by sputtering.
An Al alloy or a nitride thereof is formed to a thickness of 40 nm, and a lower electrode 36a serving as a lower electrode 36a of Ir of 100 nm or 100 nm
Of IrO ₂ and Pt of 50 nm are formed in this order. Next, on the Pt of the lower electrode 36a, a capacitive insulating film 36b made of a ferroelectric material such as an SBT film is formed to a thickness of 100 nm by spin coating, and Pt to become the upper electrode 36c is further formed thereon by sputtering. Deposit 100 nm. Then, as the conductive hydrogen barrier film 37, a TiAl alloy or a nitride of a TiAl alloy is formed to a thickness of 100 nm by a sputtering method, and the first conductive hydrogen barrier film 35,
The lower electrode 36a, the capacitor insulating film 36b, the upper electrode 36c, and the second conductive hydrogen barrier film 37 are etched as shown in FIG. Here, as the second conductive hydrogen barrier film 37, a film obtained by oxidizing a part of nitride of TiAl alloy or TiAl alloy, for example, TiAl alloy or Ti
A film obtained by oxidizing only the extreme surface of an Al alloy nitride by RTA treatment in oxygen may be used.

Subsequently, as shown in FIG. 4C, an insulating hydrogen barrier film 38 is formed, and etching is performed so as to cover the upper and side surfaces of the ferroelectric capacitor 36.
Here, as the insulating hydrogen barrier film 38, Si or SiC having an amorphous structure is used, and the thickness of the hydrogen barrier film is set to 200 nm. This amorphous structure Si
And SiC are generally formed by the CVD method.
Since hydrogen is generated at the time of film formation in the VD method, film formation of these materials is preferably performed by a sputtering method.

Thereafter, as shown in FIG. 4D, an NSG film is formed on the entire surface as a third interlayer insulating film 43 using a non-reducing CVD method using O ₃ and TEOS, and then the upper electrode 36c is formed. A contact hole 44 is formed in the insulating hydrogen barrier film 38 and the third interlayer insulating film 43 above. Then, by depositing an Al alloy or the like and processing it into a predetermined shape, a wiring layer 39 connected to the upper electrode 36c via the contact hole 44 is formed, and a protective film is formed on the wiring layer 39. .

In the above embodiment, the upper and lower surfaces of the ferroelectric capacitor 36 are covered with a conductive and hydrogen-barrier TiAl-based material film, and the upper and side surfaces of the ferroelectric capacitor are insulative and hydrogen-free. Since the ferroelectric capacitor 36 is covered with the hydrogen barrier film without gaps, it is covered with the amorphous Si or SiC film having a barrier property. Therefore, even in a process in a hydrogen reducing atmosphere after the formation of the ferroelectric capacitor, the capacitor insulating film 36 made of an oxide ferroelectric material can be used.
b to prevent the diffusion of hydrogen into the capacitor insulating film 36.
The characteristics of the ferroelectric material constituting b are not deteriorated by the reduction. Therefore, a ferroelectric memory device having high reliability can be obtained, and a high yield can be realized.

(Embodiment 3) FIG. 5 is a side sectional view of a ferroelectric memory device according to a third embodiment of the present invention.

In this ferroelectric memory device, an element isolation oxide film 52 and a contact plug 53 are formed on a silicon substrate 51.
Interlayer insulating film 54 having a thickness and first insulating hydrogen barrier film 5
5. First conductive hydrogen barrier film 56, lower electrode 57a, capacitive insulating film 57b made of ferroelectric material, and upper electrode 57
c, a second conductive hydrogen barrier film 58, a second insulating hydrogen barrier film 59, a third
The insulating hydrogen barrier film 60 and the wiring layer 61 are formed in this order, and the entire ferroelectric capacitor 57 is covered with the hydrogen barrier film. A gate electrode 64 is formed on the gate oxide film 63 between the impurity diffusion regions 62 of the silicon substrate 51.
Are formed.

Next, a method of manufacturing the ferroelectric capacitor according to the third embodiment configured as described above will be described with reference to FIG.

First, as shown in FIG.
Between the impurity diffusion regions 62 on the silicon substrate 51 by the OS process (separated from the element isolation oxide film 52)
A gate electrode 64 is formed on the gate oxide film 63 to form a transistor portion.

After that, the first interlayer insulating film 54 of the BPSG layer and the first insulating hydrogen barrier film 55 of S
i ₃ N ₄ or SiON is formed by a CVD method, and FIG.
A contact hole is formed by etching as shown in FIG. 10 nm of Ti by sputtering and 1 N of TiN by CVD on the side and bottom of the contact hole.
After depositing 0 nm, W is buried in the contact hole by the CVD method, and etched back by the CMP to form the contact plug 53.

Next, as shown in FIG. 6B, a first conductive hydrogen barrier film 56 of Ti
An Al alloy or a nitride thereof is formed to a thickness of 40 nm, and a lower electrode 57a serving as the lower electrode 57a is formed of Ir of 100 nm and Ir of 100 nm.
O ₂ and Pt of 50 nm are formed in this order. then,
A 100 nm thick insulating film 57b made of a ferroelectric material such as an SBT film is formed on the Pt of the lower electrode 57a by spin coating, and a 100 nm thick Pt to be the upper electrode 57c is formed thereon by sputtering. .
Then, a TiAl alloy or a nitride thereof is formed to a thickness of 100 nm by a sputtering method as the conductive hydrogen barrier film 58, and the first conductive hydrogen barrier film 56, the lower electrode 57a,
The capacitance insulating film 57b, the upper electrode 57c, and the second conductive hydrogen barrier film 58 are etched as shown in FIG. Here, as the second conductive hydrogen barrier film 58, a film obtained by oxidizing a part of a TiAl alloy or a nitride thereof,
For example, a film obtained by oxidizing only the outer surface of a TiAl alloy or a nitride thereof by RTA treatment in oxygen may be used.

Subsequently, as shown in FIG.
TiO ₂ , which is an insulating hydrogen barrier film 59, is formed to a thickness of 200 nm by a sputtering method.
Etching is performed so as to cover the upper surface and side surfaces of 7.

Thereafter, as shown in FIG. 6D, the third insulating hydrogen barrier film 60, ie, Si ₃ N ₄ or SiON, is formed on the entire surface of the substrate having the second insulating hydrogen barrier film 59 by the CVD method. After that, a contact hole 65 is formed in the second insulating hydrogen barrier film 59 and the third insulating hydrogen barrier film 60 so as to reach the upper electrode 57c. Then, an Al alloy or the like is deposited and processed into a predetermined shape to form a wiring layer 61 connected to the upper electrode 57c via the contact hole 65, and a protective film is formed on the wiring layer 61. .

In the third embodiment, the entire ferroelectric capacitor is made of TiAl-based material,
It has a configuration in which it is covered with an iO ₂ film and further covered with a film of Si ₃ N ₄ or SiON which is a hydrogen diffusion reducing material. Therefore, even in a process under a hydrogen reducing atmosphere after the formation of the ferroelectric capacitor, it is possible to completely prevent hydrogen from diffusing into the capacitor insulating film 57b made of an oxide ferroelectric material, thereby constituting the capacitor insulating film 57b. It is possible to prevent the characteristics of the ferroelectric material from being deteriorated by reduction. Therefore, a ferroelectric memory device having high reliability can be obtained, and a high yield can be realized.

In the third embodiment, TiO ₂ is used as the second insulating hydrogen barrier film 59. However, similar results can be obtained by using an oxide of a TiAl alloy instead.

Further, in the present embodiment, the first insulating hydrogen barrier film 55 and the third insulating hydrogen barrier film 6
Although Si ₃ N ₄ or SiON, which is 0, also functions as an interlayer insulating film, the ferroelectric capacitor 57 is formed by etching the first insulating hydrogen barrier film 55 and the third insulating hydrogen barrier film 60. CVD using O ₃ and TEOS as an interlayer insulating film on the entire surface
Similar effects can be obtained even if an NSG film is formed by the method.

In addition, in the third embodiment, hydrogen storage
TiAl-based materials and TiO _TwoConstituent elements such as
The material which contains Ti is used for this hydrogen storage material
Ta, V, Y, Zr or Nb as constituent elements
Similar results can be obtained by using a material containing the same.

[0049]

As described above, in the ferroelectric memory device of the present invention, it is possible to prevent the ferroelectric material, which is the oxide constituting the capacitive insulating film, from being deteriorated by hydrogen, and to maintain the ferroelectric material even after the process under a reducing atmosphere. Since good capacitance characteristics can be obtained, a ferroelectric memory device with high reliability and high yield can be realized. In addition, since a manufacturing process by the CVD method of W becomes possible after the formation of the ferroelectric capacitor, the cell area required for the capacitor portion can be reduced, and a contact portion having a high aspect ratio can be formed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a ferroelectric memory device according to a first embodiment of the present invention;

FIG. 2 is a process sectional view illustrating the method of manufacturing the ferroelectric memory device according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a ferroelectric memory device according to a second embodiment of the present invention;

FIG. 4 is a process cross-sectional view illustrating a method for manufacturing a ferroelectric memory device according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a ferroelectric memory device according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing a step of the method for manufacturing a ferroelectric memory device according to the third embodiment of the present invention.

FIG. 7 is a sectional view showing the configuration of a conventional ferroelectric memory device.

[Explanation of symbols]

 11, 31, 51 silicon substrate 12, 32, 52 device isolation oxide film 13, 33, 53 contact plug 14, 21, 22, 34, 43, 54 interlayer insulating film 15, 36, 57 ferroelectric capacitor 15a, 36a, 57a Lower electrode 15b, 36b, 57b Capacitance insulating film 15c, 36c, 57c Upper electrode 16, 35, 37, 56, 58 Conductive hydrogen barrier film 17, 39, 61 Wiring layer 18, 40, 62 Impurity diffusion region 19, 41, 63 Gate oxide film 20, 42, 64 Gate electrode 23, 44, 65 Contact hole 38, 55, 59, 60 Insulating hydrogen barrier film

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 21, 2001 (2001.8.2
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

According to a fourth aspect of the present invention, there is provided a ferroelectric memory device, wherein a lower electrode and a lower electrode are formed on a substrate.
Upper electrode formed on capacitive insulation made of ferroelectric material
Forming a ferroelectric capacitor having
Of TiAl alloy with hydrogen barrier properties
Characterized by being covered with an oxide film. this
In the structure, it consists of two types of phases (substances) of TiAl-based material.
A grain boundary is formed to serve as a path for hydrogen gas to form a microstructure.
It is difficult to use, and the oxide film of TiAl alloy
Al ₂ O ₃ phase is formed to improve hydrogen barrier properties.
Can be. Next, the ferroelectric memo of the invention according to claim 5 is described.
A ferroelectric capacitor having a lower electrode, a capacitor insulating film made of a ferroelectric formed on the lower electrode, and an upper electrode formed on the capacitor insulating film is formed on the substrate, The hydrogen barrier film formed so as to cover the ferroelectric capacitor and block the permeation of hydrogen has a laminated structure of a hydrogen diffusion reducing material and a hydrogen storage material.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

According to a sixth aspect of the present invention, in the ferroelectric memory device according to the fifth aspect , the hydrogen diffusion reducing material is made of SiON or Si ₃ N _4. It is. Claims of the present invention
7 ferroelectric memory device described, in the ferroelectric memory device according to claim 5, constituent elements of the hydrogen storage material, that a material containing Ti, Ta, V, Y, Zr, Nb, or Hf It is characterized by the following.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shinichiro Hayashi 1-1, Komachi, Takatsuki-shi, Osaka Matsushita Electronics Co., Ltd. F-term (reference) 5F083 FR02 GA09 GA25 JA14 JA15 JA33 JA36 JA38 JA39 JA40 JA56 MA06 MA17 NA08 PR22 PR34 PR40

Claims (6)

[Claims] 1. A ferroelectric capacitor having a lower electrode, a capacitor insulating film made of a ferroelectric material formed on the lower electrode, and an upper electrode formed on the capacitor insulating film is formed on a substrate. And, on the upper electrode, or, on the upper electrode and the side surface of the upper electrode and the capacitive insulating film,
TiAl alloy or TiAl having conductive hydrogen barrier properties
A ferroelectric memory device having a configuration in which the device is covered with a film made of an alloy nitride. 2. The film having a conductive hydrogen barrier property,
2. The ferroelectric memory device according to claim 1, wherein the ferroelectric memory device is a film obtained by oxidizing a part of a TiAl alloy or a nitride of the TiAl alloy. 3. A ferroelectric capacitor having a lower electrode, a capacitor insulating film made of a ferroelectric material formed on the lower electrode, and an upper electrode formed on the capacitor insulating film is formed on a substrate. Wherein the ferroelectric capacitor is covered with an amorphous Si film or SiC film having an insulating hydrogen barrier property. 4. A ferroelectric capacitor having a lower electrode, a ferroelectric capacitor insulating film formed on the lower electrode, and an upper electrode formed on the capacitor insulating film is formed on a substrate. A ferroelectric memory device, wherein a hydrogen barrier film formed so as to cover the ferroelectric capacitor and blocking the permeation of hydrogen has a laminated structure of a hydrogen diffusion reducing material and a hydrogen storage material. 5. The ferroelectric memory device according to claim ₄ , wherein said hydrogen diffusion reducing material is made of SiON or Si ₃ N ₄ . 6. Ti, T is a constituent element of the hydrogen storage material.
5. The ferroelectric memory device according to claim 4, comprising a material containing a, V, Y, Zr, Nb, or Hf.