JPH0786270A - Formation of metal oxide film - Google Patents

Abstract

PURPOSE:To prevent the deterioration of permittivity of a metal oxide film formed by CVD by using metal compound gas which contains at least carbon or halogen and the plasma gas of the material which contains oxygen and hydrogen as the gas for forming the metal oxide film. CONSTITUTION:In case of forming a metal oxide film by CVD, metal compound gas, which contains at least carbon or halogen, and the plasma gas of the material which contains oxygen and hydrogen are used as the gas for forming the metal oxide film. For example, the temperature of a substrate to be treated is kept at 600 deg.C-800 deg.C, the temperatures of material tanks 7 and 6 are kept at 220 deg.C and 25 deg.C, respectively, and material gas of Sr(dpm)2 and Ti (iOC3H7)4 is introduced into a film forming chamber 1 with the carrier gas Ar. Then, a microwave discharging device 18 is turned on, H2O/O2 mixed gas in plasma condition is introduced into the film forming chamber 1 and a strontium titanate film is formed on the substrate 4 to be treated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a metal oxide film, and more particularly to a method for forming a metal oxide film as an insulating film used in a semiconductor device.

[0002]

2. Description of the Related Art One of semiconductor devices, a DRAM (Dynamic Ran) is used as a semiconductor memory device that combines a capacitor and a transistor to store information.
domAccess read write Memo
ry).

In this type of semiconductor memory device, conventionally,
A silicon oxide film or a composite film of a silicon oxide film and a silicon nitride film has been used as a capacitor insulating film formed between a capacitor electrode and a semiconductor substrate.
With rapid integration of devices, three-dimensionalization of capacitors such as trench capacitors and stacked capacitors is progressing.

In order to realize a higher capacity capacitor, a material having a larger dielectric constant than a silicon oxide film or a silicon nitride film is being studied. It is necessary to use a material having a large dielectric constant as much as possible in order to cope with an increase in capacitance of the capacitor due to further miniaturization in the future.

From these requirements, a metal oxide film having a high dielectric constant of a perovskite type crystal structure such as strontium titanate or PZT, which has a dielectric constant 50 to 100 times higher than that of a silicon oxide film, is used as a capacitor insulating material. The use in membranes is being investigated. FIG. 7 shows a perovskite type crystal structure. 81, 82, 8 in the figure
3 is a different atom, typically 8
1 is Sb, Ba, Pb, 82 is O, and 83 is Ti.

It is known that a metal oxide film having a perovskite type crystal structure causes a large atomic polarization, thereby exhibiting a high dielectric constant. This is because the central atom of the crystal lattice can change greatly. Therefore, in order to develop a high dielectric constant, it is essential to form a perovskite type crystal structure without disorder.

On the other hand, in order to apply such a high-dielectric-constant metal oxide film to the capacitor insulating film of DRAM, it is necessary to provide a film forming method having a good covering property even for a three-dimensional shape such as a trench capacitor. For such requests, LPCV
Method D is suitable.

Generally, it is necessary to use an organometallic compound having a relatively high vapor pressure as a raw material for these high dielectric constant metal oxide films. Especially II like strontium and barium
With respect to the a-group element, since the organometallic compound as a raw material is limited, a large organic substance is coordinated to increase the vapor pressure due to steric hindrance. Typically, Sr (dpm) coordinated with β-diketone is used. ) ₂ , Ba (dpm) ₂ , and in addition, Sr (hfa) ₂ , Ba (hfa) _{2 and the} like, in which an organic substance containing halogen (fluorine) is coordinated to further increase the vapor pressure, are used. Here, dpm is di pival
In case of oy methanate, hfa is hexa
Abbreviation for fluoro acetolate.

However, when a metal oxide film with a high dielectric constant having a perovskite type crystal structure is formed by a CVD method using these organic metals as raw materials, decomposition products of organic substances and halogen are mixed as impurities in the metal oxide film. To do.
In addition, since alkoxide groups are usually present in many other organic metals as raw materials and a large amount of C is contained in each metal atom, a large amount of C is mixed.

Since such impurities are mixed in to impede the formation of the perovskite type crystal structure, the dielectric constant and the insulating performance are lowered, and the original charge storage and holding performance of the high dielectric film is significantly lowered. Cause.

Therefore, in a conventional DRAM using a high dielectric constant metal oxide film having a perovskite type crystal structure as a capacitor insulating film, the leak current increases and the charge retention capacity of the capacitor decreases, resulting in reliability. There was a problem that the sex was impaired.

[0012]

As described above, the DRAM
As an insulating film having a high dielectric constant, such as a capacitor insulating film of, a metal oxide film having a high dielectric constant such as an oxide film of a perovskite type crystal structure or a transition metal oxide film has the following problems. there were.

That is, when a film is formed by the CVD method in order to ensure good coverage, there is a problem that impurities generated by decomposition of the gas used for film formation are mixed in the metal oxide film and the dielectric constant is lowered. It was

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a metal oxide film capable of preventing a decrease in dielectric constant.

[0015]

In order to achieve the above object, the present invention (claim 1) provides a method for forming a metal oxide film by a CVD method, which comprises forming the metal oxide film. A metal compound gas containing at least one of carbon and halogen and a plasma gas of a substance containing oxygen and hydrogen are used as the gas supplied to the film.

The substance containing oxygen and hydrogen is preferably an alcohol or a substance containing water vapor and oxygen.

[0017]

According to the present invention (Claim 1), by using a plasma gas of a substance containing oxygen and hydrogen, which is suitable for a metal compound containing at least one of carbon and halogen, impurities can be formed during film formation. Can be prevented from being mixed into the metal oxide film, and a decrease in the dielectric constant can be prevented.

For example, when a metal compound gas containing halogen is used, if alcohols, oxygen gas, steam or the like is used as the substance containing oxygen and hydrogen, the halogen is effective due to the reaction between the OH free radical and the halogen. It can be removed selectively, and a decrease in the dielectric constant can be prevented.

When a metal compound (organic metal etc.) gas containing carbon is used, if the above-mentioned substance is used as a substance containing oxygen and hydrogen, radicals such as oxygen, hydrogen and hydroxyl groups and decomposition and production of organometal are generated. The decomposition product can be effectively removed by the reaction with the substance, and the decrease in the dielectric constant can be prevented.

[0020]

Embodiments will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing a schematic structure of a film forming apparatus used in a method for forming a metal oxide film (strontium titanate film) according to the first embodiment of the present invention.

In the figure, reference numeral 1 denotes a film forming chamber, which is evacuated by a vacuum pump 2. Inside the film forming chamber 1, a substrate 4 to be processed is placed on a heater 3 and heated.

Several supply lines for supplying a reaction gas to the film forming chamber 1 from the outside are prepared. That is, the first carrier Ar line 14 connected to the raw material tank 7 in which Sr (dpm) ₂ which is the raw material of strontium is sealed.
And a second carrier Ar line 15 connected to a raw material tank 6 in which Ti (iOC ₃ H ₇ ) ₄ which is a raw material of titanium is sealed, and an O ₂ line 13 and an H ₂ O line 16 are prepared.

H ₂ O is enclosed in a tank 8 equipped with a heater (not shown). Raw material tanks 6 and 7 are constant temperature tanks 5.
It is kept inside and kept at a constant temperature. H ₂ O supplied from the H ₂ O line 16 via a valve 17, O
_{2 The} O ₂ supplied from the line 13 merges with the microwave discharge device 1 before the gas is introduced into the film forming chamber 1.
It is made to be plasma at 8 and introduced into the film forming chamber 1.

Each line 13, 14, 15, 16 is provided with a mass flow controller 10, 11, 12, 9 for controlling the gas flow rate, respectively.

Next, a method of forming a strontium titanate film by the film forming apparatus having the above structure will be described.

First, the raw material gas (Sr (Sr ( dpm) ₂ 100SCCM, Ti
(IOC ₃ H ₇ ) ₄ 40 SCCM) as carrier gas (A
It is introduced into the film forming chamber 1 together with r). At this time, H ₂ O
The tank 8 in which is sealed is kept at about 40 ° C.
The pressure inside the film forming chamber 1 is 1 Torr.

The microwave discharge device 18 has 30
Power to the introduction of ~500W, H ₂ O / O ₂ mixed gas _{(H 2 O100SCCM, O 2 50SCCM} ) to discharge, introducing H ₂ O / O ₂ mixed gas in a plasma state in the deposition chamber 1, A strontium titanate film is formed on the substrate 1 to be processed.

According to the method of this embodiment, a good high dielectric constant strontium titanate film containing few impurities was obtained. As in this embodiment, this is because when the organometallic raw material is supplied into the film forming chamber 1, water vapor and oxygen are supplied to the film forming chamber 1.
In the microwave discharge device 18 provided in the preceding stage, once placed in a plasma state to generate radicals such as oxygen, hydroxyl group, and hydrogen, these react with the decomposition products instantly, and the decomposition products are efficiently generated. This is because it can be removed.
Such an effect is obtained by using Sr containing fluorine in the organometallic raw material.
Even when (hfa) ₂ or Ba (hfa) ₂ is used,
This is effective because the above radicals and fluorine react efficiently.

Further, according to the present embodiment, since the water vapor is supplied, it is expected that the oxidation reaction is promoted and the film formation rate is improved.

In the present embodiment, the raw materials for strontium and titanium are Sr (dpm) ₂ ) and T, respectively.
Although i (iOC ₃ H ₇ ) ₄ is used, other source gas may be used. For example, it is possible to use the above-mentioned Sr (hfa) ₂ containing fluorine as the strontium raw material, and even in this case, it is possible to form a strontium titanate film free from impurities.

In this embodiment, the case where the microwave discharge is used for generating the plasma has been described, but the same effect can be obtained even if the discharge is formed by the RF discharge or another method.

FIG. 2 shows a DR according to the second embodiment of the present invention.
It is process sectional drawing which shows the manufacturing method of AM. Here, an example in which the strontium titanate film formed by using the first embodiment is applied to a capacitor insulating film of DRAM will be taken up.

First, as shown in FIG. 2A, a thermal oxide film is formed on a P-type silicon substrate 21 having a specific resistance of 10 Ω · cm and a main surface of (100) plane, and is patterned. , Element isolation insulating film 2 for element isolation
2 and the gate oxide film 23 are formed. Next, a first n ⁺ type polysilicon film to be the gate electrode 24 is formed on the P type silicon substrate 1, and this is patterned by a normal photoetching method to form the gate oxide film 2
A gate electrode 24 is formed on the surface 3.

Next, by implanting donor ions into the P-type silicon substrate 21 using the gate electrode 24 as a mask,
The n ⁻ type source / drain diffusion layers 25 ₁ and 25 ₂ are formed in a self-aligned manner. Next, a thick CVD oxide film 26 is formed on the entire surface of the substrate, and then the thick CVD oxide film 26 is patterned by a normal photoetching method to form an opening communicating with the source / drain diffusion layer 25 ₁ . Then, after depositing tungsten silicide on the surfaces of the CVD oxide film 26 and the opening, patterning is performed according to a normal photoetching method to form the bit line 27. After that, the second CVD oxide film 28 is deposited.

Next, as shown in FIG. 2B, after forming an opening communicating with the source / drain diffusion layer 25 ₂ , a second n ⁺ type polysilicon film 29 is deposited on the entire surface and etched back. Source / drain diffusion layer 2
A second n ⁺ polysilicon film 29 to be connected to the 5 ₂ only in the opening is left behind.

Next, a TiN film 30 is formed on the entire surface, and the TiN film 30 is patterned into a predetermined shape by an ordinary photoetching method. Then, for example, a lower electrode (storage electrode) is selectively formed only on the TiN film 30 by a plating method. As P
The t film 31 is formed. The Pt film 31 may be formed by patterning a film formed by a sputtering method by etching. Then, the SrTiO ₃ film 32 as a capacitor insulating film is formed on the entire surfaces of the Pt film 31 and the CVD oxide film 28 by using the method shown in the first embodiment.

Finally, as shown in FIG. 2C, SrT
After forming a titanium nitride film serving as an upper electrode (plate electrode) 33 on the iO ₃ film 32 by a sputtering method, the titanium nitride film is patterned by a normal photoetching method to form an upper electrode 33, and the titanium oxide film of the memory cell is formed. The basic structure is completed. After that, according to a usual LSI manufacturing process, the formation of the DRAM is completed through a passivation film forming step, a wiring forming step, and the like.

FIG. 3 shows a comparison between the CV curve and the IV curve of the capacitor using the strontium titanate film formed by the method of this embodiment, compared with the conventional method.

According to the method of this embodiment from FIG. 3 (a),
It can be seen that the leak current can be reduced. Furthermore, FIG.
From (b), it can be seen that according to the method of this embodiment, the capacitance (dielectric constant) of the capacitor can be increased.

Although SrTiO ₃ is used as the material of the capacitor insulating film in this embodiment, other high dielectric materials such as PZT can be used instead of it, and Pt can also be used as the electrode material. , But not limited to titanium nitride. Further, the capacitor structure is not limited to the stacked capacitor structure, and the present invention can be applied to the trench capacitor structure.

FIG. 4 shows a DR according to the third embodiment of the present invention.
It is process sectional drawing which shows the manufacturing method of AM.

First, as shown in FIG. 4A, the specific resistance 1
After a silicon thermal oxide film 33 is formed on a single crystal silicon substrate 31 of 0 Ωcm, (100) plane, a polycrystalline silicon film 34 and a silicon oxide film (not shown) are deposited by the CVD method. Next, the silicon oxide film is patterned by a normal photo-etching method, and the polycrystalline silicon film 34, the silicon thermal oxide film 33, and the single crystal silicon substrate 31 are anisotropically etched sequentially using the silicon oxide film as a mask to isolate the elements. A groove to be a region is formed. Then, after removing the silicon oxide film used as the mask, the silicon oxide film 32 as an element isolation insulating film is embedded in the groove by the LPCVD method.

Next, as shown in FIG. 4B, the polycrystalline silicon film 34 is peeled off by a chemical dry etching method,
Then, the silicon thermal oxide film 33 is peeled off with hydrofluoric acid or the like. At this time, the silicon oxide film 32 is also etched at the same time, and the surface thereof becomes substantially flush with the surface of the substrate 31. Next, a thin silicon thermal oxide film 3 to be a gate oxide film
After forming 5, LP is formed on the entire surface of the single crystal silicon substrate 31.
The gate electrode 37 is formed by forming n ⁺ polycrystalline silicon that will become the gate electrode 37 by the CVD method and patterning it by a normal photoetching method. Then, using the gate electrode 37 as a mask, donor ions are implanted into the single crystal silicon substrate 31 to form the n ⁻ type source / drain diffusion layers 36 ₁ and 36 ₂ in a self-aligned manner.

Next, as shown in FIG. 4C, a thick CVD oxide film 38 is formed on the entire surface of the substrate and is patterned by a normal photoetching method to communicate with the source / drain diffusion layer 36 _1. Form a contact hole. Then, a tungsten silicide film is deposited on the surfaces of the CVD oxide film 38 and the contact hole, and patterned by a normal photoetching method to form the bit line 39. Next, after depositing a CVD oxide film 40 on the entire surface of the substrate, the silicon oxide films 38, 40 are patterned by a normal photoetching method to form contact holes communicating with the source / drain diffusion layers 36 ₂ .

[0046] Next, as shown in FIG. 4 (d), the n ⁺ -type polycrystalline after the silicon film 41 is formed by the LPCVD method, the etch-back method by n ⁺ -type polycrystalline silicon 41 source-drain diffusion layer 36 ₂ Leave it only in the upper contact hole. Next, a titanium nitride film 42 to be a lower electrode is formed on the entire surface of the single crystal silicon substrate 31 by a sputtering method, and patterned by a normal photoetching method to form the lower electrode 42.

Next, a niobium-added strontium titanate film 43 is formed on the entire surface of the single crystal silicon substrate 31 by the CVD method. Here, in forming the niobium-added strontium titanate film 43, strontium, titanium,
As a raw material for niobium, Sr (hfa) ₂ 100 SCC
M, Ti (i-OC ₃ H ₇ ) ₄ 40 SCCM, Nb (O
C ₂ H ₅ ) ₅ (about 1 to 2% of the total flow rate) is used, and these are bubbled and supplied with Ar gas. Deposition temperature is 15
The pressure inside the film forming chamber was 0 ° C. and 1 Torr.

At this time, methanol (CH ₃ OH) is converted into plasma by microwave discharge of 2.45 GHz and 50 W to generate OH free radicals, which are supplied together with the above source gas.

Next, after the niobium-added strontium titanate film 43 is processed by the reactive ion etching method and left only on the lower electrode 42, a strontium titanate film 44 as a capacitor insulating film is formed on the entire surface by the CVD method. To do. Here, in forming the strontium titanate film 44, Sr (hfa) ₂ 100SCCM and Ti are used as raw materials of strontium and titanium, respectively.
Using (i-OC ₃ H ₇ ) ₄ 40 SCCM,
Bubbling with r gas is supplied. Film formation temperature is 150
The temperature inside the film forming chamber was set to 1 Torr.

At this time, methanol (CH ₃ OH) having a flow rate of 30 SCCM is converted into plasma by microwave discharge of 2.45 GHz and 50 W to generate OH free radicals, which are supplied together with the above-mentioned raw material gas.

Finally, as shown in FIG. 4D, a nickel film to be the upper electrode (plate electrode) 45 is formed on the capacitor insulating film 44 by the sputtering method, and then patterned to form the upper electrode 45. To complete the basic structure of the memory cell. After that, the passivation film forming process is performed in accordance with a normal LSI manufacturing process.
The fabrication of the DRAM is completed through a wiring forming process and the like.

According to the method of this embodiment, a good high dielectric constant capacitor insulating film containing less impurities was obtained.
This is because when OH free radicals, which are active species generated by putting a gas containing a hydroxyl group such as alcohols into a plasma state during film formation as in this embodiment, are supplied together with the source gas, halogen such as F and carbonate ions. This is because the binding of the metal with the metal is suppressed.

As an example, ethanol (C ₂ H ₅ O
H) is plasma-converted in the preceding stage of the reaction tank to generate and supply OH free radicals, and Sr (hfa) ₂ is used as a gas source to form strontium titanate. The relationship of the mixed amount (shown by the ratio to Sr) is shown in FIG. The horizontal axis of FIG. 6 shows the power of the microwave input to keep the alcohol in the plasma state.

In FIG. 6, 10 W to 100 W
It can be seen that F is removed by supplying alcohol through the plasma state under moderate power conditions. On the other hand, the effect of removing the F is not seen in the sample using oxygen as the oxidizing agent, which is the conventional method, and the effectiveness of the present invention can be seen.

Although alcohol has the ability to generate OH free radicals without being made into plasma, in order to enhance reactivity and to obtain a high-quality capacitor insulating film (metal oxide film), alcohol is once passed through the plasma state. Dissociation is more effective. It can be seen that F is completely removed from the metal oxide film by increasing the microwave power.

As the microwave power is increased, F tends to remain in the film again. This is because the OH free radical generated by the dissociation of alcohol is further decomposed and the O atom , H atoms are dissociated and the ability to remove F from the film is reduced. That is, it turns out that it is necessary to supply OH free radicals.

As described above, according to this embodiment, since the metal oxide film serving as the capacitor insulating film can be formed without disturbing the perovskite type crystal structure, a capacitor having a high charge retention capability can be obtained. Therefore, a highly reliable DRAM can be obtained.

FIG. 5 shows a DR according to the fourth embodiment of the present invention.
It is process sectional drawing which shows the manufacturing method of AM.

Similar to the third embodiment, first, FIG.
As shown in FIG. 3, an element isolation insulating film 52, a gate oxide film 55, a gate electrode 57, source / drain regions 56 ₁ and 56 ₂ and a silicon oxide film 58 as a first interlayer insulating film are formed on a single crystal silicon substrate 51. , Source / drain region 56
A contact hole communicating with ₁ and a bit line 59 are formed. Then, a thick silicon oxide film 60 which is a second interlayer insulating film is formed by the CVD method, and then a second contact hole communicating with the source / drain region 56 ₂ is formed.

[0060] Next FIG 5 (b) as shown in the, n ⁺ -type polycrystalline after the silicon film 61 is formed by the LPCVD method, n ⁺ -type polycrystalline silicon film 61 to the source and drain regions 56 ₂ by the etch back method It is left only inside the upper contact hole. Then, the tungsten film 62 serving as the lower electrode is formed by the CVD method into the n ⁺ -type polycrystalline silicon film 6
Then, the lower electrode is formed by selectively growing it on the first electrode 1 and partially protruding it onto the silicon oxide film 60. After that, a platinum film 63 is formed on the entire surface of the substrate by a sputtering method, and then is left only on the tungsten film 62 by a reactive ion etching method.

Next, a barium titanate film 64 as a capacitor insulating film is formed on the entire surface by the CVD method. Here, in forming the barium titanate film 64, Ba (hfa) is used as a raw material for barium and titanium, respectively.
₂ 100 SCCM, Ti (i-OC ₃ H ₇ ) ₄ (TI
P) Using 40 SCCM, these are bubbled and supplied with Ar gas. The film forming temperature is 220 ° C., and the pressure inside the film forming chamber is 1 Torr.

At this time, ethanol (C ₂ H ₅ OH) 3
The mixed gas of 0 SCCM and oxygen 50 SCCM is 2.4.
It is turned into plasma by microwave discharge of 5 GHz and 200 W, and OH free radicals and oxygen atoms are generated and supplied together with the above source gas.

By supplying OH free radicals in this way, F and C in the barium titanate film 64 are removed, and by supplying oxygen atoms, oxygen vacancies in the barium titanate film 64 are formed. Defects such as holes are repaired and a film having a high dielectric constant is obtained.

Finally, as shown in FIG. 5C, a niobium film to be the upper electrode 65 is formed on the entire surface of the substrate by the sputtering method, and then this niobium film is patterned by a normal photoetching technique to form the upper electrode. By forming 65, the basic structure of the memory cell is completed. After that, according to a usual LSI manufacturing process, the formation of the DRAM is completed through a passivation film forming step, a wiring forming step, and the like.

The present invention is not limited to the above embodiment. For example, in the examples, the case of forming a strontium titanate film or a barium titanate film was described, but the present invention is applicable to other high dielectric constant metal oxide films such as calcium titanate and a mixture of these three. It can also be applied to the film formation of a metal oxide film. That is, the present invention can be applied to the formation of a high dielectric film made of a substance containing at least one of Sr, Ba, Ca, Y, Cu, Ti and Bi. It can also be applied to the formation of a high-dielectric-constant metal oxide film made of PZT, PLZT, or tantalum oxide. Further, the present invention can be applied to a metal oxide film having a perovskite type crystal structure as a superconductor film.

Although ethanol and methanol are used in the above embodiment, other alcohols may be used.
Further, as long as it is a substance containing OH, it may not be alcohol.

Further, in the above embodiment, the semiconductor device D
Although the RAM has been described as an example, the present invention can be applied to other semiconductor devices that require an insulating film having a high dielectric constant.

In addition, various modifications can be made without departing from the scope of the present invention.

[0069]

As described in detail above, according to the present invention, by using a plasma gas of a substance containing oxygen and hydrogen, which is suitable for a metal compound gas containing at least one of carbon and halogen, It is possible to prevent impurities from being mixed into the metal oxide film and prevent a decrease in the dielectric constant.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of a film forming apparatus used in a method for forming a metal oxide film according to a first embodiment of the present invention.

FIG. 2 is a process sectional view showing a method of manufacturing a DRAM according to a second embodiment of the present invention.

FIG. 3 is a characteristic diagram showing the effect of the present invention.

FIG. 4 is a process sectional view showing a method of manufacturing a DRAM according to a third embodiment of the present invention.

FIG. 5 is a process sectional view showing the method of manufacturing the DRAM according to the fourth embodiment of the present invention.

FIG. 6 is a characteristic diagram showing the effect of the present invention.

FIG. 7 is a diagram showing a perovskite type crystal structure.

[Explanation of symbols]

1 ... Film forming chamber, 2 ... Vacuum pump, 3 ... Heater, 4 ... Substrate to be processed, 5 ... Constant temperature bath, 6, 7 ... Raw material tank, 8 ... Tank, 9, 10, 11, 12 ... Mass flow controller, 13 ... O ₂ line, 14, 15 ... Carrier Ar line, 16 ... H ₂ O line, 17 ... Bulb, 18 ... Microwave discharge device 21 ... P-type silicon substrate, 22 ... Element isolation insulating film, 2
3 ... Gate oxide film, 24 ... Gate electrode, 25 ₁ , 25 ₂
Source / drain diffusion layer 26, CVD oxide film 27
... bit line, 28 ... CVD oxide film, 29 ... n ⁺ type polysilicon film, 30 ... TiN film, (in FIG. 2) 31 ...
Pt film (lower electrode), 32 (in FIG. 2) ... SrT
iO ₃ film (capacitor insulating film), 3 (in FIG. 2)
3 ... Titanium nitride film (upper electrode) (in FIG. 4) 31 ... Single crystal silicon substrate ((FIG. 4)
32 ... Insulation film for element isolation, 33 ... (In FIG. 4) Silicon thermal oxide film, 34 ... Polycrystalline silicon film, 35 ... Gate oxide film, 36 ₁ , 36 ₂ ... Source / drain diffusion layer, 37 ... gate electrode, 38 ... CVD oxide film, 39 ... bit line, 40 ... CVD oxide film, 41 ... n ⁺
-Type polycrystalline silicon film, 42 ... Titanium nitride film (lower electrode), 43 ... Niobium-added strontium titanate film, 4
4 ... Strontium titanate film (capacitor insulating film),
45 ... Nickel film (upper electrode) 51 ... Single crystal silicon substrate, 52 ... Insulating film for element isolation,
53 ..., 54 ..., 55 ... Gate oxide film, 56 ₁ , 56 ₂
Source / drain region, 57 ... Gate electrode, 58 ... Silicon oxide film, 59 ... Bit line, 60 ... Silicon oxide film, 61 ... N ⁺ type polycrystalline silicon film, 62 ... Tungsten film (lower electrode), 63 ... Platinum Film, 64 ... Barium titanate film (capacitor insulating film), 65 ... Niobium film (upper electrode)

Claims (2)

[Claims] 1. A method for forming a metal oxide film by forming a metal oxide film by a CVD method, wherein a metal compound gas containing at least one of carbon and halogen, oxygen and A method for forming a metal oxide film, which comprises using a plasma gas of a substance containing hydrogen. 2. The method for forming a metal oxide film according to claim 1, wherein the substance containing oxygen and hydrogen is an alcohol or a substance containing water vapor and oxygen.