JP3399079B2 - Dielectric thin film, dielectric thin film element, and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric thin film used in a small electronic circuit, a dielectric thin film element, and a method for manufacturing the same.

[0002]

2. Description of the Related Art With the development of integrated circuit technology and its miniaturization, miniaturization of circuit elements essential for various electronic circuits has become more important. Even in this rapid miniaturization, miniaturization of active elements such as capacitors has been delayed, which is a major factor preventing further high integration.

This is because the conventionally used dielectric thin film material is limited to a material having a low dielectric constant of 10 or less, such as SiO ₂ or SiN _x. This is because the problem of a low dielectric constant that prevents the miniaturization has not been solved. Therefore, for further miniaturization of integrated circuits, it is necessary to develop a dielectric thin film having a higher dielectric constant.

On the other hand, for example, a thin film of a high dielectric constant material having a perovskite structure represented by ABO ₃ has been thinned and partially put into practical use. However, these materials have many constituent elements, and it is said that it is difficult to control the composition.

[0005]

Among many dielectric materials, TiO ₂ is widely used as a capacitor material because it has a relatively high dielectric constant of around 100. Since it is not necessary to control the composition, the TiO ₂ film can be thinned relatively easily. However, the TiO ₂ thin film formed by using the CVD method is likely to have oxygen defects,
Since tan δ is large, there is a problem that the loss as a capacitor is large, and it has not been put to practical use.

Therefore, an object of the present invention is to provide a TiO ₂ thin film having a high dielectric constant and a small tan δ.

Another object of the present invention is to provide a TiO ₂ thin film dielectric thin film element having a high dielectric constant and a small tan δ.

Still another object of the present invention is to provide a method of manufacturing a dielectric thin film element comprising a TiO ₂ thin film having a high dielectric constant and a small tan δ.

[0009]

According to a first aspect of the present invention, the dielectric thin film comprises TiO ₂ containing 0.1 to 0.5 Mn.
It is characterized in that it is added and contained by mol%.

In the second aspect, the dielectric thin film is
It is characterized by comprising a CVD film containing 0.1 to 0.5 mol% of Mn added to TiO ₂ .

According to a third aspect of the present invention, in a dielectric thin film element having a lower electrode, a dielectric thin film, and an upper electrode formed on a substrate, the dielectric thin film comprises TiO ₂ and 0.1 to Mn. It is characterized by comprising 0.5 mol% added.

According to a fourth aspect of the present invention, in a dielectric thin film element having a lower electrode, a dielectric thin film and an upper electrode formed on a substrate, the dielectric thin film comprises TiO ₂ and 0.1 to Mn. It is characterized by comprising a CVD film containing 0.5 mol% added.

According to a fifth aspect of the present invention, in the method of manufacturing a dielectric thin film element, the raw material of TiO _{2 and} the raw material of Mn are vaporized at the same time, and the dielectric thin film is formed on the substrate by the CVD method. It is a thing.

According to a sixth aspect of the present invention, in the method for producing a dielectric thin film element according to the fifth aspect, the raw material of TiO ₂ is an alkoxide of titanium and the raw material of Mn is a β-diketone complex. Is.

[0015]

DETAILED DESCRIPTION OF THE INVENTION The present invention, is vaporized in the TiO ₂ material and Mn raw material at the same time by a CVD method, M to TiO ₂ on the substrate
By forming a CVD film containing 0.1 to 0.5 mol% of n added, carrier electrons are guaranteed for carrier electrons generated by oxygen defects in the TiO ₂ thin film, so that the dielectric constant is high. , _small TiO ₂ dielectric thin film tanδ can be obtained.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a dielectric thin film element of the present invention.

The whole is composed of 6 layers. First, a silicon oxide film 2 as a buffer layer is formed on a single crystal Si plate 1.
Are formed. This is one in which the surface of the Si plate 1 is forcibly oxidized in order to prevent the diffusion of Si into the platinum film 4 serving as the lower electrode. Next, on this, Si plate 1 and platinum film 4
The metal titanium film 3 is formed in order to improve the adhesiveness. A platinum film 4 as a lower electrode is provided on a substrate 13 composed of the Si plate 1, the silicon oxide film 2 and the metal titanium film 3 thus formed, and TiO ₂ is formed on the platinum film 4 by a CVD method. A dielectric thin film 5 containing 0.1 to 0.5 mol% of Mn is formed. Finally, an Ag electrode 6 is provided as an upper electrode on this.

Next, the manufacturing process of the dielectric thin film element of this embodiment will be described.

First, the substrate 13 constituting the lower layer of the dielectric thin film element and the platinum film 4 as the lower electrode formed thereon were prepared as follows.

On the single crystal Si plate 1, as a buffer layer, in order to prevent the diffusion of Si into the platinum film 4 serving as the lower electrode, the surface of the Si plate 1 is forcibly oxidized to form the silicon oxide film 2. Formed. Then, a metal titanium film 3 was formed thereon by 1000 angstrom sputtering in order to improve the adhesion between the Si plate 1 and the platinum film 4. A platinum film 4 as a lower electrode was formed on the substrate 13 composed of the Si plate 1, the silicon oxide film 2 and the metal titanium film 3 thus formed by 3000 angstrom sputtering.

Next, on the platinum film 4, TiO ₂ is contained as a main component and Mn is present in an amount of 0.1 to 0.5 mol% in the thin film by the CVD method using the apparatus shown in FIG. 2 described below. Thus, the dielectric thin film 5 was formed. And on top of this,
An Ag electrode 6 was provided as the upper electrode. The C of the present invention
In the VD method, a titanium alkoxide raw material is used as the raw material of the TiO ₂ dielectric thin film, and a β-diketone complex is used as the Mn raw material.

FIG. 2 is a schematic view of a CVD apparatus used for producing the dielectric thin films of this example, the conventional example and the comparative example.

This apparatus was provided with a vertical cold wall reactor 7, and argon was used as a carrier gas for supplying the raw materials to the reactor. Oxygen was used as the oxygen source required for the reaction.

The titanium alkoxide raw material is vaporized by argon gas in the vaporizer 8 and the Mn raw material is vaporized in the vaporizer 9 by using the argon gas as a carrier gas, and each is mixed in parallel with oxygen through the raw material introducing pipe 10. It was supplied into the container 11. Then, these were supplied onto the substrate 13 having the platinum film 4 as the lower electrode through the raw material gas supply nozzle 12.

The raw material temperature and the gas flow rate can be set to arbitrary values by a temperature control device (not shown) and the mass flow controller 14, respectively. The titanium raw material is 30 to 150 ° C. and the Mn raw material is 150. Heat to ~ 250 ° C.

Further, the substrate 13 provided with the platinum film 4 as the lower electrode is heated by the resistance heater 15 installed therebelow, and its temperature is controlled by a temperature controller (not shown).
Although it can be arbitrarily changed within the range of 300 to 1000 ° C., the substrate temperature is 500 to 1000 in this embodiment.
C. and the film formation time was 1 hour.

The inside of the reactor 7 can be evacuated by the rotary pump 16 installed at the lower part thereof to reduce the pressure, and the pressure inside the reactor 7 can be arbitrarily adjusted by a pressure controller (not shown). It can be set to a value. In this embodiment, the pressure inside the reactor 7 is 10 Torr.
Below.

The raw material gas supply nozzle 1 in the reactor 7
2 is a detachable type, and can be set to any nozzle shape depending on the shape of the dielectric thin film 5 formed on the substrate 13 having the platinum film 4 as the lower electrode. Further, in the figure, the part surrounded by the broken line indicates that the mantle heater is wound for heating.

Similarly, a thin film having Mn of 0 mol% was used as a conventional example, and 0.05 mol% and 5.0 mol% were used.
Dielectric thin film elements were prepared using mol% as a comparative example.

FIG. 3 is a characteristic diagram showing the relationship between frequency and tan δ regarding the example of the present invention, the conventional example and the comparative example.

0.1 to 0.5 mol% of Mn in TiO ₂
In the added example, tan δ was suppressed to 2% or less over a wide frequency band, and Mn addition was 0 mol of the conventional example.
% Or 0.05 mol% of the comparative example, it was found that the characteristics are improved.

FIG. 4 is a characteristic diagram showing the relationship between the frequency and the permittivity regarding the example of the present invention, the conventional example and the comparative example.

In the conventional examples and comparative examples in which Mn is added less than 0.1 mol%, and in the examples of 0.1 to 0.5 mol%, the dielectric constant is around 100, but in the comparative example in which 5.0 mol% is added. The dielectric constant was significantly reduced to 50 or less. Therefore, if the addition of Mn exceeds 0.5 mol%, tan
It was found that the object of the present invention could not be satisfied because the permittivity drops significantly even if δ is improved.

[0035]

According to the present invention, the dielectric constant is 80 to 100.
It is possible to obtain a dielectric thin film mainly composed of TiO ₂ having a high tan δ and a small tan δ of 2% or less. Since the dielectric constant can be maintained high, it is easy to obtain a large electrostatic capacitance, and the influence on the electrode area of the dielectric element can be suppressed in the miniaturization design. As a result, the size of the dielectric thin film element is further reduced, and the circuit can be further integrated.

[Brief description of drawings]

FIG. 1 is a sectional view of a dielectric thin film element according to an embodiment of the present invention.

FIG. 2 is a schematic device diagram of CVD.

FIG. 3 is a characteristic diagram of frequency and tan δ of an example of the present invention, a conventional example, and a comparative example.

FIG. 4 is a characteristic diagram of frequency and dielectric constant of an example of the present invention, a conventional example, and a comparative example.

[Explanation of symbols]

1 Si plate 2 Silicon oxide film 3 metal titanium film 4 Platinum film 5 Dielectric thin film 6 Ag electrode 13 board

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-49-29830 (JP, A) JP-A-4-25105 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01B 3/00-3/14 H01B 19/00 C23C 16/40 H01G 4/12 415

Claims (6)

(57) [Claims] 1. Mn to TiO ₂ in an amount of 0.1 to 0.5 mol
% Dielectric thin film characterized by being contained. _2. Mn to TiO ₂ in an amount of 0.1 to 0.5 mol
%. A dielectric thin film comprising a CVD film containing%. 3. A dielectric thin film element comprising a substrate, on which a lower electrode, a dielectric thin film, and an upper electrode are formed, wherein the dielectric thin film contains TiO ₂ and Mn of 0.1 to 0.5 m.
A dielectric thin film element comprising an ol% added content. 4. A dielectric thin film element having a lower electrode, a dielectric thin film and an upper electrode formed on a substrate, wherein the dielectric thin film contains TiO ₂ and Mn of 0.1 to 0.5 m.
A dielectric thin film element comprising a CVD film containing ol% added. 5. A method of manufacturing a dielectric thin film element, which comprises simultaneously vaporizing a TiO ₂ raw material and a Mn raw material and forming a dielectric thin film on a substrate by a CVD method. 6. The method for manufacturing a dielectric thin film element according to claim 5, wherein the raw material of TiO ₂ is an alkoxide of titanium, and the raw material of Mn is a β-diketone complex.