KR20040087414A - Pyrochlore conductive oxide, and layer and capacitor by using the same - Google Patents

Abstract

PURPOSE: A conductive oxide having a pyrochlore structure and an oxide thin film and a capacitor containing the oxide are provided, to obtain a precursor suitable for MOCVD(metal organic chemical vapor deposition) or ALD(atomic layer deposition) for making a 3D capacitor. CONSTITUTION: The conductive oxide has a pyrochlore structure and is represented by Bi2(Ru(2-x), Six)O(7-y) or Pb2(Ru(2-x), Six)O(7-y), wherein 0<x<2 and 0<y<1. The capacitor comprises a bottom electrode; a dielectric layer formed on the bottom electrode; and an upper electrode formed on the dielectric layer, wherein at least one of the bottom electrode and the upper electrode is formed by using the conductive oxide. Preferably the dielectric layer has a pyrochlore crystal structure and is formed by using a bismuth titanium silicon oxide represented by Bi2(Ti(2-x), Six)O(7-y), wherein 0.8<x<1.3 and -1<y<1.

Description

Pyrochlor conductive oxide, and layer and capacitor by using the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pyrochlor conductive oxide thin film and a capacitor using the same, and more particularly, to a pyrochlor conductive oxide thin film and a capacitor using the same, which can be used to form a capacitor and a transistor of a highly integrated memory device.

As memory density increases, the unit cell size and the projected area occupied by the capacitor become extremely small. Therefore, research into using a capacitor dielectric with a high dielectric constant has been continued to realize a capacitor having a large capacitance in a limited area, and as a result of these efforts, low dielectric materials such as SiO ₂ and Si ₃ N ₄ which have been used in the past A higher dielectric constant tantalum oxide (TaO) or a capacitor using a perovskite phase high-electricity (paraelectric) material has been proposed as in US Pat. No. 5,986,301.

BST (BiSrTi ₃₎ and STO (SrTiO ₃₎ and MIM (metal / insulator / metal) in the form of a capacitor used as a noble metal (noble metal) electrode, such as Pt or Ru as a dielectric constant of 100 or more specific non-full as a silicon electrode for this purpose Efforts have been made to adopt capacitors in memory cells (International Technology Roadmap for Semiconductors (ICRS capacitor technology roadmap 2003)). However, even when such a design rule is less than 0.07 μm, the height of the capacitor is relatively high compared to the gap between memory cells, thereby encountering the same process limitations experienced when using a silicon-based dielectric. In addition, the dielectric film thickness required by the design rule cannot achieve the dielectric constant as shown in the bulk state (JAP vol. 85 (1999) CS Hwang et al.) Therefore, in order to solve the problem, the high-k dielectric is thinned. Even if the permittivity does not decrease, there is a need for a technology capable of achieving the highest permittivity for the same material.

Meanwhile, in order to compensate for the reduction of the projection area while using high dielectric materials such as STO (SrTiO ₃ ) and BTO ((BaTiO ₃ ), a complex three-dimensional capacitor such as HSG (HemiSpherical Grain) has been applied. In order to fabricate a capacitor having a structure, methods such as metal organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), etc. are used. It is virtually difficult for a reason.

The above-mentioned high dielectric constant materials, that is, barium titanium oxide (BaTiO ₃ ) and strontium titanium oxide (SrTiO ₃ ) are not only difficult to prepare a precursor having a sufficient vapor pressure, but also have a poor thermal and chemical stability in actual film formation. There are many difficulties in forming a reproducible thin film. In other words, there are currently no suitable precursors that can be used in MOCVD or ALD to form three-dimensional capacitors.

In addition, in order to obtain the required vapor pressure by using the precursor, it must be vaporized and supplied at a high temperature. This results in the deposition system and equipment being used at high temperatures, shortening the life of each component. In the case of forming a multi-component film using the high dielectric constant material, when preparing a single cocktail solution as a precursor mixture for forming a thin film, there is a problem in that storage stability decreases due to a reaction between these precursors. have. Therefore, there is a need for a precursor capable of forming a three-dimensional capacitor.

ITRS's road map, on the other hand, recommends storage nodes made of materials of the same or the same crystal structure as the high dielectric materials in order to maximize the dielectric constant. For example, BSTO (Bi _0.44 Sr _0.56 TiO ₃ ) will be used as the dielectric layer, and the use of SrRuO ₃ as the storage node underneath is the method of maximizing the dielectric constant. Therefore, an appropriate precursor is required to form a three-dimensional capacitor, and an appropriate conductive material is required to maximize the dielectric constant of the dielectric by the precursor.

The first technical problem to be achieved by the present invention is to provide a pyrochlor oxide as a novel conductive material to solve the above problems.

The second technical problem to be achieved by the present invention is to provide the pyrochlor oxide thin film.

The third technical problem to be achieved by the present invention is to provide a capacitor and an electronic device using the pyrokrod oxide.

Figure 1 (a) and (b) is a Bi-Ru after the deposition of a precursor mixture for forming a pyrochlor conductive thin film according to the present invention (a), and after heat treatment at 600 ℃ in the air atmosphere (b) X-ray diffraction (XRD) analysis of the crystal phase of the -Si-O thin film is shown.

2 (a) and 2 (b) are SEM photographs showing the thin film surface before heat treatment of the pyroclaw rod conductive thin film according to the present invention.

3 (a) and 3 (b) are SEM photographs showing the thin film surface before heat treatment of the pyroclaw rod conductive thin film according to the present invention.

4 is a graph showing the surface roughness (RMS roughness) and the resistivity of the thin film before (as-dep) and after (PDA) heat treatment of the pyroclaw rod conductive thin film according to the present invention.

5A is a schematic cross-sectional view of a first embodiment of a capacitor according to the present invention.

5b is a schematic cross-sectional view of a second embodiment of a capacitor according to the invention.

6 shows an XRD pattern of a Bi-Ti-Si-O thin film applied to a capacitor according to the present invention.

According to one type of the present invention to achieve the first technical problem is represented by the formula (1) is provided with pyrochlore oxide (pyrochlore oxide).

<Formula 1>

Bi ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1)

According to another type of the present invention to achieve the first technical problem is represented by the formula (1) is provided with pyrochlor oxide.

<Formula 2>

Pb ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1)

In order to achieve the second technical problem of the present invention, represented by Chemical Formula 3 below, a thin film formed of pyrochlor oxide is provided.

<Formula 3>

Bi ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1)

In order to achieve the second technical problem of the present invention represented by the following formula (4) and pyrochlore thin films are provided respectively.

<Formula 4>

Pb ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1)

One type of capacitor according to the present invention to achieve the third technical problem of the present invention;

Lower electrode;

A dielectric layer formed of a dielectric material formed on the lower electrode; And an upper electrode formed on the dielectric layer, wherein at least one of the upper electrode and the lower electrode is formed of pyrochlor oxide represented by Formula 5 below.

<Formula 5>

Bi ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1)

Another type of capacitor according to the present invention to achieve the third technical problem of the present invention;

Lower electrode;

A dielectric layer formed of a dielectric material formed on the lower electrode; And an upper electrode formed on the dielectric layer, wherein at least one of the upper electrode and the lower electrode is formed of pyrochlor oxide represented by Chemical Formula 6 below.

<Formula 6>

Pb ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1)

According to one embodiment of the capacitor according to the two types of the present invention, the dielectric layer is formed of a bismuth titanium silicon oxide (Bi-Ti-Si-O) thin film represented by the following formula (7) having a pyrorod phase It is preferable.

<Formula 7>

Bi ₂ (Ti _2-x Si _x ) O _7-Y (0.8 <x <1.3, -1 <y <1)

According to other embodiments of the capacitor according to the two types of the present invention, the dielectric layer is preferably formed of a Bi ₂ Ti ₂ O ₇ (hereinafter referred to as Bi-Ti-O) thin film having a pyrochlore structure.

Hereinafter, exemplary embodiments of an oxide, a thin film, a capacitor, and a transistor using the same according to the present invention will be described in detail with reference to the accompanying drawings.

Pycloclode oxides represented by formulas (1) and (2) provided by the present invention, namely Bi ₂ (Ru _2-x , Si _x ) O _7-y (hereinafter Bi-Ru-Si-O), Pb ₂ (Ru _2-x , Si _x ) O _7-y (hereinafter Pb-Ru-Si-O) is a new material with electrical conductivity.

In order to obtain a Bi-Ru-Si-O conductive oxide thin film, it was deposited on a SiO ₂ / Si substrate at 400 ° C. by a cyclic CVD method. At this time, ECH (ethyl cyclo-hexan; C ₈ H ₁₆ ) was used as a solvent of the source, and Bi (mmp) ₃ , Ru (OD) ₃ , and TEOS were used as precursors. The source in which the precursor is diluted and dissolved in the solvent is supplied to a vaporizer by a direct liquid injection (DLI) method for flash evaporation, and then transferred to a reactor to form pyrochlore oxide on the substrate. .

In the thin film deposition, the four steps below constitute one cycle, and in order to deposit a thin film having a desired thickness, the thin film deposition process is performed by the corresponding number of cycles. In this example, 300 cycles were performed.

First step: Purge the chamber with argon purge gas for about 3 seconds. At this time, the flow rate is adjusted to 100 sccm.

Second step: The precursor mixture is fed in a DLI manner to a vaporizer which is heated to a constant temperature (eg 230 ° C.) to instantaneously vaporize the liquid precursor mixture and to the reactor for about 0.5 seconds.

Third Step: Purge the chamber with argon purge gas for about 3 seconds. At this time, the flow rate is also adjusted to 100 sccm.

Fourth Step: Oxygen is supplied into the reactor as a reactive gas. At this time, the flow rate is adjusted to 100 sccm.

Figure 1 shows the deposition of a precursor mixture for forming a Bi-Ru-Si-O thin film prepared according to the embodiment of the present invention (a), and after the heat treatment at 600 ℃ in the air atmosphere (b) Bi- X-ray diffraction (XRD) analysis of the crystalline phase of the Ru-Si-O thin film is shown. As shown in (a) of FIG. 1, crystal peaks observed in the thin film are present in addition to Si (400) even before the heat treatment, and a plurality of crystal peaks associated with the thin film are observed as the degree of crystallinity increases after the heat treatment.

2A and 2B are SEM photographs showing the thin film surface before heat treatment of the thin film, and FIGS. 3A and 3B are SEM photographs showing the thin film surface before heat treatment of the thin film. It can be seen that the pyrochlor oxide film deposited as shown in FIGS. 2 and 3 has a relatively smooth surface.

The graph of FIG. 4 shows the surface roughness (RMS roughness) and the resistivity of the thin film before (as-dep) and after (PDA) heat treatment of the thin film. The surface roughness of the thin film was observed using AFM. As a result of the crystal growth after the heat treatment, the surface roughness increased, and as the crystallinity increased, the resistivity decreased by more than 10 times.

In order to observe the composition of the Pyrochlor oxide thin film according to the present invention exhibiting such electrical properties, the substrate was sampled by acid treatment after depositing Bi-Ru-Si-O on MgO single crystal under the same film forming conditions, and ICP The results of the thin film composition as shown in Table 1 were obtained from the samples collected by using -AES (Inductively Coupled Plasma-Atomic Emission Spectrometer).

element mole ratio (atomic percent) Ru / (Ru + Bi + Si) 0.52 Bi / (Ru + Bi + Si) 0.36 Si / (Ru + Bi + Si) 0.12

On the other hand, the pyrochlor oxide represented by the formula (2) can be used as a conductor as a similar result.

5A and 5B show an embodiment of a capacitor according to the present invention that can be applied to a DRAM or the like.

FIG. 5A shows a simple stacked structure, and FIG. 5B shows a three dimensional stacked capacitor.

Referring to FIG. 5A, the lower electrode 11 and the upper electrode 13 are formed of the pyrochlor conductive oxide film according to the present invention as described above, and between them also the pyrochlor dielectric thin film 12 for charge accumulation. Is interposed.

Referring to FIG. 5B, a pyrochlor dielectric thin film 22 is formed on the surface of the storage node 21 as a columnar lower electrode to form a capacitor having a large area at a narrow projection area, and the upper electrode is formed on the dielectric thin film 22. 23 is formed. The lower electrode 21 and the upper electrode 23 are formed of pyrochlor conductive oxide.

The lower electrodes 11 and 21 and the upper electrodes 13 and 23 may be formed of Bi-Ru-Si-O or Pb-Ru-Si-O represented by Chemical Formulas 1 or 2 described above. In this case, the lower electrodes 11 and 21 and the upper electrodes 13 and 23 may be formed of the same material or different materials, but are preferably formed of the same material.

The feature of the capacitor of the present invention is that at least one of the upper and lower electrodes and a dielectric thin film therebetween are formed by a material having a pyrochlore crystal structure. Preferably, the lower electrode is formed of pyrochlor conductive oxide, and the upper electrode may be formed of TiN, Ru, or the like, which is used in addition to the pyrochlor conductive oxide.

As described above, the electrode and the dielectric material having the same or similar crystal structure can maximize the dielectric constant.

The pyrochlor dielectric material applied to the capacitors of the above two embodiments is Bi-Ti-Si-O or Bi-Ti-O described above.

It is confirmed by the following fact that Bi-Ti-Si-O, a bismuth titanium silicon oxide, has a pyrochlore structure.

The XRD pattern of FIG. 6 is similar to the XRD pattern of Bi ₂ Ti ₂ O ₇ (JCPDS card 32-0118, Jour. Cryst. Growth, 41, 317 (1997)) and observed with a High Resolution Transmission Electron Microscope (HRTEM). Result Not only is the crystal lattice structure uniform, but the composition analysis of the Scanning Transmission Electron Microscope-Energy Dispersive Spectrometer (STEM-EDX) performed in the thickness direction of the thin film for one particle showed that Bi was in the depth direction of the thin film. It was confirmed that the composition distribution of, Ti, Si had a uniform pyrochlore structure.

Pyrochlor structure (A ₂ B ₂ X ₇ or A ₂ B ₂ X ₆ Z, where A and B correspond to cations and X and Z correspond to anions) is an equiaxed crystal system, (BX ₆ ) n-polyhedra Is connected only at the vertices, and the A cation is formed in the lattice interstices. (Jour. Appl. Phys., Vol. 51, No. 1 (1980))

Bismuth-titanium-silicon oxide can form a thin film through a conventional film forming method. For example, metal organic chemical vapor depostition (MOCVD), atomic layer deposition (ALD), pulsed laser deposition (PLD), molecular beam epitaxy (MBE), and the like. It can be formed through. According to each of these manufacturing methods will be described later.

First, a method of forming a Bi-Ti-Si-O thin film by the ALD method is as follows.

After heating the silicon substrate on which the pyrochlor conductive oxide film is formed, the substrate is transferred to a heater to stabilize the substrate temperature within a predetermined range. The substrate temperature here is preferably 150 to 700 ° C, particularly 250 to 500 ° C. If the substrate temperature is lower than 150 ° C, a thin film with high density cannot be obtained, and impurities such as unreacted precursors, carbon, and chlorine in the film are not removed but remain in the film, resulting in deterioration of film quality such as crystallinity. When the temperature exceeds 700 ° C, the precursor is severely deformed, and thus the surface is not sufficiently vaporized to be purged in the purge step after surface adsorption. Impurities such as carbon in the film cause film degradation, which is undesirable.

Subsequently, it is made into non-oxidizing atmosphere using inert gas. At this time, argon gas, nitrogen gas, or the like is used as the inert gas, and the flow rate of these inert gases is suitably 100 to 300 sccm. If the flow rate of the inert gas is out of the above range, it takes a long time to purge the precursor present in the oxidizing gas or the gas phase, and if the amount is blown too much, the pressure with the oxidizing step or the precursor adsorption step The difference is large, the fluctuation of the pressure state of the reactor (reactor) is severe, it is difficult to obtain a stable thin film is undesirable.

The precursor mixture for Bi-Ti-Si-O thin film formation is then fed into a vaporizer, which is then evaporated and adsorbed onto the substrate surface. Here, the temperature of the vaporizer is preferably controlled to 170 to 300 ° C., particularly 200 to 250 ° C., since it is possible to sufficiently vaporize without thermal deformation of the precursor mixture, and the supply amount of the precursor mixture for Bi-Ti-Si-O thin film formation Is preferably 0.01 to 0.3 cc / min. If the temperature of the vaporizer is less than 170 ℃, it is not possible to ensure a sufficient vapor pressure to make the precursor gaseous as much as the desired amount, if it exceeds 300 ℃ there is a fear of thermal deformation of the precursor mixture and if so modified Deterioration of the vaporization properties of the precursors makes it impossible to supply a sufficient amount of precursor to the reactor, which is undesirable.

The feeding method of the precursor mixture for forming the Bi-Ti-Si-O thin film is not particularly limited. As a specific example, there is a method using a bubbler (bubbler), a method using a direct liquid injection (DLI) method. Here, the DLI method dissolves a precursor for forming a Bi-Ti-Si-O thin film in an appropriate concentration in a solvent, and then closes the vaporization temperature of each precursor or organic solvent to vaporize the source supplied at room temperature. The vaporization precursor and the organic solvent are supplied to the reactor by directly supplying to the vaporizer placed below.

Of the two methods described above, it is more preferable to use the DLI method. For this reason, according to the method using the bubbler, the precursor mixture for forming the Bi-Ti-Si-O thin film is exposed to heat for a long time, while the DLI method is used. The advantage is that it can effectively suppress the change over time of the precursor source mixture.

The precursor mixture for Bi-Ti-Si-O thin film formation is prepared by mixing the Bi precursor, Ti precursor and Si precursor as listed below in a solvent. Herein, the content of Ti precursor is 1 to 3 mol based on 1 mol of Bi precursor, and the content of Si precursor is preferably 0.5 to 3 mol based on 1 mol of Bi precursor. Do. If the content of the Ti precursor is less than the above range, a thin film containing Bi is relatively formed, and the surface state of the thin film is deteriorated. When the Ti precursor is exceeded, the surface state is good. Not preferred. If the content of the Si precursor is less than the above range, the surface state of the thin film is deteriorated, and if it exceeds the above range, the surface state is good, but the deposition rate decreases, and the electrical properties are deteriorated, which is not preferable.

<< precursor >>

Bi precursor :

1) Bi (MMP) ₃ {Tris (1-methoxy-2-methyl-2-propxy) bismuth}

2) Bi (phen) ₃ or

3) BiCl ₃

Ti precursor :

1) Ti (MMP) ₄ {Tetrakis (1-methoxy-2-methyl-2-propoxy) titanium},

2) TiO (tmhd) ₂

3) Ti (i-OPr) ₂ (tmhd) ₂ ,

4) Ti (dmpd) (tmhd) ₂

5) Ti (depd) (tmhd) ₂ or

6) TiCl ₄

Si precursor :

1) tetraethylorthosilicate (TEOS) or

2) SiCl ₄

In the composition of the precursors above, tmhd represents 2,2,6,6-tetramethylheptane-3,5-dionate (2,2,6,6-tetramethylheptane-3,5-dionate), i -OPr represents an isopropyl group. In addition, dmpd represents dimethyl pentanediol, depd represents diethyl pentanediol, and phen represents a phenyl group.

The solvent is not particularly limited as long as it can dilute or dissolve Bi precursor, Ti precursor, Si precursor, ethylcyclohexane (C ₈ H ₁₆ : hereinafter abbreviated as "ECH"), tetrahydro Furan, n-butyl acetate, butyronitrile and the like. The content of such a solvent is preferably used to such an extent that each concentration is 0.04 to 0.2 M in the precursor mixture containing Bi precursor, Ti precursor, and Si precursor.

As described above, after adsorbing the precursor mixture for Bi-Ti-Si-O thin film formation to the substrate surface, only one to three layers are left on the substrate surface, and other Bi-Ti-Si-O thin film formation The precursor mixture is purged and removed using an inert gas. Here, the flow rate of the inert gas is variable depending on the atomic layer deposition equipment and the like, but is preferably 100 to 300 sccm, and the working pressure in the reactor is preferably 0.5 to 10 torr. The purge process using such an inert gas may be omitted in some cases.

Thereafter, the precursor mixture for bi-Ti-Si-O thin film formation adsorbed on the substrate surface is oxidized by blowing oxidizing gas to deposit atomic layer 4 to form a Bi-Ti-Si-O thin film. Here, as the oxidizing gas, oxygen (O ₂ ), ozone (O ₃ ) or water vapor (H ₂ O) is used, and their flow rates are preferably 100 to 300 sccm.

The above-mentioned inert gas purge, precursor mixture adsorption for forming a Bi-Ti-Si-O thin film, and inert gas purge and oxidation steps are repeatedly performed to obtain a Bi-Ti-Si-O thin film having a desired thickness. The Bi-Ti-Si-O thin film thus formed has a thickness of 50 to 300 GPa, and a dielectric constant of about 100 to 200.

After the formation of the Bi-Ti-Si-O thin film, a high temperature heat treatment process may be performed to enhance the crystallization of Bi-Ti-Si-O to obtain a thin film having a higher dielectric constant. At this time, the heat treatment temperature is 500 to 800 ℃, the heat treatment time is 1-30 minutes, and the heat treatment atmosphere is preferably composed of an oxidizing atmosphere or a vacuum atmosphere. At this time, the oxidation atmosphere is formed using oxygen (O ₂ ), ozone (O ₃ ) or water vapor (H ₂ 0), and the vacuum conditions are preferably about 0.01 to 100 mtorr, particularly about 35 mtorr.

Next, a method of forming a Bi-Ti-Si-O thin film by MOCVD is as follows.

First, the inside of the reactor is formed in an oxidizing atmosphere. At this time, the oxidizing atmosphere is formed using an oxidizing gas such as oxygen (O ₂ ), ozone (O ₃ ), water vapor (H ₂ 0), and the flow rate of the oxidizing gas is variable depending on the deposition equipment, but is 100-300 sccm Is preferably.

Subsequently, the temperature of the silicon substrate on which the pyrochlor conductive oxide film is formed is stabilized within a predetermined range. At this time, the temperature of the substrate (meaning the temperature of the reactor) is preferably 300 to 500 ℃. The problem when the temperature of the substrate is out of the above range is the same as that described in the ALD method. The type of substrate is also the same as that described in the ALD method.

The precursor mixture for Bi-Ti-Si-O thin film formation was supplied into a reactor composed of an oxidizing atmosphere, and the precursor mixture for forming a Bi-Ti-Si-O thin film was deposited on a substrate to produce a Bi-Ti-Si-O thin film. To form. Here, the conditions of the composition, the feeding method, and the like of the precursor mixture for forming the Bi-Ti-Si-O thin film are the same as or similar to those described in the ALD method.

In addition, like the ALD method, after forming the Bi-Ti-Si-O thin film, it is also possible to perform a high temperature heat treatment process for promoting the crystallization of Bi-Ti-Si-O, and the high temperature heat treatment conditions are almost the same.

In addition, the Bi-Ti-Si-O thin film can be formed by the PLD method. In the PLD method, when a strong pulse laser light incident from the outside is irradiated onto a target, particles protruding from the target form a plasma by light energy incident later. These particles are stacked on a substrate to obtain a high quality Bi-Ti-Si-O thin film. In particular, this method can form a Bi-Ti-Si-O thin film as long as only a simple component such as a target, a substrate, a heater, and the like is provided inside the reaction chamber, so that deposition can be performed even at high oxygen partial pressure. In addition, since the kinetic energy of the particles reaching the substrate is hundreds of eV, the energy required to form the oxide phase at a relatively low temperature can be obtained without causing much damage to the already deposited thin film. Si-O thin films can be obtained. Looking at the Bi-Ti-Si-O thin film manufacturing process conditions according to an embodiment using the PLD method, the temperature of the substrate on which the thin film is to be formed is 250 to 600 ℃, ArF laser (wavelength: 193nm) is used as a laser The laser beam size is about 0.3 cm _2, the gas pressure of O ₂ is 0.1 to 0.5 torr, and the repetition rate is about 5 Hz.

Molecular Beam Epitaxy (MBE) is a method that can control oxide growth in atomic units. Looking at the process conditions, Bi, Ti and Si ₂ H ₆ are used as precursors for forming Bi-TI-Si-O thin films, respectively. Oxygen or ozone is used as the oxidizing gas.

The Bi-Ti-Si-O thin film is formed on the lower electrode by the pyrochlor conductive oxide film through the above process, and then the upper electrode is formed as the pyrochlor conductive oxide film by the same method described above.

After the upper electrode is formed, the resultant is subjected to high temperature heat treatment. This heat treatment process is to improve the crystallization and obtain high dielectric constant characteristics. In some cases, the high temperature heat treatment may be performed before forming the upper electrode. Here, the process conditions of the high temperature heat treatment process, the heat treatment temperature is 500-800 ℃, the heat treatment time is 1 to 30 minutes, the heat treatment atmosphere is oxidizing atmosphere (O ₂ , O ₃ gas), inert atmosphere (N ₂ ) or vacuum In the atmosphere. Here, if the heat treatment atmosphere is formed in a vacuum atmosphere, the vacuum pressure is preferably 0.01 to 100 mtorr, in particular about 35 mtorr.

After the heat treatment process is completed, a compensation heat treatment process is performed. This compensation heat treatment process is to compensate for the oxygen deficiency at the interface between the electrode and the Bi-Ti-Si-O thin film by performing heat treatment when the capacitor structure is susceptible to oxidation. Looking at the conditions of the compensation heat treatment process, the heat treatment temperature is 500 ℃ or less, preferably 200-450 ℃, heat treatment time is 10-60 minutes, heat treatment atmosphere is carried out under vacuum atmosphere, air atmosphere or inert atmosphere.

The pyrochlor conductive oxide according to the present invention can be used as a new material, especially as a material of a capacitor used in various applications with a pyrochlor dielectric material having a high dielectric constant. Dielectric and conductive materials of the same crystal structure maximize the permittivity of the capacitor, and thus are suitable for ultra high density DRAM and the like. In particular, the pyrochlor conductive oxide according to the present invention is easy to prepare a precursor, and thus it is possible to form a film by MOCVD or ALD to obtain a three-dimensional structure.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be defined only in the appended claims.

Claims (10)

A conductive oxide represented by Formula 1 and having a pyrochlore structure. <Formula 1> Bi ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1) A conductive oxide represented by Formula 1 and having a pyrochlore structure. <Formula 1> Pb ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1) An oxide thin film represented by Chemical Formula 1 and containing bismuth ruthenium silicon oxide having a pyrochlore structure. <Formula 1> Bi ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1) An oxide thin film represented by Chemical Formula 1 and containing bismuth ruthenium silicon oxide having a pyrochlore structure. <Formula 1> Pb ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1) Lower electrode; A dielectric layer formed of a dielectric material formed on the lower electrode; In the capacitor having an upper electrode formed on the dielectric layer, At least one of the upper electrode and the lower electrode is represented by the following Chemical Formula 1 and is formed of an oxide having a pyrochlore structure. <Formula 1> Bi ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1) The method of claim 5, wherein The dielectric layer has a pyroclorod crystal structure and is formed of bismuth titanium silicon oxide (Bi-Ti-Si-O) represented by the formula (1) below. <Formula 1> Bi ₂ (Ti _2-x Si _x ) O _7-Y (0.8 <x <1.3, -1 <y <1) The method of claim 5, wherein The dielectric layer is a capacitor, characterized in that formed of Bi ₂ Ti ₂ O ₇ having a pyrochlore structure. Lower electrode; A dielectric layer formed of a dielectric material formed on the lower electrode; In the capacitor having an upper electrode formed on the dielectric layer, At least one of the upper electrode and the lower electrode is represented by the following Chemical Formula 1 and is formed of an oxide having a pyrochlore structure. <Formula 1> Pb ₂ (Ru _2-x , Si _x ) O _7-y (0 <x <2, 0 <y <1) The method of claim 5, wherein The dielectric layer has a pyroclorod crystal structure and is formed of bismuth titanium silicon oxide (Bi-Ti-Si-O) represented by the formula (1) below. <Formula 1> Bi ₂ (Ti _2-x Si _x ) O _7-Y (0.8 <x <1.3, -1 <y <1) The method of claim 5, wherein The dielectric layer is a capacitor, characterized in that formed of Bi ₂ Ti ₂ O ₇ having a pyrochlore structure.