JPH08316098A - Method for manufacturing dielectric thin film - Google Patents

Abstract

(57) [Summary] [Object] Regarding a method for manufacturing a dielectric thin film, PMN-P having a high dielectric constant perovskite structure is manufactured by a simple manufacturing method.
The T thin film is manufactured with good reproducibility. [Constitution] Mg _x Nb ₂ O ₆ target (1 ≦ x
<2), TiO ₂ or Ti target, and PbO
Alternatively, [Pb (Mg) may be formed on the substrate 1 by a reactive sputtering method using a plurality of Pb targets.
_1/3 Nb _2/3 ) O ₃ ] _y and [PbTiO ₃ ] _1-y 2
A PMN-PT thin film 5 (provided that 0.65 ≦ y <1) of a perovskite structure made of an original solid solution is deposited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a dielectric thin film, and more particularly to a high dielectric constant [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] _y [PbTi used for a capacitor.
O ₃ ] _1-y , that is, a method for producing PMN-PT.

[0002]

2. Description of the Related Art In recent years, along with the miniaturization of electronic equipment, the miniaturization and high integration of electronic parts used in such electronic equipment have been rapidly progressing. Miniaturization and miniaturization are required.

For example, in a DRAM (Dynamic Random Access Memory), the area occupied by the capacitor portion must be reduced with high integration, but the charge storage amount does not change or tends to increase. It is in.

However, the SiO ₂ film and Si ₃ N ₄ which have been used as the dielectric material of the conventional DRAM capacitor are used.
Due to the low relative permittivity of the film, the accumulated charge could not be increased.

For downsizing of electronic equipment, MCM
(Multi-Chip Module) is one flow, but when a chip type capacitor is used in the MCM, there is a limit to noise reduction due to the presence of the inductance due to the lead between the LSI and the capacitor. Also, since there is a problem that the mounting area occupied by a chip capacitor increases and the miniaturization is hindered when the number of LSI chips on one module increases, it is considered to replace the chip type with a thin film capacitor. ing.

Further, MMIC (Monolithic)
Microwave Integrated Cir
The problems similar to those of MCM occur also in the cuts), and therefore, studies are being made to replace the capacitor of chip type with a thin film capacitor.

In recent years, in order to solve such problems, Pb (Mg) has been used as a dielectric film constituting a thin film capacitor.
_1/3 Nb _2/3 ) O ₃ or [Pb (Mg _1/3 Nb _2/3 )
O ₃ ] _y [PbTiO ₃ ] _1-y , that is, PMN or PMN
The use of a high dielectric material such as -PT is being studied.

For example, with respect to the former PMN, it is reported that a PMN having a perovskite structure with a high dielectric constant can be obtained by forming a film by a reactive sputtering method using two types of targets of Pb and MgNb ₂ O _6. Has been done.

Regarding the latter PMN-PT, 1
P formed from metal oxide powder at high temperature of 000 ° C
MN-PT ceramics have a perovskite structure,
In addition, it has been reported that it has a high dielectric constant of 10,000 to 20,000 (US Pat. No. 4,712,156, US Pat. No. 4,858,066, and US Pat. No. 5,219,810. See the specification).

In this case, PMN- is obtained by adding excess Pb (lead) and Mg (magnesium) to the reaction raw material.
The ratio of the perovskite structure in the PT ceramics can be increased, and the ratio of PMN [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] and PT [PbTiO ₃ ] in the PMN-PT ceramics can be changed. Can change the dielectric constant and the Curie point.

However, it is necessary to reduce the film thickness in order to use it for a thin film capacitor, but such a PMN-PT thin film is formed by a pulse laser deposition method using a single target.
It is reported that the film is formed at a temperature of 00 to 700 ° C (C.T.
antigate, et al. , MRS Symp.
Proc. , 1995, p. 361, is scheduled to be issued), and it is also reported that the sputtering method using a single target is performed at a temperature of 610 to 640 ° C. (MC Jiang and TB Wu,
J. Mater. Res. , Vol. 9, No. 7, J
uly, 1994, p. 1879-1886).

Further, in general, AMO ₃ (where A = C
a, Sr, Ba, Pb, M = Zr, Hf, Sn, T
The various perovskites represented by i) are manufactured by a sputtering method using a single target or a sputtering method using a plurality of targets, and these thin films are used as a thin film capacitor or for a storage device. (US Pat. No. 4,888,2
46 and US Pat. No. 4,857,802).

It is known that such a perovskite has excellent electrical characteristics as compared with a binary metal oxide. However, when manufacturing a thin film of this perovskite, manufacturing conditions and Careful selection of the composition and crystallographic orientation of the deposited substrate is required.

Further, a perovskite thin film is (100)
A perovskite thin film having excellent crystallinity is obtained when deposited on a single crystal substrate such as MgO, SrTiO ₃ or sapphire.

In order to utilize the electrical characteristics of such a thin film, it is necessary to form an electrode. Recently, as an electrode therefor, an oxide electrode such as RuO ₂ or SrRuO ₃ is replaced with a metal electrode such as Pt. As a result, an epitaxial thin film or a thin film having a good crystal orientation has been obtained, and stable electrical characteristics have been obtained. As a result, such an epitaxial thin film, or
A thin film having good crystallinity and a large crystal grain size is required in the field of ferroelectrics or the field of optics.

Further, using a single compound target, 5
It has been reported that a pyrochlore thin film and a PMN-PT thin film having a perovskite structure are produced by sputtering on various substrates at a temperature of 50 to 700 ° C. (MC Jiang and TB Wu, ibid.). .

In this case, as a deposition substrate, a Si single crystal substrate or Pt / SiO ₂ / Si, that is, a SiO ₂ film is provided on the surface of the Si single crystal substrate, and then Pt is formed on the surface.
When the substrate provided with is used, only a thin film having a pyrochlore structure can be obtained under a temperature condition of 500 to 700 ° C.

The obtained niobate having a pyrochlore structure
Lead is Pb₂Nb₂O₇Or Pb _1.8Mg_0.3Nb
_1.7O_6.4It has the same chemical composition as perovskite like
However, the crystal structure is different and the dielectric constant is 20.
Up to 200, much lower than perovskites
is there.

On the other hand, Pt (111) / Ti / SiO ₂ /
In the case of using Si, that is, a substrate in which a SiO ₂ film is provided on the surface of a Si single crystal substrate, and then Pt is provided via Ti (in this case, the crystal orientation of Pt is the (111) plane) , A perovskite structure thin film having different crystal orientations is obtained, its dielectric constant is about 2500, and the film thickness-dependent loss coefficient (loss tangent) is 0.03. Value is PMN in bulk state
-Much smaller than PT ceramics.

In this case, T provided under the Pt layer
The i layer acts as an adhesive layer for holding the Pt lower electrode on the SiO ₂ / Si substrate, and a part of Ti is Pt.
The perovskite component in the thin film is also increased by permeating and diffusing into the Pt surface to reach the Pt surface (MCJ
i ang and T.I. B. Wu, ibid., K. Aok
i, et al. , Jpn. J. Appl. Phy
s. , Vol. 34, 1995, p. 192).

That is, T existing on the surface of the Pt lower electrode
i is Pb supplied in the state of oxygen and gas, and Pb + T
By reacting i + O ₂ (or Pb + TiO ₂ ) → PbTiO _{3 in} the reaction formula, Pb is formed on the Pt lower electrode surface.
TiO ₃ is formed, and this PbTiO ₃ acts as a growth nucleus for growing the perovskite thin film. In this case, since TiO _{2 on} the Pt surface does not have a specific crystal orientation, the obtained thin film also does not have a specific crystal orientation.

[0022]

However, when a PMN-PT thin film is formed by a sputtering method using a single target, Pb and PbO have a high vapor pressure at a high deposition temperature and therefore have good reproducibility. There is a problem that results cannot be obtained.

That is, since the vapor pressures of Pb and PbO are high, they are sputtered at a faster rate than the other constituents in the target, so it is necessary to add excess Pb to the target. As a result, the components in the target will change each time it is used, so it becomes necessary to frequently replace the target with a new target. Further, the required amount of excess Pb in the target needs to be appropriately changed depending on the composition and characteristics of the thin film to be obtained.

Further, when a plurality of constituent components are sputtered using a single target, there is a problem that the deposited thin film is sputter-etched (resputtered) by oxygen ions in the discharge process. The composition will differ from that of the target. The amount of sputter etching (resputtering) generated in this case depends on the manufacturing conditions and the type of substrate (A. Hameri).
ch, et al. , J. et al. Vac. Sci. and T
ech. , A12 [5], 1994, p. 2873).

PMN-PT having a perovskite structure
When a thin film is deposited on a Pt (111) / Ti / SiO ₂ / Si substrate, Ti diffuses through the Pt layer, so it becomes very unstable at high temperatures (Screeniva).
s, et al. , J. et al. Appl. Phys. , Vo
l. 75, no. 1, 1994, p. 232).

Further, Ti formed on the surface of the Pt lower electrode
O ₂ will increase the resistivity of the Pt layer and change the characteristics of the thin film, so that a thin film having a rough surface, a small crystal grain size, different crystal orientations, and non-uniformity can be obtained. .

Therefore, it is an object of the present invention to manufacture a PMN-PT thin film having a high dielectric constant perovskite structure with good reproducibility by a simple manufacturing method.

[0028]

FIG. 1 shows the principle structure of a dielectric thin film obtained by the manufacturing method of the present invention. To solve the problem in the present invention with reference to FIG. The means will be described.

See FIG. 1 (1) The present invention relates to a method for producing a dielectric thin film, wherein [P
b (Mg_1/3Nb_2/3) O₃]_yAnd [PbTiO₃]
_1-yInduction of perovskite structure consisting of binary solid solution with
Electric thin film, that is, PMN-PT thin film 5 (however, 0.65
≦ y <1) Mg _xNb₂O₆Target (however, 1 ≦
x <2), TiO₂Or Ti target and Pb
Reaction using multiple targets of O or Pb targets
Be deposited on the substrate 1 by the reactive sputtering method.
And are characterized.

(2) Further, in the present invention according to the above (1), at least one layer of the intervening layer 2, the lower electrode 3 and the diffusion barrier layer 4 including the lower electrode 3 is sequentially deposited on the substrate 1. Then, the P of the perovskite structure composed of a binary solid solution is formed.
The MN-PT thin film 5 is deposited, and then the upper electrode 6 is deposited.

(3) Further, in the present invention according to the above (2), the substrate 1 is made of an insulating substrate or a semiconductor substrate, the intervening layer 2 has a thickness of 0 to 100 nm, and the lower electrode 3 has a thickness of 50. To 150 nm metal or oxide,
The diffusion barrier layer 4 has a thickness of 0 to 20 nm, and the upper electrode 6 has a thickness of 50 to 150 nm.

(4) In addition, according to the present invention, in the above (3), the intervening layer 2 includes MgO, TiO ₂ and Bi ₄ Ti _3.
O ₁₂ and the diffusion barrier layer 4 is Mg.
It is characterized by being any one of O, SrTiO ₃ , and Ti.

(5) The present invention also includes (1) to (4)
In any one of the above, the solid solution ratio y of the PMN-PT thin film 5 having a perovskite structure composed of a binary solid solution is the power ratio applied to each target, the deposition temperature, the ratio of oxygen to rare gas of the sputtering gas, and the annealing temperature. It is characterized by controlling by changing at least one of the above.

[0034]

[Operation] [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] _y and [Pb
TiO ₃ ] _1-y PMN-PT thin film 5 having a perovskite structure composed of a binary solid solution (provided that 0.65 ≦ y <1)
By using three targets in the production of, it is possible to suppress resputtering that causes a decrease in Mg in the thin film, and it is possible to form a thin film having a stable composition with good reproducibility.

That is, the resputtering itself should be eliminated.
Not possible, but Mg_xNb₂O ₆Target 10
% Excess Mg, or set an independent Mg target.
Or changing the power ratio of each target
Suppresses the decrease of Mg due to resputtering
Can be When y <0.65, the dielectric
The rate becomes low and it becomes impractical.

By providing the intervening layer 2 on the substrate 1, the adhesiveness of the lower electrode 3 can be increased, or
The crystal orientation of the lower electrode 3 provided thereon can be effectively controlled. Further, by providing the diffusion barrier layer 4, even when TiO ₂ is used as the intervening layer 2, PMN
The perovskite component in the -PT thin film 5 can be increased, and the dielectric constant can be increased.

The substrate 1 is made of an insulating substrate such as MgO or a semiconductor substrate such as Si, the thickness of the intervening layer 2 is set to 0 to 100 nm, and is made of a metal such as Pt or an oxide such as RuO _2. The thickness of the lower electrode 3 is 50 to 150 n
m, the thickness of the diffusion barrier layer 4 is set to 0 to 20 nm, and the thickness of the upper electrode 6 is set to 50 to 150 nm, so that the PMN-P of the perovskite structure is formed.
The T thin film 5 can be stably obtained.

As the intervening layer 2, MgO or Bi is used.
By using ₄ Ti ₃ O ₁₂ , the crystal orientation of the Pt lower electrode 3 can be made to be the (100) plane, and by using MgO, SrTiO ₃ or Ti as the diffusion barrier layer 4, a perovskite structure can be obtained. The PMN-PT thin film 5 can be stably obtained.

The solid solution ratio y of the PMN-PT thin film 5 having a perovskite structure made of a binary solid solution controls the power ratio applied to each target, the deposition temperature, and the ratio of oxygen to rare gas of the sputtering gas. It can be controlled accurately.

When the amorphous solid binary solution is deposited at a low deposition temperature and then the PMN-PT thin film 5 of polycrystalline perovskite structure is formed by annealing, the solid solution ratio y depends on the annealing temperature. Can be controlled accurately.

[0041]

EXAMPLE An example of the present invention will be described with reference to FIG. 2A is a schematic configuration diagram of a magnetron sputtering apparatus used for carrying out the present invention, and FIG. 2B is manufactured using the magnetron sputtering apparatus shown in FIG. 2A. FIG. 7 is an explanatory view of a manufacturing process of the thin film capacitor.

See FIG. 2A. The basic part of this magnetron sputtering apparatus is
A substrate holder 7, which holds the substrate 1 made of MgO, Si, or the like, and also stores a heater therein, a PbO target 8, M
_{An x} N (Mg _x Nb ₂ O ₆ ) target 9, a TiO ₂ target (not shown), and a shutter 10 for controlling sputtering from each target.

The substrate holder 7 has a central shaft 11 as a rotating shaft.
It is possible to rotate as a substrate holder 7
The distance d between each target opening 12 is 70 mm.
Yes, between this substrate holder 7 and each target 8, 9
O as sputter gas 13 ₂And Ar are introduced,
Plasma is generated by applying microwave power.
While the substrate holder 7 is rotating while
Do the data.

Next, this magnetron sputtering
A method of manufacturing a thin film capacitor using the apparatus will be described. Refer to FIG. 2B. First, a (100) plane MgO substrate or (100) plane.
SiO on the Si surface ₂A substrate 1 provided with a film is prepared.

Next, in a sputtering apparatus different from that shown in FIG. 2, at a substrate temperature of 400 to 700 ° C., TiO ₂ on the (110) plane and Mg on the (100) plane were formed on the substrate 1.
The intervening layer 2 made of O or (100) plane of Bi ₄ Ti ₃ O ₁₂ is deposited in a thickness of 0 to 10 nm.

The intervening layer 2 is a lower portion provided on the intervening layer 2.
Improving the adhesion of the electrode 3 and crystallizing the lower electrode 3
Has a function of controlling the position, and the TiO of (110) plane₂For
If it is present, the crystal orientation of Pt becomes the (111) plane,
Bi on (100) plane_FourTi₃O ₁₂When using Pt
Has a crystal orientation of (100) plane, and Mg of (100) plane is
When O is used, the crystal orientation of Pt is the (100) plane.
It

Next, at a substrate temperature of 20 to 620 ° C., Pt, RuO ₂ or Sr is formed on the substrate 1 or the intervening layer 2.
After depositing a lower electrode 3 made of RuO ₃ and having a thickness of 80 to 100 nm, a diffusion barrier layer 4 made of Ti, MgO, or SrTiO ₃ and having a thickness of 0 to 5 nm is provided on the lower electrode 3. When Ti is used as the diffusion barrier layer 4, Ti is oxidized to form TiO ₂ .

Next, the substrate 1 provided with the intervening layer 2 to the diffusion barrier layer 4 is fixed to the substrate holder 7 of the magnetron sputtering apparatus, and then the substrate temperature is raised to the deposition temperature by the heater.

Next, the sputtering gas 13 composed of O ₂ and Ar is introduced into the reaction chamber of the magnetron sputtering apparatus. In this case, the flow rate of the sputter gas 13 is controlled by the mass flow controller, and the O in the sputter gas 13 is controlled.
_{The 2} flow rate ratio [O ₂ / (O ₂ + Ar)] is controlled to be 0.1 to 0.2.

Further, the pressure of the reaction system in this case is controlled by a capacity pressure gauge, an automatic pressure controller (APC), and a valve, and is adjusted to 1.3 Pa by the valve adjusting position of the automatic pressure controller and the gas flow rate. It

Next, microwave power is supplied from the magnetron to generate plasma discharge, and then the shutter 10
In the closed state, pre-sputtering is performed at a preset power for about 30 minutes, and when the surfaces of the targets 8 and 9 reach a stable state, the shutter 10 is opened and the deposition of the PMN-PT thin film 5 is started. The deposition time of this PMN-PT thin film 5 is
The time is 1 to 10 hours, depending on the deposition conditions and the required film thickness.

Next, the substrate 1 is transferred to another sputtering apparatus, and the upper electrode 6 made of Pt, RuO ₂ or SrRuO _{3 having} a thickness of 80 to 100 nm is formed on the PMN-PT thin film 5 by sputtering. Total thickness is 0
Form a capacitor of ˜5 μm.

PMN-PT thin film 5 thus obtained
X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP),
Alternatively, it was examined using X-ray fluorescence spectroscopy (XRF). The electrical characteristics of the PMN-PT thin film 5 were measured using an impedance analyzer.

The results thus obtained are shown in FIGS. 3 to 5. In this case, the perovskite component in the PMN-PT thin film 5 is measured by a 2θ-XRD pattern obtained by scanning the diffraction component of the X-ray incident at a low incident angle in the range of 20 to 50 °. The perovskite composition ratio (%) is expressed by a value obtained by dividing the intensity of diffraction due to perovskite by the total intensity of diffraction peaks and multiplying it by 100.

The dielectric properties of the PMN-PT thin film 5 are
The measurement sample in which the terminal 15 of the impedance analyzer 14 is connected to the upper electrode 6 and the lower electrode 3 constituting the thin film capacitor is stored in an oven, and the capacitance of the thin film is changed in the temperature range of -15 ° C to 150 ° C. The dielectric constant here indicates the maximum value calculated from the capacitance measurement of the thin film, and the maximum value of this dielectric constant is observed at the so-called Curie temperature (Curie point). Was done.

The composition ratio of cations in the PMN-PT thin film 5, that is, Pb / (Nb + Ti + Mg), and P
The MN / (PMN + PT) ratio, that is, the solid solution ratio y indicates a value calculated based on the measurement results of ICP and XRF.

The thickness of the diffusion barrier layer 4 may be physically measured by a profilometer or a high resolution transmission electron microscope (TEM), or it may be measured electrically by an AC impedance spectroscopy. Nondestructive measurement method (M. Sayer, et al., Integrat.
Ferr. , Vol. 1, 1992, p. 129), the film thickness may be calculated based on the measured impedances of the PMN-PT thin film 5 and the diffusion barrier layer 4.

As shown in FIGS. 3 to 5, the crystal structure of the thin film, the Curie point, and the electrical characteristics are as follows.
It strongly depends on the crystal orientation, composition, and manufacturing conditions of the substrate and the electrode.

That is, as the substrate 1, MgO of the (100) plane is used.
If the PMN-PT thin film 5 is directly deposited on the MgO substrate (# 1, 2), the MgO substrate 1
When the Pt lower electrode 3 having a thickness of 80 nm is provided on the upper side (#
A PMN-PT thin film 5 having a perovskite structure was also obtained in 3), and its dielectric constant was 2400 in the case of sample # 3.
Is. Note that the dielectric constant cannot be measured without the electrodes.

However, when SiO ₂ / Si was used as the substrate 1, Pt with a thickness of 80 nm was used as in sample # 3.
Even if the lower electrode 3 is provided, PMN-having a perovskite structure is formed.
The PT thin film 5 could not be obtained (# 4).

However, when SiO ₂ / Si is used as the substrate 1 and RuO ₂ (# 6) or SrRuO ₃ (# 5) is used as the lower electrode 3, a PMN-PT thin film having a perovskite structure is used. 5 was obtained and its dielectric constants are 2400 and 2900, respectively.

Further, from FIG. 4, the intervening layer 2 is the lower electrode 3.
It can be seen that it affects the crystal structure and crystal orientation of.
That is, when the Pt lower electrode is directly provided on the (100) surface Si substrate having the SiO ₂ film on the surface, the crystal orientation of the Pt lower electrode is the (111) surface (# 4), but the SiO ₂ film The MgO layer (# 7,
8) or Bi ₄ Ti ₃ O ₁₂ (Bi) on the (100) plane
When the intervening layer 2 made of the (TO) layer (# 14 to 16) is provided, the crystal orientation of the Pt lower electrode as the lower electrode 3 changes from the (111) plane to the (100) plane. The lower electrode 3 is RuO ₂ (# 6) or SrRuO ₃ (# 5).
Also in the case of, the result similar to Pt was obtained.

When a thin film is deposited at high temperature on the Pt lower electrode 3 on the (111) plane where the intervening layer 2 is not provided (#
In 4), a thin film having a pyrochlore structure was obtained. By providing the intervening layer 2 to make the crystal orientation of the Pt lower electrode 3 the (100) plane, a perovskite structure having a high degree of orientation even at high temperatures was obtained. PMN-PT thin film 5 was obtained (# 8, 14-16). However,
Even when MgO having a thickness of 10 nm was provided as the intervening layer 2, the PMN-PT thin film 5 having the perovskite structure could not be obtained when the deposition temperature was 500 ° C (# 7).

Further, the crystal orientation of the Pt lower electrode 3 is (11
Also in the case of 1), a low temperature (20
Deposition of an amorphous thin film at 500 ° C (#
18) or 600 ° C. (# 19, 20) and subjected to rapid thermal annealing (RTA) for 15 seconds to crystallize (H. Hu, et al., Thin Soli.
d Films, Vol. 223, 1993, p. 32
7) The PMN-PT thin film 5 having a perovskite structure having different crystal orientations can be formed. However, the PMN-PT thin film 5 thus formed has a dielectric constant of 1
000 to 2200, which is slightly smaller than the dielectric constant of the PMN-PT thin film having high orientation formed at high temperature. The as-deposited PMN-PT thin film 5 at 20 ° C. naturally does not contain a perovskite component (# 1
7).

The Curie point of the PMN-PT thin film 5 is 20 to 40 ° C., and the Curie point tends to decrease as the solid solution ratio y of the PMN-PT thin film 5 increases, that is, as the PMN component increases. There is.

When the diffusion barrier layer 4 is not provided,
No perovskite structure was obtained at a deposition temperature of 500 ° C. (# 9), and even when deposited at 620 ° C., only PMN-PT thin film 5 having 10% perovskite component was obtained (# 10). By providing a diffusion barrier layer 4 of MgO, SrTiO ₃ , or Ti, PM
The perovskite component in the N-PT thin film 5 increases (#
13).

That is, 99% of the PMN-PT thin film 5 deposited on the Pt lower electrode 3 on the (111) plane having the diffusion barrier layer 4 made of oxide on the surface has a perovskite crystal structure from the XRD pattern. I found out that (#
13). However, when the deposition temperature is 500 ° C (# 11,
No perovskite was obtained even if the diffusion barrier layer 4 was provided in 12).

Of these, the dielectric constants of TiO ₂ formed by the oxidation of MgO and Ti are 10 and 15, respectively, and P
It is much smaller than the dielectric constant of MN-PT. Therefore, when MgO or Ti is deposited as the diffusion barrier layer 4 on the lower electrode 3, the capacitance of the entire capacitor is lowered due to the low dielectric constant of TiO ₂ formed by the oxidation of MgO and Ti. However, when the thickness of MgO or TiO ₂ is thin, MgO and TiO ₂
Decrease in the dielectric constant of the entire capacitor due to the offset by the improvement of the dielectric constant due to the improvement of the crystallinity of the PMN-PT thin film 5 due to the provision of MgO and TiO _2, the dielectric constant as a whole becomes rather high.

On the SiO ₂ film, a (100) -plane Bi ₄ Ti ₃ O ₁₂ (BiTO) layer (# 1) having a thickness of 10 nm is formed.
4 to 16) when the intervening layer 2 is formed, MgO,
The PMN-PT thin film 5 having a perovskite structure is provided by providing the diffusion barrier layer 4 of SrTiO ₃ or Ti.
In particular, the PMN-PT thin film 5 deposited on the diffusion barrier layer 4 such as MgO and SrTiO ₃ is 35
It had a high dielectric constant of 00 or more (# 14, 15).
This value is the highest value of the dielectric constant of PMN-PT thin films reported to date.

When Ti was provided as the diffusion barrier layer 4 on the Pt lower electrode 3 having the (111) plane, a PMN-PT thin film having a perovskite structure having different crystal orientations was obtained. Is relatively low (# 13, 16).

That is, from the above results, by carefully selecting the deposition conditions, the intervening layer 2, and the diffusion barrier layer 4, it is possible to obtain a highly oriented perovskite thin film 5 having a high dielectric constant. it is obvious.

It should be noted that the present invention is not limited to the numerical values of the above-mentioned embodiment, and the deposition temperature is 20 to 700 ° C., and the temperature and time of the rapid thermal annealing treatment when deposited at a low temperature are 500 to 500, respectively. 600 ° C and 0-3600
Seconds, the pressure is 0.5 to 10 Pa, and O ₂ / (O ₂ + A
The ratio r) is preferably in the range of 0.05 to 1.0. In addition,
Ar may be replaced with another rare gas such as He.

The power applied to each target is
PbO ceramic target is 10-50W, TiO₂
Ceramic target is 0 ~ 100W and M_xN
(Mg _1.1Nb₂O₆) Compressed powder target is 50-2
It is in the range of 00W. In addition, PbO ceramic target
May be replaced with a Pb metal target, or
TiO₂Ceramic target also Ti metal target
You may replace it.

Further, the thickness of the intervening layer 2 is 0 to 100n.
m, the lower electrode 3 and the upper electrode 6 have a thickness of 0 to 150 n.
m and the thickness of the diffusion barrier layer 4 are preferably in the range of 0 to 50 nm.

[0075]

According to the present invention, a PMN-PT thin film having a perovskite structure can be easily and reproducibly manufactured by a reactive sputtering method using three targets, and when Si is used as a substrate. In addition, it is possible to integrally provide a Si device having a high level of performance with a small capacitor having a large capacitance, which largely contributes to the performance improvement of electronic devices such as semiconductor devices.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a principle configuration of the present invention.

FIG. 2 is an explanatory diagram of an example of the present invention.

FIG. 3 is an explanatory diagram of manufacturing conditions relating to an example of the present invention.

FIG. 4 is an explanatory diagram of substrate conditions relating to an example of the present invention.

FIG. 5 is an explanatory diagram of an experimental result regarding an example of the present invention.

[Explanation of symbols]

1 substrate 2 intermediate layer 3 lower electrode 4 diffusion barrier layer 5 PMN-PT thin film 6 upper electrode 7 substrate holder 8 PbO target 9 M _x N target 10 shutter 11 central axis 12 opening 13 sputter gas 14 impedance analyzer 15 pin

Claims (5)

[Claims] 1. A ferroelectric thin film having a perovskite structure composed of a binary solid solution of [Pb (Mg _1/3 Nb _2/3 ) O ₃ ] _y and [PbTiO ₃ ] _{1- y} (provided that 0.65 ≦ y <1)
A Mg _x Nb ₂ O ₆ target (where 1 ≦ x <2),
TiO ₂ or Ti target and PbO or P
A method for producing a dielectric thin film, which comprises depositing on a substrate by a reactive sputtering method using a plurality of targets consisting of b targets. 2. An intervening layer, a lower electrode, and
Among the diffusion barrier layers, one layer including at least the lower electrode is sequentially deposited, a ferroelectric thin film having a perovskite structure made of the binary solid solution is deposited, and then an upper electrode is deposited. The method for producing a dielectric thin film according to claim 1. 3. The substrate is an insulating substrate or a semiconductor substrate, the intervening layer has a thickness of 0 to 100 nm, the lower electrode is made of a metal or an oxide having a thickness of 50 to 150 nm, and the diffusion barrier. The layer has a thickness of 0 to 20 nm, and the upper electrode has a thickness of 50 to 150 nm.
3. The method of manufacturing a dielectric thin film according to claim 2, wherein 4. The intervening layer comprises MgO, TiO ₂ , and
_4. The dielectric thin film according to claim ₃ , wherein the diffusion barrier layer is any one of Bi ₄ Ti ₃ O _{12 and} the diffusion barrier layer is any one of MgO, SrTiO ₃ and Ti. Production method. 5. A solid solution ratio y of a ferroelectric thin film having a perovskite structure composed of the binary solid solution, a power ratio applied to each of the targets, a deposition temperature, a ratio of oxygen to rare gas of a sputtering gas, and annealing. The method for producing a dielectric thin film according to claim 1, wherein the temperature is controlled by changing at least one of the temperatures.