JPWO2013069471A1 - Solid state electronic equipment - Google Patents

Abstract

One solid-state electronic device of the present invention includes an oxide layer (which may include inevitable impurities) made of bismuth (Bi) and niobium (Nb), and the oxide layer has a pyrochlore crystal structure and / or β-BiNbO 4. It has a crystal phase of a type crystal structure, and the carbon content in the oxide layer is 1.5 atm% or less.

Description

  The present invention relates to a solid-state electronic device.

Conventionally, in a solid-state electronic device, a device including a ferroelectric thin film that can be expected to operate at high speed has been developed. Metal oxides are currently being actively developed as dielectric materials for use in solid-state electronic devices, but BiNbO ₄ is a dielectric ceramic that does not contain Pb and can be fired at a relatively low temperature. As for this BiNbO ₄ , the dielectric properties of BiNbO ₄ formed by the solid phase growth method have been reported (Non-patent Document 1).

Effect of phase transition on the microwave selective properties of BiNbO4, Eung So Kim Kim, Wong Choi, Journal of the Europe 26

However, the dielectric constant of BiNbO ₄ formed by the solid phase growth method does not have a large relative dielectric constant, and it is necessary to further improve the dielectric characteristics in order to use it as an insulator of a solid-state electronic device.

  In addition, in terms of manufacturing, a solid electronic device including an insulator obtained by a manufacturing method excellent in industriality or mass productivity is desired.

  Accordingly, an object of the present invention is to provide a solid-state electronic device that has electrical characteristics that can be applied as a solid-state electronic device and that has a simple manufacturing process and is excellent in industrial and mass productivity.

  The inventors of the present application diligently researched oxides that can be applied to solid-state electronic devices such as capacitors and thin film transistors and that can be formed even by using an inexpensive and simple method. As a result of many trials and errors, the inventors have found that a specific oxide material replacing the conventionally widely used oxide is relatively inexpensive and simplifies the manufacturing process. It has been found that it has high insulation and relative dielectric constant. It was also found that the oxide can be applied to a solid-state electronic device. The present invention was created based on the above viewpoint.

The solid-state electronic device according to the first aspect includes an oxide layer (which may include inevitable impurities) made of bismuth (Bi) and niobium (Nb), and the oxide layer has a pyrochlore crystal structure and / or β- It has a crystal phase of BiNbO ₄ type crystal structure, and the carbon content in the oxide layer is 1.5 atm% or less.

In the solid-state electronic device according to the second aspect, the oxide layer has a crystal phase of a pyrochlore crystal structure and a β-BiNbO ₄ crystal structure.

In the solid-state electronic device according to the third aspect, the pyrochlore type crystal structure is substantially the same as (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ .

  In the solid-state electronic device according to the fourth aspect, the oxide layer further has an amorphous phase.

  The solid state electronic device according to the fifth aspect is a capacitor.

  The solid state electronic device according to the sixth aspect is a semiconductor device.

  The solid-state electronic device according to the seventh aspect is a MEMS device.

  According to the solid-state electronic device according to the first aspect, it is possible to obtain a solid-state electronic device having an excellent electrical characteristic because it includes an oxide serving as an insulating layer having a high relative dielectric constant and suppressed leakage current. It becomes.

  According to the solid state electronic device according to the third aspect from the solid state electronic device according to the second aspect, more excellent electrical characteristics can be obtained.

  According to the solid-state electronic device which concerns on a 4th aspect, reduction of a leakage current can be aimed at.

  According to the solid-state electronic device according to the fifth aspect, it is possible to provide a capacitor having good electrical characteristics.

  With the solid-state electronic device according to the sixth aspect, it is possible to provide a semiconductor device with good electrical characteristics.

  According to the solid-state electronic device which concerns on a 7th aspect, it becomes possible to provide a MEMS device with a favorable electrical property.

It is a figure which shows the whole structure of the thin film capacitor which is an example of the solid-state electronic device in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 2nd Embodiment of this invention. It is a figure which shows the whole structure of the thin film capacitor which is an example of the solid-state electronic device in the 2nd Embodiment of this invention. It is a figure which shows the whole structure of the thin film capacitor which is an example of the solid-state electronic device in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 3rd Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 4th Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 4th Embodiment of this invention. It is a cross-sectional schematic diagram which shows one process of the manufacturing method of the thin film capacitor in the 4th Embodiment of this invention. It is a figure which shows the whole structure of the thin film capacitor which is an example of the solid-state electronic device in the 4th Embodiment of this invention. It is the cross-sectional TEM photograph and electron beam diffraction image which show the crystal structure of the oxide layer used as the insulating layer in the 1st Embodiment of this invention. It is a cross-sectional TEM photograph and electron diffraction image which show the crystal structure of the oxide layer used as the insulating layer in a comparative example.

10 Substrate 20, 220, 320, 420 Lower electrode layer 220a, 320a, 420a Lower electrode layer precursor layer 30, 230, 330, 430 Oxide layer 30a, 230a, 330a, 430a Oxide layer precursor layer 40, 240, 340, 440 Upper electrode layer 240a, 340a, 440a Precursor layer for upper electrode layer 100, 200, 300, 400 Thin layer capacitor which is an example of solid-state electronic device M1 Lower electrode layer type M2 Insulating layer type M3 Upper part Electrode layer mold M4 Laminate mold

  A solid-state electronic device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In this description, common parts are denoted by common reference symbols throughout the drawings unless otherwise specified. In the drawings, elements of the present embodiment are not necessarily described with each other kept to scale. Further, some symbols may be omitted to make each drawing easier to see.

<First Embodiment>
1. FIG. 1 is a diagram showing an overall configuration of a thin film capacitor 100 that is an example of a solid-state electronic device according to the present embodiment. As shown in FIG. 1, the thin film capacitor 100 includes a lower electrode layer 20 from the substrate 10 side, an oxide layer 30 that is an insulating layer made of a dielectric, and an upper electrode layer 40 on the substrate 10. Further, the present embodiment is not limited to this structure. Further, in order to simplify the drawing, description of patterning of the extraction electrode layer from each electrode layer is omitted.

The substrate 10 is, for example, a high heat resistant glass, a SiO ₂ / Si substrate, an alumina (Al ₂ O ₃ ) substrate, an STO (SrTiO) substrate, an STO (SrTiO) layer on the surface of the Si substrate via an SiO ₂ layer and a Ti layer. Various insulating base materials can be used including a semiconductor substrate (eg, Si substrate, SiC substrate, Ge substrate, etc.).

  As a material of the lower electrode layer 20 and the upper electrode layer 40, a metal material such as a refractory metal such as platinum, gold, silver, copper, aluminum, molybdenum, palladium, ruthenium, iridium, tungsten, or an alloy thereof is used. .

In the present embodiment, the insulating layer made of a dielectric is made of an oxide layer 30 made of bismuth (Bi) and niobium (Nb) (which may contain unavoidable impurities). Note that the oxide layer formed of bismuth (Bi) and niobium (Nb) is also referred to as a BNO layer. Moreover, it was confirmed that the oxide layer 30 contains a crystalline phase and an amorphous phase. More specifically, the oxide layer 30 includes a crystalline phase, a microcrystalline phase, and an amorphous phase. In the present application, the term “microcrystalline phase” refers to a crystalline phase that is not a crystalline phase that has grown uniformly from the upper end to the lower end in the film thickness direction when a layered material is formed. Means. More specifically, the BNO oxide layer is composed of a microcrystalline phase having a pyrochlore crystal structure represented by a general formula of A ₂ B ₂ O ₇ (where A is a metal element, B is a transition metal element, the same applies hereinafter). And at least one of crystal phases of a triclinic β-BiNbO ₄ type crystal structure.

The pyrochlore type crystal structure is in particular a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure or (Bi _1.5 Zn _0.5 ) (Zn _{0. Since} it is substantially the same as or approximate to the ₅ Nb _1.5 ) O ₇ type structure, it is possible to obtain good electrical characteristics as the insulating layer of the thin layer capacitor. Furthermore, the oxide layer serving as an insulating layer has both a microcrystalline phase having a pyrochlore type crystal structure and a crystal phase having a β-BiNbO ₄ type crystal structure, thereby providing better electrical characteristics as an insulating layer of a solid electronic device. Can be obtained.

  In addition, since the carbon content in the oxide layer 30 is 1.5 atm% or less and the carbon content in the oxide layer is 1.5 atm% or less, the leakage current can be suppressed, and the insulating layer The electrical characteristics of the oxide layer to be improved.

2. Method for Manufacturing Thin Film Capacitor 100 Next, an example of a method for manufacturing the thin film capacitor 100 will be described. In the present embodiment, a manufacturing method based on a so-called solution method is described, but the present invention is not limited to this method. The same applies to other embodiments. In addition, the display of the temperature in this application represents the preset temperature of a heater. 2 to 5 are cross-sectional schematic views showing one process of the method of manufacturing the thin film capacitor 100, respectively. As shown in FIG. 2, first, the lower electrode layer 20 is formed on the substrate 10. Next, the oxide layer 30 is formed on the lower electrode layer 20, and then the upper electrode layer 40 is formed on the oxide layer 30.

(1) Formation of Lower Electrode Layer FIG. 2 is a diagram illustrating a process for forming the lower electrode layer 20. In the present embodiment, an example in which the lower electrode layer 20 of the thin film capacitor 100 is formed of platinum (Pt) will be described. As the lower electrode layer 20, a layer made of platinum (Pt) is formed on the substrate 10 by a known sputtering method.

(2) Formation of Oxide Layer as Insulating Layer Next, the oxide layer 30 is formed on the lower electrode layer 20. The oxide layer 30 is formed in the order of (a) formation of a precursor layer and preliminary baking, and (b) main baking. 3 and 5 are diagrams showing a process of forming the oxide layer 30. FIG. In the present embodiment, an example in which the oxide layer 30 in the manufacturing process of the thin film capacitor 100 is formed of an oxide composed of bismuth (Bi) and niobium (Nb) will be described.

(A) Formation of Precursor Layer and Pre-Baking As shown in FIG. 3, a precursor containing bismuth (Bi) and a precursor containing niobium (Nb) are formed on the lower electrode layer 20 by a known spin coating method. A precursor layer 30a is formed using a precursor solution as a solute (referred to as a precursor solution, hereinafter the same for a precursor solution) as a starting material. Here, examples of the precursor containing bismuth (Bi) for the oxide layer 30 include bismuth octylate, bismuth chloride, bismuth nitrate, or various bismuth alkoxides (for example, bismuth isopropoxide, bismuth butoxide, bismuth ethoxy). And bismuth methoxyethoxide) may be employed. Examples of the precursor containing niobium (Nb) for the oxide layer 30 in this embodiment include niobium octylate, niobium chloride, niobium nitrate, and various niobium alkoxides (for example, niobium isopropoxide, niobium butoxide). , Niobium ethoxide, niobium methoxyethoxide) may be employed. Moreover, the solvent of the precursor solution is one alcohol solvent selected from the group of ethanol, propanol, butanol, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol, or acetic acid, propionic acid, and octylic acid. A solvent that is one carboxylic acid selected from the group is preferred.

  After that, as preliminary baking, preliminary baking is performed in a temperature range of 80 ° C. to 250 ° C. for a predetermined time in an oxygen atmosphere or in the air (collectively, also referred to as “oxygen-containing atmosphere”). In the pre-baking, the solvent in the precursor layer 30a is sufficiently evaporated, and in order to develop characteristics that enable future plastic deformation (preferably in a gel state (before thermal decomposition, the organic chain remains). Is considered). In order to realize the above-mentioned viewpoint with higher accuracy, the pre-baking temperature is preferably 80 ° C. or higher and 250 ° C. or lower. Moreover, the desired thickness of the oxide layer 30 can be obtained by repeating the formation and preliminary baking of the precursor layer 30a by the above-described spin coating method a plurality of times.

(B) Main calcination Thereafter, as the main calcination, the precursor layer 30a is subjected to a temperature within a range of 520 ° C. or higher and 650 ° C. or lower for a predetermined time in an oxygen atmosphere (for example, 100% by volume, but not limited thereto). Heat with. As a result, as shown in FIG. 4, an oxide layer 30 (which may contain unavoidable impurities. The same applies hereinafter) made of bismuth (Bi) and niobium (Nb) is formed on the electrode layer. Here, as the main baking in the solution method, the heating temperature for forming the oxide layer is 520 ° C. or higher and 650 ° C. or lower, but the upper limit is not limited. However, when the heating temperature exceeds 650 ° C., it is more preferable to set the heating temperature to 650 ° C. or less because crystallization of the oxide layer proceeds and the amount of leakage current tends to increase remarkably. . On the other hand, when the heating temperature is less than 520 ° C., the solvent in the precursor solution and the carbon in the solute remain, and the amount of leakage current increases remarkably, so the heating temperature is 520 ° C. or more and 650 ° C. or less. It is preferable to do.

The crystal structure of the oxide layer 30 varies depending on the main firing temperature of the precursor layer 30a. In the present embodiment, a crystal phase having a β-BiNbO ₄ type crystal structure is obtained when the main firing temperatures are 600 ° C. and 650 ° C. The temperature of the firing is 520 ° C., it can be in the case of 530 ° C., and 550 ° C., to obtain both a crystalline phase of the fine crystalline phase and beta-BiNbO ₄ crystal structure of pyrochlore-type crystal structure.

  The range of the thickness of the oxide layer 30 is preferably 30 nm or more. If the thickness of the oxide layer 30 is less than 30 nm, it is not preferable to apply it to a solid-state electronic device due to an increase in leakage current and dielectric loss accompanying a decrease in the thickness.

  Table 1 shows the results of measuring the relationship between the atomic composition ratio of bismuth (Bi) and niobium (Nb) in the oxide layer 30, the relative dielectric constant at 1 KHz, and the leakage current value when 0.5 MV / cm is applied. .

  Regarding the atomic composition ratio of bismuth (Bi) and niobium (Nb), elemental analysis of bismuth (Bi) and niobium (Nb) is performed using Rutherford backscattering spectroscopy (RBS method), and bismuth (Bi) and niobium are analyzed. The atomic composition ratio of (Nb) was determined. The details of the method for measuring the relative permittivity and the leak current value will be described later. As for Table 1, the relative permittivity when an AC voltage of 1 KHz is applied and the leak current value when a voltage of 0.5 MV / cm is applied. Shows the results. As shown in Table 1, regarding the atomic composition ratio of bismuth (Bi) and niobium (Nb) in the oxide layer 30, when (Bi) is 1, niobium (Nb) is 0.8 or more and 3.3 or less. In this range, the relative permittivity and the leakage current value were values applicable as a device.

(3) Formation of Upper Electrode Layer Next, the upper electrode layer 40 is formed on the oxide layer 30. FIG. 5 is a diagram illustrating a process of forming the upper electrode layer 40. In the present embodiment, an example in which the upper electrode layer 40 of the thin film capacitor 100 is formed of platinum (Pt) will be described. Similar to the lower electrode layer 20, the upper electrode layer 40 is formed of a layer made of platinum (Pt) on the oxide layer 30 by a known sputtering method.

According to this embodiment, the oxide layer comprising bismuth (Bi) and niobium (Nb) is provided, and the oxide layer has a crystal phase of a pyrochlore type crystal structure and / or a β-BiNbO ₄ type crystal structure. In addition, since the carbon content in the oxide layer is 1.5 atm% or less, it has good electrical characteristics and can be manufactured by a simple manufacturing process. Therefore, a solid electronic device excellent in industrial and mass productivity can be obtained. Can be obtained.

Second Embodiment
1. Overall Configuration of Thin Film Capacitor of this Embodiment In this embodiment, the lower electrode layer and the upper electrode layer of a thin film capacitor which is an example of a solid-state electronic device are conductive oxides (including inevitable impurities) made of a metal oxide. It consists of The overall configuration of a thin film capacitor 200, which is an example of a solid-state electronic device in the present embodiment, is shown in FIG. This embodiment is the same as the first embodiment except that the lower electrode layer and the upper electrode layer are made of a conductive oxide made of a metal oxide. Therefore, regarding the configuration of the present embodiment, the same reference numerals are assigned to the configurations corresponding to those in FIG. As shown in FIG. 10, the thin film capacitor 200 includes a substrate 10. On the substrate 10, a lower electrode layer 220 from the substrate 10 side, an oxide layer 30 that is an insulating layer made of a dielectric, and an upper electrode Layer 240 is provided.

  Examples of the lower electrode layer 220 and the upper electrode layer 240 include an oxide layer made of lanthanum (La) and nickel (Ni), an oxide layer made of antimony (Sb) and tin (Sn), and indium (In). And an oxide composed of tin (Sn) (however, inevitable impurities may be included; the same shall apply hereinafter) can be employed.

2. Manufacturing Process of Thin Film Capacitor 200 Next, a manufacturing method of the thin film capacitor 200 will be described. 6 to 9 are cross-sectional schematic views showing one process of the method of manufacturing the thin film capacitor 200, respectively. As shown in FIG. 6, first, the lower electrode layer 220 is formed on the substrate 10. Next, the oxide layer 30 is formed on the lower electrode layer 220, and then the upper electrode layer 240 is formed. In addition, in the manufacturing process of the thin film capacitor 200, the description which overlaps with 1st Embodiment is abbreviate | omitted.

(1) Formation of Lower Electrode Layer FIGS. 6 and 7 are diagrams showing a process for forming the lower electrode layer 220. FIG. In the present embodiment, an example will be described in which the lower electrode layer 220 of the thin film capacitor 200 is formed of a conductive oxide layer made of lanthanum (La) and nickel (Ni). The lower electrode layer 220 is formed in the order of (a) a precursor layer formation and preliminary firing step, and (b) a main firing step.

(A) Formation of Precursor Layer and Pre-Baking As shown in FIG. 6, a precursor containing lanthanum (La) and a precursor containing nickel (Ni) are formed on a substrate 10 by a known spin coating method as a solute. The lower electrode layer precursor layer 220a starting from the precursor solution (referred to as the lower electrode layer precursor solution, hereinafter the same as the lower electrode layer precursor solution) is formed. Here, an example of a precursor containing lanthanum (La) for the lower electrode layer 220 is lanthanum acetate. As other examples, lanthanum nitrate, lanthanum chloride, or various lanthanum alkoxides (for example, lanthanum isopropoxide, lanthanum butoxide, lanthanum ethoxide, lanthanum methoxyethoxide) may be employed. An example of a precursor containing nickel (Ni) for the lower electrode layer precursor layer 220a is nickel acetate. As other examples, nickel nitrate, nickel chloride, or various nickel alkoxides (for example, nickel indium isopropoxide, nickel butoxide, nickel ethoxide, nickel methoxyethoxide) may be employed.

  When a conductive oxide layer made of antimony (Sb) and tin (Sn) is employed as the lower electrode layer, examples of the precursor for the lower electrode layer containing antimony (Sb) include antimony acetate, antimony nitrate, Antimony chloride or various antimony alkoxides (for example, antimony isopropoxide, antimony butoxide, antimony ethoxide, antimony methoxyethoxide) may be employed. Examples of precursors containing tin (Sn) include tin acetate, tin nitrate, tin chloride, or various tin alkoxides (for example, antimony isopropoxide, antimony butoxide, antimony ethoxide, antimony methoxyethoxide). Can be done. Further, when a conductive oxide composed of indium (In) and tin (Sn) is employed as the lower electrode layer, examples of the precursor containing indium (In) include indium acetate, indium nitrate, indium chloride, and various types. Indium alkoxides (eg, indium isopropoxide, indium butoxide, indium ethoxide, indium methoxyethoxide) can be employed. Moreover, the example of the precursor for lower electrode layers containing tin (Sn) is the same as the above-mentioned example.

  Thereafter, preliminary firing is performed in a temperature range of 80 ° C. or higher and 250 ° C. or lower for a predetermined time in an oxygen-containing atmosphere for the same reason as the oxide layer of the first embodiment. Moreover, the desired thickness of the lower electrode layer 220 can be obtained by repeating the formation and preliminary baking of the lower electrode layer precursor layer 220a by the spin coating method described above a plurality of times.

(B) Main baking Thereafter, as the main baking, the lower electrode layer precursor layer 220a is heated to 550 ° C. in an oxygen atmosphere for about 20 minutes. As a result, as shown in FIG. 7, a lower electrode layer 220 made of lanthanum (La) and nickel (Ni) (however, inevitable impurities may be included. The same applies hereinafter) is formed on the substrate 10. Here, as the main baking in the solution method, the heating temperature for forming the conductive oxide layer is preferably 520 ° C. or higher and 650 ° C. or lower for the same reason as the oxide layer of the first embodiment. Note that the conductive oxide layer made of lanthanum (La) and nickel (Ni) is also called an LNO layer.

(2) Formation of Oxide Layer as Insulating Layer Next, the oxide layer 30 is formed on the lower electrode layer 220. As in the first embodiment, the oxide layer 30 of this embodiment is formed in the order of (a) formation of a precursor layer and preliminary baking, and (b) main baking. FIG. 8 is a diagram illustrating a state in which the oxide layer 30 is formed on the lower electrode layer 220. As in the first embodiment, the thickness range of the oxide layer 30 is preferably 30 nm or more.

(3) Formation of Upper Electrode Layer Next, as shown in FIGS. 9 and 10, the upper electrode layer 240 is formed on the oxide layer 30. In the present embodiment, an example will be described in which the upper electrode layer 240 of the thin film capacitor 200 is formed of a conductive oxide layer made of lanthanum (La) and nickel (Ni), like the lower electrode layer 220. Similar to the lower electrode layer 220, the upper electrode layer 240 is formed in the order of (a) formation of a precursor layer and preliminary firing, and (b) main firing. The lower electrode layer precursor layer 240a formed on the oxide layer 30 is shown in FIG. 9, and the upper electrode layer 240 formed on the oxide layer 30 is shown in FIG.

The present embodiment also includes an oxide layer made of bismuth (Bi) and niobium (Nb), and the oxide layer has a crystal phase of a pyrochlore crystal structure and / or a β-BiNbO ₄ type crystal structure, Since the carbon content in the oxide layer is 1.5 atm% or less, it has excellent electrical characteristics and can be manufactured by a simple manufacturing process, so that a solid electronic device having excellent industrial and mass productivity is obtained. be able to. In addition, since the lower electrode layer, the oxide layer serving as an insulating layer, and the upper electrode layer are all made of metal oxide, all steps can be performed in an oxygen-containing atmosphere without using a vacuum process. In addition, mass productivity can be significantly improved.

<Third Embodiment>
1. Overall Configuration of Thin Film Capacitor of this Embodiment In this embodiment, embossing is performed in the formation process of all layers of a thin film capacitor that is an example of a solid-state electronic device. The entire configuration of a thin film capacitor 300 which is an example of a solid-state electronic device in the present embodiment is shown in FIG. In the present embodiment, the lower electrode layer and the oxide layer are the same as those in the second embodiment except that the stamping process is performed. Therefore, regarding the configuration of the present embodiment, the same reference numerals are assigned to the configurations corresponding to those in FIG. As shown in FIG. 11, the thin film capacitor 300 includes a substrate 10. On the substrate 10, a lower electrode layer 320 from the substrate 10 side, an oxide layer 330 that is an insulating layer made of a dielectric, an upper electrode Layer 340 is provided.

  By the way, in the present application, “embossing” is sometimes referred to as “nanoimprint”.

2. Manufacturing Process of Thin Film Capacitor 300 Next, a manufacturing method of the thin film capacitor 300 will be described. 12 to 21 are cross-sectional schematic views showing one process of the method of manufacturing the thin film capacitor 300. In the thin film capacitor 300, first, a lower electrode layer 320 that is embossed is formed on the substrate 10. Next, an oxide layer 330 that has been embossed is formed on the lower electrode layer 320. Thereafter, the upper electrode layer 340 is formed on the oxide layer 330. Also in the manufacturing process of the thin film capacitor 300, the description which overlaps with 2nd Embodiment is abbreviate | omitted.

(1) Formation of Lower Electrode Layer In this embodiment, an example in which the lower electrode layer 320 of the thin film capacitor 300 is formed of a conductive oxide layer made of lanthanum (La) and nickel (Ni) will be described. The lower electrode layer 320 is formed in the order of (a) formation of a precursor layer and preliminary baking, (b) stamping process, and (c) main baking process. First, a lower electrode using a precursor solution for a lower electrode layer having a precursor containing lanthanum (La) and a precursor containing nickel (Ni) as a solute on a substrate 10 by a known spin coating method. A layer precursor layer 320a is formed.

  Thereafter, as preliminary firing, the lower electrode layer precursor layer 320a is heated in a temperature range of 80 ° C. or higher and 250 ° C. or lower for a predetermined time in an oxygen-containing atmosphere. Moreover, the desired thickness of the lower electrode layer 320 can be obtained by repeating the formation and preliminary baking of the lower electrode layer precursor layer 320a by the spin coating method described above a plurality of times.

(B) Embossing Next, in order to perform patterning of the precursor layer 320a for the lower electrode layer, as shown in FIG. 12, in the state heated within the range of 80 ° C. or higher and 300 ° C. or lower, for the lower electrode layer Using the mold M1, embossing is performed at a pressure of 1 MPa or more and 20 MPa or less. Examples of the heating method in the embossing process include a method of bringing the substrate 10 into a predetermined temperature atmosphere using a chamber, an oven, or the like, a method of heating the base on which the substrate 10 is mounted from the lower part with a heater, There is a method in which a die pressing process is performed using a die heated to a temperature of ℃ or less. In this case, it is more preferable in terms of workability to use a method in which the base is heated from below by a heater and a mold heated in advance to 80 ° C. or more and 300 ° C. or less.

  The reason why the heating temperature of the mold is set to 80 ° C. or more and 300 ° C. or less is as follows. When the heating temperature during the embossing process is lower than 80 ° C., the plastic deformation ability of the lower electrode layer precursor layer 320a is reduced due to the lower temperature of the lower electrode layer precursor layer 320a. Therefore, the feasibility of molding at the time of molding the embossed structure, or the reliability or stability after molding becomes poor. Further, when the heating temperature during the stamping process exceeds 300 ° C., the decomposition (oxidative thermal decomposition) of the organic chain, which is the source of the plastic deformability, proceeds, so that the plastic deformability decreases. Furthermore, from the above viewpoint, it is a more preferable aspect that the precursor layer 320a for the lower electrode layer is heated within a range of 100 ° C. or more and 250 ° C. or less during the embossing process.

  Further, if the pressure in the stamping process is a pressure in the range of 1 MPa or more and 20 MPa or less, the lower electrode layer precursor layer 320a is deformed following the surface shape of the mold, and a desired stamping structure is obtained. Can be formed with high accuracy. Moreover, the pressure applied when embossing is performed is set to a low pressure range of 1 MPa to 20 MPa. As a result, it is difficult for the mold to be damaged when the stamping process is performed, and it is advantageous for increasing the area.

  Thereafter, the entire lower electrode layer precursor layer 320a is etched. As a result, as shown in FIG. 13, the lower electrode layer precursor layer 320a is completely removed from the region other than the region corresponding to the lower electrode layer (etching process for the entire surface of the lower electrode layer precursor layer 320a).

  Further, in the above-described embossing process, in advance, a mold release treatment for the surface of each precursor layer that will be brought into contact with the stamping surface and / or a mold release treatment for the die pressing surface of the mold is performed. It is preferable that an embossing process is performed on each precursor layer. Such processing is performed. As a result, since the frictional force between each precursor layer and the mold can be reduced, the stamping process can be performed on each precursor layer with higher accuracy. Examples of the release agent that can be used for the release treatment include surfactants (for example, fluorine surfactants, silicon surfactants, nonionic surfactants, etc.), fluorine-containing diamond-like carbon, and the like. can do.

(C) Main baking Next, main baking is performed with respect to the precursor layer 320a for lower electrode layers. As a result, as shown in FIG. 14, a lower electrode layer 320 (however, inevitable impurities may be included. The same applies hereinafter) made of lanthanum (La) and nickel (Ni) is formed on the substrate 10.

(2) Formation of Oxide Layer serving as Insulating Layer Next, an oxide layer 330 serving as an insulating layer is formed on the lower electrode layer 320. The oxide layer 330 is formed in the order of (a) precursor layer formation and preliminary firing step, (b) stamping step, and (c) main firing step. 15 to 18 are diagrams showing a process for forming the oxide layer 330.

(A) Formation of Precursor Layer and Pre-Firing As shown in FIG. 15, on the substrate 10 and the patterned lower electrode layer 320, a precursor containing bismuth (Bi) and niobium (as in the second embodiment) A precursor layer 330a starting from a precursor solution having a precursor containing Nb) as a solute is formed. Thereafter, preliminary firing is performed in an oxygen-containing atmosphere while being heated to 80 ° C. or higher and 250 ° C. or lower.

(B) Embossing process In this embodiment, as shown in FIG. 16, an embossing process is performed with respect to the precursor layer 330a which performed only preliminary baking. Specifically, in order to perform patterning of the oxide layer, embossing is performed at a pressure of 1 MPa or more and 20 MPa or less using the insulating layer mold M2 while being heated to 80 ° C. or more and 300 ° C. or less.

  Thereafter, the entire surface of the precursor layer 330a is etched. As a result, as shown in FIG. 17, the precursor layer 330a is completely removed from a region other than the region corresponding to the oxide layer 330 (etching process for the entire surface of the precursor layer 330a). In addition, although the etching process of the precursor layer 330a of this embodiment was performed using the wet etching technique which does not use a vacuum process, it does not prevent etching using what is called dry etching technique using plasma.

(C) Main baking Thereafter, the precursor layer 330a is main-fired as in the second embodiment. As a result, as shown in FIG. 18, an oxide layer 330 (however, it may contain unavoidable impurities; the same applies hereinafter) is formed on the lower electrode layer 320 as an insulating layer. As the main firing, the precursor layer 330a is heated in an oxygen atmosphere in a temperature range of 520 ° C. or more and 650 ° C. or less for a predetermined time.

  Although the etching process for the entire surface of the precursor layer 330a can be performed after the main baking, as described above, the precursor layer is entirely etched between the embossing process and the main baking process. It is a more preferable aspect that the process is included. This is because unnecessary regions can be removed more easily than etching after each precursor layer is finally fired.

(3) Formation of upper electrode layer Thereafter, a precursor containing lanthanum (La) and a precursor containing nickel (Ni) are formed on the oxide layer 330 in the same manner as the lower electrode layer 320 by a known spin coating method. A precursor layer 340a for the upper electrode layer is formed using a precursor solution as a solute as a starting material. Thereafter, preliminary firing is performed by heating the precursor layer 340a for the upper electrode layer in an oxygen-containing atmosphere in a temperature range of 80 ° C. to 250 ° C.

  Subsequently, as shown in FIG. 19, the upper electrode layer precursor layer 340 a is heated to 80 ° C. or higher and 300 ° C. or lower in order to perform patterning of the pre-baked upper electrode layer precursor layer 340 a. Thus, using the upper electrode layer mold M3, the upper electrode layer precursor layer 340a is embossed at a pressure of 1 MPa to 20 MPa. Then, as shown in FIG. 20, the upper electrode layer precursor layer 340a is completely removed from the region other than the region corresponding to the upper electrode layer 340 by etching the entire surface of the upper electrode layer precursor layer 340a.

  After that, as shown in FIG. 21, the main electrode precursor layer 340a is heated to 530 ° C. to 600 ° C. for a predetermined time in the oxygen atmosphere as the main firing, thereby being formed on the oxide layer 330. An upper electrode layer 340 made of lanthanum (La) and nickel (Ni) (however, it may contain inevitable impurities; the same applies hereinafter) is formed.

The present embodiment also includes an oxide layer made of bismuth (Bi) and niobium (Nb), and the oxide layer has a crystal phase of a pyrochlore crystal structure and / or a β-BiNbO ₄ type crystal structure, Since the carbon content in the oxide layer is 1.5 atm% or less, it has excellent electrical characteristics and can be manufactured by a simple manufacturing process, so that a solid electronic device having excellent industrial and mass productivity is obtained. be able to.

  In the present embodiment, a stamping process including the lower electrode layer 320 from the substrate 10 side, the oxide layer 330 that is an insulating layer made of a dielectric, and the upper electrode layer 340 is performed on the substrate 10. An embossing process is employed in which an embossing structure is formed. As a result, a process using a relatively long time and / or expensive equipment such as a vacuum process, a process using a photolithography method, or an ultraviolet irradiation process becomes unnecessary. In the present embodiment, a solution method and an embossing process are employed. As a result, since the upper electrode layer and the oxide layer can be easily patterned, the thin film capacitor 300 of this embodiment is extremely excellent in industrial property or mass productivity.

<Fourth embodiment>
1. Overall Configuration of Thin Film Capacitor of this Embodiment Also in this embodiment, embossing is performed in the formation process of all layers of a thin film capacitor which is an example of a solid-state electronic device. The overall configuration of a thin film capacitor 400, which is an example of a solid-state electronic device in the present embodiment, is shown in FIG. In this embodiment, the lower electrode layer, the oxide layer, and the upper electrode layer are pre-fired after the precursor layers are stacked. All precursor layers that have been pre-fired are subjected to embossing and then subjected to main firing. Therefore, regarding the configuration of the present embodiment, the same reference numerals are assigned to the components corresponding to those in FIG. As shown in FIG. 25, the thin film capacitor 400 includes a substrate 10, and on the substrate 10, a lower electrode layer 420 from the substrate 10 side, an oxide layer 430 that is an insulating layer made of a dielectric, and an upper electrode. Layer 440 is provided.

2. Manufacturing Process of Thin Film Capacitor 400 Next, a manufacturing method of the thin film capacitor 400 will be described. 22 to 24 are schematic cross-sectional views showing one process of the method for manufacturing the thin film capacitor 400. In the thin film capacitor 400, first, a lower electrode layer precursor layer 420 a that is a precursor layer of the lower electrode layer 420, a precursor layer 430 a that is a precursor layer of the oxide layer 430, and an upper electrode layer 440 are formed on the substrate 10. A laminate of the upper electrode layer precursor layer 440a, which is the precursor layer, is formed. Next, this laminated body is embossed and subjected to main firing. In the manufacturing process of the thin film capacitor 400, the description overlapping with that of the third embodiment is omitted.

(1) Formation of Laminate of Precursor Layer As shown in FIG. 22, first, a precursor layer for a lower electrode layer 420a, which is a precursor layer for the lower electrode layer 420, and a precursor for an oxide layer 430 are formed on the substrate 10. A laminate of a precursor layer 430a that is a layer and a precursor layer 440a for the upper electrode layer that is a precursor layer of the upper electrode layer 440 is formed. In the present embodiment, as in the third embodiment, the lower electrode layer 420 and the upper electrode layer 440 of the thin film capacitor 400 are formed of a conductive oxide layer made of lanthanum (La) and nickel (Ni) and insulated. An example in which the oxide layer 430 to be a layer is formed of an oxide layer made of bismuth (Bi) and niobium (Nb) will be described. First, a lower electrode using a precursor solution for a lower electrode layer having a precursor containing lanthanum (La) and a precursor containing nickel (Ni) as a solute on a substrate 10 by a known spin coating method. A layer precursor layer 420a is formed. Thereafter, as preliminary firing, the lower electrode layer precursor layer 420a is heated in a temperature range of 80 ° C. or higher and 250 ° C. or lower in an oxygen-containing atmosphere for a predetermined time. Moreover, the desired thickness of the lower electrode layer 420 can be obtained by repeating the formation and preliminary baking of the lower electrode layer precursor layer 420a by the spin coating method described above a plurality of times.

  Next, the precursor layer 430a is formed on the precursor layer 420a for the lower electrode layer that has been pre-fired. First, on the lower electrode layer precursor layer 420a, a precursor layer 430a is formed using a precursor solution containing a precursor containing bismuth (Bi) and a precursor containing niobium (Nb) as a solute. Thereafter, as preliminary firing, the precursor layer 430a is heated in a temperature range of 80 ° C. or higher and 250 ° C. or lower for a predetermined time in an oxygen-containing atmosphere.

  Next, a precursor containing lanthanum (La) and nickel (Ni) are contained on the precursor layer 430a that has been pre-fired by a known spin coating method in the same manner as the precursor layer 420a for the lower electrode layer. A precursor layer 440a for the upper electrode layer is formed using a precursor solution having the precursor as a solute as a starting material. Thereafter, preliminary firing is performed by heating the precursor layer 440a for the upper electrode layer in an oxygen-containing atmosphere in a temperature range of 80 ° C. to 250 ° C.

(2) Embossing Next, in order to perform patterning of the laminate (420a, 430a, 440a) of each precursor layer, as shown in FIG. 23, a state of heating within a range of 80 ° C. or higher and 300 ° C. or lower Then, using the laminate mold M4, the stamping process is performed at a pressure of 1 MPa or more and 20 MPa or less.

  Thereafter, the entire stack of the precursor layers (420a, 430a, 440a) is etched. As a result, as shown in FIG. 24, the stacked body (420a, 430a, 440a) of each precursor layer is completely removed from regions other than the region corresponding to the lower electrode layer, the oxide layer, and the upper electrode layer ( Etching step for the entire surface of each precursor layer (420a, 430a, 440a).

(3) Main baking Next, main baking is performed with respect to the laminated body (420a, 430a, 440a) of each precursor layer. As a result, as shown in FIG. 25, a lower electrode layer 420, an oxide layer 430, and an upper electrode layer 440 are formed on the substrate 10.

The present embodiment also includes an oxide layer made of bismuth (Bi) and niobium (Nb), and the oxide layer has a crystal phase of a pyrochlore crystal structure and / or a β-BiNbO ₄ type crystal structure, Since the carbon content in the oxide layer is 1.5 atm% or less, it has excellent electrical characteristics and can be manufactured by a simple manufacturing process, so that a solid electronic device having excellent industrial and mass productivity is obtained. be able to. Further, in this embodiment, since the main firing is performed after the stamping process is performed on the precursor layers of all the oxide layers that have been pre-fired, the manufacturing process can be further simplified. It becomes.

<Example>
Hereinafter, in order to describe the present invention in more detail, examples and comparative examples will be described, but the present invention is not limited to these examples.

About the Example and the comparative example, the following method measured the physical property of the solid-state electronic device, and implemented the composition analysis of the BNO oxide layer.
1. Electrical characteristics (1) Leakage current A voltage of 0.25 MV / cm was applied between the lower electrode layer and the upper electrode layer to measure the current. For this measurement, Model 4156C manufactured by Agilent Technologies was used.

(2) Dielectric loss (tan δ)
The dielectric loss of the examples and comparative examples was measured as follows. At room temperature, a dielectric loss was measured by applying a voltage of 0.1 V and an AC voltage of 1 KHz between the lower electrode layer and the upper electrode layer. For this measurement, a 1260-SYS type broadband dielectric constant measurement system manufactured by Toyo Corporation was used.

(3) Relative permittivity The relative permittivity of the examples and comparative examples was measured as follows. The relative dielectric constant was measured by applying a voltage of 0.1 V and an AC voltage of 1 KHz between the lower electrode layer and the upper electrode layer. For this measurement, a 1260-SYS type broadband dielectric constant measurement system manufactured by Toyo Corporation was used.

2. Carbon and hydrogen content of BNO oxide layer Rutherford Backscattering Spectrometry (RBS analysis method), Hydrogen Forward Scatter analysis method (HydrogenStressFrequency Analysis method) ) And a nuclear reaction analysis method ((Nuclear Reaction Analysis: NRA analysis method)), and the carbon and hydrogen contents of the BNO oxide layer in the examples and comparative examples were obtained.

3. Cross-sectional TEM photograph of BNO oxide layer and crystal structure analysis by electron beam diffraction The cross-sectional TEM (Transmission Electron Microscopy) photograph V and electron beam diffraction image of the BNO oxide layer in Examples and Comparative Examples were observed. Further, using the electron diffraction images of the BNO oxide layers in the examples and comparative examples, the Miller index and the interatomic distance were determined, and the structural analysis was performed by fitting with a known crystal structure model. (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ , β-BiNbO ₄ , and Bi ₃ NbO ₇ were used as known crystal structure models.

(Example 1)
In Example 1, a thin film capacitor was created based on the manufacturing method of the embodiment of the present embodiment. First, a lower electrode layer is formed on a substrate, and then an oxide layer is formed. Thereafter, an upper electrode layer is formed on the oxide layer. High heat-resistant glass was used as the substrate. As the lower electrode layer, a layer made of platinum (Pt) was formed on a substrate by a known sputtering method. The film thickness of the lower electrode layer at this time was 200 nm. The precursor containing bismuth (Bi) for the oxide layer to be an insulating layer was bismuth octylate, and niobium octylate was used as the precursor containing niobium (Nb). As pre-baking, it was heated to 250 ° C. for 5 minutes, and the formation of the precursor layer by spin coating and pre-baking were repeated 5 times. As the main firing, the precursor layer was heated to 520 ° C. for about 20 minutes in an oxygen atmosphere. The thickness of the oxide layer 30 was about 170 nm. The film thickness of each layer was determined by measuring the level difference between each layer and the substrate using a stylus method. The atomic composition ratio between bismuth (Bi) and niobium (Nb) in the oxide layer was set to 1 when bismuth (Bi) was 1. As the upper electrode layer, a layer made of platinum (Pt) was formed on the oxide layer by a known sputtering method. The size of the upper electrode layer at this time was 100 μm × 100 μm, and the film thickness was 150 nm. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. In addition, regarding the electrical characteristics, the leakage current value was 3.0 × 10 ⁻⁴ A / cm ² , the dielectric loss was 0.025, and the relative dielectric constant was 62.

(Example 2)
In Example 2, a thin film capacitor was produced under the same conditions as Example 1 except that the precursor layer was heated to 520 ° C. for 1 hour in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. The carbon content was 1.5 atm% or less, a small value below the detection limit, and the hydrogen content was 1.6 atm%. In addition, regarding the electrical characteristics, the leakage current value was 3.0 × 10 ⁻⁸ A / cm ² , the dielectric loss was 0.01, and the relative dielectric constant was 70.

(Example 3)
In Example 3, a thin film capacitor was produced under the same conditions as in Example 1 except that the precursor layer was heated to 530 ° C. for 20 minutes in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. As for the electrical characteristics, the leakage current value was 3.0 × 10 ⁻⁶ A / cm ² , the dielectric loss was 0.01, and the relative dielectric constant was 110.

Example 4
In Example 4, a thin film capacitor was produced under the same conditions as Example 1 except that the precursor layer was heated to 530 ° C. for 2 hours in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. Further, the carbon content was 1.5 atm% or less and a small value below the detection limit, and the hydrogen content was 1.4 atm%. As for electrical characteristics, the leak current value was 8.8 × 10 ⁻⁸ A / cm ² , the dielectric loss was 0.018, and the relative dielectric constant was 170.

(Example 5)
In Example 5, a thin film capacitor was prepared under the same conditions as in Example 1 except that the precursor layer was heated to 550 ° C. for 1 minute in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. As for the electrical characteristics, the leakage current value was 5.0 × 10 ⁻⁷ A / cm ² , the dielectric loss was 0.01, and the relative dielectric constant was 100.

(Example 6)
In Example 6, a thin film capacitor was produced under the same conditions as in Example 1 except that the precursor layer was heated to 550 ° C. for 20 minutes in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. Further, the carbon content was 1.5 atm% or less and the hydrogen content was 1.0 atm% or less, both values being smaller than the detection limit. As for the electrical characteristics, the leakage current value was 1.0 × 10 ⁻⁶ A / cm ² , the dielectric loss was 0.001, and the relative dielectric constant was 180.

(Example 7)
In Example 7, a thin film capacitor was produced under the same conditions as Example 1 except that the precursor layer was heated to 550 ° C. for 12 hours in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The pyrochlore crystal structure is more specifically a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure, or (Bi _1.5 Zn _{0. 5} ) It was almost the same or approximated to the (Zn _0.5 Nb _1.5 ) O ₇ type structure. As for electrical characteristics, the leakage current value was 2.0 × 10 ⁻⁵ A / cm ² , the dielectric loss was 0.004, and the relative dielectric constant was 100.

(Example 8)
In Example 8, a thin film capacitor was produced under the same conditions as in Example 1 except that the precursor layer was heated to 600 ° C. for 20 minutes in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, a crystal phase having a β-BiNbO ₄ type crystal structure could be obtained. As for electrical characteristics, the leakage current value was 7.0 × 10 ⁻⁶ A / cm ² , the dielectric loss was 0.001, and the relative dielectric constant was 80.

Example 9
In Example 9, a thin film capacitor was produced under the same conditions as in Example 1 except that the precursor layer was heated to 650 ° C. for 20 minutes in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, a crystal phase having a β-BiNbO ₄ type crystal structure could be obtained. As for the electrical characteristics, the leakage current value was 5.0 × 10 ⁻³ A / cm ² , the dielectric loss was 0.001, and the relative dielectric constant was 95.

(Example 10)
In Example 10, a thin film capacitor was created based on the manufacturing method of the fourth embodiment of the present embodiment. High heat-resistant glass was used as the substrate 10. As the lower electrode layer and the upper electrode layer, an oxide layer made of lanthanum (La) and nickel (Ni) was formed. Lanthanum acetate was used as a precursor containing lanthanum (La) for the lower electrode layer and the upper electrode layer. In addition, an oxide layer made of bismuth (Bi) and niobium (Nb) was formed as the oxide layer serving as an insulating layer. The precursor containing bismuth (Bi) for the oxide layer was bismuth octylate, and the precursor containing niobium (Nb) was niobium octylate. First, a precursor layer of a lower electrode layer was formed on a substrate and pre-baked. As pre-baking, heating was performed at 250 ° C. for about 5 minutes, and formation of the precursor layer by spin coating and pre-baking were repeated five times. Next, a precursor layer of a BNO oxide layer to be an insulating layer was formed on the precursor layer of the lower electrode layer, and heated to 250 ° C. for about 5 minutes as pre-baking. Thereafter, the precursor layer of the upper electrode layer was formed on the precursor layer of the BNO oxide layer under the same conditions as the precursor layer of the lower electrode layer. Next, as pre-baking, it was heated to 150 ° C. for about 5 minutes, and the formation of the precursor layer by spin coating and pre-baking were repeated five times. Thereafter, the laminate of these precursor layers was heated to 650 ° C. for 20 minutes in an oxygen-containing atmosphere as main firing. The thickness of the oxide layer serving as the insulating layer was about 170 nm. The atomic composition ratio of bismuth (Bi) and niobium (Nb) in the BNO oxide layer was set to 1 when bismuth (Bi) was 1. The thickness of the upper electrode layer and the lower electrode layer was about 60 nm. The size of the upper electrode layer at this time was 100 μm × 100 μm. As the composition of the crystal phase of the BNO oxide layer, a crystal phase having a β-BiNbO ₄ type crystal structure could be obtained. As for electrical characteristics, the leakage current value was 2.4 × 10 ⁻⁵ A / cm ² , the dielectric loss was 0.015, and the relative dielectric constant was 120.

(Comparative Example 1)
In Comparative Example 1, a thin film capacitor was produced under the same conditions as in Example 1 except that the precursor layer was heated to 500 ° C. for 20 minutes in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. As for electrical characteristics, the leakage current value was 1.0 × 10 ⁻² A / cm ² , the dielectric loss was 0.001, and the relative dielectric constant was 100.

(Comparative Example 2)
In Comparative Example 2, a thin film capacitor was formed under the same conditions as in Example 1 except that the precursor layer was heated to 500 ° C. for 2 hours in an oxygen atmosphere as the main firing. As the composition of the crystal phase of the BNO oxide layer, both a microcrystalline phase having a pyrochlore crystal structure and a crystal phase having a β-BiNbO ₄ crystal structure could be obtained. The carbon content was 6.5 atm%, and the hydrogen content was 7.8 atm%. As for the electrical characteristics, the leak current value was as large as 1.0 × 10 ⁻¹ A / cm ² , the dielectric loss was 0.007, and the relative dielectric constant was 180.

(Comparative Example 3)
In Comparative Example 3, a BNO oxide layer serving as an insulating layer was formed on the lower electrode layer at room temperature by a known sputtering method, and then heat-treated at 550 ° C. for 20 minutes. About the others, the thin film capacitor was created on the conditions similar to Example 1. FIG. As the composition of the crystalline phase of the BNO oxide layer, a microcrystalline phase of Bi ₃ NbO ₇ type crystal structure could be obtained. Further, the carbon content was 1.5 atm% or less and the hydrogen content was 1.0 atm% or less, both values being smaller than the detection limit. As for the electrical characteristics, the leak current value was 1.0 × 10 ⁻⁷ A / cm ² , the dielectric loss was 0.005, and the relative dielectric constant was 50.

Table 1 shows the structure of the thin layer capacitor and the film formation conditions of the oxide layer, the obtained electrical characteristics, the carbon and hydrogen content of the BNO oxide layer, and the crystal structure in Examples 1 to 7 and Comparative Examples 1 to 3. 2 and Table 3. In addition, the “crystal phase composition” in Tables 2 and 3 includes a crystal phase and a microcrystalline phase. Further, BiNbO ₄ in Tables 2 and 3 represents β-BiNbO ₄ .

1. FIG. 26 is a cross-sectional TEM photograph and an electron beam diffraction image showing the crystal structure of the BNO oxide layer in Example 6. FIG. 26A is a cross-sectional TEM photograph of the BNO oxide layer in Example 6. FIG. FIG. 26B is an electron diffraction image in region X of the cross-sectional TEM photograph of the BNO oxide layer shown in FIG. 27 shows a cross-sectional TEM photograph and an electron beam diffraction image showing the crystal structure of the oxide layer serving as the insulating layer in Comparative Example 3. FIG. 27A is a cross-sectional TEM photograph showing the crystal structure of the BNO oxide layer in Comparative Example 3. FIG. FIG. 27B is an electron beam diffraction image in a region Y of the cross-sectional TEM photograph of the BNO oxide layer shown in FIG. As shown in FIG. 26, it was confirmed from the results of the cross-sectional TEM photograph and the electron diffraction image that the BNO oxide layer of this example includes a crystalline phase and an amorphous phase. If it sees in detail, it turned out that the BNO oxide layer contains the crystalline phase, the microcrystalline phase, and the amorphous phase. Further, by fitting with a known crystal structure model from the Miller index and the interatomic distance, the BNO oxide layer is made of A ₂ B ₂ O ₇ (where A is a metal element, B is a transition metal element, It was shown to have at least one of a microcrystalline phase of a pyrochlore type crystal structure represented by the general formula (same) and a crystal phase of a triclinic β-BiNbO ₄ type crystal structure. More specifically, the pyrochlore type crystal structure is a (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ type structure or (Bi _1.5 Zn _{0). .5} ) (Zn _0.5 Nb _1.5 ) O ₇ type structure was found to be substantially the same or approximate.

The appearance of the microcrystalline phase of the pyrochlore type crystal structure and the crystal phase of the β-BiNbO ₄ type crystal structure differ depending on the main firing temperature of the precursor layer of the oxide layer to be the insulating layer. As shown in Examples 8, 9, and 10, when the firing temperature was 600 ° C. and 650 ° C., a crystal phase having a β-BiNbO ₄ type crystal structure could be obtained. In addition, as shown in Examples 1 to 7, when the main baking temperatures are 520 ° C., 530 ° C., and 550 ° C., the microcrystalline phase of the pyrochlore crystal structure and the crystal phase of the β-BiNbO ₄ crystal structure I was able to get both.

On the other hand, in the oxide layer formed by sputtering in Comparative Example 3, a microcrystalline phase having a pyrochlore type crystal structure and a crystal phase having a β-BiNbO ₄ type crystal structure could not be confirmed, and a microcrystalline phase having a Bi ₃ NiO ₇ type crystal structure was found. Had.

Among the measured electrical characteristics, as shown in Tables 2 and 3, regarding the leakage current, in each example, the leakage current value when applying 0.25 MV / cm was 5.0 × 10 ⁻³ A / It became cm ² or less, and sufficient characteristics as a capacitor could be obtained. As shown in Tables 2 and 3, the dielectric loss (tan δ) was 0.03 or less at 1 KHz in the examples, and sufficient characteristics as a capacitor could be obtained. Regarding the relative dielectric constant, as shown in Tables 2 and 3, in the examples, the relative dielectric constant at 1 KHz was 60 or more, and sufficient characteristics as a capacitor could be obtained. On the other hand, the BNO layer having the Bi ₃ NbO ₇ type crystal structure of Comparative Example 3 had a low relative dielectric constant of 50.

From the measurement results of the examples, the BNO layer has both a microcrystalline phase having a pyrochlore type crystal structure and a crystal phase having a β-BiNbO ₄ type crystal structure. It has been found that a dielectric constant can be obtained.

2. Carbon and hydrogen content and electrical properties of the BNO oxide layer For Examples 2, 4 and 6 where the temperature of the main firing is in the range of 520 ° C. to 650 ° C., the carbon content of the BNO oxide layer is 1.5 atm. % Or less. Here, since the measurement lower limit of the carbon content by this measurement method is about 1.5 atm%, the actual concentration is considered to be less than or equal to this measurement lower limit. In these examples, the carbon content was found to be the same level as that of the BNO oxide layer formed by the sputtering method of Comparative Example 3. On the other hand, as shown in Comparative Example 2, when the temperature of the main calcination is as low as 500 ° C., carbon in the solvent of the precursor solution is considered to remain, and the carbon content shows a large value of 6.5 atm%. It was. As a result, it is considered that the leak current was as large as 1.0 × 10 ⁻¹ A / cm ² .

As for the hydrogen content, in Examples 2, 4 and 6 in which the temperature of the main firing is in the range of 520 ° C. to 650 ° C., the hydrogen content of the BNO oxide layer is 1.6 atm% or less and good results Met. Here, since the measurement lower limit of the hydrogen content by this measurement method is about 1.0 atm%, the actual concentration in Example 6 is considered to be less than or equal to this measurement lower limit. In Example 6, the hydrogen content was found to be at the same level as the BNO oxide layer formed by the sputtering method of Comparative Example 3. On the other hand, as shown in Comparative Example 2, when the temperature of the main calcination is as low as 500 ° C., it is considered that the solvent in the precursor solution and hydrogen in the solute remain, and the hydrogen content is as large as 7.8 atm%. showed that. Such a high hydrogen content is also considered to be the cause of the leak current having a large value of 1.0 × 10 ⁻¹ A / cm ² .

As described above, the solid-state electronic device in each of the above embodiments includes an oxide layer made of bismuth (Bi) and niobium (Nb), and the oxide layer has a pyrochlore type crystal structure or a β-BiNbO ₄ type crystal structure. Or having a pyrochlore type crystal structure and a β-BiNbO ₄ type crystal structure, and having a carbon content of 1.5 atm% or less in the oxide layer, good electrical characteristics can be obtained. It is to be prepared. Therefore, the solid-state electronic device of the present invention is composed of a metal oxide composed only of bismuth and niobium without including zinc (Zn) or the like that has been conventionally used in the oxide layer serving as the insulating layer. It can be said that it is excellent in that the performance of the solid-state electronic device can be realized by providing the insulating layer.

<Other embodiments>
As mentioned above, although embodiment of this invention was described, this invention is not limited to the thing of the content demonstrated above.

  In each of the above-described embodiments, the manufacturing method of the BNO oxide layer is described as a manufacturing method based on a so-called solution method. However, the manufacturing method is not limited to this method, and other chemical vapor deposition methods or physical vapor deposition methods are used. It is also possible to use the method.

  The solid-state electronic device in each of the embodiments described above is suitable for a solid-state electronic device that controls a large current with a low driving voltage. As the solid-state electronic device in each of the above-described embodiments, in addition to the above-described thin film capacitor, for example, a capacitor such as a multilayer thin film capacitor and a variable capacitance thin film capacitor, a metal oxide semiconductor junction field effect transistor (MOSFET), and a nonvolatile memory The present invention can also be applied as a semiconductor device such as a micro TAS (Total Analysis System), a microchemical chip, a MEMS chip such as a DNA chip, and the like.

  As described above, the disclosure of each of the embodiments described above is described for explaining the embodiments, and is not described for limiting the present invention. In addition, modifications within the scope of the present invention including other combinations of the embodiments are also included in the claims.

Claims (7)

An oxide layer composed of bismuth (Bi) and niobium (Nb) (which may contain inevitable impurities);
The oxide layer has a crystal phase of a pyrochlore crystal structure and / or a β-BiNbO ₄ crystal structure;
The carbon content in the oxide layer is 1.5 atm% or less.
Solid electronic device. The oxide layer has a crystal phase of a pyrochlore type crystal structure and a β-BiNbO ₄ type crystal structure;
The solid-state electronic device according to claim 1. The pyrochlore type crystal structure is substantially the same structure as (Bi _1.5 Zn _0.5 ) (Zn _0.5 Nb _1.5 ) O ₇ .
The solid-state electronic device according to claim 1 or 2. The oxide layer further has an amorphous phase;
The solid-state electronic device according to any one of claims 1 to 3. The solid-state electronic device is a capacitor;
The solid-state electronic device according to claim 1. The solid-state electronic device is a semiconductor device;
The solid-state electronic device according to claim 1. The solid-state electronic device is a MEMS device;
The solid-state electronic device according to claim 1.