Electronic Components

Abstract

To provide an electronic component being able to accumulate charges and having a rectifying action of making a resistance value in one direction lower than a resistance value in the other direction.SOLUTION: An electronic component includes an element assembly including a first internal electrode layer, a second internal electrode layer, and a dielectric layer stacked between the first internal electrode layer and the second internal electrode layer. A Ni oxide particle exists at a first border between the first internal electrode layer and the dielectric layer. The dielectric layer includes dielectric large particles in contact with both the second internal electrode layer and the Ni oxide particle at the first border.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an electronic component having a dielectric layer and an internal electrode layer. [Background technology]

[0002] Electronic circuits, power supply circuits, and other circuits incorporate a variety of electronic components, such as ceramic capacitors, diodes, resistors, transistors, inductors, etc. Each electronic component in a circuit has its own specific function, but if a single electronic component could combine the functions of multiple elements, it might be possible to reduce the number of electronic components that make up the circuit.

[0003] For example, a ceramic capacitor such as that disclosed in Patent Document 1 has a structure in which dielectric layers and internal electrode layers are laminated, and has the functions of storing electric charge and passing AC current without passing DC current, etc. If this ceramic capacitor could have not only the above functions but also a rectifying action like a diode, it would be possible to simplify the circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-220224 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of exemplary embodiments of the present disclosure is to provide an electronic component that is capable of storing charge and has a rectifying effect such that the resistance in one direction is lower than the resistance in the other direction. [Means for solving the problem]

[0006] In order to achieve the above object, an electronic component according to a first aspect of the present disclosure comprises: an element body including a first internal electrode layer, a second internal electrode layer, and a dielectric layer laminated between the first internal electrode layer and the second internal electrode layer; Ni oxide particles are present at a first boundary between the first internal electrode layer and the dielectric layer, The dielectric layer includes large dielectric particles in contact with both the Ni oxide particles at the first boundary and the second internal electrode layer.

[0007] In conventional ceramic capacitors including dielectric layers and internal electrode layers, it has been considered desirable to have a high resistance value, as shown in Patent Document 1. In contrast, the electronic component according to the first aspect has the above-described characteristics, and can therefore have a resistance value in one direction lower than the resistance value in the other direction. In other words, the electronic component according to the first aspect is capable of storing charge as a capacitor, and also has a rectifying effect like a diode.

[0008] Preferably, the Ni oxide particles are in contact with both of the two adjacent dielectric layers via the first internal electrode layer.

[0009] the element body includes a plurality of first internal electrode layers, a plurality of second internal electrode layers, and a plurality of dielectric layers, Preferably, the first internal electrode layer is in contact with an average of two or more Ni oxide particles in one cross section of the element body.

[0010] the element body includes a plurality of first internal electrode layers, a plurality of second internal electrode layers, and a plurality of dielectric layers, The total number of Ni oxide particles observed in the cross section of the element body is defined as NP0, The number of the Ni oxide particles present at the first boundary among the Ni oxide particles observed in the cross section is defined as NP1, Preferably, NP1 / NP0 is 0.6 or more.

[0011] the element body includes a plurality of first internal electrode layers, a plurality of second internal electrode layers, and a plurality of dielectric layers, The total length of the first internal electrode layer and the second internal electrode layer observed in the cross section of the element body is defined as LE, Within the range of the total length LE, the number of the Ni oxide particles in contact with the first internal electrode layer or the second internal electrode layer is set to NP L As, Preferably, NP L / LE is 0.002 particles / μm or more.

[0012] The average grain size of the metal crystals contained in the first internal electrode layer and the second internal electrode layer is d M year, The average particle size of the Ni oxide particles is d P As, Preferably, d P / d M is 3 or more.

[0013] An electronic component according to a second aspect of the present disclosure has an element body including a first internal electrode layer, a second internal electrode layer, and a dielectric layer laminated between the first internal electrode layer and the second internal electrode layer, p-type semiconductor particles are present at a first boundary between the first internal electrode layer and the dielectric layer; The dielectric layer includes large dielectric particles in contact with both the p-type semiconductor particles at the first boundary and the second internal electrode layer.

[0014] The electronic component according to the second aspect has the above-described characteristics, and thus can make the resistance value in one direction lower than the resistance value in the other direction. In other words, like the electronic component according to the first aspect, the electronic component according to the second aspect can store charge as a capacitor, and also has a rectifying effect like a diode. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram showing a cross section of an electronic component according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged schematic diagram of a cross section of the element body shown in FIG. [Figure 3A] FIG. 3A is a schematic diagram showing an enlarged portion of the boundary between the dielectric layer and the internal electrode layer. [Figure 3B] FIG. 3B is a conceptual diagram showing the circuitry associated with the structure shown in FIG. 3A. [Figure 4A] FIG. 4A is a schematic diagram showing an enlarged portion of the boundary between the dielectric layer and the internal electrode layer. [Figure 4B] FIG. 4B is a conceptual diagram showing an equivalent circuit related to the structure shown in FIG. 4A. [Figure 5A] FIG. 5A is a schematic diagram showing an enlarged portion of the boundary between the dielectric layer and the internal electrode layer. [Figure 5B] FIG. 5B is a conceptual diagram showing a circuit related to the structure shown in FIG. 5A. [Figure 6] FIG. 6 is a schematic diagram showing a modified example of Ni oxide particles. [Figure 7] FIG. 7 is a circuit diagram showing an example of an AC / DC converter circuit. [Figure 8A] FIG. 8A is a graph showing an example of an AC voltage waveform input to the AC / DC converter circuit shown in FIG. [Figure 8B] FIG. 8B is a graph showing an example of a voltage waveform output from the AC / DC converter circuit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.

[0017] As shown in FIG. 1, the multilayer ceramic electronic component 2 of this preferred embodiment includes an element body 4 and a pair of external electrodes 6 formed on the outer surface of the element body 4.

[0018] The element body 4 shown in FIG. 1 is typically shaped like a rectangular parallelepiped, with two end faces 4a, 4b along the YZ plane and four side faces 4c connecting the two end faces 4a, 4b. However, the shape of the element body 4 is not particularly limited and may be an elliptical cylinder, a circular cylinder, a rectangular column, or the like. The outer dimensions of the element body 4 are also not particularly limited. For example, the length L0 in the X-axis direction may be 0.2 mm to 5.7 mm, the width W0 in the Y-axis direction may be 0.1 mm to 5.0 mm, and the height T0 in the Z-axis direction may be 0.1 mm to 3.0 mm. In this embodiment, the X-axis, Y-axis, and Z-axis are perpendicular to each other.

[0019] The multilayer ceramic electronic component 2 has a pair of external electrodes 6: a first external electrode 6a in contact with one end face 4a and a second external electrode 6b in contact with the other end face 4b. The first external electrode 6a and the second external electrode 6b are electrically insulated so as not to contact each other in the X-axis direction. Each external electrode 6 need only be conductive, and the specifications (material, structure, thickness, etc.) of each external electrode 6 are not particularly limited. Each external electrode 6 may include a baked electrode layer, a resin electrode layer, a plated electrode layer, etc., and may have a single-layer structure or a multilayer structure including multiple electrode layers. For example, each external electrode 6 may have a three-layer structure (layered in the order listed) of a baked electrode layer containing Cu, a Ni-plated layer, and a Sn-plated layer.

[0020] The element body 4 has a capacitance region 40 and an exterior region 41 located outside the capacitance region 40. The capacitance region 40 has dielectric layers 10 and internal electrode layers 20 that are substantially parallel to a plane including the X-axis and Y-axis, and inside the capacitance region 40, the dielectric layers 10 and internal electrode layers 20 are alternately stacked along the Z-axis. Here, "substantially parallel" means that most of the portions are parallel, but there may be some portions that are not parallel, and both the dielectric layers 10 and the internal electrode layers 20 may have some irregularities or be tilted.

[0021] The internal electrode layers 20 in the capacitive region 40 can be classified into first internal electrode layers 21 and second internal electrode layers 22. A portion of the edge of each first internal electrode layer 21 is exposed at one end face 4a, and each first internal electrode layer 21 is electrically connected to a first external electrode 6a. A portion of the edge of each second internal electrode layer 22 is exposed at the other end face 4b, and each second internal electrode layer 22 is electrically connected to a second external electrode 6b.

[0022] Each dielectric layer 10 in the capacitance region 40 is laminated between the first internal electrode layer 21 and the second internal electrode layer 22. In other words, the first internal electrode layer 21 and the second internal electrode layer 22 are insulated from each other via the dielectric layer 10. Thus, the capacitance region 40 has a structure in which the first internal electrode layer 21, the dielectric layer 10, and the second internal electrode layer 22 are repeatedly laminated in the order described above. When a voltage is applied to the multilayer ceramic electronic component 2, the first external electrode 6a and the second external electrode 6b have polarities opposite to each other, making it possible to apply a voltage to each dielectric layer 10 in the capacitance region 40. In other words, charge can be stored in each dielectric layer 10, and the multilayer ceramic electronic component 2 functions as a capacitor due to the laminated structure of the dielectric layers 10 and the internal electrode layers 20.

[0023] In this embodiment, the bonding interface between the dielectric layer 10 and the first internal electrode layer 21 is referred to as a first boundary 31, and the bonding boundary between the dielectric layer 10 and the second internal electrode layer 22 is referred to as a second boundary 32. In the description of this embodiment, when the first internal electrode layer 21 and the second internal electrode layer 22 are not distinguished from each other and the term "internal electrode layer 20" is used as a general term, the description using the term "internal electrode layer 20" means that the description relates to both the first internal electrode layer 21 and the second internal electrode layer 22.

[0024] The exterior region 41 is laminated outside the capacitive region 40 in the Z-axis direction and covers the top and bottom surfaces of the capacitive region 40. The exterior region 41 may also be present outside the capacitive region 40 in the Y-axis direction. That is, the side surface of the capacitive region 40 that intersects with the Y-axis may be covered with the exterior region 41 that does not include the internal electrode layer 20. The material and thickness of the exterior region 41 are not particularly limited. For example, the exterior region 41 may contain a dielectric compound having the same composition as the dielectric layer 10, or may contain a glass component together with the dielectric compound. In principle, the exterior region 41 is a region that does not include the internal electrode layer 20, but may include a dummy electrode that does not contribute to capacitance.

[0025] The dielectric layer 10 contains a dielectric compound as a main component. The main component of the dielectric layer 10 means a component that occupies 80 mol % or more of the dielectric layer 10, and the material of the dielectric compound as the main component is not particularly limited. For example, the main component of the dielectric layer 10 may be a dielectric compound with a perovskite structure such as BaTiO3, Ba(Ti,Zr)O3, (Ba,Ca)TiO3, (Ba,Ca)(Ti,Zr)O3, (Ca,Sr)TiO3, (Ca,Sr)ZrO3, (Ca,Sr)(Zr,Ti)O3, or (K,Na)NbO3, or Ba3ZrNb4O 15 , Ba3TiNb4O 15 , (K,Na)Sr2Nb5O 15 The dielectric compound may be selected from tungsten bronze structure compounds such as:

[0026] Furthermore, the dielectric layer 10 may contain one or more subcomponents in addition to the main component. The type and content of the subcomponents contained in the dielectric layer 10 are not particularly limited. For example, the dielectric layer 10 may contain, as the subcomponent, a Si compound, an Al compound, a Mn compound, an Mg compound, a Cr compound, a Ni compound, a compound containing a rare earth element, a Li compound, a B compound, or a V compound. The main component and subcomponents of the dielectric layer 10 can be identified by component analysis using a wavelength dispersive X-ray spectrometer (WDS), an energy dispersive X-ray spectrometer (EDS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), or the like.

[0027] The average thickness T of each dielectric layer 10 DL is preferably 1.7 μm or less, and more preferably 0.17 μm or more and 0.86 μm or less. The capacitance region 40 only needs to include at least one dielectric layer 10, and the number of dielectric layers 10 stacked in the capacitance region 40 is not particularly limited. For example, the capacitance region 40 preferably includes 20 or more dielectric layers 10, and more preferably includes 50 or more dielectric layers 10. The average thickness T DL can be calculated by observing the cross section of the element body 4 using a metallurgical microscope or an electron microscope. For example, it is preferable to analyze five or more dielectric layers 10, and the thickness of each of the analyzed dielectric layers 10 is measured at at least 30 points to calculate the average thickness T DL It is preferable to calculate

[0028] Each dielectric layer 10 includes a plurality of dielectric particles 11 and grain boundaries 17 that are interfaces between adjacent dielectric particles 11. The dielectric particles 11 are crystal grains that include the main component of the dielectric layer 10, and the dielectric particles 11 in the dielectric layer 10 can be analyzed by observing a cross section of the element body 4 using an electron microscope such as a scanning electron microscope (SEM) or a scanning transmission electron microscope (STEM). The dielectric particles 11 may contain a solid solution of the minor component of the dielectric layer 10, or the dielectric particles 11 may have a core-shell structure due to the solid solution of the minor component. The dielectric layer 10 may also include a segregation phase in which the concentration of a predetermined element is higher than that of the dielectric particles 11.

[0029] Average particle size d of the dielectric particles 11 DP is preferably 0.05 μm or more, and more preferably 0.1 μm or more and 1 μm or less. DP Average thickness T of the dielectric layer 10 DL The ratio (T DL / d DP ) is preferably 1.5 or less, and more preferably 1 or less. The average particle size d DP is the arithmetic mean value of the circle-equivalent diameters of the dielectric particles 11. For example, it is preferable to observe the cross section of the dielectric layer 10 and analyze five or more dielectric layers 10, and measure the circle-equivalent diameters of at least 50 dielectric particles 11 to determine the average particle size d DP It is preferable to calculate

[0030] When a cross section along the thickness direction (Z-axis direction) of the dielectric layer 10 is analyzed, the dielectric particles 11 can be classified into large particles 13 and small particles 15. In other words, in the description of this embodiment, the term "dielectric particles 11" is a general term for the large particles 13 and the small particles 12, and the dielectric particles 11 include the large particles 13 and the small particles 12.

[0031] The large particles 13 are dielectric particles 11 that contact both the first boundary 31 (the junction boundary between the dielectric layer 10 and the first internal electrode layer 21) and the second boundary 32 (the junction boundary between the dielectric layer 10 and the second internal electrode layer 22). In other words, the large particles 13 are dielectric particles 11 that appear on both the upper and lower surfaces of the dielectric layer 10 that contains the large particles 13. The length of the large particles 13 in the Z-axis direction is approximately equal to the thickness of the dielectric layer 10 at the location where the large particles 13 are present. On the other hand, the small particles 15 are dielectric particles 11 other than the large particles 13. In other words, the small particles 15 include dielectric particles 11 that contact only either the first boundary 31 or the second boundary 32, and dielectric particles 11 that contact neither the first boundary 31 nor the second boundary 32.

[0032] The average number of large particles 13 contained in dielectric layer 10 per unit length is preferably 0.05 particles / μm or more, and more preferably 0.1 particles / μm or more. The upper limit of the average number of large particles 13 is not particularly limited and may be, for example, 3 particles / μm or less.

[0033] The average number of the large particles 13 described above is expressed as ND / LD, where LD is the total length of the dielectric layer 10 observed in the cross section of the capacitance region 40, and ND is the number of large particles 13 contained in the dielectric layer 10 of the total length LD. When calculating ND / LD, it is preferable to analyze five or more dielectric layers 10, and it is preferable that the total length LD of the dielectric layers 10 is 30 μm or more. It is also preferable to set the analysis field so that the edge of the analysis field is approximately parallel to the dielectric layer 10. In this case, the length of the edge of the analysis field that is approximately parallel to the dielectric layer 10 can be considered as the length of the dielectric layer 10 in the analysis field. For example, the length of each dielectric layer 10 in FIG. 2 is expressed as the length L in the X-axis direction of the analysis field. X It can be considered as such.

[0034] Each internal electrode layer 20 is conductive and contains a metal component. The composition of the internal electrode layer 20 is not particularly limited, and for example, the internal electrode layer 20 may contain at least one metal component selected from Ni, Cu, Ag, Pd, Au, and Pt. When the main component of the dielectric layer 10 is resistant to reduction, the metal component of the internal electrode layer 20 is preferably pure Ni or a Ni alloy containing 85 wt% or more of Ni. In this case, the Ni alloy may contain subcomponents such as Cu, Cr, and Mn. The metal component of the internal electrode layer 20 can be identified by component analysis using WDS, EDS, LA-ICP-MS, etc.

[0035] The internal electrode layer 20 may contain, as a common material, particles of a dielectric compound having the same composition as the main component of the dielectric layer 10. The internal electrode layer 20 may also contain a small amount (for example, about 0.1 mass % or less) of a non-metallic element such as S or P, and may also contain voids. When the internal electrode layer 20 is observed in a cross section as shown in Figure 1 or Figure 2, there may be some portions where the internal electrode layer 20 appears to be partially discontinued.

[0036] The internal electrode layers 20 are stacked between the dielectric layers 10 in the Z-axis direction, and the number of stacked internal electrode layers 20 in the capacitance region 40 is determined according to the number of stacked dielectric layers 10. In addition, the average thickness T EL is not particularly limited, and is preferably 3 μm or less, and more preferably 0.2 μm or more and 1 μm or less. EL can be calculated by observing the cross section of the element body 4 using a metallurgical microscope or an electron microscope. For example, it is preferable to analyze five or more internal electrode layers 20, and the thickness of each internal electrode layer 20 to be analyzed is measured at at least 30 points, and the average thickness T EL It is preferable to calculate

[0037] When a cross section of the internal electrode layer 20 is analyzed by a combination of STEM or SEM and EDS or WDS, it can be confirmed that the internal electrode layer 20 contains crystal grains of a metal component (hereinafter referred to as metal crystals). The average grain size d of the metal crystals contained in each internal electrode layer 20 is M is not particularly limited, and is preferably 1 μm or less, and more preferably 0.03 μm or more and 0.8 μm or less. M is the arithmetic mean value of the circle-equivalent diameter of the metal crystals. For example, it is preferable to observe the cross section of the internal electrode layer 20 and analyze five or more internal electrode layers 20, and measure the circle-equivalent diameters of at least 50 metal crystals contained in each internal electrode layer 20 to be analyzed, thereby determining the average particle size d M It is preferable to calculate

[0038] As shown in FIG. 2, the capacitance region 40 contains Ni oxide particles 30. The Ni oxide particles 30 mainly contain NiO and may contain trace amounts of elements contained in the dielectric layer 10 and the internal electrode layer 20. The content of components other than NiO in the Ni oxide particles 30 is not particularly limited, but the total content of Ni and O in each Ni oxide particle 30 is preferably 80 mol % or more. The Ni oxide particles 30 in the capacitance region 40 can be identified by performing a mapping analysis on a cross section of the element body 4 as shown in FIG. 2. For example, a mapping image of Ni and a mapping image of O (oxygen) are taken, and a region having a higher Ni concentration than the dielectric layer 10 and a higher O concentration than the internal electrode layer 20 can be identified as the Ni oxide particle 30.

[0039] The Ni oxide particles 30 in the capacitance region 40 can be classified into two particle groups depending on their location. Specifically, the capacitance region 40 includes Ni oxide particles 30 present at the first boundary 31 between the dielectric layer 10 and the first internal electrode layer 21, and may also include Ni oxide particles 30 present at locations other than the first boundary 31.

[0040] In this embodiment, the Ni oxide particles 30 present at the first boundaries 31 are referred to as "first Ni oxide particles 30a," and the Ni oxide particles 30 other than the first Ni oxide particles 30a are referred to as "second Ni oxide particles 30b." Here, "present at the first boundaries 31" more specifically means that the first Ni oxide particles 30a are in contact with both the dielectric particles 11 of the dielectric layer 10 and the metal component of the first internal electrode layer 21. The first Ni oxide particles 30a may be present so as to penetrate from the first boundaries 31 into the first internal electrode layer 21, or may be present so as to penetrate from the first boundaries 31 into the dielectric layer 10.

[0041] The second Ni oxide particles 30b are Ni oxide particles 30 that exist at locations other than the first boundary 31. For example, the Ni oxide particles 30 that exist at the second boundary 32, the Ni oxide particles 30 that are contained in the internal electrode layer 20 and are not in contact with the dielectric layer 10, and the Ni oxide particles 30 that are contained in the dielectric layer 10 and are not in contact with the internal electrode layer 20 correspond to the second Ni oxide particles 30b.

[0042] To describe the first Ni oxide particles 30a in more detail, the capacitance region 40 may include first Ni oxide particles 30a that are in contact with the large particles 13 of the dielectric layer 10, and may also include first Ni oxide particles 30a that are not in contact with the large particles 13 but are in contact with the small particles 15. In other words, the dielectric layer 10 may include large particles 13 that are in contact with the first Ni oxide particles 30a, and may also include large particles 13 that are not in contact with the first Ni oxide particles 30a. In this embodiment, the large particles 13 that are in contact with the first Ni oxide particles 30a are referred to as "first large particles 13a," and the large particles 13 that are not in contact with the first Ni oxide particles 30a are referred to as "second large particles 13b." It is preferable that the first large particles 13a are in contact with the metal component of the second internal electrode layer 22 at the second boundary 32 and are not in contact with the second Ni oxide particles 30b.

[0043] Fig. 3A is a schematic diagram showing an enlarged cross section of a contact point between the first Ni oxide particle 30a and the first large particle 13a. As shown in Fig. 3A, at the contact point between the first Ni oxide particle 30a and the first large particle 13a, a structure is formed in which the metal component of the first internal electrode layer 21, the first Ni oxide particle 30a, the first large particle 13a, and the metal component of the second internal electrode layer 22 are connected in the order shown. When the capacitance region 40 of the multilayer ceramic electronic component 2 has the structure shown in Fig. 3A, a rectifying effect like that of a diode can be obtained.

[0044] Here, "rectification like a diode" means that the resistance value in one direction is lower than the resistance value in the other direction, and "one direction" and "other direction" refer to the direction of the voltage applied to the multilayer ceramic electronic component 2. For example, the resistance value when a voltage is applied with the first external electrode 6a side as the positive electrode (i.e., the first internal electrode layer 21 side as the positive electrode) and the second external electrode 6b side as the negative electrode (i.e., the second internal electrode layer 22 side as the negative electrode) is R I On the other hand, when a voltage is applied with the first external electrode 6a as the negative electrode and the second external electrode 6b as the positive electrode, the resistance value is R II "The resistance in one direction is lower than the resistance in the other direction" means that R I <R II , or R I >R II This means that the following condition is satisfied. The reason why such rectification is achieved is not entirely clear, but it is thought to be related to the Schottky junction. Below, we will explain the hypothesis regarding the rectification based on Figures 3A and 3B.

[0045] First, at the first boundary 31, there is a junction interface A between the metal component of the first internal electrode layer 21 and the first Ni oxide particle 30a, and at the second boundary 32, there is a junction interface B2 between the metal component of the second internal electrode layer 22 and the first large particle 13a (see FIG. 3A). Here, the dielectric compound that is the main component of the dielectric layer 10 is considered to be an n-type semiconductor that uses free electrons as carriers to carry electric charge. In other words, the dielectric particle 11 is considered to have the properties of an n-type semiconductor particle. On the other hand, NiO is unusual for an oxide and is considered to be a p-type semiconductor that uses holes as carriers. In other words, the Ni oxide particle 30 is considered to have the properties of a p-type semiconductor particle.

[0046] At junction interface A, a Schottky junction between the metal and the p-type semiconductor is thought to occur, and current is thought to easily flow from the first Ni oxide particle 30a toward the first internal electrode layer 21. On the other hand, at junction interface B2, a Schottky junction between the metal and the n-type semiconductor is thought to occur, and current is thought to easily flow from the second internal electrode layer 22 toward the first large particle 13a. Due to the above-mentioned two types of Schottky junctions, an equivalent circuit EC shown in FIG. 3B is thought to be formed at the contact point between the first Ni oxide particle 30a and the first large particle 13a.

[0047] In the equivalent circuit EC, the Schottky diode SD-p corresponds to the junction interface A between the first internal electrode layer 21 and the first Ni oxide particle 30a, and the Schottky diode SD-n corresponds to the junction interface B2 between the first large particle 13a and the second internal electrode layer 22. In addition, in the equivalent circuit EC, the resistance R1 corresponds to the first large particle 13a, and the resistance R2 corresponds to the first Ni oxide particle 30a. In the equivalent circuit EC, a current flows more easily counterclockwise, and the resistance value when a current flows counterclockwise is lower than the resistance value when a current flows clockwise.

[0048] That is, at the contact point between the first Ni oxide particles 30a and the first large particles 13a, it is considered that the current I easily flows in the direction of the broken line shown in Fig. 3A. When a voltage is applied with the second internal electrode layer 22 as the positive electrode and the first internal electrode layer 21 as the negative electrode, the resistance value is considered to be lower than that when a voltage is applied from the opposite direction (the first internal electrode layer 21 as the positive electrode and the second internal electrode layer 22 as the negative electrode). As described above, it is considered that the two types of Schottky junctions occurring at the bonding interface A and the bonding interface B2 contribute to the manifestation of the rectifying action.

[0049] Fig. 4A is an enlarged schematic cross-sectional view of the location where the second large particles 13b are present. As shown in Fig. 4A, at the location where the second large particles 13b are present, a structure is formed in which the metal components of the first internal electrode layer 21, the second large particles 13b, and the metal components of the second internal electrode layer 22 are connected in the described order. The first boundary 31 includes the bonding interface B1 between the metal component of the first internal electrode layer 21 and the second large particles 13b, and the second boundary 32 includes the bonding interface B2 between the metal component of the second internal electrode layer 22 and the second large particles 13b.

[0050] At the bonding interfaces B1 and B2 shown in Fig. 4A, it is considered that Schottky junctions between the metal and the n-type semiconductor occur, and it is considered that the current easily flows from the internal electrode layer 20 toward the dielectric particles 11 (the second large particles 13b). At the location where the second large particles 13b are present, it is considered that the circuit C1 shown in Fig. 4B is formed.

[0051] In the circuit C1, the Schottky diode SD-n1 corresponds to the junction interface B1, the resistor R1 corresponds to the second large particle 13b, and the Schottky diode SD-n2 corresponds to the junction interface B2. In the circuit C1, when a current flows clockwise (i.e., the first internal electrode layer 21 is positive and the second internal electrode layer 22 is negative), the Schottky diode SD-n2 at the junction interface B2 acts as a barrier and prevents the current from flowing. On the other hand, when a current flows counterclockwise (i.e., the first internal electrode layer 21 is negative and the second internal electrode layer 22 is positive), the Schottky diode SD-n1 at the junction interface B1 acts as a barrier and prevents the current from flowing. Therefore, in the circuit C1, the resistance value hardly changes even when the direction of the voltage is changed (the resistance value when a current flows clockwise and the resistance value when a current flows counterclockwise are approximately equal). Since the circuit C1 as described above is formed where the second large particles 13b exist, it is considered that the second large particles 13b do not contribute to the development of a rectifying effect.

[0052] 5A is an enlarged schematic diagram of a cross section of a portion where the first Ni oxide particle 30a is in contact with a small particle 15 without being in contact with the first large particle 13a. When the first Ni oxide particle 30a is in contact with a small particle 15, a grain boundary 17 is interposed between the small particle 15 in contact with the first Ni oxide particle 30a and the small particle 15 in contact with the second internal electrode layer 22. A double Schottky barrier is thought to be formed at the grain boundary 17 between the small particles 15. At the contact portion between the first Ni oxide particle 30a and the small particle 15, the double Schottky barrier of the grain boundary 17 is thought to form a circuit C2 shown in FIG. 5B.

[0053] As shown in Figure 5B, the double Schottky barrier DSB in circuit C2 corresponds to grain boundary 17. In circuit C2, the double Schottky barrier DSB prevents the current flow whether the current is passed clockwise or counterclockwise, and the resistance value hardly changes even when the direction of the voltage is changed. Therefore, it is thought that the small particles 15 and grain boundary 17 do not contribute to the occurrence of rectification.

[0054] The capacitance region 40 of the multilayer ceramic electronic component 2 has a plurality of dielectric layers 10, a plurality of first internal electrode layers 21, and a plurality of second internal electrode layers 22, and a plurality of first boundaries 31. When observing a cross section of the capacitance region 40 along the Z-axis direction, it is sufficient that the Ni oxide particles 30 are present at at least one first boundary 31. In other words, the capacitance region 40 may include first internal electrode layers 21 and dielectric layers 10 that are not in contact with the first Ni oxide particles 30a. The capacitance region 40 may also have a region that includes the first Ni oxide particles 30a and a region that does not include the first Ni oxide particles 30a. In this case, the region that includes the first Ni oxide particles 30a is considered to be a region that contributes greatly to the rectification effect.

[0055] If the total number of first internal electrode layers 21 included in the capacitance region 40 is E0, and the number of first internal electrode layers 21 in contact with the first Ni oxide particles 30a out of the total number E0 is E1, the ratio of E1 to E0 (E1 / E0) is preferably 10% or more, and more preferably 20% or more.

[0056] The total length of the first internal electrode layer 21 and the second internal electrode layer 22 observed in the cross section of the capacitance region 40 as shown in Fig. 2 is defined as LE. In addition, within the range of the total length LE, the number of Ni oxide particles 30 in contact with the first internal electrode layer 21 or the second internal electrode layer 22 is defined as NP. L The average number of Ni oxide particles 30 in contact with the internal electrode layer 20 per unit length is expressed as NP to LE. L It can be expressed as the ratio of NP L The / LE is preferably 0.002 particles / μm or more, and more preferably 0.005 particles / μm or more. L By setting / LE within the above range, the difference between the resistance value in one direction and the resistance value in the other direction can be made larger, and the rectification effect can be further enhanced.

[0057] NP L The upper limit of / LE is not particularly limited. For example, NP LThe / LE is preferably 0.05 particles / μm or less, which allows for a high capacitance. L When calculating / LE, the cross section of the capacitance region 40 is set to 500 μm 2 It is preferable to analyze the above, and the total length LE is preferably set to 500 μm or more. Also, it is preferable to set the analysis field so that some edges of the analysis field are approximately parallel to the internal electrode layer 20, and in this case, the length of the edge of the analysis field that is approximately parallel to the internal electrode layer 20 can be considered as the length of the internal electrode layer 20 in the analysis field. For example, in the cross section shown in FIG. 2, the total length LE of the internal electrode layer 20 is 4L X (Edge length L X Since there are seven Ni oxide particles 30 in the cross section of FIG. 2, the NP calculated for the cross section of FIG. L / LE is 7 / 4L X (pieces / μm).

[0058] The above-mentioned NP L corresponds to the total number of the first Ni oxide particles 30a and the second Ni oxide particles 30b, but from the viewpoint of enhancing the rectification effect, the number of the first Ni oxide particles 30a and the number of the first large particles 13a in the dielectric layer 10 are considered to be particularly important.

[0059] In a cross section such as that shown in FIG. 2, if the total number of Ni oxide particles 30 is NP0 and the number of first Ni oxide particles 30a is NP1, the average ratio of NP1 to NP0 (NP1 / NP0) is preferably 0.6 or more, more preferably 0.75 or more. In other words, it is preferable that the Ni oxide particles 30 are concentrated at one pole. By setting NP1 / NP0 to 0.6 or more, the rectification effect can be further enhanced. There is no particular upper limit for NP1 / NP0, and all Ni oxide particles 30 observed in the cross section may be present at the first boundary 31 (i.e., NP1 / NP0 = 1.0). When calculating NP1 / NP0, the cross section of the capacitance region 40 is measured from a 200 μm 2 It is preferable to analyze the above.

[0060] The first internal electrode layer 21 is preferably in contact with two or more first Ni oxide particles 30a (more preferably, three or more first Ni oxide particles 30a) on average in one cross section along the Z-axis direction of the capacitance region 40. That is, in one cross section of the element body 4 as shown in FIG. 1, the average number AN of first Ni oxide particles 30a in contact with each first internal electrode layer 21 (first internal electrode layer 21 per layer) is P However, it is preferable that the number of AN is 2 or more, and more preferably 3 or more. P By satisfying the above condition, the difference between the resistance value in one direction and the resistance value in the other direction can be made larger, and the rectification effect can be further enhanced. P can be calculated by counting the number of first Ni oxide particles 30a in contact with each first internal electrode layer 21 of length L1 in a cross section such as that shown in FIG.

[0061] The dielectric layer 10 preferably contains two or more first large particles 13a on average in a cross section along the Z-axis direction of the capacitance region 40. That is, the average number of first large particles 13a contained in each dielectric layer 10 is preferably two or more. Furthermore, if the total length of the dielectric layer 10 observed in the cross section of the capacitance region 40 is LD and the number of first large particles 13a contained in the dielectric layer 10 of the total length LD is ND1, the average number of first large particles 13a contained in the dielectric layer 10 per unit length can be expressed as ND1 / LD. ND1 / LD is preferably 0.005 particles / μm or more. When the first large particles 13a in contact with the first Ni oxide particles 30a are contained in the dielectric layer 10 at the above ratio, the rectification effect can be further enhanced.

[0062] When calculating ND1 / LD, NP L As in the case of / LE, the cross section of the capacitance region 40 is set to 500 μm 2 It is preferable to analyze the above, and the total length LD is preferably set to 500 μm or more. There is no particular upper limit to ND1 / LD, and for example, ND1 / LD is preferably 2 particles / μm or less.

[0063] The capacitance region 40 preferably contains α-type first Ni oxide particles 30a indicated by the symbol "30a(α)" in FIG. 6. The α-type first Ni oxide particles 30a are in contact with both of two adjacent dielectric layers 10 via the first internal electrode layer 21. That is, the α-type first Ni oxide particles 30a exist so as to penetrate the front and back surfaces of the first internal electrode layer 21 in the cross section of the capacitance region 40. Note that the α-type first Ni oxide particles 30a are preferably not in contact with the second internal electrode layer 22.

[0064] In the present embodiment, the first Ni oxide particles 30a indicated by the symbol "30a(β)" in FIG. 6 are referred to as "β-type first Ni oxide particles 30a". The β-type first Ni oxide particles 30a are in contact with only one of two adjacent dielectric layers 10 via the first internal electrode layer 21.

[0065] As shown in FIG. 6, the α-type first Ni oxide particles 30a can contact more first large particles 13a than the β-type first Ni oxide particles 30a. That is, it is considered that the α-type first Ni oxide particles 30a can form more equivalent circuits EC than the β-type first Ni oxide particles 30a. Therefore, by including the α-type first Ni oxide particles 30a in the capacitance region 40, the rectifying action can be further enhanced.

[0066] In a cross section as shown in FIG. 2, when the number of the α-type first Ni oxide particles 30a is NPα and the number of the β-type first Ni oxide particles 30β is NPβ, it is preferable to satisfy NPβ < NPα. That is, when the first Ni oxide particles 30a are classified into α-type and β-type based on the state of the first Ni oxide particles 30a observed in the body cross section, the first Ni oxide particles 30a preferably mainly contain the α-type first Ni oxide particles 30a. When measuring NPα and NPβ, similar to the case of NP1 / NP0, it is preferable to analyze a cross section of the capacitance region 40 with a size of 200 μm 2 as described above.

[0067] The average particle diameter d of the Ni oxide particles 30 Pis not particularly limited, and is preferably 0.03 μm or more and 1.5 μm or less, and more preferably 0.05 μm or more and 1 μm or less. P is the average grain size d of the metal crystals contained in the internal electrode layer 20 M It is preferable that the value is larger than d M d against P The ratio (d P / d M ) is preferably 3 or more, which can further enhance the rectifying effect. P / d M The upper limit of is not particularly limited, and for example, d P / d M The average particle diameter d of the Ni oxide particles 30 can be set to 10 or less. P is preferably calculated by observing the cross section of the capacitance region 40 and measuring the circle-equivalent diameters of at least five Ni oxide particles 30.

[0068] Next, an example of a method for manufacturing the multilayer ceramic electronic component 2 shown in FIG. 1 will be described.

[0069] First, a dielectric paste and an internal electrode paste are prepared. The dielectric paste can be produced by adding a dielectric raw material powder (main component powder) and a sub-component powder to a known organic vehicle or a known aqueous vehicle and kneading them. In addition to the above, a dispersant, a plasticizer, a glass frit, etc. may be added to the dielectric paste. On the other hand, the internal electrode paste can be produced by adding a metal powder such as Ni powder and NiO powder to a known organic vehicle or a known aqueous vehicle and kneading them. The internal electrode paste may contain a dielectric raw material powder as a co-material, and may also contain a dispersant, a plasticizer, etc.

[0070] Here, the NiO powder added to the internal electrode paste is the raw material of the Ni oxide particles 30. L / LE, NP1 / NP0, AN p, NPα, and NPβ can be controlled based on the compounding ratio of NiO powder in the internal electrode paste, the particle size of the NiO powder, the thickness of the internal electrode layer 20, etc. The first internal electrode layer 21 and the second internal electrode layer 22 may be formed using the same internal electrode paste. However, in order to selectively have the Ni oxide particles 30 present at the first boundary 31, it is preferable to prepare a first internal electrode paste and a second internal electrode paste.

[0071] For example, in the first internal electrode paste, the average particle size of the NiO powder is preferably 0.03 μm or more, and more preferably 0.05 μm or more and 0.8 μm or less. The compounding ratio of the NiO powder in the first internal electrode paste is preferably 10 parts by weight or more and 25 parts by weight or less, and more preferably 15 parts by weight or more and 20 parts by weight or less, relative to 100 parts by weight of the metal powder. Meanwhile, the compounding ratio of the NiO powder in the second internal electrode paste is preferably 10 parts by weight or less, and more preferably 5 parts by weight or less, relative to 100 parts by weight of the metal powder. It is not necessary to add NiO powder to the second internal electrode paste. When NiO powder is added to the second internal electrode paste, the average particle size of the NiO powder in the second internal electrode paste is not particularly limited, and is preferably, for example, 0.8 μm or less. The average particle size of the metal powder used in the first internal electrode paste and the second internal electrode paste is preferably 0.8 μm or less, and more preferably 0.03 μm or more and 0.5 μm or less.

[0072] Furthermore, the ND / LD and ND1 / LD ratios for the large particles 13 in the dielectric layer 10 can be controlled based on the particle size of the dielectric raw material powder and the thickness of the dielectric layer 10. For example, the average particle size of the dielectric raw material powder is preferably 0.05 μm or more, and more preferably 0.06 μm or more and 0.2 μm or less.

[0073] Next, the dielectric paste is formed into a sheet by a method such as a doctor blade method to obtain a green sheet. DLThe average thickness T of the green sheet is preferably 2 μm or less, and more preferably 0.2 μm or more and 1 μm or less. Then, the internal electrode paste is applied in a predetermined pattern onto the green sheet by various printing methods such as screen printing or transfer method. The average thickness T of the internal electrode layer 20 is EL This can be controlled by the thickness of the internal electrode paste applied onto the green sheet, and the thickness of the internal electrode paste is preferably 2 μm or less, and more preferably 0.2 μm or more and 1 μm or less.

[0074] Next, multiple green sheets coated with the internal electrode paste are stacked and pressed in the stacking direction to obtain a mother laminate. To selectively have the Ni oxide particles 30 present at the first boundary 31, first green sheets coated with the first internal electrode paste and second green sheets coated with the second internal electrode paste are prepared, and the first and second green sheets are alternately stacked. To form a region in the capacitance region 40 that does not contain the Ni oxide particles 30, a third green sheet coated with an internal electrode paste that does not contain NiO is prepared, and a region in which the first and second green sheets are alternately stacked and a region in which the third green sheet is stacked are formed.

[0075] At least one green sheet not coated with the internal electrode paste is laminated at the top and bottom of the mother laminate in the lamination direction. By laminating the green sheets not coated with the internal electrode paste in this manner, it is possible to form the exterior regions 41 above and below the capacitance region 40.

[0076] The mother laminate obtained by the above steps is cut into a predetermined size by dicing or cutting to obtain a plurality of green chips. If necessary, the green chips may be dried to remove plasticizers and the like, and after drying, may be barrel polished using a horizontal centrifugal barrel machine or the like.

[0077] Next, the green chip obtained above is subjected to a binder removal process and a firing process to obtain an element body 4.

[0078] The conditions for the binder removal process are not particularly limited and may be determined appropriately depending on the types of binders contained in the dielectric paste and the internal electrode paste. For example, the temperature rise rate is preferably 5 to 300°C / hour, the holding temperature is preferably 180 to 400°C, and the temperature holding time is preferably 0.5 to 24 hours. The binder removal atmosphere can be an atmospheric atmosphere (i.e., air) or a reducing atmosphere, and an atmospheric atmosphere is preferred.

[0079] The firing conditions are not particularly limited and may be appropriately set depending on the main component composition of the dielectric layer 10 and the metal components of the internal electrode layer 20. For example, the holding temperature during firing is preferably 1200 to 1350°C, more preferably 1220 to 1300°C, and the holding time is preferably 0.05 to 8 hours, more preferably 0.1 to 3 hours. The firing atmosphere is preferably a reducing atmosphere, and the atmospheric gas may be, for example, a humidified mixed gas of N2 and H2. Furthermore, when the internal electrode layer 20 is made of a base metal such as Ni or a Ni alloy, the oxygen partial pressure in the firing atmosphere should be set to 1.0 x 10 -14 MPa~1.0×10 -10 It is preferable to set it to MPa.

[0080] The fired element 4 may be subjected to an annealing treatment. For example, the annealing treatment is preferably performed to reoxidize the dielectric layer 10 or to remove distortion caused by firing. The conditions for the annealing treatment are not particularly limited and may be determined appropriately depending on the main component composition of the dielectric layer 10. For example, the holding temperature is preferably 650 to 1150°C, the temperature holding time is preferably 0 to 20 hours, and the temperature rise rate and temperature fall rate are preferably 50 to 500°C / hour. Furthermore, it is preferable to use dry N2 gas or humidified N2 gas as the atmospheric gas.

[0081] In the above-mentioned binder removal treatment, firing treatment, and annealing treatment, a wetter or the like may be used to humidify the N2 gas or mixed gas, and in this case, the water temperature is preferably about 5 to 75° C. Furthermore, the binder removal treatment, firing treatment, and annealing treatment may be performed consecutively or independently.

[0082] The end faces 4a and 4b of the element body 4 may be polished before forming the external electrodes 6. Examples of polishing methods include barrel polishing, sandblasting, and laser. Polishing the end faces 4a and 4b of the element body 4 makes it easier to electrically connect the internal electrode layers 20 and the external electrodes 6.

[0083] Next, a pair of external electrodes 6 are formed on the outer surface of the element body 4. There are no particular restrictions on the method for forming the external electrodes 6, and any known method may be used. Through the above steps, the multilayer ceramic electronic component 2 shown in FIG. 1 is obtained.

[0084] After the multilayer ceramic electronic component 2 is manufactured or before use (before the multilayer ceramic electronic component 2 is incorporated into a circuit), a screening test is performed to determine the direction of rectification. In the multilayer ceramic electronic component 2, the resistance value changes depending on the direction of voltage application due to the rectification effect, but the direction of rectification cannot be determined simply by observing the appearance of the multilayer ceramic electronic component 2. Therefore, in the screening test, a DC voltage is applied to the multilayer ceramic electronic component 2, and the direction in which the resistance value is low and the direction in which the resistance value is high are determined. In this embodiment, the direction in which the resistance is low is referred to as the "forward direction," and the direction in which the resistance is high is referred to as the "reverse direction."

[0085] The resistance when a voltage is applied in the forward direction to the multilayer ceramic electronic component 2 is R Low The resistance when voltage is applied in the reverse direction is R High In the multilayer ceramic electronic component 2, R High / R Lowis preferably 10 or more, more preferably 50 or more, and further preferably 100 or more. In consideration of the above-mentioned hypothesis regarding the rectification action (the equivalent circuit EC shown in FIG. 3B), in the multilayer ceramic electronic component 2 of this embodiment, when a voltage is applied with the first internal electrode layer 21 side as the negative electrode and the second internal electrode layer 22 side as the positive electrode, a low resistance value R Low It is thought that the following can be obtained.

[0086] The multilayer ceramic electronic component 2 of this embodiment may be applicable to, for example, an AC / DC converter circuit as shown in Fig. 7. The AC / DC converter circuit of Fig. 7 is a rectifier circuit that converts alternating current into direct current, in which C1 to C3 in Fig. 7 are capacitors, R3 to R6 are resistors, and D1 to D5 are diodes.

[0087] Circuit F, enclosed by a bold line in FIG. 7, is a full-wave rectifier circuit including a bridge formed by four diodes D2 to D5. When an AC voltage having the waveform shown in FIG. 8A is input to this circuit F, the negative voltage is converted to a positive voltage. Meanwhile, circuit G1, enclosed by a dashed line in FIG. 7, and circuit G2, enclosed by a dashed line, are both circuits that divide the full-wave rectified voltage output from circuit F to reduce the voltage value. Circuit G1 includes capacitor C1, diode D1, resistors R3, and resistor R4, and these three electronic components divide the full-wave rectified voltage. Meanwhile, circuit G2 includes capacitor C2 and resistor R6, and these two electronic components divide the full-wave rectified voltage.

[0088] The solid line in Figure 8B shows the waveform of the divided voltage Vout output from circuit G1, and the dashed line in Figure 8B shows the waveform of the divided voltage Vout2 output from circuit G2. In the case of circuit G2, which divides the voltage using two types of elements (a capacitor and a resistor), the voltage waveform becomes out of phase and a negative voltage occurs, as shown in Figure 8B. In contrast, circuit G1, which divides the voltage using three types of elements (a capacitor, a diode, and a resistor), can suppress both the phase shift and the negative voltage. Furthermore, the rise from 0V of the voltage output from circuit G1 coincides with the zero crossing (zero point) of the input AC voltage (Figure 8A). For example, if capacitor C1 in circuit G1 is replaced with a resistor (not shown), circuit G1 becomes a conventional voltage divider circuit. In this case, loss occurs in the resistor (not shown). By using capacitor C1 instead of a resistor (not shown) in circuit G1, the loss is limited to the tan δ component of capacitor C1, thereby reducing loss.

[0089] In AC / DC converter circuits, normally, reducing the number of components as in circuit G2 makes it difficult to properly divide voltages, making it difficult to simplify the circuit. The multilayer ceramic electronic component 2 of this embodiment functions as a capacitor (i.e., it can store charge in the dielectric layer 10) and also has a rectifying effect like a diode. Therefore, the three types of electronic components (capacitor, diode, and resistor) included in circuit G1 can be substituted with a single type of multilayer ceramic electronic component 2, potentially simplifying the circuit. Note that when the capacitor, diode, and resistor of circuit G1 are substituted with a single type of multilayer ceramic electronic component 2, multiple multilayer ceramic electronic components 2 may be connected in series to ensure sufficient withstand voltage.

[0090] (Summary of the embodiment) The multilayer ceramic electronic component 2 of this embodiment has first internal electrode layers 21, second internal electrode layers 22, and a dielectric layer 10 laminated between the first internal electrode layers 21 and the second internal electrode layers 22. The capacitance region 40 of the element body 4 has first Ni oxide particles 30a present at first boundaries 31 between the first internal electrode layers 21 and the dielectric layer 10. The dielectric layer 10 includes the first Ni oxide particles 30a at the first boundaries 31 and first large particles 13a in contact with the second internal electrode layers 22.

[0091] As described above, the multilayer ceramic electronic component 2 has the capacitance region 40 in which the first internal electrode layers 21, the second internal electrode layers 22, and the dielectric layers 10 are laminated, and therefore, electric charges can be stored in the dielectric layers 10. In other words, the multilayer ceramic electronic component 2 functions as a capacitor. It has been considered preferable for conventional multilayer ceramic capacitors to have a high resistance value (see Patent Document 1). In contrast, the multilayer ceramic electronic component 2 of this embodiment has a rectification effect (specifically, R High / R Low The reason why the rectification effect is obtained is not entirely clear, but it is thought that the two types of Schottky junctions are related to the occurrence of the rectification effect. Specifically, it is thought that an equivalent circuit EC as shown in FIG. 3B is formed at the contact point between the first large particle 13a and the first Ni oxide particle 30a, and it is thought that this equivalent circuit EC causes the rectification effect.

[0092] 3B, it is sufficient that the p-type semiconductor particles are present at the first boundary 31 and are in contact with the first large particles 13a of the dielectric layer 10. In other words, in FIGS. 2 and 3A, the particles indicated by the reference symbol "30a" are not necessarily limited to Ni oxide particles (NiO), and may be p-type semiconductor particles.

[0093] The capacitance region 40 of the element body 4 preferably contains first α-type Ni oxide particles 30a that contact two adjacent dielectric layers 10 via the first internal electrode layers 21. The first α-type Ni oxide particles 30a may be able to contact more first large particles 13a than the other first Ni oxide particles 30a. In other words, when the capacitance region 40 contains first α-type Ni oxide particles 30a, the rectification effect can be further enhanced (R High / R Low can be made larger).

[0094] The average number AN of first Ni oxide particles 30a in contact with each first internal electrode layer 21 P However, it is preferable that the number of the conductive layers is 2 or more. When the multilayer ceramic electronic component 2 satisfies this requirement, the rectifying effect can be further improved.

[0095] If the total number of Ni oxide particles 30 observed in the cross section of the element body 4 is defined as NP0 and the number of first Ni oxide particles 30a is defined as NP1, it is preferable that NP1 / NP0 be 0.6 or more. By satisfying the above requirement, the rectifying effect can be further improved.

[0096] The average number of Ni oxide particles 30 in contact with the internal electrode layer 20 per unit length (NP L / LE) is preferably 0.002 particles / μm or more. When the multilayer ceramic electronic component 2 satisfies this requirement, the rectifying effect can be further improved.

[0097] The average grain size of the metal crystals contained in the internal electrode layer 20 is d M The average particle size of the Ni oxide particles 30 is d P As, d P / d M is preferably equal to or greater than 3. When the multilayer ceramic electronic component 2 satisfies this requirement, the rectifying effect can be further enhanced.

[0098] In addition, the above-mentioned AN PWhen analyzing the cross section of the capacitance region 40 to calculate NP1 / NP0 or NP1 / NP0, the first internal electrode layers 21 and the second internal electrode layers 22 may be identified by one of the following three methods.

[0099] For example, when observing a cross section of the capacitance region 40, it may be possible to confirm that the internal electrode layer 20 in contact with the Ni oxide particle 30, the dielectric layer 10, and the internal electrode layer 20 not in contact with the Ni oxide particle 30 are repeatedly stacked in the order described above. In this case, of a pair of internal electrode layers 20 facing each other via the dielectric layer 10, the internal electrode layer 20 in contact with the Ni oxide particle 30 can be identified as the first internal electrode layer 21, and the internal electrode layer 20 not in contact with the Ni oxide particle 30 can be identified as the second internal electrode layer 22.

[0100] Furthermore, when both of a pair of internal electrode layers 20 are in contact with Ni oxide particles 30, the internal electrode layer 20 in contact with more Ni oxide particles 30 is identified as the first internal electrode layer 21, and the internal electrode layer 20 on the other side is identified as the second internal electrode layer 22.

[0101] Furthermore, before observing the cross section, a screening test may be performed to distinguish between the first internal electrode layer 21 and the second internal electrode layer 22. For example, the screening test may be performed to distinguish between the first internal electrode layer 21 and the second internal electrode layer 22. Low is obtained, the positive electrode side is identified as the second external electrode 6b, and the negative electrode side is identified as the first external electrode 6a. Then, during cross-sectional observation, the internal electrode layer 20 connected to the first external electrode 6a may be identified as the first internal electrode layer 21, and the internal electrode layer 20 connected to the second external electrode 6b may be identified as the second internal electrode layer 22.

[0102] The above describes embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments and can be modified in various ways within the scope of the gist of the present disclosure.

[0103] For example, the external electrode 6 may be a pad-shaped electrode present on one side surface of the element body 4. In this case, the pad-shaped external electrode 6 may be electrically connected to the internal electrode layer 20 via a through-hole electrode or a via-hole electrode.

[0104] Furthermore, the electronic component of the present disclosure is not limited to the multilayer ceramic electronic component 2 shown in FIG. 1 as long as it has at least one first internal electrode layer 21, one second internal electrode layer 22, and one dielectric layer 10. [Example]

[0105] The present disclosure will be described below in more detail based on examples, but the present disclosure is not limited to these examples.

[0106] (Experiment 1) In Experiment 1, multilayer ceramic electronic components according to Example A1, Comparative Example 1, and Comparative Example 2 were manufactured according to the following procedure.

[0107] Example A1 First, a dielectric paste, which is a raw material for the dielectric layers, was prepared using (Ba,Ca)(Ti,Zr)O3 powder (main component powder) having an average particle size of 0.09 μm and subcomponent powders (MgCO3 powder, Y2O3 powder, MnCO3 powder, V2O5 powder, and SiO2 powder). Furthermore, a first internal electrode paste and a second internal electrode paste were prepared as raw materials for the internal electrode layers. Ni powder having an average particle size of 0.18 μm and NiO powder having an average particle size of 0.15 μm were added to the first internal electrode paste, and the compounding ratio of the NiO powder in the first internal electrode paste was 17 parts by weight relative to 100 parts by weight of the Ni powder. Meanwhile, Ni powder having an average particle size of 0.18 μm was added to the second internal electrode paste, but no NiO powder was added.

[0108] Next, the dielectric paste was applied onto a PET film and formed into a sheet to obtain a green sheet having a thickness of 0.65 μm, and then the first internal electrode paste was applied onto this green sheet in a predetermined pattern to produce a first green sheet. Also, the dielectric paste was applied onto a PET film and formed into a sheet to obtain a green sheet having a thickness of 0.65 μm, and then the second internal electrode paste was applied onto this green sheet in a predetermined pattern to produce a second green sheet. The application amounts of the first internal electrode paste and the second internal electrode paste were determined based on the average thickness T of the internal electrode layer after firing. EL The thickness was controlled to be 0.55 μm.

[0109] Next, the first green sheets and the second green sheets were alternately stacked and pressed to obtain a mother laminate. At this time, green sheets without any internal electrode paste were stacked at the top and bottom of the stacking direction of the mother laminate. The number of stacked first and second green sheets was controlled so that the number of stacked dielectric layers in the capacitance region was 350. The thickness of the exterior region 41 after firing was controlled so that it was 20 μm or more.

[0110] The mother laminate was cut to a specified size to obtain green chips, which were then subjected to binder removal, firing, and annealing. External electrodes containing sintered bodies primarily composed of Cu were then formed on each end face of the element. These steps resulted in a multilayer ceramic electronic component with a cross-sectional structure similar to that shown in Figure 1. The average dimensions of the element in this multilayer ceramic electronic component were L0 × W0 = 0.7 mm × 0.45 mm.

[0111] Comparative Example 1 In Comparative Example 1, both the first internal electrode layer and the second internal electrode layer were formed using an internal electrode paste that did not contain NiO powder. Specifically, in Comparative Example 1, an internal electrode paste was prepared using Ni powder with an average particle size of 0.18 μm, and no NiO powder was added to the internal electrode paste. Then, the internal electrode paste was applied in a predetermined pattern onto a green sheet with a thickness of 0.65 μm to obtain a first green sheet and a second green sheet. In Comparative Example 1, a dielectric paste with the same specifications as in Example A1 was used, and the thickness of the green sheet was also controlled to be approximately the same as in Example A1. The manufacturing conditions other than those described above were the same as in Example A1, and a multilayer ceramic electronic component according to Comparative Example 1 was manufactured.

[0112] Comparative Example 2 In Comparative Example 2, first and second internal electrode layers were formed using a first internal electrode paste and a second internal electrode paste having the same specifications as those in Example A1. However, in Comparative Example 2, dielectric layers were formed under conditions different from those in Example A1. Specifically, in Comparative Example 2, a dielectric paste containing a (Ba,Ca)(Ti,Zr)O3 powder (main component powder) having an average particle size of 0.04 μm was prepared, and a green sheet having a thickness of 0.65 μm was produced using the dielectric paste. As described above, the (Ba,Ca)(Ti,Zr)O3 powder used in Comparative Example 2 had an average particle size different from that in Example A1, but the accessory component powders added to the dielectric paste and the compounding ratio of the accessory component powders were the same as those in Example A1. A multilayer ceramic electronic component according to Comparative Example 2 was manufactured under the same manufacturing conditions as those in Example A1, except for the above.

[0113] Cross-sectional analysis of the element The cross section of the element in the lamination direction (the cross section of the capacitance region as shown in Figures 1 and 2) was observed with STEM, and the average thickness T EL (μm), the average thickness of the dielectric layer T DL (μm), and the average particle size d of the dielectric particles contained in the dielectric layer DP In addition, in the cross-sectional observation, elemental mapping analysis by EDS was performed on five analysis fields (each analysis field had an area of ​​54 μm2 ) to investigate whether or not Ni oxide particles were present within the analysis range. In Table 1, the "Presence or Absence of Ni Oxide Particles" column contains the entries "Y" and "N." "Y" means that Ni oxide particles were present at the boundary between the dielectric layer and the internal electrode layer, and "N" means that Ni oxide particles were not observed at the boundary between the dielectric layer and the internal electrode layer.

[0114] Furthermore, in samples in which Ni oxide particles could be identified by the above-mentioned cross-sectional analysis, of a pair of internal electrode layers facing each other via a dielectric layer, the internal electrode layer in contact with more Ni oxide particles was identified as the first internal electrode layer, and the internal electrode layer in contact with fewer Ni oxide particles was identified as the second internal electrode layer.

[0115] Furthermore, in the above cross-sectional analysis, the dielectric particles that were in contact with Ni oxide particles at the boundary with one internal electrode layer (first boundary 31) and in contact with the metal component of the internal electrode layer at the boundary with the other internal electrode layer (second boundary 32) were identified as first large particles (13a). In the "Presence or absence of first large particles" column in Table 1, "Y" means that the dielectric layer 10 contained the first large particles 13a, and "N" means that the dielectric layer 10 did not contain the first large particles 13a.

[0116] Evaluation of rectification A DC voltage of 4 V was applied to the multilayer ceramic electronic component from any direction for 30 seconds, and the resistance value r1 of the multilayer ceramic electronic component was measured. The direction of the voltage application was then reversed, and a DC voltage of 4 V was again applied to the multilayer ceramic electronic component for 30 seconds, and the resistance value r2 of the multilayer ceramic electronic component was measured. The lower of the resistance values ​​r1 and r2 was designated as R. Low The higher value is R High As, R Low R High The ratio (unitless) was calculated.

[0117] In this experiment, R High / R LowIf R is 10 or more, it is judged that "the measured sample has a rectifying effect." High / R Low Samples with a value of 50 or more but less than 100 are judged as "good," and R High / R Low Samples with a value of 100 or more were judged to be "particularly good."

[0118] Capacitance measurement To determine whether or not the component has capacitor properties, an LCR meter was used to measure the capacitance (μF) of the multilayer ceramic electronic component. The measurement temperature was set to room temperature (25°C), and a signal with a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms was input to the component. In this experiment, if the capacitance was 3.8 μF or higher, it was determined that the measured sample had the ability to adequately store charge as a capacitor.

[0119] The evaluation results of Example A1, Comparative Example 1, and Comparative Example 2 are shown in Table 1. [Table 1]

[0120] In Comparative Example 1, an internal electrode paste containing no NiO powder was used, so no Ni oxide particles were present at the boundary between the dielectric layer and the internal electrode layer, and the first large particles in contact with the Ni oxide particles were not contained in the dielectric layer. In Comparative Example 2, Ni oxide particles were observed at the boundary between the dielectric layer and the internal electrode layer. However, the dielectric layer of Comparative Example 2 contained almost no large particles (reference numeral 13), and cross-sectional analysis of Comparative Example 2 failed to detect the first large particles (reference numeral 13a) in contact with the Ni oxide particles. In other words, in Comparative Example 2, the Ni oxide particles in the capacitance region were in contact with the small particles (reference numeral 15) of the dielectric layer, but not with the large particles.

[0121] On the other hand, in the cross-sectional analysis of Example A1, Ni oxide particles were observed at the boundary between the dielectric layer and the internal electrode layer, and it was confirmed that first large particles in contact with the Ni oxide particles were present in the dielectric layer. In other words, it was confirmed that in Example A1, the cross-sectional structure shown in Figure 3A existed in the capacitance region.

[0122] It was confirmed that the multilayer ceramic electronic component of Example A1 had sufficient capacitance and functioned as a capacitor to store electric charge in the dielectric layer. High / R Low was far larger than those of Comparative Examples 1 and 2, and it was confirmed that the multilayer ceramic electronic component of Example A1 had a rectifying function like a diode.

[0123] (Experiment 2) In Experiment 2, multilayer ceramic electronic components according to Examples B1 and B2 shown in Table 2 were manufactured, and the characteristics of each Example were compared. Specifically, in Example B1, a first internal electrode paste was manufactured using NiO powder with a finer particle size than that of Example A1. In Example B2, a first internal electrode paste was manufactured using NiO powder with an even finer particle size than that of Example B1. The manufacturing conditions other than the specifications of the NiO powder were the same as those of Example A1.

[0124] In the cross-sectional analysis of Experiment 2, elemental mapping analysis by EDS was performed on five analysis fields (each analysis field area was 54 μm 2 ) and identified the Ni oxide particles present at the boundary between the dielectric layer and the internal electrode layer within the analysis range. These Ni oxide particles were then classified into "α-type" and "β-type." The number of α-type Ni oxide particles (NPα) and the number of β-type Ni oxide particles (NPβ) were then measured. Note that α-type Ni oxide particles are Ni oxide particles that contact two adjacent dielectric layers via an internal electrode layer, and β-type Ni oxide particles are Ni oxide particles that contact one of the two adjacent dielectric layers via an internal electrode layer (see Figure 6).

[0125] In addition, in the cross-sectional analysis of Experiment 2, the average grain size d of the metal crystals contained in the internal electrode layer wasM , and the average particle size of Ni oxide particles d P Measure and d M d against P The ratio (unitless) was calculated.

[0126] In Examples B1 and B2, as in Example A1, Ni oxide particles were observed at the boundaries between the dielectric layers and the internal electrode layers, and it was confirmed that first large particles in contact with the Ni oxide particles were present in the dielectric layers. The evaluation results of Experiment 2 are shown in Table 2.

[0127] [Table 2]

[0128] As shown in Table 2, Example A1, which has a high ratio of α-type Ni oxide particles, has a higher R than Example B1, which has a low ratio of α-type Ni oxide particles. High / R Low This result indicates that the α-type Ni oxide particles contribute to the improvement of the rectification effect. P / d M It was found that it is preferable that the value be 3 or more.

[0129] (Experiment 3) In Experiment 3, NiO powder was added to both the first internal electrode paste and the second internal electrode paste to manufacture four types of multilayer ceramic electronic components shown in Table 3. Ni powder with an average particle size of 0.18 μm and NiO powder with an average particle size of 0.2 μm were added to the first internal electrode paste and the second internal electrode paste used in each of Examples C1 to C4, respectively, and the compounding ratio of NiO powder in the first internal electrode paste was made higher than the compounding ratio of NiO powder in the second internal electrode paste. Conditions other than the compounding ratio of NiO powder were the same as those in Example A1 of Experiment 1.

[0130] In the cross-sectional analysis of Experiment 3, of a pair of internal electrode layers facing each other via a dielectric layer, the internal electrode layer that is in contact with more Ni oxide particles is identified as the first internal electrode layer, and the internal electrode layer that is in contact with fewer Ni oxide particles is identified as the second internal electrode layer. In this case, the cross section of the element (capacitor region) was analyzed in three fields, with the area of ​​each analyzed field being 54 μm 2 Then, the number NP0 of Ni oxide particles and the number NP1 of Ni oxide particles present at the boundary (first boundary 31) between the first internal electrode layer and the dielectric layer were measured.

[0131] In Examples C1 to C4, it was confirmed that the first large particles in contact with the Ni oxide particles were present in the dielectric layer, as in Example A1. The evaluation results of Experiment 3 are shown in Table 3.

[0132] [Table 3]

[0133] The results in Table 3 show that NP1 / NP0 is preferably 0.6 or more, and more preferably 0.75 or more.

[0134] (Experiment 4) In Experiment 4, the compounding ratio of NiO powder in the first internal electrode paste was changed to manufacture multilayer ceramic electronic components according to Examples D1 to D3. In all of Examples D1 to D3, a second internal electrode paste not containing NiO powder was used (that is, the specifications of the second internal electrode paste were the same as in Example A1). The manufacturing conditions other than the compounding ratio of NiO were the same as in Example A1.

[0135] In the cross-sectional analysis of Experiment 4, of a pair of internal electrode layers facing each other via a dielectric layer, the internal electrode layer in contact with more Ni oxide particles was identified as the first internal electrode layer, and the internal electrode layer in contact with fewer Ni oxide particles was identified as the second internal electrode layer. Then, the average number of Ni oxide particles in contact with each first internal electrode layer, AN P was measured.

[0136] Also, 1134 μm 2 The internal electrode layers with a total length of 920 μm or more included in the cross section of the sample were analyzed, and the average number of Ni oxide particles NP in contact with the internal electrode layer per unit length was calculated. L / LE was calculated. Note that, in Examples D1 to D3, it was confirmed that the first large particles in contact with the Ni oxide particles were present in the dielectric layer, as in Example A1. The evaluation results of Experiment 4 are shown in Table 4.

[0137] [Table 4]

[0138] From the results in Table 4, AN P It was found that the number of contacts is preferably 2 or more, and more preferably 3 or more. In other words, it was found that it is preferable that the first internal electrode layer is in contact with an average of 2 or more (more preferably an average of 3 or more) Ni oxide particles in one cross section of the element body, and this leads to a further improvement in the rectification effect.

[0139] Also, from the results in Table 4, NP L It was found that / LE is preferably 0.002 particles / μm or more, and more preferably 0.005 particles / μm or more. [Explanation of symbols]

[0140] 2... Multilayer ceramic electronic components 4... Base body 4a,4b … End face 4c…side 40 … Capacity area 41 … Exterior area 6 … External electrode 6a … 1st external electrode 6b…Second external electrode 10...Dielectric layer 11...Dielectric particles 13...Large particles 13a … First large particle 13b … Second large particle 15… small particles 17 … Particle boundary 20 … Internal electrode layer 21 … First inner electrode layer 22 … Second inner electrode layer 31 … First Realm 32 … Second Realm 30…Ni acid compound particles 30a… 1st Ni acid compound particle 30b … Second Ni oxide particle

Claims

1. an element body including a first internal electrode layer, a second internal electrode layer, and a dielectric layer laminated between the first internal electrode layer and the second internal electrode layer; Ni oxide particles are present at a first boundary between the first internal electrode layer and the dielectric layer; The electronic component, wherein the dielectric layer includes large dielectric particles in contact with both the Ni oxide particles at the first boundary and the second internal electrode layer.

2. 2. The electronic component according to claim 1, wherein the Ni oxide particles are in contact with both of the two adjacent dielectric layers via the first internal electrode layer.

3. the element body includes a plurality of first internal electrode layers, a plurality of second internal electrode layers, and a plurality of dielectric layers, 3. The electronic component according to claim 1, wherein the first internal electrode layer is in contact with an average of two or more of the Ni oxide particles in one cross section of the element body.

4. the element body includes a plurality of first internal electrode layers, a plurality of second internal electrode layers, and a plurality of dielectric layers, The total number of the Ni oxide particles observed in the cross section of the element body is defined as NP0, The number of the Ni oxide particles present at the first boundary among the Ni oxide particles observed in the cross section is defined as NP1, 3. The electronic component according to claim 1, wherein NP1 / NP0 is 0.6 or more.

5. the element body includes a plurality of first internal electrode layers, a plurality of second internal electrode layers, and a plurality of dielectric layers, a total length of the first internal electrode layer and the second internal electrode layer observed in a cross section of the element body is defined as LE; In the range of the total length LE, the number of the Ni oxide particles in contact with the first internal electrode layer or the second internal electrode layer is set to NP L As, NP L 3. The electronic component according to claim 1, wherein / LE is 0.002 pieces / μm or more.

6. The average grain size of the metal crystals contained in the first internal electrode layer and the second internal electrode layer is d M year, The average particle size of the Ni oxide particles is d P As, d P / d M 3. The electronic component according to claim 1, wherein the number of saturations is 3 or more.

7. an element body including a first internal electrode layer, a second internal electrode layer, and a dielectric layer laminated between the first internal electrode layer and the second internal electrode layer; p-type semiconductor particles are present at a first boundary between the first internal electrode layer and the dielectric layer; The electronic component, wherein the dielectric layer includes large dielectric particles in contact with both the p-type semiconductor particles at the first boundary and the second internal electrode layer.

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