JP2010062265A - Variable resistor element, method of manufacturing the same, and method of driving the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable resistor element capable of increasing the repeatability of a switching operation and facilitating its construction design. <P>SOLUTION: In the variable resistor element, a first electrode 13, a second electrode 16 and a variable resistor 15 formed between the electrodes are formed on a substrate 11 and electric resistance between the electrodes is reversibly changed by applying voltage pulses between the electrodes. The variable resistor 15 is constituted of a predetermined variable resistor film and includes at least one seam 32 extending from the first electrode 13 toward the second electrode 16 in an area thicker than other areas. The variable resistor 15 is formed to have the seam by film-deposition at its step or an opening. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes a first electrode, a second electrode, and a variable resistor formed between the two electrodes, and an electric resistance between the two electrodes is obtained by applying a voltage pulse between the two electrodes. The present invention relates to a reversible variable resistance element, a manufacturing method thereof, and a driving method thereof.

  In recent years, various devices such as next-generation non-volatile random access memory (NVRAM: Nonvolatile Random Access Memory) capable of operating at high speed instead of flash memory include FeRAM (Ferroelectric RAM), MRAM (Magnetic RAM), and PRAM (Phase Change RAM). A structure has been proposed, and intense development competition has been conducted from the viewpoint of high performance, high reliability, low cost, and process consistency. However, each of these current memory devices has advantages and disadvantages, and it is still far from the ideal realization of a “universal memory” having the advantages of SRAM, DRAM, and flash memory.

  For these existing technologies, a resistive non-volatile memory RRAM (Resistive Random Access Memory) (registered trademark) using a variable resistive element whose electric resistance reversibly changes by applying a voltage pulse has been proposed. This configuration is shown in FIG.

  As shown in FIG. 50, the variable resistance element of the conventional configuration has a structure in which a lower electrode 103, a variable resistor 102, and an upper electrode 101 are sequentially stacked, and a voltage is applied between the upper electrode 101 and the lower electrode 103. By applying a pulse, the resistance value can be reversibly changed. A novel nonvolatile semiconductor memory device can be realized by reading a resistance value that changes by this reversible resistance change operation (hereinafter referred to as “switching operation”).

As this conventional variable resistance element, for example, Patent Document 1 listed below discloses a resistance change type memory made of a binary oxide having a high affinity with a semiconductor process and having a simple composition. Specifically, Patent Document 1 discloses that “a data storage material layer has NiO, V ₂ O ₅ as a transition metal oxide film having different resistance characteristics at different voltages and whose resistance rapidly increases in a predetermined voltage range. , ZnO, Nb ₂ O ₅ , TiO ₂ , WO ₃ or CoO ”is disclosed.

Non-Patent Document 1 below includes an upper electrode and a lower electrode, and NiO, TiO ₂ , ZrO ₂ , or HfO ₂ that is a binary transition metal oxide sandwiched between the two electrodes. An example of a nonvolatile resistance change memory element has been reported.

  As described above, the resistance change type memory made of the binary transition metal oxide disclosed in Patent Document 1 or Non-Patent Document 1 has a high affinity with a semiconductor process and has a simple structure and composition. Therefore, there is an advantage that it can be easily applied to a highly integrated nonvolatile memory.

JP 2004-363604 A Baek, I. et al. G. In addition, “Highly Scalable Non-volatile Resistive Memory Using Simple Binary Oxide Driven Asymmetric Universal Voltage Pulses”, IEDM Tech. 587-590, 2004

  According to each of the conventional techniques described above, the element structure is a variable resistance element having a laminated structure in which a lower electrode, a variable resistor, and an upper electrode are formed in this order on a substrate. As for the resistance change of the element, a region in which the resistivity is locally reduced (hereinafter referred to as “filament path” as appropriate) is formed in the variable resistor due to the heat rise due to the current flowing into the variable resistance element depending on the voltage pulse application condition. It is said that this is based on the phenomenon that the resistance becomes low or high by disassembling the filament path. Prior to the switching operation, in order to form the filament path, an electrical process called a “forming process” for applying a voltage larger than that used in the normal switching operation is required.

  In this forming process, for example, when the variable resistor is a metal oxide that is essentially an insulator, a voltage several times to ten times as large as the voltage used for the normal switching operation must be applied for a certain time or more. In the forming process, the current path is formed by a phenomenon similar to dielectric breakdown in the insulator, and therefore, the formation location of the filament path that would have been most electrically fragile in the variable resistor cannot be limited. . This makes it difficult to design the structure of the variable resistance element.

  Further, there is a variation in the read resistance value after the forming process, and the filament path state control after the forming process is not performed. If the read resistance value after the forming process is different, the resistance value in the low resistance state, the resistance value in the high resistance state, the voltage condition in the set operation, the voltage condition in the reset operation, etc. are different in each switching operation. The characteristics are not uniform.

  In view of the above-described problems, the present invention provides a variable resistance element that improves the reproducibility of switching operation and facilitates structural design by limiting the formation region of the filament path formed by the forming process. For the purpose.

  In order to achieve the above object, a variable resistance element according to the present invention has a first electrode, a second electrode, and a variable resistor formed between the two electrodes on a substrate, and between the two electrodes. A variable resistance element in which an electrical resistance between the electrodes changes reversibly by applying a voltage pulse, wherein the variable resistor extends in a direction from the first electrode toward the second electrode. It has two seams.

  According to the above feature of the variable resistance element according to the present invention, since a seam extending in the direction from the first electrode to the second electrode is formed in the variable resistor film, a voltage is applied between both electrodes. Sometimes this seam can be used as a filament path. That is, since there are more structural defects in the seam than in the variable resistor (bulk portion), electric field concentration is likely to occur. For this reason, when a voltage is applied to perform the forming process, a filament path is easily formed in or near the seam where electric field concentration is likely to occur. For this reason, by intentionally forming a seam at a specific location in advance during manufacturing, the filament path formation region formed by the forming process can be kept within a specific range, and the reproducibility of the switching operation is improved. Can do.

  In addition, as described above, since the electric field concentration is likely to occur in or near the seam, the voltage required for executing the forming process can be reduced as compared with the conventional configuration.

  In the above feature, the shape of the seam may be linear, annular, or discrete point. Further, it is not always necessary to form the seam so as to contact one or both of the first electrode and the second electrode, and even if the seam is formed in the variable resistor film without contacting both the electrodes. good. Even in this case, by performing the forming process, a filament path is formed in or near the seam in the seam formation region. Therefore, the filament path is compared with the conventional configuration in which no seam is formed. The forming region can be specified, and the switching operation can be performed with good reproducibility.

  Further, as the variable resistor film, it is possible to use oxides or oxynitrides of metals such as Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Hf, Ta, and W.

  At this time, a seam may be formed in a thick film region where the variable resistor film is locally thickened. The “thick film region” as used herein refers to both the front and back surfaces of the variable resistor film (one surface is at least partially in contact with the first electrode and the other surface is at least partially in contact with the second electrode). On one surface, the shortest distance from the point on the surface to the point on the other surface is longer than the deposited film thickness (the film thickness of the portion where both the front and back surfaces extend in parallel) Point to. For example, the variable resistor film formed in the step portion corresponds to the corner region of the step, and the variable resistor film formed so as to fill the opening portion corresponds to the axial center region in the opening portion. To do.

  In addition to the above characteristics, the variable resistance element according to the present invention may be configured such that at least one of the seams applies a voltage between the first electrode and the second electrode, thereby forming a part of the filament path. Another feature is forming.

  In addition to the above features, the variable resistance element according to the present invention is configured such that the variable resistor is coupled to a first structure portion configured parallel to the substrate surface, and a lower end is coupled to an end portion of the first structure portion. And a second structure portion configured in a direction perpendicular to the substrate surface, and the seam is provided in a corner region where the first structure portion and the second structure portion are coupled to each other.

  In this case, in addition to the above characteristics, the variable resistance element according to the present invention includes an insulating film on a part of the first electrode. The upper surface is in contact with the upper surface of one electrode, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the first surface is in contact with the side surface of the insulating film, and the first surface and the variable resistor are The second surfaces facing each other with a film thickness may be formed so as to be in contact with the side surface of the second electrode.

  In addition to the above features, the variable resistance element according to the present invention includes an insulating film that is thicker than the first electrode in the same layer as the first electrode, and the variable resistor includes the first resistor. In the structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the first surface is in contact with the side surface of the insulating film, A second surface opposing one surface with a film thickness of the variable resistor may be formed so as to be in contact with the side surface of the second electrode.

  At this time, the variable resistor includes a third structure portion configured parallel to the substrate surface and having a height position higher than that of the first structure portion and coupled to an upper end of the second structure portion at an end portion, In the third structure portion, the lower surface may be formed so as to be in contact with the upper surface of the insulating film, and the upper surface may be formed in contact with the lower surface of the second electrode.

  In addition to the above characteristics, the variable resistance element according to the present invention has a configuration in which the first electrode has a step by having regions with different formation film thicknesses, and the variable resistor has the first structure. The lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the first surface is in contact with the side surface of the first electrode, A second surface opposing one surface with a film thickness of the variable resistor may be formed so as to be in contact with the side surface of the second electrode.

  In addition to the above characteristics, the variable resistance element according to the present invention includes an insulating film having a step by having regions with different formed film thicknesses, and the first electrode is formed on the insulating film. The variable resistor has a lower surface in contact with the upper surface of the first electrode in the first structure portion, and the upper surface is in the second structure. The second surface is in contact with the lower surface of the electrode, and in the second structure portion, the first surface is in contact with the side surface of the first electrode, and the second surface facing the first surface with a film thickness of the variable resistor is It may be formed so as to be in contact with the side surface of the second electrode.

  In addition to the above features, the variable resistance element according to the present invention includes an insulating film, the first electrode is formed on a part of the insulating film, and the variable resistor includes the first structure. In the portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the first surface is in contact with the side surface of the first electrode, and the first The second surface that faces the surface of the variable resistor with the film thickness of the variable resistor may be formed so as to be in contact with the side surface of the second electrode.

  The variable resistance element according to the present invention includes, in addition to the above characteristics, an insulating film having a thickness smaller than that of the first electrode in the same layer as the first electrode. In the structure portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the first surface is in contact with the side surface of the first electrode, A second surface opposing one surface with a film thickness of the variable resistor may be formed so as to be in contact with the side surface of the second electrode.

  At this time, the variable resistor includes a third structure portion configured parallel to the substrate surface and having a height position higher than that of the first structure portion and coupled to an upper end of the second structure portion at an end portion, In the third structure portion, the lower surface may be formed so as to be in contact with the upper surface of the first electrode, and the upper surface may be in contact with the lower surface of the second electrode.

  Furthermore, in addition to the above characteristics, the variable resistance element according to the present invention is configured such that the second structure portion has an annular cross section parallel to the substrate surface, and the lower end and the inner side of the second structure portion. A configuration in which the end portion of the first structure portion is coupled may be possible.

  At this time, the variable resistance element according to the present invention includes an insulating film on a part of the first electrode, and the variable resistor has a lower surface in contact with the upper surface of the first electrode in the first structure portion. The upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the outer surface is in contact with the side surface of the insulating film, and the inner surface is opposed to the outer surface with a film thickness of the variable resistor. May be formed so as to be in contact with the side surface of the second electrode.

  In addition to the above features, the variable resistance element according to the present invention includes an insulating film that is thicker than the first electrode in the same layer as the first electrode, and the variable resistor includes the first resistor. In the structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the outer surface is in contact with the side surface of the insulating film, And the inner surface facing the variable resistor with a film thickness therebetween may be formed so as to be in contact with the side surface of the second electrode.

  At this time, in the variable resistance element according to the present invention, the variable resistor is configured to be parallel to the substrate surface and has a height position higher than that of the first structure portion, and an end portion of the variable resistor element is outside the second structure portion. A third structure unit coupled to the upper end of the second structure unit, wherein the lower surface of the third structure unit is in contact with the upper surface of the insulating film, and the upper surface is in contact with the lower surface of the second electrode; It doesn't matter if you have

  In addition to the above characteristics, the variable resistance element according to the present invention has a configuration in which the first electrode has a step by having regions with different formation film thicknesses, and the variable resistor has the first structure. The lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the outer surface is in contact with the side surface of the first electrode, and the outer surface And the inner surface facing the variable resistor with a film thickness therebetween may be formed so as to be in contact with the side surface of the second electrode.

  In addition to the above characteristics, the variable resistance element according to the present invention includes an insulating film having a step by having regions with different formed film thicknesses, and the first electrode is formed on the insulating film. The variable resistor has a lower surface in contact with the upper surface of the first electrode in the first structure portion, and the upper surface is in the second structure. In contact with the lower surface of the electrode, in the second structure portion, the outer surface is in contact with the side surface of the first electrode, and the inner surface facing the outer surface with a film thickness of the variable resistor is the second electrode. It may be formed so as to be in contact with the side surface of the plate.

  In addition to the above features, the variable resistance element according to the present invention further includes an insulating film, the first electrode is formed on a part of the insulating film, and the variable resistor includes the first structure. The lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the outer surface is in contact with the side surface of the first electrode, The inner surface which opposes across the film thickness of the variable resistor may be formed so as to be in contact with the side surface of the second electrode.

  The variable resistance element according to the present invention includes, in addition to the above characteristics, an insulating film having a thickness smaller than that of the first electrode in the same layer as the first electrode. In the structure portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode, and in the second structure portion, the outer surface is in contact with the side surface of the first electrode, and the outer surface. And the inner surface facing the variable resistor with a film thickness therebetween may be formed so as to be in contact with the side surface of the second electrode.

  At this time, in the variable resistance element according to the present invention, the variable resistor is configured to be parallel to the substrate surface and has a height position higher than that of the first structure portion, and an end portion of the variable resistor element is outside the second structure portion. A third structure unit coupled to an upper end of the second structure unit, wherein the lower surface of the third structure unit is in contact with the upper surface of the first electrode and the upper surface is in contact with the lower surface of the second electrode; It does not matter as long as it is.

  In addition to the above features, the variable resistance element according to the present invention is formed by embedding the variable resistor in a buried region surrounded by the same material film at least on the outer surface. The seam extending in the height direction may be included, and the material film may be configured by the first electrode or the insulating film.

  At this time, the variable resistance element according to the present invention further includes the insulating film on a part of the first electrode, and the variable resistor has a lower surface in contact with the upper surface of the insulating film in the buried region. The outer surface may be formed so as to be in contact with the side surface of the insulating film.

  In addition to the above characteristics, the variable resistance element according to the present invention has a configuration in which the first electrode has a step by having regions having different formation thicknesses, and the variable resistor is in the embedded region. , The lower surface may be in contact with the upper surface of the first electrode, and the outer surface may be formed in contact with the side surface of the first electrode.

  At this time, in the variable resistance element according to the present invention, the variable resistor is connected to the variable resistor formed in the buried region in the buried outer region outside the buried region, and The lowermost surface is formed so that the height of the lowermost surface is higher than the lowermost surface in the buried region, the lower surface is in contact with the upper surface of the insulating film in the outer region, and the upper surface is the lower surface of the second electrode. It does not matter even if it contacts with.

  In addition to the above characteristics, the variable resistance element according to the present invention includes an insulating film having a step due to a region having a different formation film thickness, and the first electrode includes the insulating film. The variable resistor is formed in a state having a height position difference on the uppermost surface, and the lower surface of the variable resistor is in contact with the upper surface of the first electrode in the embedded region, The variable resistor is configured to have a step by having a region having a different thickness formed so that the outer surface is in contact with the side surface of the first electrode, and the lower surface of the variable resistor is in the embedded region. The outer surface may be in contact with the upper surface of one electrode, and the outer surface may be in contact with the side surface of the first electrode.

  Here, the shape of the variable resistor in the embedded region is not limited to the columnar shape, and may be a cone shape whose cross-sectional area parallel to the substrate surface decreases toward the bottom surface, for example. The shape may also be

  In the variable resistance element according to the present invention, the variable resistor is connected to the variable resistor formed in the embedded region in the embedded outer region outside the embedded region, and the embedded The lowermost surface is formed so that the height of the lowermost surface is higher than the lowermost surface in the region, and the lower surface is in contact with the upper surface of the first electrode and the upper surface is the lower surface of the second electrode. It may be in contact with

  The variable resistance element manufacturing method according to the present invention includes a step forming step for forming a seam forming step on the substrate, a variable resistor forming step for forming the variable resistor, and A second electrode forming step of forming the second electrode, wherein the step forming step includes a step of forming the first electrode, and forming the first electrode makes it parallel to the substrate surface. A first upper surface, a second upper surface configured parallel to the substrate surface and lower in height than the first upper surface, an upper end coupled to an end portion of the first upper surface, and a lower end coupled to an end portion of the second upper surface. An intermediate surface that connects the first upper surface and the second upper surface in a direction perpendicular to the substrate surface by coupling and at least one of the second upper surface and the intermediate surface is the first electrode. Forming the seam forming step composed of In the variable resistor forming step, the variable resistor film is formed on the entire surface by a sputtering method, or a predetermined material film is formed on the entire surface by a sputtering method, and then an oxidation treatment is performed to change the variable resistor film. By forming a body film, the variable resistor film includes the first structure part in which the variable resistor film contacts the second upper surface, and the second structure part in which the variable resistor film contacts the intermediate surface. Forming a seam, and forming the seam in the variable resistor in the corner region where the first structure part and the second structure part are coupled, and the second electrode forming process comprises the seam This is a step of forming the second electrode on the upper surface of the variable resistor film on which is formed.

  According to the above feature of the variable resistance element manufacturing method according to the present invention, after the step for forming the seam is formed in which the second upper surface or the intermediate surface is formed by the first electrode in the step forming step, the variable resistor film is formed. A film is formed on the entire surface. At this time, it is important to form the variable resistor film without taking measures to prevent the seam from being formed. Accordingly, in the corner region where the variable resistor film growing from the second upper surface and the variable resistor film growing from the intermediate surface are coupled to each other while the variable resistor film is in contact with the first electrode, It is possible to intentionally form a seam extending in a direction from the region where the surfaces are combined, that is, the region where the first electrode is formed to the second upper surface. Then, by forming the second electrode on the upper surface of the variable resistor film on which the seam is formed, a variable resistance element having a variable resistor sandwiched between the first electrode and the second electrode and having a seam inside is provided. Can be manufactured.

  As the variable resistor film, a metal oxide or oxynitride such as Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Hf, Ta, and W can be used. At this time, in the variable resistor forming step, the variable resistor film made of metal oxide or oxynitride may be formed as it is, or the metal film or metal nitride film may be oxidized after being formed. Processing may be performed to form the variable resistor film.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention includes forming the first electrode on the substrate in the step forming step, and then forming an insulating film on the upper surface of the first electrode. After the film is formed, the insulating film is etched until a partial upper surface of the first electrode is exposed, whereby the first upper surface and the intermediate surface formed of the insulating film, and the first The seam forming step having the second upper surface constituted by electrodes may be formed.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention includes forming the first electrode in a partial region on the substrate and forming the first electrode on the substrate in the step forming step. By forming an insulating film thicker than the first electrode in the outer region, the first upper surface and the intermediate surface made of the insulating film, and the second upper surface made of the first electrode are formed. The seam forming step may be formed.

  In addition to the above characteristics, the variable resistance element manufacturing method according to the present invention forms an electrode film constituting the first electrode on the substrate in the step forming step, and then a partial region. Etching may be performed on the electrode film according to the above to form the seam forming step in which the first upper surface, the intermediate surface, and the second upper surface are all configured by the first electrode. Absent.

  In addition to the above characteristics, the method of manufacturing a variable resistance element according to the present invention includes, in the step forming step, forming an insulating film on the substrate and then etching a part of the insulating film to form the insulating film. And forming an electrode film constituting the first electrode on the entire upper surface of the insulating film on which the step is formed, thereby forming the first upper surface, the intermediate surface, and the first surface. It is possible to form the seam-forming step whose entire upper surface is composed of the first electrode.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention further includes forming an insulating film on the substrate in the step forming step, and then forming the first electrode on the upper surface of the insulating film. After forming the electrode film to be formed, the first electrode is formed by performing etching until the upper surface of the insulating film is partially exposed to the electrode film, thereby forming the first electrode. The seam forming step having the first upper surface, the intermediate surface, and the second upper surface made of the insulating film may be formed.

  In addition to the above characteristics, the variable resistance element manufacturing method according to the present invention forms the first electrode in a partial region on the substrate in the step forming step, and the first electrode on the substrate. By forming an insulating film having a thickness smaller than that of the first electrode in a region outside the electrode formation, the first upper surface and the intermediate surface configured by the first electrode, and the second configured by the insulating film. The seam forming step having an upper surface may be formed.

  The variable resistance element manufacturing method according to the present invention includes an opening forming step of forming a seam forming opening on the substrate, a variable resistor forming step of forming the variable resistor, and a subsequent step. A second electrode forming step of forming the second electrode, wherein the opening forming step includes a step of forming the first electrode, and the first electrode is formed to form the substrate. An exposed inner surface having an annular cross section parallel to the surface, a first upper surface where an upper end and an end of the exposed inner surface are joined outside the exposed inner surface, and the exposed inner surface inside the exposed inner surface Forming a seam-forming opening in which at least one of the exposed inner surface and the exposed bottom surface is configured by the first electrode. , The variable resistance In the body forming step, a variable resistor film is formed on the entire surface by a sputtering method, or a predetermined material film is formed on the entire surface by a sputtering method, and then an oxidation treatment is performed to completely complete the inside of the seam forming opening. Forming the variable resistor film under a film thickness condition that does not fill the first structure portion where the variable resistor film contacts the exposed bottom surface, and the variable resistor film contacts the exposed inner surface Forming the variable resistor including the second structure part, and forming the seam in the variable resistor in the corner region where the first structure part and the second structure part are coupled; The second electrode forming step is a step of forming the second electrode on an upper surface of the variable resistor film on which the seam is formed.

  According to the above feature of the variable resistance element manufacturing method according to the present invention, the seam forming opening is formed after the exposed inner surface or the exposed bottom surface of the first electrode is formed in the opening forming step. A variable resistor film is formed on the entire surface under a film thickness condition that does not completely fill the opening. At this time, it is important to form the variable resistor film without taking measures to prevent the seam from being formed. As a result, in the corner region where the variable resistor film growing from the exposed bottom surface and the variable resistor film growing from the exposed inner surface are coupled while the variable resistor film is in contact with the first electrode, the exposed bottom surface and the exposed inner surface are exposed. It is possible to intentionally form a seam that extends in a direction from the region where the side surfaces are combined, that is, the region where the first electrode is formed, upward to the exposed bottom surface. Then, by forming the second electrode on the upper surface of the variable resistor film on which the seam is formed, a variable resistance element having a variable resistor sandwiched between the first electrode and the second electrode and having a seam inside is provided. Can be manufactured.

  As the variable resistor film, a metal oxide or oxynitride such as Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Hf, Ta, and W can be used. At this time, in the variable resistor forming step, the variable resistor film made of metal oxide or oxynitride may be formed as it is, or the metal film or metal nitride film may be oxidized after being formed. Processing may be performed to form the variable resistor film.

  In addition to the above characteristics, the variable resistance element manufacturing method according to the present invention forms the first electrode on the substrate in the opening forming step, and then insulates the upper surface of the first electrode. After forming the film, etching is performed until the upper surface of the first electrode is partially exposed to the insulating film, so that the first upper surface and the exposed inner surface composed of the insulating film, and the The seam forming opening having the exposed bottom surface constituted by the first electrode may be formed.

  The variable resistance element manufacturing method according to the present invention, in addition to the above features, in the opening forming step, the first electrode on a part of the substrate and the first electrode on the substrate. By forming an insulating film thicker than the first electrode on the outer peripheral portion of the formation region, the first upper surface and the exposed inner surface made of the insulating film, and the first electrode made of the first electrode The seam forming opening having an exposed bottom surface may be formed.

  In addition to the above characteristics, the variable resistance element manufacturing method according to the present invention forms an electrode film constituting the first electrode on the substrate in the opening forming step, and then partially Etching the electrode film in the region forms the seam forming opening in which the first upper surface, the exposed inner surface, and the exposed bottom surface are all configured by the first electrode. It doesn't matter.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention includes the step of forming an insulating film on the substrate and then etching the partial region in the opening forming step to perform the insulating process. An opening is formed in the film, and then an electrode film constituting the first electrode is formed with a film thickness within a range that does not fill the opening over the entire upper surface of the insulating film in which the opening is formed. Thus, the first electrode may be formed, and the first top surface, the exposed inner surface, and the exposed bottom surface may all form the seam forming opening formed of the first electrode.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention includes forming an insulating film on the substrate in the opening forming step, and then forming the first electrode on the upper surface of the insulating film. The first electrode is formed by etching the electrode film until the partial upper surface of the insulating film is exposed to form the first electrode. The seam forming opening having the first upper surface, the exposed inner surface, and the exposed bottom surface constituted by the insulating film may be formed.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention may further include forming an insulating film in a partial region on the substrate and forming the insulating film on the substrate in the opening forming step. By forming the first electrode thicker than the insulating film on the outer peripheral portion, the first upper surface and the exposed inner surface composed of the first electrode, and the exposed bottom surface composed of the insulating film It is possible to form the seam-forming opening having

  The variable resistance element manufacturing method according to the present invention includes an opening forming step of forming a seam forming opening on the substrate, a variable resistor forming step of forming the variable resistor, and a subsequent step. A second electrode forming step of forming the second electrode, wherein the opening forming step includes a step of forming the first electrode, and the first electrode is formed to form the substrate. An exposed inner surface having an annular cross section parallel to the surface, a first upper surface where an upper end and an end of the exposed inner surface are joined outside the exposed inner surface, and the exposed inner surface inside the exposed inner surface Forming a seam forming opening in which at least one of the exposed inner surface and the exposed bottom surface is configured by the first electrode. The variable resistor type The step is to form a variable resistor film on the entire surface by the CVD method, or to form a predetermined material film on the entire surface by the CVD method and then perform an oxidation treatment to open the inside of the seam forming opening. By forming the variable resistor film under a film thickness condition in which no part remains, the variable resistor is formed in the embedded region surrounded by the material film constituting the exposed inner surface, and the Forming the seam extending in a height direction in the variable resistor body in the embedded region, wherein the second electrode forming step includes forming the second electrode on an upper surface of the variable resistor film on which the seam is formed. It is the process of forming.

  According to the above feature of the variable resistance element manufacturing method of the present invention, the seam formation is performed after the opening for seam formation in which the exposed inner surface or the exposed bottom surface is formed by the first electrode in the opening forming step. A variable resistor film is formed on the entire surface under a film thickness condition in which the opening does not remain inside the opening for use. At this time, it is important to form the variable resistor film without taking measures to prevent the seam from being formed. As a result, the region where the variable resistor film that grows inward from the outermost surface of the inner wall of the seam forming opening is coupled, that is, in the substantially central region (near the axis) of the region surrounded by the outermost surface. A seam extending in the longitudinal direction can be intentionally formed. Then, by forming the second electrode on the upper surface of the variable resistor film on which the seam is formed, a variable resistance element having a variable resistor sandwiched between the first electrode and the second electrode and having a seam inside is provided. Can be manufactured.

  As the variable resistor film, a metal oxide or oxynitride such as Ti, V, Mn, Fe, Co, Ni, Zn, Zr, Nb, Hf, Ta, and W can be used. At this time, in the variable resistor forming step, the variable resistor film made of metal oxide or oxynitride may be formed as it is, or the metal film or metal nitride film may be oxidized after being formed. Processing may be performed to form the variable resistor film.

  In addition to the above characteristics, the variable resistance element manufacturing method according to the present invention forms the first electrode on the substrate in the opening forming step, and then insulates the upper surface of the first electrode. After forming the film, etching is performed until the upper surface of the first electrode is partially exposed to the insulating film, so that the first upper surface and the exposed inner surface composed of the insulating film, and the The seam forming opening having the exposed bottom surface constituted by the first electrode may be formed.

  In addition to the above characteristics, the variable resistance element manufacturing method according to the present invention forms an electrode film constituting the first electrode on the substrate in the opening forming step, and then partially Etching the electrode film in the region forms the seam forming opening in which the first upper surface, the exposed inner surface, and the exposed bottom surface are all configured by the first electrode. It doesn't matter.

  In addition to the above features, the variable resistance element manufacturing method according to the present invention includes the step of forming an insulating film on the substrate and then etching the partial region in the opening forming step to perform the insulating process. An opening is formed in the film, and then an electrode film constituting the first electrode is formed on the entire upper surface of the insulating film in which the opening is formed with a film thickness within a range not filling the opening. By doing so, the first electrode may be formed, and the first top surface, the exposed inner surface, and the exposed bottom surface may all form the seam forming opening formed of the first electrode. .

  In the variable resistance element manufacturing method having the above characteristics, the opening formed in the opening forming step is not necessarily limited to a cylindrical shape in which an inner surface is formed in a direction perpendicular to the substrate surface. For example, it may have a conical shape in which the cross-sectional area parallel to the substrate surface increases toward the upper surface, or may have another shape.

  In the driving method of the variable resistance element according to the present invention, a filament path is formed in the variable resistance body through at least the seam by applying a voltage between the first electrode and the second electrode. It is characterized by that.

  According to the variable resistance element driving method of the present invention, since a filament path is formed by applying a voltage to a variable resistance element in which a seam is formed in the variable resistor, the seam itself or the seam is formed in the variable resistor. A filament path is formed in the vicinity of the formation region. Thereby, the filament path can be formed in a specific region, and the reproducibility of the switching operation can be improved. In addition, since the filament path is formed through the seam, the applied voltage required to form the filament path can be lowered.

  According to the variable resistance element of the present invention, the formation region of the filament path formed by the forming process is limited. Thereby, since the reproducibility of the switching operation between the manufactured variable resistance elements is increased, the structure design can be facilitated. Further, since the seam is formed in the variable resistor body during the forming process, the applied voltage required during the forming process can be reduced compared to the conventional configuration.

  Hereinafter, embodiments of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to the drawings.

[First Embodiment]
A variable resistance element according to the present invention, a manufacturing method thereof, and a first embodiment of the driving method thereof (hereinafter referred to as “this embodiment” as appropriate) will be described with reference to FIGS. In addition, each following drawing is illustrated typically to the last, and the dimensional ratio on a drawing does not necessarily correspond with an actual dimensional ratio. Further, the numerical values of the thicknesses of the respective films deposited in the respective steps are merely examples, and are not limited to these values. The same applies to the following embodiments.

  FIG. 1 is a process cross-sectional view illustrating a method for manufacturing a variable resistance element according to the present embodiment, and FIG. 2 is a flowchart illustrating a process procedure in the manufacturing method. Represents each step in FIG.

  First, as shown in FIG. 1A, a conductive material film 13 (for example, a Pt film) is formed on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by a sputtering method to a thickness of about 100 nm. (Step # 1). By this step # 1, the first electrode 13 is formed.

Next, an insulating material film (for example, SiO ₂ film) 14 is deposited on the entire surface with a film thickness of about 300 nm by the CVD method (Chemical Vapor Deposition) method (step # 2). Thereafter, using the resist formed by a known photolithography technique as a mask, the SiO ₂ film 14 is patterned by a known etching technique until a partial upper surface of the first electrode 13 is exposed (step # 3). By this step # 3, as shown in FIG. 1B, the stepped portion 22 is formed by the upper surface and side surfaces of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate) and the exposed upper surface of the first electrode 13. It is formed. FIG. 3 is a schematic plan view after the completion of Step # 3, and a WW ′ cross section corresponds to FIG.

  Next, as shown in FIG. 1C, under the state in which the step portion 22 is formed, the variable resistor film 15 (for example, CoO film) is formed on the entire surface with a film thickness of about 100 nm by sputtering. Deposit (Step # 4). By this step # 4, the seam 32 is formed at the step portion 22 at the portion where the CoO film 15 as the variable resistor film grown from each of the side surface of the insulating film 14 and the exposed upper surface of the first electrode 13 is joined. Is done.

  Next, as shown in FIG. 1D, a conductive material film 16 (for example, a Pt film) is formed on the entire upper surface of the variable resistor film 15 on which the seam 32 is formed to a thickness of about 100 nm by sputtering. Deposit (Step # 5). By this step # 5, the second electrode 16 is formed.

  According to this embodiment, the step portion 22 (corresponding to a seam forming step) has already been formed immediately before the variable resistor film forming step according to Step # 4. The step portion 22 includes a first upper surface parallel to the substrate surface of the substrate 11, a second upper surface configured parallel to the substrate surface and lower in height than the first upper surface, and an upper end that is an end portion of the first upper surface. The intermediate surface connecting the first upper surface and the second upper surface in a direction perpendicular to the substrate surface by combining the lower end with the end of the second upper surface. Among these, the upper surface of the insulating film 14 constitutes the first upper surface, the side surface of the insulating film 14 constitutes the intermediate surface, and the exposed upper surface of the first electrode 13 constitutes the second upper surface.

  Under such a state, by forming a CoO film as a variable resistor film, a film grown from the intermediate surface (side surface of the insulating film 14) and a second upper surface (the exposed upper surface of the first electrode 13). ), The seam 32 is formed by overlapping the growth films. As shown in FIG. 1C, the seam 32 extends from the corner region where the intermediate surface and the second upper surface are coupled in a direction toward the upper surface of the exposed first electrode 13.

  Then, as a feature of the present invention, the second electrode forming step according to Step # 5 is executed while leaving the seam 32 as it is. That is, when the second electrode 16 is formed, the seam 32 is still formed in the variable resistor film 15. Further, as described above, the seam 32 is formed in a corner region sandwiched between the first electrode 13 and the insulating film 14 and is formed to extend in the direction from the first electrode 13 toward the second electrode 16. Will be.

  When a voltage pulse is applied between the first electrode 13 and the second electrode 16 in a state where the seam 32 is formed in the variable resistor film 15 in this way, the seam 32 has a bulk variable resistor film. Electric field concentration is likely to occur because there are more structural defects than 15. For this reason, when a voltage is applied to perform the forming process, a filament path is easily formed in or near the seam where electric field concentration is likely to occur. For this reason, by intentionally forming the seam 32 at a specific place in advance during manufacturing, the filament path forming region formed by the forming process can be within a specific range, and the reproducibility of the switching operation is improved. be able to. Furthermore, since the electric field concentration is likely to occur in the seam 32 or in the vicinity thereof, the voltage required for executing the forming process can be reduced as compared with the conventional configuration.

  The seam 32 is not necessarily formed so as to be in contact with both the first electrode 13 and the second electrode 16, but may be formed in contact with only one of the electrodes. It may be formed in the variable resistor 13 without contact. If the seam 32 is formed at least in the variable resistor 13, the filament path can be easily formed in the seam 32 forming region, so that the filament path forming region can be specified.

  In this embodiment, the first electrode 13 and the second electrode 16 are both Pt films. However, the material is not limited to the Pt film as long as it functions as an electrode. For example, other materials such as Al and TiN can be used. The conductive material (including metal) may be used. Further, for example, Ti or the like may be used as an adhesion layer between the semiconductor substrate 11 and the first electrode 13 and between the variable resistor 15 and the second electrode. The same applies to the following embodiments.

In this embodiment, the insulating film 14 is a SiO ₂ film. However, the insulating layer is not limited to the SiO ₂ film, and the oxidation resistance of the SiN film, the SiON film, the SiOF film, the SiOC film, or the like is improved. Any suitable insulating film can be used. Further, in step # 2, the insulating film 14 is deposited by the CVD method, but any suitable deposition technique such as pulsed laser deposition, rf-sputtering, electron beam evaporation, thermal evaporation, spin-on deposition, or the like is used. It is also possible to deposit. The same applies to each of the following embodiments unless otherwise specified.

  In the present embodiment, the semiconductor substrate 11 that is the base for forming the Pt film 13 is formed with a transistor circuit or the like as appropriate, but the circuit does not necessarily have to be formed. The same applies to the following embodiments.

  Further, in this embodiment, a CoO film is used as the variable resistor film 15, but the material is not limited to CoO as long as the material exhibits variable resistance. For example, Ti, V, Mn, Fe, Co, A metal oxide or oxynitride such as Ni, Zn, Zr, Nb, Hf, Ta, or W may be used. The same applies to the following embodiments.

  In this embodiment, the CoO film as the variable resistor film is formed in the variable resistor film forming process according to Step # 4. However, after the Co film is deposited on the entire surface, the oxidation treatment is performed. By applying, a CoO film may be formed. At this time, the material film to be deposited can be appropriately selected according to the material to be formed as the variable resistor film 15. The same applies to the following embodiments.

  Further, in particular, the height of the stepped portion 22 is set to 100 nm or more, and in the variable resistor film forming process according to Step # 4, sputtering is performed in such a positional relationship that the stepped portion 22 is in the back position with respect to the sputter target. By doing so, a larger seam 32 can be formed. The same applies to the following second to twelfth embodiments.

[Second Embodiment]
A variable resistance element, a manufacturing method thereof, and a driving method thereof according to a second embodiment of the present invention (hereinafter, referred to as “this embodiment” as appropriate) will be described with reference to FIGS.

  FIG. 4 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. FIG. 5 is a flowchart showing a process procedure in the manufacturing method, and each step # 11 to # 17 in the following sentence represents each step in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

First, an insulating material film (for example, SiO ₂ film) 14 is deposited on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed (step # 11). Thereafter, the SiO ₂ film 14 is etched to expose a part of the upper surface of the semiconductor substrate 11 (step # 12). Thereafter, after depositing a conductive material film (for example, Pt film) 13 on the entire surface (step # 13), the upper surfaces of the SiO ₂ film 14 (hereinafter referred to as the insulating film 14) and the Pt film 13 using a known planarization technique. Is exposed (step # 14, see FIG. 4A).

At this time, the Pt film 13 is first deposited on the entire surface, and then the Pt film 13 is etched to expose a part of the upper surface of the semiconductor substrate 11, and then the SiO ₂ film 14 is deposited on the entire surface, and then a known flat surface. Alternatively, the upper surfaces of the SiO ₂ film 14 and the Pt film 13 may be exposed by using a technology.

Next, using the resist formed by a known photolithography technique as a mask, the Pt film 13 is etched back by a known etching technique to form the stepped portion 22 (step # 15). By this step # 15, the first electrode 13 is formed, and as shown in FIG. 4B, the upper and side surfaces of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate), and the first electrode A stepped portion 22 is formed by the exposed upper surface of 13. Note that the schematic plan view after step # 15 in the present embodiment is the same as the schematic plan view after step # 3 in the first embodiment shown in FIG. It corresponds to b).

  Thereafter, as shown in FIG. 4C, as in step # 4 of the first embodiment, the variable resistor film 15 (for example, a CoO film) is sputtered in a state where the step portion 22 is formed. Is deposited on the entire surface with a film thickness of about 100 nm (step # 16). By this step # 16, the seam 32 is formed in the step portion 22 at the portion where the CoO film 15 as the variable resistance film grown from the side surface of the insulating film 14 and the upper surface of the first electrode 13 is joined. .

  Thereafter, as shown in FIG. 4D, as in step # 5 of the first embodiment, a conductive material film 16 (for example, a Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 32 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 17). By this step # 16, the second electrode 16 is formed.

  In the present embodiment as well, as in the first embodiment, the step portion 22 (corresponding to a seam forming step) has already been formed immediately before the variable resistor film forming step according to Step # 16. The step portion 22 includes a first upper surface parallel to the substrate surface of the substrate 11, a second upper surface configured parallel to the substrate surface and lower in height than the first upper surface, and an upper end that is an end portion of the first upper surface. The intermediate surface connecting the first upper surface and the second upper surface in a direction perpendicular to the substrate surface by combining the lower end with the end of the second upper surface. Among these, the upper surface of the insulating film 14 constitutes the first upper surface, the side surface of the insulating film 14 constitutes the intermediate surface, and the exposed upper surface of the first electrode 13 constitutes the second upper surface.

  Under such a state, by forming a CoO film as a variable resistor film, a film grown from the intermediate surface (side surface of the insulating film 14) and a second upper surface (the exposed upper surface of the first electrode 13). ), The seam 32 is formed by overlapping the growth films. As shown in FIG. 4C, the seam 32 extends from a corner region where the intermediate surface and the second upper surface are coupled to a direction toward the upper side of the exposed upper surface of the first electrode 13. Then, by performing the second electrode forming process according to step # 17 while leaving the seam 32 as it is, the seam 32 is still in the variable resistor film 15 at the time when the second electrode 16 is formed. Is in a state where it is formed. Further, as described above, the seam 32 is formed in a corner region sandwiched between the first electrode 13 and the insulating film 14 and is formed to extend in the direction from the first electrode 13 toward the second electrode 16. Will be.

  Accordingly, in this embodiment as well, as in the first embodiment, a voltage pulse is applied between the first electrode 13 and the second electrode 16 with the seam 32 still formed in the variable resistor film 15. In this case, the seam 32 has more structural defects than the bulk variable resistor film 15, so that electric field concentration is likely to occur. For this reason, when a voltage is applied to perform the forming process, a filament path is easily formed in or near the seam where electric field concentration is likely to occur. For this reason, by intentionally forming the seam 32 at a specific place in advance during manufacturing, the filament path forming region formed by the forming process can be within a specific range, and the reproducibility of the switching operation is improved. be able to. Furthermore, since the electric field concentration is likely to occur in the seam 32 or in the vicinity thereof, the voltage required for executing the forming process can be reduced as compared with the conventional configuration. Since the same applies to the following third to sixth embodiments, the description thereof will be omitted as appropriate.

[Third Embodiment]
A third embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 6 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. FIG. 7 is a flowchart showing a process procedure in the manufacturing method, and each step # 21 to # 24 in the following sentence represents each step in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

  First, as shown in FIG. 6A, a conductive material film 13 (for example, Pt film) is formed on the entire surface of a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by sputtering to a thickness of about 400 nm. (Step # 21). In this step # 21, deposition is performed with a thicker film thickness than in step # 1 of the first embodiment.

  Next, a step 25 having a height difference of about 300 nm is formed on the Pt film 13 by a known etching technique using a resist formed by a known photolithography technique as a mask (step # 22). By this step # 22, the first electrode 13 is formed, and as shown in FIG. 6B, the upper surface of the first electrode 13 having a high height, the side surface of the first electrode 13, and the height position A step 25 is formed by the lower upper surface of the first electrode 13. FIG. 8 is a schematic plan view after the end of Step # 22, and the W-W ′ cross section corresponds to FIG.

  Thereafter, as shown in FIG. 6C, the variable resistor film 15 is formed under the state in which the step portion 22 (corresponding to the seam forming step) is formed, as in Step # 4 of the first embodiment. (For example, a CoO film) is deposited on the entire surface with a film thickness of about 100 nm by a sputtering method (step # 23). By this step # 23, at the step portion 25, at the portion where the CoO film 15 as the variable resistor film that grows from the upper surface of the first electrode 13 and the side surface of the first electrode 13 that are low in height is joined. A seam 32 is formed.

  Thereafter, as shown in FIG. 6D, as in step # 5 of the first embodiment, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 32 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 24). By this step # 16, the second electrode 16 is formed.

[Fourth Embodiment]
A variable resistance element, a manufacturing method thereof, and a driving method thereof according to a fourth embodiment of the present invention (hereinafter, referred to as “this embodiment” as appropriate) will be described with reference to FIGS.

  FIG. 9 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. Moreover, FIG. 10 is a flowchart which shows the process sequence in this manufacturing method, and each step # 31- # 35 in the following sentences represents each step in FIG.

First, an insulating material film 14 (for example, SiO ₂ film) is deposited on the entire surface of the semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by sputtering to a thickness of, for example, about 400 nm (step) # 31), using a resist formed by a known photolithography technique as a mask, a step portion 26 having a height difference of about 300 nm is formed in the insulating material film 14 by a known etching technique (step # 32, FIG. 9A). )reference).

  Next, a conductive material film 13 (for example, a Pt film) is deposited on the entire upper surface of the insulating material film 14 (hereinafter referred to as “insulating film 14” where appropriate) where the stepped portion 26 is formed by a sputtering method to a thickness of about 100 nm. (Step # 33). By this step # 33, the first electrode 13 is formed, and as shown in FIG. 9B, the upper surface of the first electrode 13 having a high height, the side surface of the first electrode 13, and the height position A step 25 is formed by the lower upper surface of the first electrode 13. The schematic plan view after the end of step # 33 in this embodiment is the same as the schematic plan view after the end of step # 22 of the third embodiment shown in FIG. 8, and the WW ′ cross section is shown in FIG. It corresponds to b).

  After that, as shown in FIG. 9C, as in step # 4 of the first embodiment, the variable resistor film 15 is formed under the state in which the step portion 25 (corresponding to the seam forming step) is formed. (For example, a CoO film) is deposited on the entire surface with a film thickness of about 100 nm by a sputtering method (step # 34). By this step # 34, in the stepped portion 25, at the portion where the CoO film 15 as the variable resistor film grown from each of the upper surface of the first electrode 13 and the side surface of the first electrode 13 with a low height is joined, A seam 32 is formed.

  Thereafter, as shown in FIG. 9D, as in step # 5 of the first embodiment, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 32 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 35). By this step # 35, the second electrode 16 is formed.

[Fifth Embodiment]
A variable resistance element, a manufacturing method thereof, and a driving method thereof according to a fifth embodiment of the present invention (hereinafter referred to as “this embodiment” as appropriate) will be described with reference to FIGS.

  FIG. 11 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. FIG. 12 is a flowchart showing process steps in the manufacturing method. Steps # 41 to # 45 in the following sentence represent steps in FIG.

First, as shown in FIG. 11A, an insulating material film 14 (for example, SiO ₂ film) is formed on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by sputtering, for example, about 100 nm. Deposited on the entire surface with a film thickness (step # 41).

  Next, a conductive material film 13 (for example, a Pt film) is deposited on the entire surface with a film thickness of about 300 nm by a sputtering method (step # 42). Thereafter, using a resist formed by a known photolithography technique as a mask, the Pt film 13 is patterned by a known etching technique until a part of the upper surface of the insulating material film 14 (hereinafter referred to as “insulating film 14” as appropriate) is exposed. (Step # 43). By this step # 43, the first electrode 13 is formed, and the stepped portion 22 is formed by the upper surface and side surfaces of the first electrode 13 and the exposed upper surface of the insulating film 14, as shown in FIG. 11B. The FIG. 13 is a schematic plan view after the end of step # 43, and the W-W ′ cross section corresponds to FIG.

  After that, as shown in FIG. 11C, as in step # 4 of the first embodiment, the variable resistor film 15 is formed under the state in which the step portion 22 (corresponding to the seam forming step) is formed. (For example, a CoO film) is deposited on the entire surface with a film thickness of about 100 nm by sputtering (step # 44). By this step # 34, the seam 32 is formed in the step portion 22 at the portion where the CoO film 15 as the variable resistance film grown from the side surface of the first electrode 13 and the upper surface of the insulating film 14 is joined. .

  Thereafter, as shown in FIG. 11D, as in step # 5 of the first embodiment, a conductive material film 16 (for example, a Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 32 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 45). By this step # 45, the second electrode 16 is formed.

[Sixth Embodiment]
A variable resistance element according to the present invention, a manufacturing method thereof, and a driving method thereof according to a sixth embodiment (hereinafter referred to as “this embodiment” as appropriate) will be described with reference to FIGS.

  FIG. 14 is a process cross-sectional view illustrating the variable resistance element manufacturing method according to the present embodiment. FIG. 15 is a flowchart showing a process procedure in the manufacturing method, and each step # 51 to # 57 in the following sentence represents each step in FIG.

First, a conductive material film (for example, Pt film) 13 is deposited and formed on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed (step # 51). Thereafter, the Pt film 13 is etched to expose a part of the upper surface of the semiconductor substrate 11 and form the first electrode 13 (step # 52). Thereafter, after depositing an insulating material film (for example, SiO ₂ film) 14 on the entire surface (step # 53), the SiO ₂ film 14 (hereinafter referred to as the insulating film 14) and the first electrode 13 using a known planarization technique. Is exposed (step # 54, see FIG. 14A).

At this time, the SiO ₂ film 14 is first deposited on the entire surface, then the SiO ₂ film 14 is etched to expose a part of the upper surface of the semiconductor substrate 11, and then the Pt film 13 is deposited on the entire surface. The upper surfaces of the SiO ₂ film 14 and the Pt film 13 may be exposed using a planarization technique.

Next, using the resist formed by a known photolithography technique as a mask, the step portion 22 is formed by etching back the SiO ₂ film 14 by a known etching technique (step # 55). By this step # 55, as shown in FIG. 14B, the stepped portion 22 is formed by the upper surface and side surfaces of the first electrode 13 and the exposed upper surface of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate). It is formed. The schematic plan view after the end of step # 55 in the present embodiment is the same as the schematic plan view after the end of step # 43 in the fifth embodiment shown in FIG. 13, and the WW ′ cross section is shown in FIG. It corresponds to b).

  After that, as shown in FIG. 14C, the variable resistor film 15 is formed under the state in which the step portion 22 (corresponding to the seam forming step) is formed as in Step # 4 of the first embodiment. (For example, a CoO film) is deposited on the entire surface with a film thickness of about 100 nm by a sputtering method (step # 56). By this step # 56, the seam 32 is formed in the step portion 22 at the portion where the CoO film 15 as the variable resistance film grown from the side surface of the first electrode 13 and the upper surface of the insulating film 14 is joined. .

  Thereafter, as shown in FIG. 14D, as in step # 5 of the first embodiment, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 32 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 57). By this step # 57, the second electrode 16 is formed.

[Seventh Embodiment]
A sixth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 16 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. FIG. 17 is a flowchart showing a process procedure in the manufacturing method, and steps # 61 to # 65 in the following sentence represent steps in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

  First, as shown in FIG. 16A, a conductive material film 13 (for example, Pt film) is formed on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by a sputtering method to a film thickness of about 100 nm. (Step # 61). By this step # 61, the first electrode 13 is formed.

Next, an insulating material film (for example, SiO ₂ film) 14 is deposited on the entire surface with a thickness of about 300 nm by the CVD method (step # 62). Thereafter, using the resist formed by a known photolithography technique as a mask, the SiO ₂ film 14 is patterned by a known etching technique until a partial upper surface of the first electrode 13 is exposed (step # 63). In this step # 63, as shown in FIG. 16B, the exposed upper surface of the first electrode 13 is the bottom surface, and the side surface of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate) is the inner side surface. An opening 20 is formed. FIG. 18 is a schematic plan view after the end of Step # 63, and the WW ′ cross section corresponds to FIG.

  Next, as shown in FIG. 16C, the variable resistor film 15 (for example, a CoO film) is completely sputtered in the opening 20 under the state where the opening 20 is formed. Deposition is performed on the entire surface under a film thickness condition that does not fill (for example, about 100 nm) (step # 64). By this step # 64, CoO as a variable resistor film grown from each of the side surface of the insulating film 14 constituting the inner side surface of the opening 20 and the exposed upper surface of the first electrode 13 constituting the bottom surface of the opening 20 is obtained. A seam 30 is formed at a portion where the film 15 is joined.

  Next, as shown in FIG. 16D, a conductive material film 16 (for example, a Pt film) is formed on the entire upper surface of the variable resistor film 15 on which the seam 30 is formed to a thickness of about 100 nm by sputtering. Deposit (Step # 65). By this step # 65, the second electrode 16 is formed.

  In the present embodiment, the opening 20 (corresponding to the seam forming opening) has already been formed immediately before the variable resistor film forming step according to Step # 64. The opening 20 includes an exposed inner surface in which a cross section parallel to the substrate surface is formed in an annular shape, a first upper surface where an upper end and an end of the exposed inner surface are coupled to each other outside the exposed inner surface, and the exposed inner surface. It is comprised by the exposed bottom face which the lower end and end part of the said exposed inner side face couple | bond together inside a side surface. Of these, the upper surface of the insulating film 14 forms the first upper surface, the side surface of the insulating film 14 forms the exposed inner surface, and the exposed upper surface of the first electrode 13 forms the exposed bottom surface.

  Under such a state, by forming a CoO film as a variable resistor film, a film grown from the exposed inner surface (side surface of the insulating film 14) and an exposed bottom surface (exposed upper surface of the first electrode 13). ), The seam 30 is formed by the overlapping of the growth films. As shown in FIG. 16 (c), the seam 30 extends from the corner region where the exposed inner surface and the exposed bottom surface are coupled in a direction toward the upper surface of the exposed first electrode 13. Then, by performing the second electrode forming process according to step # 65 while leaving the seam 30 as it is, the seam 30 is still in the variable resistor film 15 at the time when the second electrode 16 is formed. Is in a state where it is formed. Further, as described above, the seam 30 is formed in a corner region sandwiched between the first electrode 13 and the insulating film 14 and is formed so as to extend in the direction from the first electrode 13 toward the second electrode 16. Will be.

  Accordingly, in the present embodiment as well, as in the first embodiment, a voltage pulse is applied between the first electrode 13 and the second electrode 16 with the seam 30 still formed in the variable resistor film 15. In this case, the seam 30 has more structural defects than the bulk variable resistor film 15, so that electric field concentration is likely to occur. For this reason, when a voltage is applied to perform the forming process, a filament path is easily formed in or near the seam where electric field concentration is likely to occur. For this reason, by forming the seam 30 intentionally at a specific location during manufacturing in advance, the filament path forming region formed by the forming process can be within a specific range, and the reproducibility of the switching operation is improved. be able to. Furthermore, since the electric field concentration is likely to occur in the seam 30 or in the vicinity thereof, the voltage required for executing the forming process can be reduced as compared with the conventional configuration. Since the same applies to the following eighth to twelfth embodiments, the description thereof will be omitted as appropriate.

[Eighth Embodiment]
An eighth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS. 19 to 20.

  FIG. 19 is a process cross-sectional view illustrating the variable resistance element manufacturing method according to the present embodiment. FIG. 20 is a flowchart showing process steps in the manufacturing method. Steps # 71 to # 77 in the following sentence represent steps in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

First, as in Step # 11 to Step # 14 of the second embodiment, an insulating material film (for example, SiO ₂ film) 14 is deposited on the semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed ( Step # 71), the SiO ₂ film 14 is etched to expose a part of the upper surface of the semiconductor substrate 11 (Step # 72), and a conductive material film (for example, Pt film) 13 is deposited on the entire surface (Step # 73). The upper surfaces of the SiO ₂ film 14 (hereinafter referred to as the insulating film 14) and the Pt film 13 are exposed using a known planarization technique (step # 74, see FIG. 19A). At this time, after first depositing a Pt film 13 on the entire surface, the Pt film 13 is etched to expose a part of the upper surface of the semiconductor substrate 11, and then an SiO ₂ film 14 is deposited on the entire surface. The upper surfaces of the SiO ₂ film 14 and the Pt film 13 may be exposed using

Next, using the resist formed by a known photolithography technique as a mask, the Pt film 13 is etched back by a known etching technique to form the opening 20 (step # 75). By this step # 75, the first electrode 13 is formed, and as shown in FIG. 19B, the upper and side surfaces of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate), and the first electrode An opening 20 is formed by the exposed upper surface of 13. More specifically, an opening 20 having the exposed first electrode 13 as a bottom surface and the insulating film 14 as an inner surface is formed. Note that the schematic plan view after the end of step # 75 in the present embodiment is the same as the schematic plan view after the end of step # 63 in the seventh embodiment shown in FIG. It corresponds to b).

  After that, as shown in FIG. 19C, the variable resistor film is formed under the state in which the opening 20 (corresponding to the seam forming opening) is formed as in Step # 64 of the seventh embodiment. 15 (for example, a CoO film) is deposited on the entire surface by a sputtering method with a film thickness condition that does not completely fill the opening 20 (for example, about 100 nm) (step # 76). By this step # 76, the CoO film 15 as a variable resistor film grown from the side surface of the insulating film 14 constituting the inner side surface of the opening 20 and the upper surface of the first electrode 13 constituting the bottom surface of the opening 20 is obtained. The seam 30 is formed at the portion where the two are joined.

  Thereafter, as shown in FIG. 19D, as in step # 65 of the seventh embodiment, a conductive material film 16 (for example, a Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 30 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 77). By this step # 77, the second electrode 16 is formed.

[Ninth Embodiment]
A ninth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 21 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. FIG. 22 is a flowchart showing a process procedure in the manufacturing method, and steps # 81 to # 84 in the following sentence represent steps in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

  First, as shown in FIG. 21A, like step # 21 of the third embodiment, a conductive material film 13 (for example, a Pt film) is formed on a semiconductor substrate 11 on which a transistor circuit (not shown) is appropriately formed. Is deposited on the entire surface by sputtering to a thickness of about 400 nm (step # 81).

  Next, an opening 23 having a height difference of about 300 nm is formed in the Pt film 13 by a known etching technique using a resist formed by a known photolithography technique as a mask (step # 82). By this step # 82, the first electrode 13 is formed, and as shown in FIG. 21B, the side surface of the first electrode 13 is the inner side surface, and the upper surface of the first electrode 13 having a lower height is the bottom surface. An opening 23 is formed. FIG. 23 is a schematic plan view after step # 82, and the W-W ′ cross section corresponds to FIG.

  After that, as shown in FIG. 21C, the variable resistor film is formed under the state in which the opening 23 (corresponding to the seam forming opening) is formed, as in Step # 64 of the seventh embodiment. 15 (for example, a CoO film) is deposited on the entire surface by a sputtering method in a film thickness condition that does not completely fill the opening 23 (for example, about 100 nm) (step # 83). By this step # 83, it is possible to grow from each of the side surface of the first electrode 13 constituting the inner side surface of the opening 23 and the upper surface on the lower side of the height position of the first electrode 13 constituting the bottom surface of the opening 23. A seam 30 is formed at a portion where the CoO film 15 as a resistor film is joined.

  After that, as shown in FIG. 21D, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 30 is formed, as in Step # 65 of the seventh embodiment. The film is deposited with a thickness of about 100 nm by the method (step # 84). By this step # 84, the second electrode 16 is formed.

[Tenth embodiment]
A ninth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 24 is a process cross-sectional view illustrating the method of manufacturing the variable resistance element in the present embodiment. FIG. 25 is a flowchart showing a process procedure in the manufacturing method. Steps # 91 to # 95 in the following sentence represent steps in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

First, an insulating material film 14 (for example, SiO ₂ film) is deposited on the entire surface of the semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by sputtering to a thickness of, for example, about 400 nm (step) # 91) Using the resist formed by a known photolithography technique as a mask, an opening 29 having a height difference of about 300 nm is formed in the insulating material film 14 by a known etching technique (step # 92, FIG. 24A). )reference).

  Next, a conductive material film 13 (for example, a Pt film) is formed on the entire upper surface of the insulating material film 14 (hereinafter referred to as “insulating film 14” where appropriate) in which the opening 29 is formed by sputtering to a thickness of about 100 nm. (Step # 93). By this step # 93, as shown in FIG. 24B, the side surface of the Pt film 13 (hereinafter referred to as the first electrode 13) is the inner side surface, and the upper surface of the first electrode 13 having a lower height is the bottom surface. An opening 23 is formed. Note that the schematic plan view after the end of step # 93 in this embodiment is the same as the schematic plan view after the end of step # 82 in the ninth embodiment shown in FIG. It corresponds to b).

  After that, as shown in FIG. 24C, the variable resistor film is formed under the state in which the opening 23 (corresponding to the seam forming opening) is formed as in Step # 64 of the seventh embodiment. 15 (for example, a CoO film) is deposited on the entire surface by a sputtering method with a film thickness condition that does not completely fill the opening 23 (for example, about 100 nm) (step # 94). By this step # 94, it is possible to grow from the side surface of the first electrode 13 constituting the inner side surface of the opening 23 and the upper surface on the lower side of the height position of the first electrode 13 constituting the bottom surface of the opening 23. A seam 30 is formed at a portion where the CoO film 15 as a resistor film is joined.

  Thereafter, as shown in FIG. 24D, as in step # 65 of the seventh embodiment, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 30 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 95). By this step # 95, the second electrode 16 is formed.

[Eleventh embodiment]
A ninth embodiment (hereinafter, referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 26 is a process cross-sectional view illustrating the method for manufacturing the variable resistance element according to this embodiment. FIG. 27 is a flowchart showing a process procedure in the manufacturing method. Steps # 101 to # 105 in the following sentence represent steps in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

First, as shown in FIG. 26A, as in step # 41 of the fifth embodiment, an insulating material film 14 (for example, an SiO ₂ film) is formed on a semiconductor substrate 11 on which a transistor circuit (not shown) is appropriately formed. ) Is deposited on the entire surface with a film thickness of, for example, about 100 nm by sputtering (step # 101).

  Next, a conductive material film 13 (for example, a Pt film) is deposited on the entire surface with a film thickness of about 300 nm by a sputtering method (step # 102), and then a resist formed by a known photolithography technique is used as a mask. By using this etching technique, the Pt film 13 is patterned until the upper surface of a part of the insulating material film 14 (hereinafter referred to as “insulating film 14” as appropriate) is exposed (step # 103), thereby forming the opening 20. By this step # 103, as shown in FIG. 26B, the side surface of the Pt film 13 (hereinafter referred to as “first electrode 13” as appropriate) is the inner side surface, and the upper surface where the insulating film 14 is exposed is the bottom surface. Part 20 is formed. FIG. 28 is a schematic plan view after the completion of Step # 103, and the W-W ′ cross section corresponds to FIG.

  Thereafter, as shown in FIG. 26 (c), the variable resistor film is formed under the state in which the opening 20 (corresponding to the seam forming opening) is formed as in Step # 64 of the seventh embodiment. 15 (for example, a CoO film) is deposited on the entire surface by a sputtering method in a film thickness condition (for example, about 100 nm) that does not completely fill the opening 20 (step # 104). By this step # 104, CoO as a variable resistor film grown from the side surface of the first electrode 13 constituting the inner side surface of the opening 20 and the exposed upper surface of the insulating film 14 constituting the bottom surface of the opening 20 is obtained. A seam 30 is formed at a portion where the film 15 is joined.

  Thereafter, as shown in FIG. 26D, as in step # 65 of the seventh embodiment, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 30 is formed. The film is deposited with a thickness of about 100 nm by the method (step # 105). By this step # 105, the second electrode 16 is formed.

[Twelfth embodiment]
A twelfth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 29 is a process cross-sectional view illustrating the method for manufacturing the variable resistance element according to the present embodiment. FIG. 30 is a flowchart showing a process procedure in the manufacturing method, and steps # 111 to # 117 in the following sentence represent steps in FIG.

First, similarly to steps # 51 to # 54 of the sixth embodiment, a conductive material film (for example, Pt film) 13 is deposited on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed (step #). 111), the Pt film 13 is etched to expose a part of the upper surface of the semiconductor substrate 11, and the first electrode 13 is formed (step # 112), and an insulating material film (eg, SiO ₂ film) 14 is deposited on the entire surface. (Step # 113), the SiO ₂ film 14 (hereinafter referred to as the insulating film 14) and the upper surface of the first electrode 13 are exposed using a known planarization technique (Step # 114, see FIG. 29A). .

At this time, the SiO ₂ film 14 is first deposited on the entire surface, then the SiO ₂ film 14 is etched to expose a part of the upper surface of the semiconductor substrate 11, and then the Pt film 13 is deposited on the entire surface. The upper surfaces of the SiO ₂ film 14 and the Pt film 13 may be exposed using a planarization technique.

Next, using the resist formed by a known photolithography technique as a mask, the SiO ₂ film 14 is etched back by a known etching technique to form an opening 20 (step # 115). In this step # 115, as shown in FIG. 29B, the side surface of the first electrode 13 is the inner side surface, and the exposed upper surface of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate) is the bottom surface. An opening 20 is formed. The schematic plan view after the end of step # 115 in the present embodiment is the same as the schematic plan view after the end of step # 103 in the eleventh embodiment shown in FIG. It corresponds to b).

  Thereafter, as shown in FIG. 29 (c), the variable resistor film is formed under the condition that the opening 20 (corresponding to the seam forming opening) is formed, as in Step # 64 of the seventh embodiment. 15 (for example, a CoO film) is deposited on the entire surface by a sputtering method with a film thickness condition that does not completely fill the opening 20 (for example, about 100 nm) (step # 116). By this step # 116, the CoO as a variable resistor film grown from the side surface of the first electrode 13 constituting the inner side surface of the opening 20 and the exposed upper surface of the insulating film 14 constituting the bottom surface of the opening 20 is obtained. A seam 30 is formed at a portion where the film 15 is joined.

  Thereafter, as shown in FIG. 29 (d), as in step # 65 of the seventh embodiment, the conductive material film 16 (for example, Pt film) is sputtered on the entire upper surface of the variable resistor film 15 on which the seam 30 is formed. The film is deposited by a method to a thickness of about 100 nm (step # 117). By this step # 117, the second electrode 16 is formed.

[Thirteenth embodiment]
A thirteenth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 31 is a process cross-sectional view illustrating the method for manufacturing the variable resistance element according to the present embodiment. FIG. 32 is a flowchart showing a process procedure in the manufacturing method, and each step # 121 to # 125 in the following sentence represents each step in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

  First, as shown in FIG. 31A, a conductive material film 13 (for example, Pt film) is formed on a semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by a sputtering method to a film thickness of about 100 nm. (Step # 121). By this step # 121, the first electrode 13 is formed.

Next, an insulating material film (for example, SiO ₂ film) 14 is deposited on the entire surface with a film thickness of about 300 nm by the CVD method (step # 122). Thereafter, using the resist formed by a known photolithography technique as a mask, the SiO ₂ film 14 is patterned by a known etching technique until a partial upper surface of the first electrode 13 is exposed (step # 123). In this step # 123, as shown in FIG. 31B, the exposed upper surface of the first electrode 13 is the bottom surface, and the side surface of the SiO ₂ film 14 (hereinafter referred to as “insulating film 14” as appropriate) is the inner side surface. An opening 21 is formed. FIG. 33 is a schematic plan view after the end of Step # 123, and the WW ′ cross section corresponds to FIG. 31 (b).

  Next, as shown in FIG. 31C, the variable resistor film 15 (for example, a CoO film) is formed by the LP (Low Pressure) -CVD method in a state where the opening 21 is formed. The film is deposited on the entire surface under such a film thickness condition that completely fills the inside 21 (step # 124). By this step # 124, at the portion where the CoO film 15 as the variable resistor film that grows in the axial direction of the opening 21 is joined from the side surface of the insulating film 14 constituting the inner surface of the opening 21, the height direction ( A seam 31 extending in the vertical direction is formed. FIG. 33 is a schematic plan view after the end of step # 124, and the W-W ′ cross section corresponds to FIG.

  Thereafter, as shown in FIG. 31D, a conductive material film 16 (for example, a Pt film) is deposited on the entire upper surface of the variable resistor film 15 on which the seam 31 is formed to a thickness of about 100 nm by sputtering. (Step # 125). By this step # 125, the second electrode 16 is formed.

  Also in the present embodiment, as in the seventh embodiment, the opening 21 (corresponding to the seam forming opening) has already been formed immediately before the variable resistor film forming step according to Step # 124. The opening 21 includes an exposed inner surface in which a cross section parallel to the substrate surface is formed in an annular shape, a first upper surface where an upper end and an end of the exposed inner surface are coupled to each other outside the exposed inner surface, and the exposed inner surface. It is comprised by the exposed bottom face which the lower end and end part of the said exposed inner side face couple | bond together inside a side surface. Of these, the upper surface of the insulating film 14 forms the first upper surface, the side surface of the insulating film 14 forms the exposed inner surface, and the exposed upper surface of the first electrode 13 forms the exposed bottom surface.

  Under such a state, a CoO film as a variable resistor film is formed by a CVD method, so that a film grown from the exposed inner surface (side surface of the insulating film 14) and an exposed bottom surface (first electrode 13) are formed. The seam 31 is formed by overlapping the growth films in a region where films growing from the exposed upper surface are joined. By forming the variable resistor film by the CVD method, the film grows uniformly along the base surface (the inner surface and the bottom surface of the opening 21). As a result, as shown in FIG. A seam 31 is formed in the vicinity of the axis of 21 so as to extend in the height direction (vertical direction). Then, by performing the second electrode forming process according to step # 125 while leaving the seam 31 as it is, the seam 31 is still in the variable resistor film 15 at the time when the second electrode 16 is formed. Is in a state where it is formed. Further, as described above, the seam 31 is formed so as to extend in the vertical direction in the vicinity of the axial center, and is formed so as to extend in the direction from the first electrode 13 toward the second electrode 16. Become.

  Therefore, in the case of this embodiment as well, as in the first embodiment, a voltage pulse is applied between the first electrode 13 and the second electrode 16 while the seam 31 is still formed in the variable resistor film 15. In this case, the seam 31 has more structural defects than the bulk variable resistor film 15, so that electric field concentration is likely to occur. For this reason, when a voltage is applied to perform the forming process, a filament path is easily formed in or near the seam where electric field concentration is likely to occur. For this reason, by forming the seam 31 intentionally in a specific place at the time of manufacturing, the filament path forming region formed by the forming process can be within a specific range, and the reproducibility of the switching operation is improved. be able to. Furthermore, since the electric field concentration is likely to occur in the seam 31 or in the vicinity thereof, the voltage required for executing the forming process can be reduced as compared with the conventional configuration. Since the same applies to the following fourteenth to fifteenth embodiments, the description thereof will be omitted as appropriate.

[Fourteenth embodiment]
An eighth embodiment (hereinafter referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 35 is a process cross-sectional view illustrating the method for manufacturing the variable resistance element according to this embodiment. FIG. 36 is a flowchart showing a process procedure in the manufacturing method, and each step # 131 to # 134 in the following sentence represents each step in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

  First, as shown in FIG. 35A, as in step # 21 of the third embodiment, a conductive material film 13 (for example, a Pt film) is formed on a semiconductor substrate 11 on which a transistor circuit (not shown) is appropriately formed. Is deposited on the entire surface by sputtering to a thickness of about 400 nm (step # 131).

  Next, an opening 24 having a height difference of about 300 nm is formed in the Pt film 13 by a known etching technique using a resist formed by a known photolithography technique as a mask (step # 132). By this step # 132, the first electrode 13 is formed, and as shown in FIG. 35B, the side surface of the first electrode 13 is the inner side surface, and the upper surface of the first electrode 13 having a lower height is the bottom surface. An opening 24 is formed. FIG. 37 is a schematic plan view after the end of step # 132, and the W-W ′ cross section corresponds to FIG.

  Next, as in step # 124 of the thirteenth embodiment, as shown in FIG. 35C, the variable resistor film is formed under the condition that the opening 24 (corresponding to the seam forming opening) is formed. 15 (for example, a CoO film) is deposited on the entire surface by LP (Low Pressure) -CVD under a film thickness condition that completely fills the opening 24 (step # 133). By this step # 133, in the portion where the CoO film 15 as the variable resistor film that grows in the axial direction of the opening 24 from the side surface of the first electrode 13 constituting the inner surface of the opening 24 is joined in the vertical direction. An extending seam 31 is formed. FIG. 38 is a schematic plan view after the completion of step # 133, and the W-W ′ cross section corresponds to FIG.

  Thereafter, as shown in FIG. 35 (d), a conductive material film 16 (for example, a Pt film) is deposited on the entire upper surface of the variable resistor film 15 on which the seam 31 is formed to a thickness of about 100 nm by a sputtering method. (Step # 134). By this step # 134, the second electrode 16 is formed.

  In the present embodiment, the case where the opening 24 is formed in a cylindrical shape as illustrated in FIG. 35B has been described as an example. However, the shape of the opening 24 is not limited to such a shape. . FIG. 39 illustrates the case where the opening 24 is formed in a conical shape. Even in such a case, the seam 31 is included in the variable resistor 15 through the steps # 131 to # 134. A variable resistance element can be formed.

[Fifteenth embodiment]
An eighth embodiment (hereinafter, referred to as “this embodiment” as appropriate) of a variable resistance element, a manufacturing method thereof, and a driving method thereof according to the present invention will be described with reference to FIGS.

  FIG. 40 is a process cross-sectional view illustrating the method for manufacturing the variable resistance element according to this embodiment. FIG. 41 is a flowchart showing a process procedure in the manufacturing method. Steps # 141 to # 145 in the following sentence represent steps in FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment.

First, as in steps # 91 to # 92 of the tenth embodiment, an insulating material film 14 (for example, SiO ₂ film) is formed on the semiconductor substrate 11 on which a transistor circuit or the like (not shown) is appropriately formed by sputtering, for example. After depositing on the entire surface with a film thickness of about 400 nm (step # 141), an opening having a height difference of about 300 nm is formed in the insulating material film 14 by a known etching technique using a resist formed by a known photolithography technique as a mask. The part 28 is formed (see step # 142, FIG. 40A).

  Next, a conductive material film 13 (for example, a Pt film) is formed on the entire upper layer of the insulating material film 14 (hereinafter referred to as “insulating film 14” where appropriate) in which the openings 28 are formed by sputtering to a thickness of about 100 nm. (Step # 143). By this step # 143, the first electrode 13 is formed, and as shown in FIG. 40B, the side surface of the Pt film 13 (hereinafter referred to as the first electrode 13) is the inner side surface, and the height position is low. An opening 24 whose bottom surface is the upper surface of the first electrode 13 is formed. Note that the schematic plan view after the end of step # 143 in the present embodiment is the same as the schematic plan view after the end of step # 132 of the fourteenth embodiment shown in FIG. It corresponds to b).

  Next, as in step # 124 of the thirteenth embodiment, as shown in FIG. 40C, the variable resistor film is formed under the condition that the opening 24 (corresponding to the seam forming opening) is formed. 15 (for example, a CoO film) is deposited on the entire surface by LP (Low Pressure) -CVD under a film thickness condition that completely fills the opening 24 (step # 144). By this step # 144, in the portion where the CoO film 15 as the variable resistor film that grows in the axial direction of the opening 24 from the side surface of the first electrode 13 constituting the inner surface of the opening 24 is joined in the vertical direction. An extending seam 31 is formed. Note that the schematic plan view after the end of step # 144 in this embodiment is the same as the schematic plan view after the end of step # 133 in the fourteenth embodiment shown in FIG. 38, and the WW ′ cross section is FIG. It corresponds to c).

  Thereafter, as shown in FIG. 40D, a conductive material film 16 (for example, a Pt film) is deposited on the entire upper surface of the variable resistor film 15 on which the seam 31 is formed to a thickness of about 100 nm by sputtering. (Step # 145). By this step # 145, the second electrode 16 is formed.

  In the present embodiment, the case where the openings 28 and 24 are each formed in a cylindrical shape as shown in FIGS. 40A and 40B has been described as an example, but the shape of the opening 24 is It is not restricted to such a shape. FIG. 42 illustrates the case where the openings 28 and 24 are formed in a conical shape. Even in such a case, the seam 31 is placed in the variable resistor 15 through the steps # 141 to # 145. Can be formed.

  As described above, in each of the embodiments, the variable resistance element according to the present invention intentionally forms a seam in the variable resistance body, and further, an electrode (second electrode) is formed on the variable resistance body without removing the seam. By forming the electrode, the seam is used as part or all of the filament path.

  That is, by performing the forming process under the condition that the seam is formed in the variable resistor, the filament path is easily formed in the seam formation region where electric field concentration is likely to occur and in the vicinity thereof. That is, the seam formed in the variable resistor film can be used as part or all of the filament path. This means that the generation location of the filament path generated by the forming process can be specified, and the voltage to be applied during the forming process can be lowered.

  Therefore, according to each of the above-described embodiments, a seam is formed at a specific location in the variable resistor during manufacturing, so that a filament path is formed in the seam formation region and the vicinity thereof. By manufacturing the variable resistance element below, the filament path forming area formed between the variable resistance elements can be made the same area, thereby making it possible to manufacture a variable resistance element with high reproducibility. Easy structural design can be realized.

[Another embodiment]
Hereinafter, another embodiment will be described.

  <1> In the first to sixth embodiments described above (FIGS. 1, 4, 6, 9, 11, and 14), the variable resistor 15 is more localized than the deposited film thickness near the corner of the step. In the case where the thickness of the variable resistor 15 in the vicinity of the corner is smaller than the deposited film thickness, the seam 32 is formed in the thickened region. However, similarly, a structure in which the seam 32 is formed in the vicinity of the corner portion may be used. For example, when the processes according to steps # 1 to # 5 are executed in the first embodiment, it is assumed that the structure shown in FIG. 43 is used instead of the structure shown in FIG. The same effect as in the case of the first embodiment described above can be obtained. The same applies to the second to sixth embodiments.

  Further, also in the seventh to twelfth embodiments (FIGS. 16, 19, 21, 24, 26, and 29) described above, deposition is performed in the vicinity of the corner portion where the inner wall and the bottom surface of the opening are joined. Although the film thickness is locally thick and the seam 30 is formed in the thickened area, the film thickness of the variable resistor 15 near the corner is smaller than the deposited film thickness. In this case, the seam 30 may be formed in the vicinity of the corner portion. For example, in the seventh embodiment, when each process related to steps # 61 to # 65 is executed, a structure as shown in FIG. 44 is assumed instead of the structure as shown in FIG. Even in this case, the same effect as in the case of the seventh embodiment described above can be obtained. The same applies to the eighth to twelfth embodiments.

  In FIG. 16D, the variable resistor film 15 is illustrated such that the deposited film thickness on the bottom surface of the opening is approximately the same as the deposited film thickness on the insulating film 14 constituting the inner wall of the opening. However, as shown in FIG. 44, the deposited film thickness on the bottom surface of the opening may be thinner than the deposited film thickness on the insulating film 14. At this time, the deposited film thickness on the bottom surface of the opening is thickest in the vicinity of the center, and the deposited film thickness may be reduced as the distance from the central area increases, that is, the closer to the corner region. The same applies to the eighth to twelfth embodiments.

  <2> In the above-described first embodiment (FIG. 1), the variable resistor film 15 is deposited on the upper surface of the insulating film 14 that forms the side wall of the step, but as shown in FIG. Alternatively, the variable resistor film 15 may not be deposited on the upper surface of 14. In this case, after depositing the variable resistor film 15 according to step # 4, the variable resistor film 15 deposited on the insulating film 14 is polished by, for example, CMP until the upper surface of the insulating film 14 is exposed, and then the second electrode. This is realized by forming 16. The same applies to the second, seventh, and eighth embodiments. In the case of the seventh embodiment (FIG. 16), when the variable resistor film 15 deposited on the upper surface of the insulating film 14 is removed by polishing after the variable resistor film 15 is deposited, the structure shown in FIG. 46 is obtained.

  Further, when the first electrode 13 constitutes the side wall of the step as in the third embodiment (FIG. 6), the first electrode 13 having a high height position is deposited after the variable resistor film 15 is deposited. The variable resistor film 15 deposited on the upper surface is removed by polishing, and then the electrode film constituting the second electrode 16 is formed, and then the electrode film deposited on the upper surface of the first electrode 13 having a high height is polished. A structure as shown in FIG. 47 may be realized by removing and then depositing an insulating film 41. Compared to the case of FIG. 45, the electrode film constituting the second electrode 16 is also removed by polishing so that the first electrode 13 and the second electrode 16 are not in contact with each other so as to prevent a short-circuit state. It is a measure. The same applies to the third to sixth and ninth to eleventh embodiments.

  <3> In the thirteenth embodiment, the variable resistor film 15 is deposited on the upper surface of the insulating film 14 constituting the opening side wall, but the variable resistor film 15 is insulated as shown in FIG. The structure may not be deposited on the upper surface of the film 14. In this case, it is realized by forming the second electrode 13 after the variable resistor film 15 is deposited and then polished and removed until the upper surface of the insulating film 14 is exposed. Note that by performing the polishing step, the upper surface of the variable resistor film 15 may be lower than the height position of the upper surface of the insulating film 14, as shown in FIG. Even in such a case, the seam 31 is formed substantially at the center of the variable resistor film 15 (near the axis of the opening 21). The same applies to the fourteenth and fifteenth embodiments.

  In the case of the fourteenth and fifteenth embodiments, in order to prevent the first electrode 13 and the second electrode 16 from contacting each other, a part of the electrode film constituting the second electrode 16 is deposited and then partially etched. It may be removed. For example, in the case of the fourteenth embodiment, after the variable resistor film 15 is deposited, the variable resistor film 15 deposited on the upper surface of the first electrode 13 is polished and removed, and then the electrode film constituting the second electrode 16 is deposited. Then, the electrode film of the second electrode 16 in contact with the first electrode 13 may be removed by etching. Thereafter, by depositing an insulating film 41, a structure as shown in FIG. 49 is realized.

Process sectional drawing which shows the manufacturing method of the variable resistance element of 1st Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistive element of 1st Embodiment of this invention. The plane schematic diagram which showed the area | region in which the variable resistance element of 1st Embodiment of this invention is formed Process sectional drawing which shows the manufacturing method of the variable resistive element of 2nd Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 2nd Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistive element of 3rd Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 3rd Embodiment of this invention. The plane schematic diagram which showed the area | region in which the variable resistive element of 3rd Embodiment of this invention is formed. Process sectional drawing which shows the manufacturing method of the variable resistive element of 4th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 4th Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistive element of 5th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 5th Embodiment of this invention. Plane schematic diagram showing a region where a variable resistance element according to a fifth embodiment of the present invention is formed Process sectional drawing which shows the manufacturing method of the variable resistive element of 6th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistive element of 6th Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistive element of 7th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 7th Embodiment of this invention. Plane schematic diagram showing a region where a variable resistance element according to a seventh embodiment of the present invention is formed Process sectional drawing which shows the manufacturing method of the variable resistive element of 8th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 8th Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistive element of 9th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 9th Embodiment of this invention. Plane schematic diagram showing a region in which the variable resistance element according to the ninth embodiment of the present invention is formed. Process sectional drawing which shows the manufacturing method of the variable resistive element of 10th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistive element of 10th Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistance element of 11th Embodiment of this invention The flowchart which shows the manufacturing process of the variable resistance element of 11th Embodiment of this invention. Plane schematic diagram showing a region in which the variable resistance element according to the eleventh embodiment of the present invention is formed. Process sectional drawing which shows the manufacturing method of the variable resistance element of 12th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 12th Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistive element of 13th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistive element of 13th Embodiment of this invention. Schematic plan view showing a region where a variable resistance element according to a thirteenth embodiment of the present invention is formed. Plane schematic diagram showing the region where the seam of the thirteenth embodiment of the present invention is formed Process sectional drawing which shows the manufacturing method of the variable resistive element of 14th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistance element of 14th Embodiment of this invention. Plane schematic diagram showing a region where a variable resistance element according to a fourteenth embodiment of the present invention is formed. Plane schematic diagram showing a region where a seam of a fourteenth embodiment of the present invention is formed Sectional drawing of another process which shows the manufacturing method of the variable resistive element of 14th Embodiment of this invention. Process sectional drawing which shows the manufacturing method of the variable resistive element of 15th Embodiment of this invention. The flowchart which shows the manufacturing process of the variable resistive element of 15th Embodiment of this invention. Sectional drawing of another process which shows the manufacturing method of the variable resistive element of 14th Embodiment of this invention. Schematic structural diagram of a variable resistance element of another embodiment of the present invention Another schematic structure diagram of a variable resistance element according to another embodiment of the present invention Yet another schematic structural diagram of a variable resistance element according to another embodiment of the present invention. Yet another schematic structural diagram of a variable resistance element according to another embodiment of the present invention. Yet another schematic structural diagram of a variable resistance element according to another embodiment of the present invention. Yet another schematic structural diagram of a variable resistance element according to another embodiment of the present invention. Yet another schematic structural diagram of a variable resistance element according to another embodiment of the present invention. Schematic structure diagram of variable resistance element with conventional configuration

Explanation of symbols

11: Semiconductor substrate 13: First electrode 14: Insulating film 15: Variable resistor (film)
16: 2nd electrode 20: Opening part 21: Opening part 22: Step part 23: Opening part 24: Opening part 25: Step part 28: Opening part 29: Opening part 30: Seam 31: Seam 32: Seam 41: Insulating film 101: Upper electrode 102: Variable resistor 103: Lower electrode

Claims (45)

The substrate has a first electrode, a second electrode, and a variable resistor formed between the electrodes, and the electric resistance between the electrodes is reversible by applying a voltage pulse between the electrodes. Variable resistance elements that change
The variable resistance element, wherein the variable resistor has at least one seam extending in a direction from the first electrode toward the second electrode.   The variable resistance element according to claim 1, wherein the at least one seam forms a part of a filament path by applying a voltage between the first electrode and the second electrode.   A first structure portion configured to have the variable resistor parallel to the substrate surface; a second structure portion having a lower end coupled to an end portion of the first structure portion and configured in a direction perpendicular to the substrate surface; The variable resistance element according to claim 1, wherein the seam is provided in a corner region where the first structure portion and the second structure portion are coupled to each other. An insulating film on a part of the first electrode;
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, a first surface is in contact with a side surface of the insulating film, and a second surface facing the first surface with a thickness of the variable resistor is in contact with a side surface of the second electrode. The variable resistance element according to claim 3, wherein the variable resistance element is formed as described above. In the same layer as the first electrode, having an insulating film thicker than the first electrode,
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, a first surface is in contact with a side surface of the insulating film, and a second surface facing the first surface with a thickness of the variable resistor is in contact with a side surface of the second electrode. The variable resistance element according to claim 3, wherein the variable resistance element is formed as described above. The first electrode is configured to have a step by having regions with different formed film thicknesses,
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, the first surface is in contact with the side surface of the first electrode, and the second surface facing the first surface with a thickness of the variable resistor is in contact with the side surface of the second electrode. The variable resistance element according to claim 3, wherein the variable resistance element is formed as described above. Having an insulating film having a step by having regions with different formed film thickness,
The first electrode is formed on the insulating film so as to have a height difference on the uppermost surface,
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, the first surface is in contact with the side surface of the first electrode, and the second surface facing the first surface with a thickness of the variable resistor is in contact with the side surface of the second electrode. The variable resistance element according to claim 3, wherein the variable resistance element is formed as described above. With an insulating film,
The first electrode is formed on a part of the insulating film;
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, the first surface is in contact with the side surface of the first electrode, and the second surface facing the first surface with a thickness of the variable resistor is in contact with the side surface of the second electrode. The variable resistance element according to claim 3, wherein the variable resistance element is formed as described above. An insulating film having a thickness smaller than that of the first electrode in the same layer as the first electrode;
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, the first surface is in contact with the side surface of the first electrode, and the second surface facing the first surface with a thickness of the variable resistor is in contact with the side surface of the second electrode. The variable resistance element according to claim 3, wherein the variable resistance element is formed as described above. The variable resistor is
A third structure portion configured parallel to the substrate surface and having a height higher than that of the first structure portion and coupled to an upper end of the second structure portion at an end portion;
6. The variable resistor according to claim 4, wherein the third structure portion is formed such that a lower surface is in contact with an upper surface of the insulating film and an upper surface is in contact with a lower surface of the second electrode. element. The variable resistor is
A third structure portion configured parallel to the substrate surface and having a height higher than that of the first structure portion and coupled to an upper end of the second structure portion at an end portion;
The lower surface of the third structure portion is in contact with the upper surface of the first electrode, and the upper surface is in contact with the lower surface of the second electrode. The variable resistance element according to item. The second structure part is
The cross section parallel to the substrate surface is formed in an annular shape, and the lower end and the end of the first structure portion are coupled to each other inside the second structure portion. Variable resistance element. An insulating film is provided on a part of the first electrode;
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, the outer surface is in contact with the side surface of the insulating film, and the inner surface facing the outer surface with a thickness of the variable resistor is in contact with the side surface of the second electrode. The variable resistance element according to claim 12, wherein the variable resistance element is provided. In the same layer as the first electrode, having an insulating film thicker than the first electrode,
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, the outer surface is in contact with the side surface of the insulating film, and the inner surface facing the outer surface with a thickness of the variable resistor is in contact with the side surface of the second electrode. The variable resistance element according to claim 12, wherein the variable resistance element is provided. The first electrode is configured to have a step by having regions with different formed film thicknesses,
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, an outer surface is in contact with a side surface of the first electrode, and an inner surface facing the outer surface with a film thickness of the variable resistor is in contact with a side surface of the second electrode. The variable resistance element according to claim 12, wherein the variable resistance element is formed. Having an insulating film having a step by having regions with different formed film thickness,
The first electrode is formed on the insulating film so as to have a height difference on the uppermost surface,
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the first electrode, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, an outer surface is in contact with a side surface of the first electrode, and an inner surface facing the outer surface with a film thickness of the variable resistor is in contact with a side surface of the second electrode. The variable resistance element according to claim 12, wherein the variable resistance element is formed. With an insulating film,
The first electrode is formed on a part of the insulating film;
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, an outer surface is in contact with a side surface of the first electrode, and an inner surface facing the outer surface with a film thickness of the variable resistor is in contact with a side surface of the second electrode. The variable resistance element according to claim 12, wherein the variable resistance element is formed. An insulating film having a thickness smaller than that of the first electrode in the same layer as the first electrode;
The variable resistor is
In the first structure portion, the lower surface is in contact with the upper surface of the insulating film, the upper surface is in contact with the lower surface of the second electrode,
In the second structure portion, an outer surface is in contact with a side surface of the first electrode, and an inner surface facing the outer surface with a film thickness of the variable resistor is in contact with a side surface of the second electrode. The variable resistance element according to claim 12, wherein the variable resistance element is formed. The variable resistor is
A third structure portion configured parallel to the substrate surface and having a higher height than the first structure portion, and having an end portion coupled to an upper end of the second structure portion outside the second structure portion;
15. The variable resistor according to claim 13, wherein the third structure portion is formed such that a lower surface is in contact with an upper surface of the insulating film and an upper surface is in contact with a lower surface of the second electrode. element. The variable resistor is
A third structure portion configured parallel to the substrate surface and having a higher height than the first structure portion, and having an end portion coupled to an upper end of the second structure portion outside the second structure portion;
The lower surface of the third structure portion is in contact with the upper surface of the first electrode, and the upper surface is in contact with the lower surface of the second electrode. The variable resistance element according to item. The variable resistor is configured to be embedded in a buried region surrounded at least on the outer surface by the same material film, and has the seam extending in the height direction in the buried region,
The variable resistance element according to claim 1, wherein the material film is formed of the first electrode or the insulating film. The insulating film is provided on a partial upper layer of the first electrode,
The variable resistor is
The variable resistance element according to claim 21, wherein a lower surface of the buried region is in contact with an upper surface of the insulating film, and the outer surface is in contact with a side surface of the insulating film. The first electrode is configured to have a step by having regions with different formed film thicknesses,
The variable resistor is
The variable resistor according to claim 21, wherein a lower surface of the buried region is in contact with an upper surface of the first electrode and the outer surface is in contact with a side surface of the first electrode. element. Having an insulating film having a step by having regions with different formed film thickness,
The first electrode is formed on the insulating film so as to have a height difference on the uppermost surface,
The variable resistor is
The variable resistor according to claim 21, wherein a lower surface of the buried region is in contact with an upper surface of the first electrode and the outer surface is in contact with a side surface of the first electrode. element. The variable resistor is
In a non-embedded region outside the buried region, it is connected to the variable resistor formed in the buried region, and the height position of the bottom surface is higher than the bottom surface in the buried region. 23. The variable resistance element according to claim 22, wherein the lower surface is in contact with the upper surface of the insulating film and the upper surface is in contact with the lower surface of the second electrode in the embedded outer region. The variable resistor is
In a non-embedded region outside the buried region, it is connected to the variable resistor formed in the buried region, and the height position of the bottom surface is higher than the bottom surface in the buried region. 25. The variable according to claim 23, wherein a lower surface is in contact with an upper surface of the first electrode and an upper surface is in contact with a lower surface of the second electrode within the embedded region. Resistance element. It is a manufacturing method of the variable resistance element according to any one of claims 3 to 11,
A step forming step for forming a seam forming step on the substrate;
Thereafter, a variable resistor forming step of forming the variable resistor,
Then, a second electrode forming step of forming the second electrode,
The step forming step includes
Forming the first electrode, and forming the first electrode, the first upper surface parallel to the substrate surface, the first upper surface configured parallel to the substrate surface and lower in height than the first upper surface. 2 The upper surface and the upper end are coupled to the end portion of the first upper surface, and the lower end is coupled to the end portion of the second upper surface, thereby connecting the first upper surface and the second upper surface in a direction perpendicular to the substrate surface. A step of forming the seam forming step in which at least one of the second upper surface and the intermediate surface includes the first electrode.
The variable resistor forming step includes
A variable resistor film is formed on the entire surface by sputtering, or a predetermined material film is formed on the entire surface by sputtering and then oxidized to form a variable resistor film. Forming the variable resistor including the first structure part in which the film contacts the second upper surface and the second structure part in which the variable resistor film contacts the intermediate surface; and the first structure part; Forming the seam in the variable resistor according to the corner region to which the second structure portion is coupled;
The second electrode forming step includes
A method of manufacturing a variable resistance element, comprising the step of forming the second electrode on an upper surface of the variable resistance film on which the seam is formed. In the step forming step,
Forming the first electrode on the substrate;
Thereafter, after an insulating film is formed on the upper surface of the first electrode, the insulating film is etched until a partial upper surface of the first electrode is exposed, whereby the insulating film is formed of the insulating film. 28. The method of manufacturing a variable resistance element according to claim 27, wherein the seam forming step having the first upper surface, the intermediate surface, and the second upper surface constituted by the first electrode is formed. In the step forming step,
The first electrode is formed in a partial region on the substrate, and an insulating film having a thickness larger than that of the first electrode is formed in a region outside the formation of the first electrode on the substrate. 28. The method of manufacturing a variable resistance element according to claim 27, wherein the seam forming step having the first upper surface, the intermediate surface, and the second upper surface constituted by the first electrode is formed. . In the step forming step,
Forming an electrode film constituting the first electrode on the substrate;
Thereafter, by etching the electrode film in a partial region, the seam forming step in which the first upper surface, the intermediate surface, and the second upper surface are all configured by the first electrode is formed. 28. The method of manufacturing a variable resistance element according to claim 27, wherein the variable resistance element is formed. In the step forming step,
After forming an insulating film on the substrate, a step is formed in the insulating film by performing etching on a partial region,
Thereafter, an electrode film constituting the first electrode is formed on the entire upper surface of the insulating film on which the step is formed, so that the first upper surface, the intermediate surface, and the second upper surface are all in the first surface. 28. The method of manufacturing a variable resistance element according to claim 27, wherein the seam forming step formed by one electrode is formed. In the step forming step,
Forming an insulating film on the substrate;
Thereafter, after forming an electrode film constituting the first electrode on the upper surface of the insulating film, etching is performed on the electrode film until a partial upper surface of the insulating film is exposed to form the first electrode. The step for forming the seam is formed by forming the first upper surface and the intermediate surface formed by the first electrode and the second upper surface formed by the insulating film. Item 28. A method for manufacturing a variable resistance element according to Item 27. In the step forming step,
The first electrode is formed in a partial region on the substrate, and an insulating film having a thickness smaller than that of the first electrode is formed in a region outside the first electrode formation on the substrate. 28. The variable resistance element according to claim 27, wherein the step for forming the seam includes the first upper surface and the intermediate surface, and the second upper surface composed of the insulating film. Production method. It is a manufacturing method of the variable resistance element according to any one of claims 12 to 20,
An opening forming step of forming a seam forming opening on the substrate;
Thereafter, a variable resistor forming step of forming the variable resistor,
Then, a second electrode forming step of forming the second electrode,
The opening forming step includes
Forming the first electrode, and by forming the first electrode, an exposed inner surface in which a cross section parallel to the substrate surface is formed in an annular shape, and the exposed inner surface outside the exposed inner surface. A first upper surface where an upper end and an end are coupled, and an exposed bottom surface where a lower end and an end of the exposed inner surface are coupled inside the exposed inner surface, and at least one of the exposed inner surface and the exposed bottom surface Is a step of forming the seam forming opening formed by the surface of the first electrode,
The variable resistor forming step includes
A film thickness in which the variable resistor film is formed on the entire surface by a sputtering method, or a predetermined material film is formed on the entire surface by a sputtering method and then an oxidation treatment is performed to completely fill the inside of the seam forming opening. By forming a variable resistor film under conditions, the first structure portion where the variable resistor film contacts the exposed bottom surface, and the second structure portion where the variable resistor film contacts the exposed inner surface And forming the seam in the variable resistor according to the corner region where the first structure portion and the second structure portion are coupled to each other.
The second electrode forming step includes
A method of manufacturing a variable resistance element, comprising the step of forming the second electrode on an upper surface of the variable resistance film on which the seam is formed. In the opening forming step,
Forming the first electrode on the substrate;
Thereafter, after an insulating film is formed on the upper surface of the first electrode, the insulating film is etched until a partial upper surface of the first electrode is exposed, whereby the insulating film is formed of the insulating film. 35. The method of manufacturing a variable resistance element according to claim 34, wherein the seam forming opening having the first upper surface, the exposed inner side surface, and the exposed bottom surface constituted by the first electrode is formed. In the opening forming step,
Forming the first electrode in a partial region on the substrate and forming an insulating film thicker than the first electrode on an outer periphery of the first electrode forming region on the substrate; 35. The variable resistance element according to claim 34, wherein the seam forming opening having the first upper surface and the exposed inner surface configured, and the exposed bottom surface configured by the first electrode is formed. Manufacturing method. In the opening forming step,
Forming an electrode film constituting the first electrode on the substrate;
Thereafter, the seam forming opening in which the first upper surface, the exposed inner surface, and the exposed bottom surface are all configured by the first electrode by etching the electrode film in a partial region. The method of manufacturing a variable resistance element according to claim 34, wherein: is formed. In the opening forming step,
After forming an insulating film on the substrate, an opening is formed in the insulating film by etching a partial region,
Thereafter, the first electrode is formed by forming an electrode film constituting the first electrode with a film thickness within a range in which the opening is not filled over the entire upper surface of the insulating film in which the opening is formed. 35. The variable resistance element according to claim 34, wherein the first upper surface, the exposed inner side surface, and the exposed bottom surface all form the seam forming opening formed of the first electrode. Manufacturing method. In the opening forming step,
Forming an insulating film on the substrate;
Thereafter, after forming an electrode film constituting the first electrode on the upper surface of the insulating film, etching is performed on the electrode film until a partial upper surface of the insulating film is exposed to form the first electrode. By forming, the seam forming opening having the first upper surface and the exposed inner surface constituted by the first electrode, and the exposed bottom surface constituted by the insulating film is formed. The method for manufacturing a variable resistance element according to claim 34. In the opening forming step,
An insulating film is formed in a partial region on the substrate, and the first electrode having a thickness larger than that of the insulating film is formed on an outer peripheral portion of the insulating film forming region on the substrate, thereby forming the first electrode. 35. The variable resistance element according to claim 34, wherein the seam forming opening having the exposed first upper surface, the exposed inner surface, and the exposed bottom surface made of the insulating film is formed. Method. It is a manufacturing method of the variable resistance element according to any one of claims 21 to 26,
An opening forming step of forming a seam forming opening on the substrate;
Thereafter, a variable resistor forming step of forming the variable resistor,
Then, a second electrode forming step of forming the second electrode,
The opening forming step includes
Forming the first electrode, and by forming the first electrode, an exposed inner surface in which a cross section parallel to the substrate surface is formed in an annular shape, and the exposed inner surface outside the exposed inner surface. A first upper surface where the upper end and the end are coupled, and an exposed bottom surface where the lower end and the end of the exposed inner surface are coupled inside the exposed inner surface, and at least one of the exposed inner surface and the exposed bottom surface. Is a step of forming the seam forming opening formed by the surface of the first electrode,
The variable resistor forming step includes
A variable resistor film is formed on the entire surface by the CVD method, or a predetermined material film is formed on the entire surface by the CVD method, and then an oxidation treatment is performed, so that an opening remains inside the seam forming opening. By forming the variable resistor film under a film thickness condition that does not occur, the variable resistor is formed in the buried region surrounded by the material film constituting the exposed inner surface, and the buried region is formed in the buried region. Forming the seam extending in the height direction in the variable resistor body,
The second electrode forming step includes
A method of manufacturing a variable resistance element, comprising the step of forming the second electrode on an upper surface of the variable resistance film on which the seam is formed. In the opening forming step,
Forming the first electrode on the substrate;
Thereafter, after an insulating film is formed on the upper surface of the first electrode, the insulating film is etched until a partial upper surface of the first electrode is exposed, whereby the insulating film is formed of the insulating film. 42. The method of manufacturing a variable resistance element according to claim 41, wherein the seam forming opening having the first upper surface, the exposed inner surface, and the exposed bottom surface configured by the first electrode is formed. In the opening forming step,
Forming an electrode film constituting the first electrode on the substrate;
Thereafter, the seam forming opening in which the first upper surface, the exposed inner surface, and the exposed bottom surface are all configured by the first electrode by etching the electrode film in a partial region. 42. The method of manufacturing a variable resistance element according to claim 41, wherein: is formed. In the opening forming step,
After forming an insulating film on the substrate, an opening is formed in the insulating film by etching a partial region,
Thereafter, an electrode film constituting the first electrode is formed on the entire upper surface of the insulating film in which the opening is formed, with a film thickness within a range not filling the opening. 42. The variable resistance according to claim 41, wherein the first upper surface, the exposed inner surface, and the exposed bottom surface all form the seam forming opening formed by the first electrode. Device manufacturing method. A driving method of a variable resistance element according to any one of claims 1 to 26,
A variable resistance element driving method, wherein a voltage is applied between the first electrode and the second electrode to form a filament path in the variable resistor through at least the seam.

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