Magnetic storage device and method of manufacturing a magnetic storage device
By using non-nitrogen materials to construct the surrounding components of the magnetic storage device, the problem of reduced MR ratio was solved, and the electrical characteristics of the storage cell and the device performance were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- KIOXIA CORP
- Filing Date
- 2022-08-31
- Publication Date
- 2026-05-19
AI Technical Summary
In the manufacturing process of existing magnetic storage devices, the magnetoresistive ratio (MR ratio) of the storage cell is easily reduced due to the adhesion and re-deposition of nitrogen materials, resulting in poor electrical characteristics.
The surrounding components of the magnetic storage device, including conductors, insulators, electrodes, and masks, are constructed using non-nitrogen materials, avoiding the use of nitrogen materials to reduce the impact on magnetoresistive elements.
The electrical characteristics of the storage cells in the magnetic storage device have been improved, the stability of the MR ratio has been enhanced, and the performance of the device has been improved.
Smart Images
Figure CN115802866B_ABST
Abstract
Description
[0001] This application enjoys priority to Japanese Patent Application No. 2021-146822 (filed September 9, 2021) and U.S. Patent Application No. 17 / 691652 (filed March 10, 2022). This application incorporates the entire contents of the basic applications by reference to them. Technical Field
[0002] The implementation methods generally involve magnetic storage devices. Background Technology
[0003] Magnetic storage devices are known as a type of storage device. Magnetic storage devices use storage cells containing elements that utilize the magnetoresistive effect to store data. To improve the characteristics of magnetic storage devices, it is desirable for the storage cells to have high electrical characteristics. Summary of the Invention
[0004] The problem to be solved by the present invention is to provide a magnetic storage device comprising storage cells having high electrical characteristics.
[0005] One embodiment of a magnetic storage device includes a first conductor, a first insulator, a second conductor, a variable resistivity material, a third conductor, a first ferromagnetic layer, an insulating layer, a second ferromagnetic layer, a fourth conductor, a second insulator, and a third insulator. The first conductor is substantially formed of a non-magnetic, non-nitrogen material. The first insulator covers the sides of the first conductor and is substantially formed of a non-nitrogen material. The second conductor is located on the first conductor and is substantially formed of a non-magnetic, non-nitrogen material. The variable resistivity material is located on the second conductor. The third conductor is located on the variable resistivity material and is substantially formed of a non-magnetic, non-nitrogen material. The first ferromagnetic layer is located on the third conductor. The insulating layer is located on the first ferromagnetic layer. The second ferromagnetic layer is located on the insulating layer. The fourth conductor is located on the second ferromagnetic layer and is substantially formed of a non-magnetic, non-nitrogen material. The second insulator covers the side surfaces of the first ferromagnetic layer, the side surfaces of the insulating layer, and the side surfaces of the second ferromagnetic layer, and is substantially formed of a non-nitrogen material. The third insulator is located on the surface of the second insulator. Attached Figure Description
[0006] Figure 1 The functional block diagram and associated elements of the magnetic storage device according to the first embodiment are shown.
[0007] Figure 2 This is a circuit diagram of the memory cell array according to the first embodiment.
[0008] Figure 3 The structure of a cross-section of a portion of the memory cell array of the first embodiment is shown.
[0009] Figure 4 The structure of a cross-section of a portion of the memory cell array of the first embodiment is shown.
[0010] Figure 5 A cross-section showing an example of the construction of the storage cell in the first embodiment.
[0011] Figure 6 This shows a state between manufacturing processes of a portion of the magnetic storage device of the first embodiment.
[0012] Figure 7 Showing the continuation Figure 6 The subsequent state.
[0013] Figure 8 Showing the continuation Figure 7 The subsequent state.
[0014] Figure 9 A cross-section showing the structure of a storage cell in a magnetic storage device for reference is shown.
[0015] Figure 10 The results of the experiment show that the decrease in MR ratio was suppressed are shown.
[0016] Figure 11 The results of the experiment show that the decrease in MR ratio was suppressed are shown.
[0017] Figure 12 The results of the experiment show that the decrease in MR ratio was suppressed are shown.
[0018] Figure 13 The functional block diagram and associated elements of the magnetic storage device according to the second embodiment are shown.
[0019] Figure 14 The circuit configuration of the storage cell in the second embodiment is shown.
[0020] Figure 15 A cross-section showing an example of the construction of the storage cell in the second embodiment.
[0021] Figure 16 This shows a state between manufacturing processes of a portion of the magnetic storage device of the second embodiment.
[0022] Explanation of reference numerals in the attached figures
[0023] 1…Magnetic storage device, 2…Storage controller, 11…Storage cell array, 12…Input / output circuit, 13…Control circuit, 14…Row selection circuit, 15…Column selection circuit, 16…Write circuit, 17…Read circuit, MC…Storage cell, WL…Word line, BL…Bit line, MTJ…Magnetic reluctance element, SE…Switching element, 21…Conductor, 22…Conductor, 23…Interlayer insulator, 24…Lower electrode, 25…Variable resistivity material, 26…Intermediate electrode, 31…Ferromagnetic layer, 32…Insulating layer, 33…Ferromagnetic layer, 35…Hard mask, 41…Sidewall insulator, 42…Interlayer insulator. Detailed Implementation
[0024] Hereinafter, embodiments will be described with reference to the accompanying drawings. In the following description, there are instances where constituent elements having substantially the same function and structure are labeled with the same reference numerals and repeated descriptions are omitted.
[0025] The accompanying drawings are schematic, and the relationship between thickness and planar dimensions, the ratio of thicknesses of each layer, etc., may differ from reality. The drawings may also contain portions where the dimensional relationships and ratios differ from each other. Regarding the description of a particular embodiment, it is appropriate to describe other embodiments as well, unless all are explicitly stated or automatically excluded. Each embodiment exemplifies apparatus and methods for embodying the technical concept of that embodiment; the technical concept of the embodiments does not specify the material, shape, structure, arrangement, etc., of the constituent components as described below.
[0026] In this specification and claims, the term "connected" to other second elements includes the first element being directly or always or selectively connected to the second element via an element that is conductive.
[0027] The following description uses an orthogonal xyz coordinate system to illustrate the implementation method. In the following description, the term "below" and its derivatives and related terms refer to the position of a smaller coordinate on the z-axis, and the term "above" and its derivatives and related terms refer to the position of a larger coordinate on the z-axis.
[0028] 1.1. First Implementation Method
[0029] 1.1. Structure (Composition)
[0030] 1.1.1. Overall Structure
[0031] Figure 1 A functional block diagram of the magnetic storage device according to the first embodiment is shown. For example... Figure 1As shown, the magnetic storage device 1 is controlled by the storage controller 2. The magnetic storage device 1 is a storage device that uses ferromagnetic materials to store data. The magnetic storage device 1 includes a storage cell array 11, an input / output circuit 12, a control circuit 13, a row selection circuit 14, a column selection circuit 15, a write circuit 16, and a read circuit 17.
[0032] The storage cell array 11 is a collection of multiple storage cells MC. Each storage cell MC can store data non-volatilely. Multiple word lines WL and multiple bit lines BL are located in the storage cell array 11. Each storage cell MC is connected to one word line WL and one bit line BL. The word line WL is associated with a row. The bit line BL is associated with a column. A storage cell MC is determined by selecting one row and one column.
[0033] Input / output circuit 12 is a circuit for inputting and outputting data and signals. Input / output circuit 12 receives control signal CNT, command CMD, address signal ADD, and data (write data) DAT from memory controller 2. Input / output circuit 12 sends data (read data) DAT to memory controller 2.
[0034] The row selection circuit 14 receives the address signal ADD from the input / output circuit 12, and makes one word line WL associated with the row determined according to the received address signal ADD selected.
[0035] The column selection circuit 15 receives the address signal ADD from the input / output circuit 12, and makes one or more bit lines BL associated with the column determined according to the received address signal ADD selected.
[0036] Control circuit 13 receives control signal CNT and command CMD from input / output circuit 12. Based on the control signal CNT and command CMD, control circuit 13 controls write circuit 16 and read circuit 17. Specifically, during data writing to memory cell array 11, control circuit 13 supplies the voltage used for data writing to write circuit 16. Conversely, during data reading from memory cell array 11, control circuit 13 supplies the voltage used for data reading to read circuit 17.
[0037] The write circuit 16 receives write data DAT from the input / output circuit 12 and supplies the voltage to the voltage select circuit 15 used in the data writing process based on the control of the control circuit 13 and the write data DAT.
[0038] Based on the control of the control circuit 13, the readout circuit 17 calculates the data held in the memory cell MC using the voltage used in data readout. The calculated data is supplied to the input / output circuit 12 as readout data DAT. The readout circuit 17 includes a sense amplifier.
[0039] 1.1.2. Circuit Structure of a Memory Cell Array
[0040] Figure 2 This is a circuit diagram of the memory cell array 11 according to the first embodiment. Figure 2 As shown, in the storage cell array 11, M+1 (M is a natural number) word lines WLA are set. <0> WLA <1> , ..., WLA <m>) and M+1 word lines WLB (WLB <0> WLB <1> WLB <m>In the memory cell array 11, an additional N+1 (N is a natural number) bit lines BL are set. <0> BL <1> , ..., BL <n>).
[0041] Each memory cell MC (MCA and MCB) has a first node and a second node. Each memory cell MC is connected to a word line WL at the first node and to a bit line BL at the second node. More specifically, memory cell MCA includes all combinations of all cases where α is an integer greater than or equal to 0 and less than M, and all cases where β is an integer greater than or equal to 0 and less than N, and is connected between word line WLA<α> and bit line BL<β>. Similarly, memory cell MCB includes all combinations of all cases where α is an integer greater than or equal to 0 and less than M, and all cases where β is an integer greater than or equal to 0 and less than N, and is connected between word line WLB<α> and bit line BL<β>.
[0042] Each memory cell MC includes one magnetoresistive element MTJ (MTJA or MTJB) and one switching element SE (SEA or SEB). More specifically, for all combinations of all cases where α is an integer greater than or equal to 0 and less than M, and for all combinations of all cases where β is an integer greater than or equal to 0 and less than N, memory cell MCA<α, β> includes the magnetoresistive element MTJA<α, β> and the switching element SEA<α, β>. Furthermore, for all combinations of all cases where α is greater than or equal to 0 and less than M, and for all combinations of all cases where β is an integer greater than or equal to 0 and less than N, memory cell MCB<α, β> includes the magnetoresistive element MTJB<α, β> and the switching element SEB<α, β>.
[0043] In each memory cell (MC), the magnetoresistive element (MTJ) and the switching element (SE) are connected in series. The magnetoresistive element (MTJ) is connected to one word line (WL), and the switching element (SE) is connected to one bit line (BL).
[0044] A magnetoresistive element (MTJ) can switch between a low-resistance state and a high-resistance state. MTJs utilize the difference between these two resistance states to store one bit of data. MTJs exhibit the tunneling magnetoresistive effect, and are, for example, devices containing a magnetic tunnel junction (MTJ). The following description and accompanying figures are based on the premise that the magnetoresistive element is an example of an MTJ device.
[0045] A switching element SE is a component used to select a memory cell MC containing the switching element SE. The switching element SE can be a switching element as described below. The switching element has two terminals. When a voltage below a first threshold is applied between the two terminals in a first direction, the switching element is in a high-resistance state, for example, an electrically non-conducting state (off state). On the other hand, when a voltage above the first threshold is applied between the two terminals in the first direction, the switching element is in a low-resistance state, for example, an electrically conducting state (on state). Furthermore, the switching element also has the same function as switching between a high-resistance state and a low-resistance state based on the magnitude of the voltage applied in the first direction, with respect to a second direction opposite to the first direction. That is, the switching element is a bidirectional switching element. By turning the switching element on or off, the presence or absence of current supplied to the magnetoresistive element MTJ connected to the switching element can be controlled, i.e., the selection or non-selection of the magnetoresistive element MTJ.
[0046] 1.1.3. Construction of a Storage Cell Array
[0047] Figure 3 and Figure 4 The structure of a cross-section of a portion of the memory cell array 11 of the first embodiment is shown. Figure 3 The cross-section along the xz plane is shown. Figure 4 The cross-section along the yz plane is shown.
[0048] like Figure 3 and Figure 4 As shown, a plurality of conductors 21 are disposed above a semiconductor substrate (not shown). The conductors 21 extend along the y-axis and are arranged along the x-axis. Each conductor 21 functions as a word line WL.
[0049] Each conductor 21 is connected on its upper surface to the lower surface of each of the plurality of memory cells MCBs. The memory cells MCBs are, for example, circular in the xy-plane. The memory cells MCBs are arranged along the y-axis on each conductor 21, forming a matrix along the xy-plane. Each memory cell MCB includes a structure that functions as a switching element SEB and a structure that functions as a magnetoresistive element MTJB. The structures that function as switching elements SEB and MTJB, respectively, each include one or more layers, as described later.
[0050] Above the memory cell MCB, a plurality of conductors 22 are disposed. The conductors 22 extend along the x-axis and are arranged along the y-axis. Each conductor 22 is in contact with the upper surface of the plurality of memory cells MCB arranged along the x-axis on its lower surface. Each conductor 22 functions as a bit line BL.
[0051] Each conductor 22 is connected to the lower surface of each of the plurality of memory cell MCAs on its upper surface. The memory cell MCAs are, for example, circular in the xy-plane. The memory cell MCAs are arranged along the x-axis on each conductor 22, forming a matrix along the xy-plane. Each memory cell MCA includes a structure that functions as a switching element SEA and a structure that functions as a magnetoresistive effect element MTJA. The structures that function as switching elements SEA and as magnetoresistive effect elements MTJA each contain one or more layers, as described later.
[0052] On the upper surface of each of the multiple memory cells MCA arranged along the y-axis, another conductor 21 is provided.
[0053] 1.1.4. Construction of Storage Units
[0054] Figure 5 A cross-section showing an example of the construction of the storage cell in the first embodiment. Figure 5 The diagram shows the structure from the layer where conductor 22 is located to the layer where conductor 21 is located one position above it along the z-axis. That is, Figure 5 The storage cell MC shown is equivalent to storage cell MCA. Storage cell MCB also has the same structure as storage cell MCA. (Regarding references...) Figure 5 The materials of several of the constituent elements described below are described later.
[0055] like Figure 5 As shown, an interlayer insulator 23 is disposed above a semiconductor substrate (not shown). At least a portion of the upper surface of the interlayer insulator 23 is bent inward. The interlayer insulator 23 may also be composed of multiple layers.
[0056] A conductor 22 is disposed within the interlayer insulator 23. The two upper corners of the conductor 22 are bent inward. The conductor 22 may also be composed of multiple sublayers.
[0057] The memory cell MC is located on the upper surface of each conductor 22. Each memory cell MC includes a lower electrode 24, a variable resistive material 25, an intermediate electrode 26, a magnetoresistive element MTJ, and a hard mask 35. The memory cell MC may also include another layer. Each memory cell MC may, for example, have a frustum-shaped cone. When the memory cell MC has a frustum-shaped cone, the memory cell MC is in relation to... Figure 5 The structures in the different cross-sections shown are similar to those in the cross-sections. Figure 5 The construction shown is the same as that described below.
[0058] Each lower electrode 24 is an electrode formed of a conductor. The lower electrode 24 is located on the upper surface of a conductor 22. The lower electrode 24 may also be composed of multiple sublayers.
[0059] Each variable resistor material 25 is a material with a dynamically variable resistance. The variable resistor material 25 is located on the upper surface of a lower electrode 24. The variable resistor material 25 functions as a switching element SE. For example, the variable resistor material 25 is a two-terminal switching element, where the first terminal of the two terminals is one of the upper and lower surfaces of the variable resistor material 25, and the second terminal of the two terminals is the other of the upper and lower surfaces of the variable resistor material 25. When the voltage applied between the two terminals is below a threshold value, the switching element is in a "high resistance" state, for example, a non-conductive state. When the voltage applied between the two terminals is above the threshold value, the switching element is in a "low resistance" state, for example, a conductive state.
[0060] The variable resistance material 25 is substantially formed of a material exhibiting such properties. In this specification and claims, although the word "substantially" and phrases containing it are originally intended to refer to a complete state that does not contain anything "substantially" present, states that are not such a complete state are permitted due to unavoidable reasons, and "substantially" is used for this purpose. For example, the description "substantially formed" or "substantially constituted" means that a constituent element "substantially formed" or "substantially constituted" by a certain material, due to unavoidable reasons, although it is desired that it be formed solely by that material, may contain impurities that were not originally intended to be present. Examples of unintentional impurities include elements diffused from other constituent elements and impurities contained in the environment used during the manufacture of the magnetic storage device 1.
[0061] As a material capable of functioning as a two-terminal switching element as described above, the variable resistor material 25 is known to contain an insulator containing dopants introduced by ion implantation. The insulator is, for example, an oxide, containing SiO2 or a material substantially formed of SiO2. The dopants include arsenic (As) and germanium (Ge). The variable resistor material 25 is substantially formed of a non-nitride material and does not contain nitrogen. In this specification and claims, the statement that a material "does not contain nitrogen" means that the material substantially does not contain nitrides or nitrogen. Materials that (substantially) do not contain nitrogen are sometimes referred to hereinafter as non-nitrogen materials. That is, the variable resistor material 25 is substantially formed of a non-nitrogen material.
[0062] Each intermediate electrode 26 is an electrode formed of a conductor. The intermediate electrode 26 is located on the upper surface of a variable resistive material 25. The intermediate electrode 26 may also be composed of multiple sublayers.
[0063] A magnetoresistive element MTJ is located on the upper surface of each intermediate electrode 26. The magnetoresistive element MTJ includes a ferromagnetic layer 31, an insulating layer 32, and a ferromagnetic layer 33.
[0064] The ferromagnetic layer 31 is a layer of ferromagnetic material. The ferromagnetic layer 31 has an easy magnetization axis along the interface penetrating the ferromagnetic layer 31, the insulating layer 32, and the ferromagnetic layer 33. For example, it has an easy magnetization axis at an angle of 45° or more and 90° or less relative to the interface, or it has an easy magnetization axis perpendicular to the interface. The orientation of the magnetization of the ferromagnetic layer 31 means that it will not change due to reading and writing data in the magnetic storage device 1. The ferromagnetic layer 31 functions as a so-called reference layer.
[0065] The ferromagnetic layer 31 is substantially formed of a non-nitrogen material, comprising one or more of iron (Fe), cobalt (Co), and nickel (Ni). The ferromagnetic layer 31 may also contain boron (B). More specifically, the ferromagnetic layer 31 may contain cobalt-iron-boron (CoFeB) or iron boride (FeB).
[0066] The ferromagnetic layer 31 can also be composed of multiple sublayers. In this case, the sublayers are all substantially formed of non-nitrogen materials.
[0067] Insulating layer 32 is an insulating layer. Insulating layer 32 is substantially formed of a non-nitrogen material, such as containing magnesium oxide (MgO), or substantially formed of MgO. Insulating layer 32 functions as a so-called tunnel barrier.
[0068] The ferromagnetic layer 33 is a layer of ferromagnetic material. The ferromagnetic layer 33 is substantially formed of a non-nitrogen material, such as containing cobalt iron boron or iron boride, or substantially formed of cobalt iron boron or iron boride. The ferromagnetic layer 33 has an easy magnetization axis along the interface penetrating the ferromagnetic layer 31, the insulating layer 32, and the ferromagnetic layer 33, for example, having an easy magnetization axis at an angle of 45° or more and 90° or less relative to the interface, or having an easy magnetization axis orthogonal to the interface. The orientation of the magnetization of the ferromagnetic layer 33 can be changed due to data writing, and the ferromagnetic layer 33 functions as a so-called storage layer.
[0069] The ferromagnetic layer 33 can also be composed of multiple sublayers. In this case, the sublayers are all substantially formed of non-nitrogen materials.
[0070] If the magnetization orientation of ferromagnetic layer 33 is parallel to the magnetization orientation of ferromagnetic layer 31, then the magnetoresistive element MTJ has a low resistance. If the magnetization orientation of ferromagnetic layer 33 is antiparallel to the magnetization orientation of ferromagnetic layer 31, then the magnetoresistive element MTJ has a higher resistance than when the magnetization orientations of ferromagnetic layers 31 and 33 are parallel.
[0071] When a write current of a certain magnitude flows from ferromagnetic layer 33 toward ferromagnetic layer 31, the magnetization orientation of ferromagnetic layer 33 becomes parallel to the magnetization orientation of ferromagnetic layer 31. On the other hand, when a write current of other magnitude flows from ferromagnetic layer 31 toward ferromagnetic layer 33, the magnetization orientation of ferromagnetic layer 33 becomes antiparallel to the magnetization orientation of ferromagnetic layer 31.
[0072] Each hard mask 35 is a conductor. The hard mask 35 is located on the upper surface of a magnetoresistive element MTJ. The hard mask 35 can also be composed of multiple sublayers.
[0073] The sidewall insulator 41 at least covers the sides of each stack composed of ferromagnetic layer 31, insulating layer 32, and ferromagnetic layer 33. The sidewall insulator 41 may also cover the sides of each stack composed of lower electrode 24, variable resistor material 25, intermediate electrode 26, ferromagnetic layer 31, insulating layer 32, ferromagnetic layer 33, and hard mask 35. Figure 5 The following description is based on this example. The sidewall insulator 41 further covers the two curved corners on the upper side of each conductor 22. The sidewall insulator 41 also covers the portion of the upper surface of the interlayer insulator 23 between the layers consisting of the lower electrode 24, the variable resistive material 25, the intermediate electrode 26, the ferromagnetic layer 31, the insulating layer 32, the ferromagnetic layer 33, and the hard mask 35.
[0074] An interlayer insulator 42 is provided on the surface of the sidewall insulator 41, above the portion between the layers consisting of the lower electrode 24, the variable resistive material 25, the intermediate electrode 26, the ferromagnetic layer 31, the insulating layer 32, the ferromagnetic layer 33, and the hard mask 35. That is, the interlayer insulator 42 fills the area between the structure consisting of the layered structure including the lower electrode 24, the variable resistive material 25, the intermediate electrode 26, the ferromagnetic layer 31, the insulating layer 32, the ferromagnetic layer 33, and the hard mask 35, and the sidewall insulator 41 on its sidewalls. The interlayer insulator 42 comprises silicon nitride (SiN), or is substantially formed of silicon nitride.
[0075] A conductor 21 is disposed on the upper surface of the hard mask 35, the sidewall insulator 41, and the interlayer insulator 42. The conductor 21 may contain, for example, titanium nitride (TiN), or be substantially formed of titanium nitride.
[0076] 1.1.5. Materials Constituting Elements
[0077] For reference Figure 5 The materials of the constituent elements other than those described in the material description are described. Such constituent elements are conductor 22, interlayer insulator 23, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41.
[0078] For reference Figure 5 As explained, both the variable resistor material 25 and the magnetoresistive element MTJ are essentially formed from non-nitrogen materials.
[0079] The remaining conductor 22, interlayer insulator 23, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41, as described below, contain at least no nitrides and no nitrogen; that is, they are substantially formed of non-nitrogen materials. By selecting such materials, all the constituent elements surrounding the magnetoresistive element MTJ are substantially formed of non-nitrogen materials. More specifically, the materials of conductor 22, interlayer insulator 23, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41 are as follows.
[0080] The sidewall insulator 41 is substantially formed of a non-magnetic and stable (difficult to undergo chemical reactions) oxide. Specifically, the stable oxide has a standard electrode potential of -1.5 or less. More specifically, the sidewall insulator 41 is substantially formed of an oxide of one or more of a first element, or an oxide of a substance (compound or alloy) containing two or more of the first element. The first element includes, for example, beryllium (Be), magnesium (Mg), aluminum (Al), silicon (Si), calcium (Ca), scandium (Sc), vanadium (V), zinc (Zn), gallium (Ga), germanium (Ge), strontium (Sr), yttrium (Y), zirconium (Zr), barium (Ba), hafnium (Hf), lanthanum (La), cesium (Cs), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).
[0081] The conductor 22, lower electrode 24, intermediate electrode 26, and hard mask 35 are substantially formed of a non-magnetic conductor with a high melting point. Specifically, the conductor 22, lower electrode 24, intermediate electrode 26, and hard mask 35 are substantially formed of a material with a melting point of 1800 degrees Celsius or higher. More specifically, the conductor 22, lower electrode 24, intermediate electrode 26, and hard mask 35 are substantially formed of one or more of a second element. The second element is hafnium (Hf), tantalum (Ta), tungsten (W), zirconium (Zr), niobium (Nb), molybdenum (Mo), titanium (Ti), vanadium (V), chromium (Cr), silicon (Si), boron (B), and carbon (C).
[0082] Interlayer insulator 23 is essentially formed of silicon oxide.
[0083] Conductor 21 may also be formed substantially from one or more of the second element.
[0084] In cases where the conductor 22, the lower electrode 24, the intermediate electrode 26, and the hard mask 35 are composed of multiple sublayers, the sublayers are all substantially formed of non-nitrogen materials.
[0085] 1.3. Manufacturing Method
[0086] Figure 6 This shows a state between manufacturing processes of a portion of the magnetic storage device of the first embodiment.
[0087] like Figure 6 As shown, the conductor 22a, interlayer insulator 23a, lower electrode 24a, variable resistor material 25a, intermediate electrode 26a, ferromagnetic layer 31a, insulating layer 32a, ferromagnetic layer 33a, and hard mask 35a are formed. The conductor 22a, interlayer insulator 23a, lower electrode 24a, variable resistor material 25a, intermediate electrode 26a, ferromagnetic layer 31a, insulating layer 32a, ferromagnetic layer 33a, and hard mask 35a are formed into the elements of conductor 22, interlayer insulator 23, lower electrode 24, variable resistor material 25, intermediate electrode 26, ferromagnetic layer 31, insulating layer 32, ferromagnetic layer 33, and hard mask 35 respectively through subsequent processes.
[0088] Specifically, a conductor 22a is formed within the interlayer insulator 23a. Next, a lower electrode 24a, a variable resistance material 25a, an intermediate electrode 26a, a ferromagnetic layer 31a, an insulating layer 32a, a ferromagnetic layer 33a, and a hard mask 35a are sequentially deposited on the upper surfaces of the interlayer insulator 23a and the conductor 22a. Examples of deposition methods include chemical vapor deposition (CVD) and sputtering. The hard mask 35a remains directly above the predetermined region where the magnetoresistive element MTJ is formed, and has openings 35a1 in other regions.
[0089] like Figure 7 As shown, the structure obtained through the processes up to this point is partially removed using ion beam etching (IBE). IBE is performed using a hard mask 35a as the mask. Using IBE, the ferromagnetic layer 31a, insulating layer 32a, and ferromagnetic layer 33a are shaped into multiple independent portions with spaces 45 therebetween. Material removed from the constituent elements by the ion beam impact through IBE deposits on the surrounding constituent elements, potentially forming a re-deposited layer. Such material includes material removed from the hard mask 35a. In the example where the sidewall insulator 41 only covers the sides of the ferromagnetic layer 31, insulating layer 32, and ferromagnetic layer 33, Figure 7 After the process, sidewall insulators 41 can be formed on the sides of the ferromagnetic layer 31a, the insulating layer 32a and the ferromagnetic layer 33a.
[0090] like Figure 8 As shown, an interlayer insulator 23, a conductor 22, a lower electrode 24, a variable resistive material 25, an intermediate electrode 26, a ferromagnetic layer 31, an insulating layer 32, and a ferromagnetic layer 33 are formed. Specifically, the structure obtained through the processes up to this point is partially removed by IBE. IBE is performed using a laminate composed of a hard mask 35a, a ferromagnetic layer 33a, an insulating layer 32a, and a ferromagnetic layer 31a as a mask. Through IBE, the lower electrode 24a, the variable resistive material 25a, and the intermediate electrode 26a are formed into multiple groups of lower electrode 24, variable resistive material 25, and intermediate electrode 26. Furthermore, through IBE, the ferromagnetic layer 33a, the insulating layer 32a, and the ferromagnetic layer 31a are further partially removed, forming ferromagnetic layer 33, insulating layer 32, and ferromagnetic layer 31, respectively. That is, a memory cell MC is formed.
[0091] IBE is performed under over-etching conditions to ensure that the lower electrodes 24a are reliably separated into individual lower electrodes 24 contained in each memory cell MC. Therefore, through IBE, the two upper corners of each conductor 22a and the portion between adjacent memory cells MC on the upper surface of the interlayer insulator 23a are partially removed. As a result, the conductor 22a and the interlayer insulator 23a are shaped into conductor 22 and interlayer insulator 23.
[0092] Material removed from the constituent elements by IBE (Ion Beam Embedding) may deposit on the surrounding constituent elements to form a re-deposited layer. Such material includes material removed from the intermediate electrode 26a, the lower electrode 24a, and the interlayer insulator 23a.
[0093] like Figure 5 As shown, a sidewall insulator 41, an interlayer insulator 42, and a conductor 21 are formed. The interlayer insulator 42 is formed, for example, by CVD under a plasma atmosphere.
[0094] 1.4. Advantages (Effects)
[0095] According to the first embodiment, as described below, a magnetic storage device 1 comprising a storage cell MC having high electrical characteristics can be provided.
[0096] Figure 9 A cross-section showing the structure of the memory cell MCR of the reference magnetic storage device 100 is shown. The memory cell MCR does not include the sidewall insulator 41 in the magnetic storage device 1 of the first embodiment, and the area between the memory cells MCR is filled by the interlayer insulator 42 without passing through the sidewall insulator 41.
[0097] Furthermore, several components of the magnetic storage device 100 are formed of silicon nitride or titanium nitride. Specifically, the magnetic storage device 100 includes an interlayer insulator 123, a conductor 122, a lower electrode 124, an intermediate electrode 126, a hard mask 135, and a sidewall insulator 141, replacing the interlayer insulator 23, conductor 22, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41 in the magnetic storage device 1. The interlayer insulator 123 and sidewall insulator 141 are substantially formed of silicon nitride (SiN), while the conductor 122, lower electrode 124, intermediate electrode 126, and hard mask 135 are substantially formed of titanium nitride (TiN). Silicon nitride is widely used in semiconductor devices and magnetic storage devices, for example, to meet various characteristics required in semiconductor devices and magnetic storage devices. Such characteristics include conductivity, stability, ease of formation, and price. Furthermore, silicon nitride is chemically stable at least partially due to nitriding, making it difficult for it to react chemically with substances that come into contact with it. Additionally, silicon nitride is relatively easy to form in insulators that can be used in semiconductor devices and magnetic storage devices.
[0098] Titanium nitride is also chemically stable, at least partially due to nitriding, making it difficult to react chemically with substances that come into contact with it. Furthermore, titanium nitride is relatively easy to form in conductors suitable for use in semiconductor devices and magnetic storage devices. Moreover, titanium nitride exhibits relatively high conductivity in conductors suitable for use in semiconductor devices and magnetic storage devices.
[0099] On the other hand, it is known that the MR ratio of the two ferromagnetic materials and the insulator constituting the magnetoresistive element immediately after formation decreases after several post-formation processes. The MR ratio is the ratio of the resistance of the magnetoresistive element in its low-resistance state to its resistance in its high-resistance state. The decrease in the MR ratio is believed to have various causes, and despite countermeasures, the decrease has not been suppressed to the desired extent.
[0100] Under these circumstances, the inventors discovered that nitrogen attached to the magnetoresistive element reduces the MR ratio. That is, as explained below, it was discovered that nitrogen or a nitrogen-containing material (hereinafter, sometimes simply referred to as nitrogen material) attached to the magnetoresistive element MTJ during the formation of the magnetic storage device 100 reduces the MR ratio of the magnetoresistive element MTJ.
[0101] The magnetic storage device 100 is manufactured through the same processes as the magnetic storage device 1 of the first embodiment, and undergoes the same manufacturing process as the first embodiment. Figure 7 , Figure 8 as well as Figure 5 The same process as the previous process. To manufacture the magnetic storage device 100, instead of the interlayer insulator 23a, conductor 122a, lower electrode 124a, intermediate electrode 126a, and hard mask 135a, interlayer insulator 123a, conductor 122a, lower electrode 124a, intermediate electrode 126a, and hard mask 135a are used. The interlayer insulator 123a, conductor 122a, lower electrode 124a, intermediate electrode 126a, and hard mask 135a are materials formed into the interlayer insulator 123, conductor 122, lower electrode 124, intermediate electrode 126, and hard mask 135.
[0102] For reference Figure 7 and Figure 8 As explained, in Figure 7 and Figure 8 In the IBE, re-stacking may occur. In the equivalent of the magnetic storage device 100 used for manufacturing... Figure 7 and Figure 8 The material that may be re-deposited during the process may include an interlayer insulator 123a, a conductor 122a, a lower electrode 124a, an intermediate electrode 126a, and a hard mask 135a. The interlayer insulator 123a is substantially formed of silicon nitride, and the conductor 122a, lower electrode 124a, intermediate electrode 126a, and hard mask 135a are substantially formed of titanium nitride. Therefore, a re-deposited layer of nitrogen material may be formed on the sidewalls of the magnetoresistive element MTJ. The inventors believe that such a re-deposited layer will reduce the MR ratio of the magnetoresistive element MTJ.
[0103] Based on this, the inventors obtained the experimental data shown below. Figures 10-12 The results of the experiment show that the decrease in MR ratio was suppressed are shown. Figure 10 and Figure 11 Each shows the MR ratio when different materials are applied to a certain component of the magnetic storage device. Figure 10 and Figure 11 To illustrate the difference in MR ratio caused by the different materials, the MR ratio for the reference magnetic storage device 100 and the MR ratio for a certain component of the reference magnetic storage device 100 using a material different from the material in the magnetic storage device 100 are shown respectively. Figure 12 The MR ratio is shown when the sidewall insulator 41 is present and when it is absent. That is, Figures 10 to 12 Each figure shows two scenarios of the MR ratio object, which have the same structure and composition except for the different constituent elements of the different objects shown in each figure. Figures 10-12 The horizontal axis represents the "size of the MTJ", such as the width of the MTJ element (the distance between the ends passing through the center in the xy plane), such as the width of the lower end of the MTJ element.
[0104] Figure 10 The conductor 122 and lower electrode 124, and the conductor 22 and lower electrode 24 are shown. That is, the case where the magnetic storage device includes the conductor 122 and lower electrode 124, and the case where the magnetic storage device includes the conductor 22 and lower electrode 24 are shown. The case where the magnetic storage device includes the conductor 22 and lower electrode 24 is equivalent to the case where the magnetic storage device 100 includes the conductor 22 and lower electrode 24 instead of the conductor 122 and lower electrode 124, respectively. The conductor 122 and lower electrode 124 are as described with reference to... Figure 9 As explained, it is essentially formed of titanium nitride. As an example of the case of conductor 22 and lower electrode 24, conductor 22 and lower electrode 24 are essentially formed of tantalum. Figure 10 As shown, the MR ratio is higher across the entire range of dimensions illustrated, in the case of conductor 22 and lower electrode 24 which are substantially formed of tantalum, than in the case of conductor 122 and lower electrode 124 which are substantially formed of titanium nitride.
[0105] Figure 11 Interlayer insulator 123 and interlayer insulator 23 are shown. Specifically, the cases where the magnetic storage device includes interlayer insulator 123 and the cases where the magnetic storage device includes interlayer insulator 23 are shown. The case where the magnetic storage device includes interlayer insulator 23 is equivalent to the case where the magnetic storage device 100 replaces interlayer insulator 123 and includes interlayer insulator 23. Interlayer insulator 123 is as described above. Figure 9 As explained, it is essentially formed of silicon nitride. Interlayer insulator 23 is as shown in the reference. Figure 5 As explained, it is essentially formed from silicon dioxide. (For example...) Figure 11 As shown, across the entire range of dimensions illustrated, the MR ratio is higher in the case of interlayer insulator 23, which is substantially formed of silicon oxide, than in the case of interlayer insulator 123, which is substantially formed of silicon nitride.
[0106] Figure 12 The presence or absence of the sidewall insulator 41 is shown. That is, the cases where the magnetic storage device does not include the sidewall insulator 41 of the first embodiment and the cases where the magnetic storage device includes the sidewall insulator 41 are shown. The case where the magnetic storage device includes the sidewall insulator 41 is equivalent to the case where the sidewall insulator 41 is provided in the magnetic storage device 100. For example... Figure 12 As shown, across the entire range of dimensions illustrated, the MR ratio is higher in the case of including the sidewall insulator 41, which is substantially made of non-nitrogen material, than in the case of not including the sidewall insulator 41.
[0107] Based on the above experimental data, the inventors discovered that the nitrogen material attached to the magnetoresistive element during the formation of the magnetic storage device 100 reduces the MR ratio of the magnetoresistive element MTJ.
[0108] Furthermore, the magnetic storage device 100 does not include the sidewall insulator 41 found in the magnetic storage device 1 of the first embodiment. Therefore, the interlayer insulator 42, which is essentially formed of silicon nitride, is in contact with the sidewall of the magnetoresistive element MTJ. The nitrogen material of the interlayer insulator 42 may also reduce the MR ratio of the magnetoresistive element MTJ. Moreover, the silicon nitride interlayer insulator 42 is formed using CVD under a plasma atmosphere. When the interlayer insulator 42 in the magnetic storage device 100 begins to form, at least partially, the sidewall of the magnetoresistive element MTJ is exposed. Therefore, due to the plasma, the sidewall of the magnetoresistive element MTJ is damaged, and from this point of view, the MR ratio of the magnetoresistive element MTJ may also deteriorate.
[0109] Based on the above facts and insights, the first implementation method is constituted.
[0110] According to the first embodiment, the constituent elements in contact with the magnetoresistive element MTJ and the constituent elements surrounding the magnetoresistive element MTJ do not contain nitrides and are formed of a non-nitrogen material that is substantially free of nitrogen. The constituent elements in contact with the magnetoresistive element MTJ include an intermediate electrode 26 and a sidewall insulator 41. The constituent elements surrounding the magnetoresistive element MTJ are at least those that can supply material that may be re-deposited on the surface of the magnetoresistive element MTJ during the process of forming the stacked material into a plurality of independent memory cells MC by IBE. Specifically, such constituent elements are the interlayer insulator 23, the conductor 22, the lower electrode 24, the intermediate electrode 26, and the hard mask 35. By selecting such materials, the re-deposition of nitrogen material on the surface of the magnetoresistive element MTJ is suppressed or prevented during the process of forming the stacked material into a plurality of independent memory cells MC by IBE. Therefore, since the constituent elements in contact with the magnetoresistive element (MTJ) and the constituent elements surrounding the MTJ are essentially formed of non-nitrogen materials, nitrogen material is almost or completely absent from the surface of the MTJ after its formation. Thus, the decrease in the MR ratio of the MTJ due to nitrogen material adhesion is suppressed.
[0111] Furthermore, the magnetoresistive element MTJ is covered by the sidewall insulator 41. Therefore, the magnetoresistive element MTJ is not exposed when the interlayer insulator 42 is formed in a plasma atmosphere. This suppresses or prevents damage to the magnetoresistive element MTJ caused by plasma. It also suppresses the decrease in the MR ratio of the magnetoresistive element MTJ.
[0112] 1.5. Variations
[0113] An example has been described in which the interlayer insulator 23, conductor 22, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41 are all substantially formed of non-nitrogen materials. The first embodiment is not limited to this example. It is also possible that one or more of the interlayer insulator 23, conductor 22, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41 are substantially formed of nitrogen materials. However, in this case, the degree of suppression of the MR ratio of the magnetoresistive element MTJ is lower than the degree of suppression of the MR ratio in the example where the interlayer insulator 23, conductor 22, lower electrode 24, intermediate electrode 26, hard mask 35, and sidewall insulator 41 are all substantially formed of non-nitrogen materials.
[0114] 2. Second Implementation Method
[0115] The second embodiment differs from the first embodiment in that it comprises the elements of a single memory cell. Hereinafter, the features that differ from the first embodiment will be primarily described. Elements in the second embodiment that differ from those in the first embodiment are distinguished by further appending characters or numbers to the end of the reference numerals of the elements in the first embodiment. For example, the memory cell MC in the second embodiment may be referred to as memory cell MCb. Points other than those described in the second embodiment apply to those described in the first embodiment.
[0116] 2.1. Structure (Composition)
[0117] Figure 13 A functional block diagram of the magnetic storage device according to the second embodiment is shown. For example... Figure 13 As shown, the magnetic storage device 1b of the second embodiment includes a storage cell array 11b. Within the storage cell array 11b, there are also multiple bit lines BL. One bit line BL and one bit line BL constitute a bit line pair. Each storage cell MCb is connected between one bit line pair and connected to one word line WL.
[0118] Figure 14 The circuit configuration of the memory cell in the second embodiment is shown. For example... Figure 14 As shown, each memory cell MCb contains a magnetoresistive element MTJ and a transistor TR. The transistor TR is, for example, an n-type MOSFET (Metal Oxide Semiconductor Field Effect Transistor). Figure 14 The following explanation is based on this example. The magnetoresistive element MTJ includes a first terminal and a second terminal. At the first terminal of the magnetoresistive element MTJ, it is connected to the first terminal of the transistor TR. The first terminal of the transistor TR is either the source or the drain. The second terminal of the magnetoresistive element MTJ is connected to a bit line BL.
[0119] The second terminal of transistor TR is the other of the source and drain terminals, and is connected to the bit line BL. The control terminal (gate electrode) of transistor TR is connected to a word line WL.
[0120] Figure 15 A cross-section showing an example of the construction of the storage cell in the second embodiment. For example... Figure 15 As shown, an interlayer insulator 23 is disposed above a semiconductor substrate (not shown). A conductor 22 is disposed within the interlayer insulator 23. At its lower end, the conductor 22 is connected to one of a pair of source / drain regions of a transistor TR (not shown) formed on the surface of the substrate. The other of the pair of source / drain regions of each transistor TR is connected to a conductor that functions as a bit line BL.
[0121] Instead of being located on the switching element SE in the first embodiment, the magnetoresistive element MTJ is located on the conductor 22. Based on this, the sidewall insulator 41b covers the sides of each stack formed by the ferromagnetic layer 31, insulating layer 32, ferromagnetic layer 33, and hard mask 35, the two curved corners on the upper side of each conductor 22, and the portion of the upper surface of the interlayer insulator 23 between the stacks formed by the ferromagnetic layer 31, insulating layer 32, ferromagnetic layer 33, and hard mask 35. The sidewall insulator 41b is substantially formed of the same material as the sidewall insulator 41.
[0122] Interlayer insulator 42 is located on the surface of the sidewall insulator 41, in the portion between the layers formed by the ferromagnetic layer 31, insulating layer 32, ferromagnetic layer 33, and hard mask 35, filling the area between the structure formed by the layered structure including the ferromagnetic layer 31, insulating layer 32, ferromagnetic layer 33, and hard mask 35 and the sidewall insulator 41b on its sidewalls. Interlayer insulator 42 is also located in a region above the upper surface of hard mask 35. A conductor 51 is provided on the upper surface of each hard mask 35 within interlayer insulator 42. Each conductor 51 is connected to a conductor that functions as a bit line BL.
[0123] 2.2. Manufacturing Method
[0124] Figure 16 This shows a state between manufacturing processes of a portion of the magnetic storage device of the second embodiment.
[0125] exist Figure 16 Prior to the process described above, a transistor TR is formed on the surface of a semiconductor substrate. An interlayer insulator 23a, in which a conductor 22a is formed internally, is formed on the surface of the semiconductor substrate. A ferromagnetic layer 31a, an insulating layer 32a, a ferromagnetic layer 33a, and a hard mask 35a are sequentially deposited on the upper surface of the interlayer insulator 23a and the upper surface of the conductor 22a.
[0126] like Figure 16 As shown, utilizing the same method as in the first embodiment Figure 7 and Figure 8 The same IBE process is used, but the structure obtained through the processes up to this point is partially removed. IBE is performed using a hard mask 35a as a mask. Through IBE, the group of ferromagnetic layers 31a, insulating layers 32a, and ferromagnetic layers 33a is separated into multiple independent portions with spaces 52 therebetween. That is, a memory cell MCb is formed.
[0127] IBE is performed under over-etching conditions to ensure that the ferromagnetic layers 31a are reliably separated into individual ferromagnetic layers 31 contained in each memory cell MCb. Therefore, through IBE, the two upper corners of each conductor 22a and portions between adjacent memory cells MCb on the upper surface of the interlayer insulator 23a are partially removed. As a result, the conductor 22a and the interlayer insulator 23a are formed into conductor 22 and interlayer insulator 23.
[0128] Material removed from the constituent elements by IBE (Ion Beam Embedding) may deposit on the surrounding constituent elements to form a re-deposited layer. Such material includes material removed from the interlayer insulator 23a, conductor 22a, and hard mask 35a.
[0129] Next, as Figure 15 As shown, a sidewall insulator 41, an interlayer insulator 42, and a conductor 51 are formed.
[0130] 2.3. Advantages (Effects)
[0131] According to the second embodiment, similar to the first embodiment, the constituent elements in contact with the magnetoresistive element MTJ and the constituent elements surrounding the magnetoresistive element MTJ do not contain nitrides and are substantially formed of non-nitrogen materials. The constituent elements in contact with the magnetoresistive element MTJ include a conductor 22 and a sidewall insulator 41b. The constituent elements surrounding the magnetoresistive element MTJ are the conductor 22 and the hard mask 35. By making the constituent elements in contact with the magnetoresistive element MTJ and the constituent elements surrounding the magnetoresistive element MTJ substantially non-nitrogen materials, the same advantages as in the first embodiment can be obtained.
[0132] Furthermore, similar to the first embodiment, the magnetoresistive element MTJ is covered by the sidewall insulator 41b. This provides the same advantages as the first embodiment.
[0133] 2.4. Variations
[0134] An example has been described in which the interlayer insulator 23, conductor 22, hard mask 35, and sidewall insulator 41b are all substantially formed of non-nitrogen materials. The second embodiment is not limited to this example. It is also possible that one or more of the interlayer insulator 23, conductor 22, hard mask 35, and sidewall insulator 41b are substantially formed of nitrogen materials. However, in this case, the degree of suppression of the MR ratio of the magnetoresistive element MTJ is less than the degree of suppression of the MR ratio in the example where the interlayer insulator 23, conductor 22, hard mask 35, and sidewall insulator 41b are all substantially formed of non-nitrogen materials.
[0135] 3. Variations
[0136] For reference Figure 5 As explained, the memory cell MC can, in addition to reference... Figure 5 The storage cell MCb may contain additional components beyond those described. In this case, the additional components include those in contact with the magnetoresistive element and... Figure 7 and Figure 8 The components of the material that could be deposited on the surface of the magnetoresistive element MTJ during the IBE period are essentially composed of non-nitrogen materials.
[0137] Several embodiments of the present invention have been described, but these embodiments are provided by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and / or variations thereof are included in the scope and spirit of the invention, and likewise included in the scope of the invention as set forth in the claims and its equivalents.< / n> < / m> < / m>
Claims
1. A magnetic storage device comprising: Essentially, it is the first conductor formed from non-magnetic, non-nitrogen-based materials; A first insulator covering the sides of the first conductor and substantially formed of a non-nitrogen material; A second conductor formed of a non-magnetic, non-nitrogen material on top of the first conductor; The variable resistance material on the second conductor; A third conductor formed of a non-magnetic, non-nitrogen material on the variable resistance material; The first ferromagnetic layer on the third conductor; The insulating layer on the first ferromagnetic layer; The second ferromagnetic layer on the insulating layer; The fourth conductor, formed of a non-magnetic, non-nitrogen material on the second ferromagnetic layer; A second insulator, substantially formed of a non-nitrogen material, covering the sides of the first ferromagnetic layer, the sides of the insulating layer, and the sides of the second ferromagnetic layer; and The third insulator on the surface of the second insulator.
2. The magnetic storage device according to claim 1, The first conductor, the second conductor, the third conductor, and the fourth conductor are substantially formed of materials having a melting point of 1800 degrees or higher.
3. The magnetic storage device according to claim 1, The first conductor, the second conductor, the third conductor, and the fourth conductor are substantially formed of one or more of hafnium, tantalum, tungsten, zirconium, niobium, molybdenum, titanium, vanadium, chromium, silicon, boron, and carbon.
4. The magnetic storage device according to claim 1, The second insulator is essentially formed of an oxide having a standard electrode potential below -1.
5.
5. The magnetic storage device according to claim 1, The second insulator is substantially formed of one or more oxides of the first element or oxides of two or more substances containing the first element. The first element is beryllium, magnesium, aluminum, silicon, calcium, scandium, vanadium, zinc, gallium, germanium, strontium, yttrium, zirconium, barium, hafnium, lanthanum, cesium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
6. The magnetic storage device according to claim 1, The first insulator is essentially formed of silicon oxide.
7. The magnetic storage device according to claim 1, The first insulator bends on its first surface on the first side where the second conductor is located, toward a second side opposite to the first side. The first conductor bends at the angle of the third side where the second conductor is located toward the fourth side, which is opposite to the third side.
8. The magnetic storage device according to claim 7, The second insulator covers the side surface of the third conductor, the side surface of the variable resistance material, the side surface of the second conductor, the corner of the first conductor, and the first surface of the first insulator.
9. The magnetic storage device according to any one of claims 1 to 8, The third insulator comprises silicon nitride.
10. A magnetic storage device comprising: The first conductor is essentially formed from non-nitrogen materials; A first insulator covering the sides of the first conductor and substantially formed of a non-nitrogen material; The first ferromagnetic layer on the first conductor; The insulating layer on the first ferromagnetic layer; The second ferromagnetic layer on the insulating layer; The second conductor on the second ferromagnetic layer is formed of a non-magnetic, non-nitrogen material; A second insulator, substantially made of a nonmagnetic, non-nitrogen material, covering the sides of the first ferromagnetic layer, the sides of the insulating layer, and the sides of the second ferromagnetic layer; and The third insulator on the surface of the second insulator.
11. The magnetic storage device according to claim 10, The first conductor and the second conductor are substantially formed of materials having a melting point of 1800 degrees or higher.
12. The magnetic storage device according to claim 10, The first conductor and the second conductor are substantially formed of one or more of hafnium, tantalum, tungsten, zirconium, niobium, molybdenum, titanium, vanadium, chromium, silicon, boron, and carbon.
13. The magnetic storage device according to claim 10, The second insulator is essentially formed of an oxide having a standard electrode potential below -1.
5.
14. The magnetic storage device according to claim 10, The second insulator is substantially formed of one or more oxides of the first element or oxides of two or more substances containing the first element. The first element is beryllium, magnesium, aluminum, silicon, calcium, scandium, vanadium, zinc, gallium, germanium, strontium, yttrium, zirconium, barium, hafnium, lanthanum, cesium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium.
15. The magnetic storage device according to claim 10, The first insulator is essentially formed of silicon oxide.
16. The magnetic storage device according to claim 10, The first insulator bends on its first surface on the first side where the first ferromagnetic layer is located, toward a second side opposite to the first side. The first conductor bends at the angle of the third side where the first ferromagnetic layer is located toward the fourth side, which is opposite to the third side.
17. The magnetic storage device according to claim 16, The second insulator covers the corner of the first conductor and the first surface of the first insulator.
18. The magnetic storage device according to claim 10, The third insulator comprises silicon nitride.
19. A method for manufacturing a magnetic storage device, comprising: A first laminate is formed on the upper surface of a first conductor made of a substantially nonmagnetic, non-nitrogen material and on the upper surface of a first insulator made of a substantially non-nitrogen material. The first laminate includes: a second conductor made of a substantially nonmagnetic, non-nitrogen material; a variable resistive material on the second conductor; a third conductor made of a substantially nonmagnetic, non-nitrogen material on the variable resistive material; a first ferromagnetic layer on the third conductor; an insulating layer on the first ferromagnetic layer; a second ferromagnetic layer on the insulating layer; and a fourth conductor made of a substantially nonmagnetic, non-nitrogen material on the second ferromagnetic layer. The second conductor, the variable resistance material, the third conductor, the first ferromagnetic layer, the insulating layer, the second ferromagnetic layer, and the fourth conductor are partially removed using an ion beam. The sides of the first ferromagnetic layer, the sides of the second ferromagnetic layer, and the sides of the fourth conductor remaining after the partial removal are covered by a second insulator formed substantially of non-nitrogen material; and A third insulator is formed on the surface of the second insulator.
20. The method for manufacturing a magnetic storage device according to claim 19, The removal using the ion beam includes the partial removal of the first conductor and the first insulator.