New system switch material, device and preparation and application thereof

Abstract

The invention relates to a novel system switch material, a device and preparation and application thereof. The chemical general formula of the OTS switch material is (Sb < x > S < 100-x >) < 100-y > M < y >, wherein M is one or more of As, Si, Te, C, W, N, P and ln; 10 < = x < = 50, and 0 < = y < = 90. According to the invention, high switching speed, large turn-on current, high switching ratio and lower leakage current are realized, and high-density mass information storage can be realized.

Description

Technical Field

[0001] This invention belongs to the field of micro-nano electronics technology, and specifically relates to a new system of switching materials, devices, their preparation and application. Background Technology

[0002] With the advent of the big data era dominated by technologies such as artificial intelligence, the Internet of Things, and big data, people have increasingly higher requirements for information storage and computing. Memory, as a semiconductor device, is the storage device in a computer system and has always occupied an important position in the international semiconductor market. Among the many new types of memory, phase-change memory (PCM) is considered a next-generation solution for non-volatile memory due to its high density, multi-value storage, fast operation speed, long lifespan, and low power consumption.

[0003] Threshold switch (OTS) materials, primarily composed of chalcogenides, are considered the most promising switching materials for integration with PCMs (Polymer Crystal Arrays). However, current common OTS switches typically use selenium-based compounds to achieve low leakage current in order to meet the requirements of 3D integration in memory arrays. Although selenium-based switching materials meet the performance requirements of switching materials in terms of switching speed, turn-on current, and on / off ratio, the inherent toxicity of these materials poses additional risks and pressures to production and the environment. Therefore, there is an urgent need to develop an environmentally friendly OTS switching material that combines high switching speed, large turn-on current, and high on / off ratio with low leakage current to solve the aforementioned technical problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a new system of switching materials, devices, and their preparation and application.

[0005] This invention provides an OTS switching material, comprising an Sb-S composition and a doping element (M), wherein the general chemical formula of the OTS switching material is (Sb... x S 100-x ) 100-y M y M is one or more of As, Si, Te, C, W, N, P, and ln; 10≤x≤50, 0≤y≤90.

[0006] Preferably, the 35 <x<45,20<y<50。

[0007] The OTS switch material can achieve an instantaneous transition from a high-resistance state to a low-resistance state under the action of an external electric field, and can achieve an instantaneous transition from a low-resistance state to a high-resistance state when the external electric field is removed.

[0008] The on / off current ratio of the OTS switch material is 2 or higher.

[0009] The present invention provides an OTS switch unit, the OTS switch unit comprising a lower electrode layer, an OTS switch material layer, and an upper electrode layer; wherein the OTS switch material layer is disposed between the upper electrode layer and the lower electrode layer; wherein the OTS switch material is any of the OTS switch materials described herein.

[0010] Preferably, the thickness of the OTS switch material layer is 5nm to 50nm.

[0011] Preferably, the thickness of the upper electrode layer is 5nm to 50nm.

[0012] Preferably, the thickness of the lower electrode layer is 5nm to 50nm.

[0013] The upper electrode layer material and the lower electrode layer material are both selected from one or more of C, single metal materials, nitrides of single metal materials, oxides of single metal materials, carbides of single metal materials, and alloy materials; wherein the single metal materials are all selected from one of W, Pt, Au, Ti, Al, Ag, Cu, Ni, Ta, and Co; and the alloy materials are two or more alloy materials selected from W, Pt, Au, Ti, Al, Ag, Cu, Ni, Ta, and Co.

[0014] Furthermore, the upper electrode layer material and the lower electrode layer material are both selected from one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0015] The lower electrode layer includes a first lower electrode layer and a second lower electrode layer, wherein an insulating layer is provided between the first lower electrode layer and the second lower electrode layer.

[0016] The OTS switch unit also includes lead-out electrodes, which are disposed on the upper electrode layer.

[0017] The material of the lead-out electrode is selected from one or more of C, single metal materials, nitrides of single metal materials, oxides of single metal materials, carbides of single metal materials, and alloy materials; wherein the single metal materials are all selected from one of W, Pt, Au, Ti, Al, Ag, Cu, Ni, Ta, and Co; and the alloy materials are two or more alloy materials selected from W, Pt, Au, Ti, Al, Ag, Cu, Ni, Ta, and Co.

[0018] The turn-on current of the OTS switching unit is greater than or equal to 10. -7 A, On / off ratio greater than or equal to 2, threshold voltage less than or equal to 10V, maximum cycle count greater than or equal to 10. 4 Second-rate.

[0019] This invention provides a method for fabricating any of the aforementioned OTS switching units, comprising:

[0020] S1: Form the lower electrode layer;

[0021] S2: An OTS switching material layer is formed on the lower electrode layer;

[0022] S3: An upper electrode layer is formed on the OTS switch material layer.

[0023] Lead-out electrodes are formed on the upper electrode layer.

[0024] In S2, an OTS switch material layer is formed by depositing an OTS switch material thin film on the surface of the lower electrode layer using one or more of the following methods: sputtering, chemical vapor deposition, atomic layer deposition, and electron beam evaporation.

[0025] Furthermore, the sputtering method includes single-target co-sputtering or alloy target sputtering.

[0026] This invention provides an application of any of the OTS switch materials or any of the OTS switch units in the field of micro-nano electronics.

[0027] The OTS material provided by this invention can achieve an instantaneous transition from a high-resistivity state to a low-resistivity state when the voltage reaches a threshold voltage under the action of an external electric field; and can immediately switch from a low-resistivity state to a high-resistivity state when the external electric field is removed. OTS switching units fabricated based on this OTS material have advantages such as high switching speed, large turn-on current, high on / off ratio, and low leakage current, and can be used in the manufacture of high-density and three-dimensional mass storage devices.

[0028] Beneficial effects

[0029] This invention provides a novel switching material, device, and fabrication method, which exhibits high switching speed, large turn-on current, and high on / off ratio while maintaining low leakage current, facilitating high-density, massive information storage. Furthermore, the fabrication method of the OTS switching unit is compatible with CMOS processes, allowing for precise control of the phase-change material composition. The reduction in material leakage current facilitates the advancement of phase-change memory fabrication processes with CMOS technology nodes from 40, 28, 20, 14, and 7 nanometers, improving device fabrication and enhancing the yield, performance consistency, and reliability of the memory array. Specifically, this is manifested in reducing ineffective heat dissipation and parasitic current during operation, directly addressing key bottlenecks in process miniaturization: firstly, it makes the high-temperature phase-change process easier to control within the process thermal budget, ensuring compatibility with advanced processes and fabrication feasibility; secondly, it fundamentally improves the electrical performance of the memory cells by suppressing inter-cell crosstalk, reducing reset current, and stabilizing the resistive state window, thereby significantly improving the yield of the memory array, the consistency of read / write operations, and the reliability of long-term cycling. Attached Figure Description

[0030] Figures 1-4 This is a schematic diagram of the fabrication steps of the OTS switch unit provided in an embodiment of the present invention; wherein 1-insulating layer, 2-lower electrode layer, 3-OTS switch material layer, 4-upper electrode layer, and 5-lead-out electrode;

[0031] Figure 5 Voltage-current curve of the OTS switching unit provided in the embodiment of the present invention;

[0032] Figure 6 The response speed test curve of the OTS switching unit provided in the embodiment of the present invention. Detailed Implementation

[0033] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0034] For the terms defined below, unless a different definition is given elsewhere in the claims or this specification, these definitions shall apply. All numerical values, whether explicitly indicated or not, are defined herein as being modified by the term "about." The term "about" generally refers to a range of numerical values ​​that a person skilled in the art would consider equivalent to the stated values ​​to produce substantially the same properties, functions, results, etc. A range of numerical values ​​indicated by a low value and a high value is defined as including all numerical values ​​included within that range and all subranges included within that range.

[0035] The following describes an OTS switching material provided by the present invention. The OTS switching material comprises an Sb-S composition and a dopant element (M). The general chemical formula of the OTS switching material is (Sb... x S 100-x ) 100-y M y , where M is one or more of As, Si, Te, C, W, N, P, ln, and x, y, z satisfy 10≤x≤50, 0≤y≤90.

[0036] In some embodiments, the (Sb) x S 100-x ) 100-y M y It is an alloy material.

[0037] Preferably, x and y satisfy 35 <x<45,20<y<50。

[0038] In the embodiments described in this specification, the OTS switch material can be a bidirectional threshold switch type switch material.

[0039] In the embodiments described in this specification, the OTS switch material can achieve an instantaneous transition from a high-resistance state to a low-resistance state under the action of an external electric field, and an instantaneous transition from a low-resistance state to a high-resistance state when the external electric field is removed.

[0040] In the embodiments described in this specification, the on / off current ratio of the OTS switch material can be greater than or equal to 2.

[0041] Preferably, the on / off current ratio of the OTS switch material can be greater than or equal to 3.

[0042] Preferably, the on / off current ratio of the OTS switch material can be greater than or equal to 2 and less than or equal to 10.

[0043] Preferably, the on / off current ratio of the OTS switch material can be greater than or equal to 3 and less than or equal to 9.

[0044] In the embodiments described in this specification, the thickness of the OTS switch material is 5nm~50nm.

[0045] In the embodiments of this specification, the OTS switch material can be synthesized using methods including but not limited to sputtering, chemical vapor deposition, atomic layer deposition, or electron beam evaporation.

[0046] In the embodiments described in this specification, the OTS switch material can be synthesized using a single-target co-sputtering method or an alloy target sputtering method.

[0047] In one embodiment, the OTS switching material can be synthesized from an Sb₂S₃ target by sputtering. During material preparation, when using an alloy target or single-target sputtering to prepare the switching material, the doping element M can reduce the number of homogeneous bonds and improve the performance of the material system.

[0048] Thus, the present invention provides (Sb) x S 100-x ) 100-y M y The switching material can overcome the shortcomings of Se-containing OTS switching materials when used as switching materials, and can exhibit excellent comprehensive performance by adjusting the content of dopant element M.

[0049] The following describes an OTS switching unit provided by the present invention, the unit comprising:

[0050] Lower electrode layer;

[0051] Upper electrode layer;

[0052] OTS switch material layer: located between the lower electrode layer and the upper electrode layer, including the OTS switch material described above.

[0053] In the embodiments described in this specification, preferably, the thickness of the OTS switch material layer can be 5nm~50nm.

[0054] In the embodiments described in this specification, preferably, the thickness of the upper electrode layer can be 5nm to 50nm.

[0055] In the embodiments described in this specification, preferably, the thickness of the lower electrode layer can be 5nm to 50nm.

[0056] In the embodiments described in this specification, the material of the upper electrode layer can be one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0057] In the embodiments described in this specification, the material of the lower electrode layer can be one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0058] In the embodiments described in this specification, the turn-on current I of the OTS switching unit is... on It can be greater than or equal to 10 -7 A; the threshold voltage V of the switching unit th The voltage can be less than or equal to 10V; the leakage current I of the switching unit off ≤10 -7 A; The maximum number of cycles for the switching unit can be greater than or equal to 10. 4 The switching ratio of the switching unit can be greater than or equal to 2.

[0059] Preferably, the switching current I of the switching unit on ≥10 -6 A; the leakage current I of the switching unit off ≤10 - 7 A; the threshold voltage V of the switching unit th ≤ 5V; the maximum number of cycles for the switching unit can be greater than or equal to 10. 5 The switching ratio of the switching unit can be greater than or equal to 3.

[0060] Preferably, the switching current I of the switching unit on ≥10 -3 A, the switching ratio of the switching unit can be greater than or equal to 5, and the leakage current I of the switching unit... off ≤ 10 -9 A.

[0061] Preferably, the threshold voltage V of the switching unit th It can be 1V, 2V, 3V, 4V, 5V, 6V, 7V, 8V or 9V.

[0062] Preferably, the switching ratio of the switching unit can be greater than or equal to 3 and less than or equal to 9.

[0063] Preferably, the gating ratio of the switching unit can be 4, 5, 6, 7 or 8.

[0064] The following describes a method for fabricating an OTS switching unit provided by the present invention. The preparation method includes the following steps:

[0065] S1: Form the lower electrode layer;

[0066] S2: An OTS switching material layer is formed on the lower electrode layer. The OTS switching material comprises an Sb-S composition and a dopant element (M). The general chemical formula of the OTS switching material is (Sb... x S 100-x ) 100-y M yM is one or more of As, Si, Te, C, W, N, P, and ln, and x, y, and z satisfy 10≤x≤50 and 0≤y≤90;

[0067] S3: Form the upper electrode layer on the OTS switch material layer;

[0068] S4: The lead-out electrode is formed on the upper electrode layer.

[0069] In the embodiments described in this specification, the shape of the unit includes, but is not limited to, a columnar or strip-shaped structure having a lower electrode layer / OTS switching material layer / upper electrode layer. This invention does not limit the shape of the unit.

[0070] In the embodiments of this specification, the material of the lower electrode layer can be one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni; the material of the upper electrode layer can be one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0071] Preferably, x and y satisfy 35 <x<45,20<y<50。

[0072] In the embodiments described in this specification, preferably, the thickness of the OTS switch material layer can be 5nm~50nm.

[0073] Preferably, the thickness of the OTS switch material layer can be 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, or 45 nm, etc.

[0074] In the embodiments described in this specification, preferably, the diameter of the lower electrode layer can be 5~200nm.

[0075] In the embodiments described in this specification, preferably, the diameter of the upper electrode layer can be 5~200nm.

[0076] In the embodiments of this specification, the deposition of an OTS switch material layer thin film on the surface of the lower electrode layer may include, but is not limited to, depositing an OTS switch material layer thin film on the surface of the lower electrode layer using sputtering, chemical vapor deposition, atomic layer deposition, or electron beam evaporation.

[0077] Preferably, the sputtering method can be magnetron sputtering.

[0078] In the embodiments of this specification, the deposition of an OTS switch material layer thin film on the surface of the lower electrode layer may include: depositing the OTS switch material layer thin film on the surface of the lower electrode layer using a single-target co-sputtering method or an alloy target sputtering method.

[0079] In one embodiment, the OTS switch material layer thin film can be deposited using a single-target co-sputtering method with an Sb2S3 target.

[0080] In the embodiments of this specification, the methods for preparing the upper electrode layer and the lower electrode layer may include, but are not limited to, physical vapor deposition, chemical vapor deposition, electron beam evaporation, and molecular beam epitaxy.

[0081] Furthermore, the methods that can be used to form the upper electrode layer on the upper surface of the OTS switch material layer include, but are not limited to, sputtering, evaporation, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), metal compound vapor deposition (MOCVD), molecular beam epitaxy (MBE), atomic vapor deposition (AVD), or atomic layer deposition (ALD).

[0082] Furthermore, the methods that can be used to form the lower electrode layer on the substrate include, but are not limited to, sputtering, evaporation, CVD, PECVD, LPCVD, MOCVD, MBE, AVD, or ALD.

[0083] Example 1

[0084] This embodiment provides a method for fabricating an OTS switching unit device, the method comprising the following steps:

[0085] S1: Form the lower electrode layer 2. (See also...) Figure 1 As an example, the lower electrode layer 2 can be prepared by any one of sputtering, evaporation, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), metal compound vapor deposition (MOCVD), molecular beam epitaxy (MBE), atomic vapor deposition (AVD), or atomic layer deposition (ALD). In this embodiment, the lower electrode layer 2 is preferably prepared by magnetron sputtering. The material of the lower electrode layer 2 may include, for example, any one of W, Pt, Au, Ti, Al, Ag, Cu, and Ni, or an alloy material composed of any two or more of the above single metal materials W, Pt, Au, Ti, Al, Ag, Cu, and Ni, or a nitride or oxide containing one of the above single metal materials W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0086] Specifically, in this embodiment, the material of the lower electrode layer 2 is preferably TiN. The diameter of the electrode of the TiN lower electrode layer 2 prepared by magnetron sputtering is one of 60nm, 120nm, 150nm, and 200nm, and the height is 200nm.

[0087] S2: Using magnetron sputtering, Si and Sb₂S₃ targets are selected for sputtering to deposit a 20nm thick OTS switch material layer thin film on the lower electrode layer 2, forming the OTS switch material layer 3. The general chemical formula of the OTS switch material is (Sb₂S₃). 40 S 60 ) 95 Si5;

[0088] S3: The upper electrode layer 4 is formed on the OTS switch material layer 3. (See also...) Figure 3 As an example, the upper electrode layer 4 can be prepared on the OTS switch material layer 3 using any one of the following methods: sputtering, evaporation, chemical vapor deposition, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, metal compound vapor deposition (MOCVD), molecular beam epitaxy, atomic vapor deposition, or atomic layer deposition. The material of the upper electrode layer 4 can, for example, include any one of the single metal materials W, Pt, Au, Ti, Al, Ag, Cu, and Ni, or an alloy material composed of any two or more of the aforementioned single metal materials W, Pt, Au, Ti, Al, Ag, Cu, and Ni, or a nitride or oxide containing one of the aforementioned single metal materials W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0089] Specifically, in this embodiment, the upper electrode layer 4 is made of TiN with a thickness of 50 nm.

[0090] S4: Please refer to Figure 4 A lead-out electrode 5 is fabricated on the upper electrode layer 4. For example, the lead-out electrode 5 can be fabricated using any one of the following methods: sputtering, evaporation, chemical vapor deposition, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, metal compound vapor deposition, molecular beam epitaxy, atomic vapor deposition, or atomic layer deposition. Thus, through the lead-out electrode 5, the upper and lower electrode layers 1 and 4 can be integrated with other components in the OTS switching device unit, such as memory cells, drive circuits, and peripheral circuits, to fabricate a complete device unit. The fabrication method used is a conventional semiconductor process.

[0091] As an example, the material of the lead electrode 5 may include any one of the single metal materials W, Pt, Au, Ti, Al, Ag, Cu and Ni, or an alloy material composed of any two or more of the above single metal materials W, Pt, Au, Ti, Al, Ag, Cu and Ni, or a nitride or oxide containing one of the above single metal materials W, Pt, Au, Ti, Al, Ag, Cu and Ni.

[0092] Specifically, in this embodiment, the lead electrode 5 is preferably prepared by magnetron sputtering, the material is Al, and the thickness of the prepared lead electrode 5 is 200 nm.

[0093] The voltage-current curves of the aforementioned unit device obtained through electrical testing are as follows: Figure 5 As shown, by Figure 5 As can be seen, in this embodiment, after the activation of the unit device is completed in the first operation, when the voltage applied to the unit is less than about 3V, the unit is in a closed state, and the current through the unit is less than 10V. -10 A; When the voltage applied to the switching unit exceeds the threshold voltage (approximately 3V), the unit is instantaneously turned on, entering a low-resistance state, and the current through the unit increases sharply to 10. -3 A; When the voltage applied to the unit is removed, the unit is instantly switched off, returning to a high-resistance state. The current through the switching unit decreases sharply, according to... Figure 6 It can be seen that the opening and closing speeds of the unit are both less than 50 ns.

[0094] It should be noted that the OTS switch material layer can be formed by, but is not limited to, magnetron sputtering.

[0095] It should be noted that the thickness of the OTS switch material layer can be set according to actual needs. Preferably, the thickness of the OTS switch material layer can be 5nm~50nm. More preferably, in this embodiment, the thickness of the OTS switch material layer is 20nm.

[0096] It should be noted that the upper electrode material may include, but is not limited to, one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni. The lower electrode material may include, but is not limited to, one or more of C, Ta, TiN, TaC, TaN, Co, W, Pt, Au, Ti, Al, Ag, Cu, and Ni.

[0097] In this embodiment, the turn-on current I of the switching unit on ≥10 -4A, the switching ratio of the switching unit is greater than or equal to 3, and the leakage current I of the switching unit is... off ≤10 -7 A, the threshold voltage V of the switching unit th ≤ 5V.

[0098] In summary, the OTS switch material of the present invention is a novel, Se-free component (Sb). 40 S 60 ) 95 Si5, while ensuring nanosecond-level switching speed, has a lower leakage current compared to Si-containing compounds (Sb). 40 Se 60 ) 95 Si5) further reduces leakage current by more than an order of magnitude, which can more ideally suppress creeping current in storage arrays, realizing a new environmentally friendly low leakage current switching material, which helps to realize high-density massive information storage.

Claims

1. An OTS switch material, characterized in that, The general chemical formula of the OTS switch material is (Sb x S 100-x ) 100-y M y M is one or more of As, Si, Te, C, W, N, P, and ln; 10≤x≤50, 0≤y≤90.

2. The OTS switch material according to claim 1, characterized in that, The OTS switch material can achieve an instantaneous transition from a high-resistance state to a low-resistance state under the action of an external electric field, and can achieve an instantaneous transition from a low-resistance state to a high-resistance state when the external electric field is removed.

3. The OTS switch material according to claim 1, characterized in that, The on / off current ratio of the OTS switch material is 2 or higher.

4. An OTS switching unit, characterized in that, The OTS switch unit includes a lower electrode layer, an OTS switch material layer, and an upper electrode layer; wherein the OTS switch material layer is disposed between the upper electrode layer and the lower electrode layer; wherein the OTS switch material is any one of the OTS switch materials described in claims 1-3.

5. The OTS switching unit according to claim 4, characterized in that, The thickness of the OTS switch material layer is 5nm~50nm.

6. The OTS switch material according to claim 4, characterized in that, The upper electrode layer material and the lower electrode layer material are both selected from one or more of C, single metal materials, nitrides of single metal materials, oxides of single metal materials, carbides of single metal materials, and alloy materials; wherein the single metal materials are all selected from one of W, Pt, Au, Ti, Al, Ag, Cu, Ni, Ta, and Co; and the alloy materials are two or more alloy materials selected from W, Pt, Au, Ti, Al, Ag, Cu, Ni, Ta, and Co.

7. The OTS switching unit according to claim 4, characterized in that, The lower electrode layer includes a first lower electrode layer and a second lower electrode layer, wherein an insulating layer is provided between the first lower electrode layer and the second lower electrode layer. The OTS switch unit also includes lead-out electrodes, which are disposed on the upper electrode layer.

8. A method for manufacturing an OTS switching unit according to any one of claims 4-7, comprising: S1: Form the lower electrode layer; S2: An OTS switching material layer is formed on the lower electrode layer; S3: An upper electrode layer is formed on the OTS switch material layer.

9. The preparation method according to claim 8, characterized in that, Lead-out electrodes are formed on the upper electrode layer.

10. The application of any OTS switch material according to claims 1-3, or any OTS switch unit according to claims 4-7, in the field of micro-nano electronics technology.

Images