Programmable nonvolatile ferroelectric Schottky diode and method for manufacturing the same

Abstract

The present application relates to a programmable non-volatile ferroelectric Schottky diode and a method for manufacturing the same. The programmable non-volatile ferroelectric Schottky diode comprises: a control structure comprising an insulating layer and a conductive layer; and a diode structure, the diode structure being located on the side of the insulating layer facing away from the conductive layer. The diode structure comprises a ferroelectric semiconductor layer and a semi-metal layer, the ferroelectric semiconductor layer being made of a two-dimensional α-In2Se3 material, the semi-metal layer being in Schottky contact with the ferroelectric semiconductor layer, and the semi-metal layer being made of a two-dimensional 1T'-MoTe2 material. The programmable non-volatile ferroelectric Schottky diode fills a technological gap in the application of ferroelectric materials.

Description

Technical Field

[0001] The present application relates to the technical field of ferroelectric semiconductors, and in particular to a programmable non-volatile ferroelectric Schottky diode and a manufacturing method thereof. Background Art

[0002] In recent years, electronic devices based on ferroelectric materials have become a research hotspot. Due to their tunable polarization properties, ferroelectric materials have shown great application prospects in memory, field-effect transistors, neuromorphic computing, and other fields.

[0003] Devices that have been widely studied include ferroelectric memory (FeRAM), ferroelectric tunnel junction (FTJ) and ferroelectric field-effect transistor (FeFET). Ferroelectric materials have demonstrated the advantages of non-volatile storage and controllable electrical properties.

[0004] Although the research on ferroelectric materials is relatively rich, the application of ferroelectric materials still has room for expansion, and new ferroelectric materials devices are still to be discovered. Summary of the Invention

[0005] Based on this, it is necessary to provide a programmable non-volatile ferroelectric Schottky diode and a manufacturing method thereof to address the above problems.

[0006] In the first aspect, the present application provides a programmable non-volatile ferroelectric Schottky diode, which includes: a control structure, including an insulating layer and a conductive layer; and a diode structure, the diode structure is located on the side of the insulating layer facing away from the conductive layer, the diode structure includes a ferroelectric semiconductor layer and a semi-metal layer, the material of the ferroelectric semiconductor layer includes two-dimensional α-In2Se3, the semi-metal layer Schottky contacts the ferroelectric semiconductor layer, and the material of the semi-metal layer includes two-dimensional 1T'-MoTe2.

[0007] By combining a two-dimensional ferroelectric semiconductor layer of α-In2Se3 and a two-dimensional semimetallic layer of 1T'-MoTe2, the resulting diode structure is a ferroelectric Schottky contact diode. By configuring a control structure, the ferroelectric semiconductor layer can be controlled, thereby adjusting the rectification characteristics of the Schottky diode structure. This programmable non-volatile ferroelectric Schottky diode fills a technological gap in the application of ferroelectric materials. It features a high rectification ratio and a low ideality factor, while also enabling programmability, non-volatile control, and multi-state storage.

[0008] Illustratively, the thickness of the ferroelectric semiconductor layer ranges from 30 nm to 50 nm.

[0009] Such an arrangement can ensure the conductivity of the ferroelectric semiconductor layer while ensuring sufficiently strong ferroelectricity.

[0010] Exemplarily, the thickness of the semi-metal layer ranges from 10 nm to 30 nm.

[0011] With such a configuration, the resistivity of the semi-metal layer is low, the carrier mobility is high, the semi-metallic property is more obvious, and the reduction of conductivity due to the quantum confinement effect is avoided.

[0012] In some embodiments, the insulating layer is made of SiO2; the conductive layer is made of highly conductive silicon; the ferroelectric semiconductor layer is a few-layer two-dimensional α-In2Se3; and the semi-metal layer is a few-layer two-dimensional 1T'-MoTe2.

[0013] With such an arrangement, the control structure is easy to implement; and the diode structure has good performance.

[0014] In some embodiments, a semi-metal layer, a ferroelectric semiconductor layer, an insulating layer, and a conductive layer are stacked in sequence; the programmable non-volatile ferroelectric Schottky diode further includes a first electrode and a second electrode, the first electrode is in ohmic contact with the ferroelectric semiconductor layer, and the second electrode is in ohmic contact with the semi-metal layer.

[0015] With such a configuration, the conductive performance of the programmable nonvolatile ferroelectric Schottky diode is good.

[0016] In some embodiments, at least one of the first electrode and the second electrode is a composite electrode, the composite electrode including an ohmic contact layer and a covering layer, the material of the ohmic contact layer includes chromium, and the material of the covering layer includes at least one of gold, silver, copper, platinum and palladium.

[0017] With this arrangement, the ohmic contact effect achieved by chromium is good, effectively ensuring that in the path of the first electrode, the ferroelectric semiconductor layer, the semi-metal layer and the second electrode, the Schottky barrier comes from the ferroelectric semiconductor layer and the semi-metal layer, effectively avoiding the formation of a barrier between the metal material and the ferroelectric material, which affects the control of the diode structure by the conductive layer; the service life of the first electrode and the second electrode is long.

[0018] In a second aspect, the present application provides a device comprising: the aforementioned programmable non-volatile ferroelectric Schottky diode; and a control circuit electrically connected to the conductive layer and the ferroelectric semiconductor layer.

[0019] By setting up a programmable non-volatile ferroelectric Schottky diode, a tunable rectification characteristic is achieved. After the device is fabricated, the device's rectification characteristics can be dynamically adjusted while maintaining the adjusted characteristics.

[0020] In a third aspect, the present application provides a method for manufacturing a programmable non-volatile ferroelectric Schottky diode, the method comprising: providing a control structure, the control structure comprising an insulating layer and a conductive layer; and forming a diode structure stacked on the control structure, the diode structure being located on the side of the insulating layer facing away from the conductive layer, the steps of forming the diode structure comprising: achieving Schottky contact between the semi-metal layer and the ferroelectric semiconductor layer; wherein the material of the ferroelectric semiconductor layer comprises two-dimensional α-In2Se3, and the material of the semi-metal layer comprises two-dimensional 1T'-MoTe2.

[0021] The method provided in the embodiments of the present application can be used to manufacture a programmable non-volatile ferroelectric Schottky diode, and the method manufactures a new product based on ferroelectric materials.

[0022] In some embodiments, the steps of forming a diode structure include: transferring a few-layer two-dimensional α-In2Se3 onto an insulating layer by mechanical exfoliation to obtain a ferroelectric semiconductor layer; and transferring a few-layer two-dimensional 1T'-MoTe2 onto the ferroelectric semiconductor layer by mechanical exfoliation.

[0023] With this setup, the transfer of few-layer two-dimensional materials is reliable, which helps to ensure device performance.

[0024] In some embodiments, the method for manufacturing a programmable non-volatile ferroelectric Schottky diode also includes: forming a mask through a laser direct write exposure process, the mask including a first pattern corresponding to the ferroelectric semiconductor layer and a second pattern corresponding to the semi-metal layer; forming an ohmic contact layer at the first pattern and the second pattern respectively through a first thermal evaporation process, the material of the ohmic contact layer including chromium; and forming a corresponding covering layer on the ohmic contact layer through a second thermal evaporation process, the material of the covering layer including at least one of gold, silver, copper, platinum and palladium, wherein the process temperature of the laser direct write exposure process, the process temperature of the first thermal evaporation process and the process temperature of the second thermal evaporation process are all less than 180°C.

[0025] Such an arrangement can form a first electrode and a second electrode with good electrical performance and long service life, and can protect the ferroelectric material and avoid phase change.

[0026] In a fourth aspect, the present application provides a programming method, which is based on the aforementioned programmable non-volatile ferroelectric Schottky diode or the aforementioned device or a programmable non-volatile ferroelectric Schottky diode manufactured according to the steps of the aforementioned method, and the programming method includes: applying a polarization voltage between the conductive layer and the ferroelectric semiconductor layer.

[0027] With such an arrangement, the polarization characteristics of the ferroelectric semiconductor layer can be regulated, and the rectification characteristics of the diode structure can be regulated; the regulated rectification characteristics can be maintained in the absence of an external voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic flow chart of a method for manufacturing a programmable non-volatile ferroelectric Schottky diode according to one or more embodiments;

[0029] Figure 2 FIG1 is a process flow diagram of a method for manufacturing a programmable non-volatile ferroelectric Schottky diode according to one or more embodiments;

[0030] Figure 3 is a schematic circuit diagram of a device according to one or more embodiments;

[0031] Figure 4 is a schematic circuit diagram of a device and a testing apparatus according to one or more embodiments;

[0032] Figure 5 is an energy band diagram of a ferroelectric semiconductor layer at an insulating layer interface in a positive voltage-controlled state according to one or more embodiments;

[0033] Figure 6 is an energy band diagram of a ferroelectric semiconductor layer at the interface of a semi-metal layer in a positive voltage-controlled state according to one or more embodiments;

[0034] Figure 7 is an energy band diagram of a ferroelectric semiconductor layer at an insulating layer interface in a negative voltage-controlled state according to one or more embodiments;

[0035] Figure 8 An energy band diagram of a ferroelectric semiconductor layer at the interface of a semi-metal layer in a negative voltage-controlled state according to one or more embodiments;

[0036] Figure 9 is a rectification curve of a diode structure in an initial state according to one or more embodiments;

[0037] Figure 10 is a schematic flow chart of a programming method according to one or more embodiments;

[0038] Figure 11 is a rectification curve of a diode structure in a negative voltage regulation state according to one or more embodiments;

[0039] Figure 12 is a rectification curve of a diode structure in a positive voltage regulation state according to one or more embodiments;

[0040] Figure 13 is a rectification curve of the diode structure under different control states according to one or more embodiments;

[0041] Figure 14 is a numerical scatter diagram of the rectification ratio of the diode structure under different control states according to one or more embodiments;

[0042] Figure 15 is a numerical scatter plot of the ideality factor of the diode structure under different control states according to one or more embodiments;

[0043] Figure 16 The performance retention curve of the diode structure after polarization according to one or more embodiments is shown.

[0044] Description of reference numerals: 1. control structure; 11. conductive layer; 12. insulating layer; 2. diode structure; 21. ferroelectric semiconductor layer; 22. semi-metal layer; 23. first electrode; 24. second electrode;

[0045] 100. Programmable nonvolatile ferroelectric Schottky diode; 200. Control circuit; 201. Voltage source; 300. Device; 400. Testing device. DETAILED DESCRIPTION

[0046] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotations of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0047] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "perpendicular", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0048] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0049] In addition, the terms "first," "second," "third," etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. For example, a first electrode may also be referred to as a second electrode, and a second electrode may also be referred to as a first electrode. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0050] In this application, unless otherwise clearly specified and limited, the terms "connected", "connect", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a flexible connection, or a rigid connection along at least one direction; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or directly connected with an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. The terms "install", "set", "fix", etc. can be broadly understood as connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0051] The terms "layer" and "region" used in this application refer to a material portion that includes a certain area and has a certain thickness. The layer can extend horizontally, vertically and / or along a tapered surface. A layer can be an area of ​​a uniform or non-uniform continuous structure, and its thickness perpendicular to the extension direction may not be greater than the thickness of the continuous structure. A layer can include multiple layers, which can be multiple stacked layers or multiple layers extending discretely. The shapes of the various areas and layers in the accompanying drawings and their relative sizes and positional relationships are only exemplary and may deviate from the actual ones due to manufacturing tolerances or technical limitations, and the design can be adjusted according to actual needs.

[0052] refer to Figure 1 , Figure 1 A method 1000 for manufacturing a programmable nonvolatile ferroelectric Schottky diode in an embodiment of the present application is shown. In an exemplary embodiment, the method 1000 for manufacturing a programmable nonvolatile ferroelectric Schottky diode includes step S110 and step S120.

[0053] Combine Figure 2 As shown, in step S110, a control structure 1 is provided. The control structure 1 may include an insulating layer 12 and a conductive layer 11. For example, step S110 may include: step S111, forming the conductive layer 11; and step S112, forming the insulating layer 12, which may be performed before or after.

[0054] The conductive layer 11 may be a highly conductive silicon layer, specifically highly doped silicon. The resistivity of the conductive layer 11 may be less than 0.005 Ω·cm, for example, the resistivity of the highly conductive silicon layer may be within a range of 0.001 Ω·cm to 0.005 Ω·cm. The insulating layer 12 may be a silicon dioxide layer.

[0055] Optionally, the conductive layer 11 may be made of metal. Optionally, the insulating layer 12 may be made of oxides such as aluminum oxide or hafnium oxide, or other types of dielectric materials.

[0056] Method 1000 for manufacturing a programmable nonvolatile ferroelectric Schottky diode may further include cleaning control structure 1. Specifically, the cleaning solution may include at least one of acetone, isopropyl alcohol, and deionized water, and the cleaning process may be performed in multiple steps. The cleaning step ensures that the surface of control structure 1 is clean and free of contamination, particularly the surface of insulating layer 12 to be used.

[0057] Step S120 , forming a diode structure 2 . Various parts of the diode structure 2 can be formed on the control structure 1 . When the diode structure 2 is obtained, the diode structure 2 is stacked on the control structure 1 . Specifically, the diode structure 2 is located on the side of the insulating layer 12 facing away from the conductive layer 11 .

[0058] refer to Figure 1 Step S120 may include step S121 and step S122. The step of forming the diode structure 2 includes: step S121, forming a ferroelectric semiconductor layer 21; and step S122, forming a semi-metal layer 22.

[0059] refer to Figure 2 , step S121 can be performed first. Based on control structure 1, a few-layer two-dimensional α-In2Se3 can be transferred onto insulating layer 12 via mechanical exfoliation to obtain a ferroelectric semiconductor layer 21. The transfer setup of the few-layer two-dimensional material is reliable and helps ensure device performance. For example, the few-layer two-dimensional α-In2Se3 can be 3 to 10 layers of two-dimensional α-In2Se3. The two-dimensional α-In2Se3 can be an N-type two-dimensional semiconductor material.

[0060] When step S122 is performed later, the two-dimensional few-layer 1T'-MoTe2 can be transferred to the ferroelectric semiconductor layer 21 via mechanical exfoliation to obtain a semi-metallic layer 22. The two-dimensional 1T'-MoTe2 material is a semi-metallic two-dimensional material capable of achieving a Schottky contact with the two-dimensional α-In2Se3 material. Step S122 can be the step in step S120 where the semi-metallic layer 22 and the ferroelectric semiconductor layer 21 are Schottky-contacted. The reliable transfer setup of the few-layer two-dimensional material helps ensure device performance.

[0061] In other embodiments, the diode structure 2 may be formed first, and then the control structure 1 may be formed. For example, step S122 may be performed first. The semi-metal layer 22 may be disposed on the insulating layer 12, and the ferroelectric semiconductor layer 21 may be disposed on a side of the semi-metal layer 22 facing away from the control structure 1.

[0062] refer to Figure 2 The conductive layer 11, the insulating layer 12, the ferroelectric semiconductor layer 21, and the semi-metal layer 22 are stacked in order from bottom to top along the Z-axis. The ferroelectric semiconductor layer 21 extends out of the semi-metal layer 22 along the X-axis. The semi-metal layer 22 may cover a portion of the ferroelectric semiconductor layer 21, leaving another portion of the ferroelectric semiconductor layer 21 exposed outside the semi-metal layer 22.

[0063] Method 1000 for manufacturing a programmable nonvolatile ferroelectric Schottky diode may further include step S130 of forming a first electrode 23 and a second electrode 24. The steps of forming the first electrode 23 and forming the second electrode 24 may be performed simultaneously, thereby forming electrodes having substantially the same structure. The first electrode 23 and the second electrode 24 may also be different.

[0064] Exemplarily, step S130 includes steps S131 to S133.

[0065] Step S131: Form a mask (not shown). Specifically, the mask can be formed by a laser direct write exposure process. The mask includes a first pattern corresponding to the ferroelectric semiconductor layer 21 and a second pattern corresponding to the semi-metal layer 22. The first pattern is used to define the first electrode 23, and the second pattern is used to define the second electrode 24.

[0066] Step S132: Forming an ohmic contact layer. Specifically, a first thermal evaporation process can be used to form the ohmic contact layer at the first pattern and the second pattern, respectively. The ohmic contact layer is made of a metal, such as titanium, nickel, platinum, or chromium. The metal can be plated on the ferroelectric semiconductor layer 21 and the semi-metal layer 22. The ohmic contact layer can be made of chromium, which provides a good ohmic contact effect.

[0067] Exemplarily, the thickness of the ohmic contact layer ranges from 3 nm to 20 nm. For example, the ohmic contact layer is a 10 nm thick chromium layer.

[0068] Step S133 forms a corresponding covering layer. Specifically, a second thermal evaporation process can be used to form a corresponding covering layer on the ohmic contact layer. The covering layer covers the ohmic contact layer, and the material of the covering layer has better oxidation resistance than the ohmic contact layer. Optionally, the material of the covering layer can be selected from gold, silver, copper, platinum, and palladium.

[0069] Exemplarily, the thickness of the cover layer ranges from 30 nm to 80 nm. For example, the cover layer is a 50 nm thick gold layer.

[0070] Step S130 forms first and second electrodes 23 and 24 with excellent electrical performance and long service life. The process temperatures of the laser direct writing exposure process, the first thermal evaporation process, and the second thermal evaporation process are all below 180°C, which protects the ferroelectric material, particularly the two-dimensional α-In2Se3, and prevents phase transitions.

[0071] refer to Figure 2 and Figure 3 The method 1000 for manufacturing a programmable nonvolatile ferroelectric Schottky diode according to an embodiment of the present application can manufacture the programmable nonvolatile ferroelectric Schottky diode 100. The steps of the method 1000 for manufacturing a programmable nonvolatile ferroelectric Schottky diode can also be used to manufacture the device 300. This method manufactures a new product based on ferroelectric materials.

[0072] refer to Figure 2 In an exemplary embodiment, the programmable nonvolatile ferroelectric Schottky diode 100 provided herein may include a control structure 1 and a diode structure 2. The control structure 1 includes an insulating layer 12 and a conductive layer 11. The diode structure 2 is located on the side of the insulating layer 12 facing away from the conductive layer 11. The diode structure 2 includes a ferroelectric semiconductor layer 21 and a semi-metal layer 22. The material of the ferroelectric semiconductor layer 21 includes two-dimensional α-In2Se3. The semi-metal layer 22 is in Schottky contact with the ferroelectric semiconductor layer 21. The material of the semi-metal layer 22 includes two-dimensional 1T'-MoTe2.

[0073] refer to Figure 3 In an exemplary embodiment, device 300 includes a programmable nonvolatile ferroelectric Schottky diode 100. Device 300 may also include circuitry electrically connected to conductive layer 11, ferroelectric semiconductor layer 21, and semi-metal layer 22. Device 300 may include a control circuit 200, which may be used to form the aforementioned circuitry. Control circuit 200 is electrically connected to conductive layer 11 and is also electrically connected to ferroelectric semiconductor layer 21, for example, via first electrode 23. Control circuit 200 may include a voltage source 201 (Us) for applying a polarization voltage to control ferroelectric semiconductor layer 21. Furthermore, the circuitry may be capable of applying a scan voltage to diode structure 2 for current reading.

[0074] The rectification characteristics of traditional Schottky diodes are fixed once fabricated and cannot be dynamically adjusted. While some semiconductor devices can modify their characteristics through methods such as electric fields and stress, most controls lack the non-volatile properties required to maintain these characteristics even after a power outage. Once the applied bias is removed, the device often returns to its initial state. Furthermore, the fabrication and process integration of many semiconductor devices is challenging.

[0075] The programmable nonvolatile ferroelectric Schottky diode 100 fills a technological gap. By providing a two-dimensional ferroelectric semiconductor layer 21 of α-In2Se3 and a two-dimensional semi-metallic layer 22 of 1T'-MoTe2, the resulting diode structure 2 is a ferroelectric Schottky contact diode. By providing a control structure 1, the ferroelectric semiconductor layer 21 can be controlled, thereby adjusting the rectification characteristics of the Schottky diode structure 2.

[0076] refer to Figure 5 and Figure 6 After applying a positive voltage between the conductive layer 11 of high-conductivity silicon material and the ferroelectric semiconductor layer 21 of α-In2Se3 material, the diode structure 2 can be in a positive voltage control state P up Programmable nonvolatile ferroelectric Schottky diode 100 can also be said to be in a positive voltage regulation state. With the Z-axis as the vertical direction, when polarization is upward, the negative polarization charge causes the energy band at the interface with the SiO2 insulating layer 12 to bend upward, placing the ferroelectric semiconductor layer 21 in a high-resistance state. This upward polarization also increases the Schottky barrier at the interface with the 1T'-MoTe2 semi-metallic layer 22. Figure 6 In the case of 1T'-MoTe2 and α-In2Se3, there may be a van der Waals gap (vdW gap). is the Fermi level, is the conduction band, is the valence band, is the Schottky barrier when the polarization is upward.

[0077] refer to Figure 7 and Figure 8 After applying a negative voltage between the conductive layer 11 and the ferroelectric semiconductor layer 21, the diode structure 2 can be in a negative voltage control state P down When polarization is downward, the polarization charge distribution is opposite to that when polarization is upward. The positive polarization charge causes the energy band at the interface of the insulating layer 12 to bend downward. When polarization is downward, it also causes the Schottky barrier at the interface of the semi-metal layer 22 to become smaller. Figure 8 middle, is the Schottky barrier when polarization is downward.

[0078] The programmable nonvolatile ferroelectric Schottky diode 100 features a high rectification ratio and low ideality factor, while also enabling programmability, nonvolatile control, and multi-state storage. The programmable nonvolatile ferroelectric Schottky diode 100 has broad application prospects in new memory, reconfigurable circuits, and neuromorphic computing.

[0079] In some embodiments, in the programmable non-volatile ferroelectric Schottky diode 100, a semi-metal layer 22, a ferroelectric semiconductor layer 21, an insulating layer 12, and a conductive layer 11 are stacked in sequence. The first electrode 23 is in ohmic contact with the ferroelectric semiconductor layer 21, and the second electrode 24 is in ohmic contact with the semi-metal layer 22. At least one of the first electrode 23 and the second electrode 24 is a composite electrode, and the composite electrode includes an ohmic contact layer and a covering layer. The material of the ohmic contact layer includes chromium, and chromium can have a good ohmic contact effect with the ferroelectric semiconductor layer 21 or the semi-metal layer 22, effectively ensuring that the Schottky barrier in the path of the first electrode 23, the ferroelectric semiconductor layer 21, the semi-metal layer 22, and the second electrode 24 comes from the ferroelectric semiconductor layer 21 and the semi-metal layer 22, effectively avoiding the formation of a barrier between the metal material and the ferroelectric material, which affects the control of the diode structure 2 by the conductive layer 11. The material of the covering layer includes at least one of gold, silver, copper, platinum and palladium. The covering layer is difficult to be oxidized and is suitable for external connection. In addition, the first electrode 23 and the second electrode 24 have a long service life.

[0080] The thickness of the ferroelectric semiconductor layer 21 ranges from 30 nm to 50 nm. This ensures that the ferroelectric semiconductor layer 21 is not too thick, resulting in poor conductivity of the diode structure 2, while also being thin enough to maintain ferroelectric properties and the programmable and non-volatile capabilities of the diode structure 2. The thickness of the semi-metallic layer 22 ranges from 10 nm to 30 nm. The thickness of the semi-metallic layer 22 can affect its electrical properties. A thinner semi-metallic layer 22 has lower resistivity, higher carrier mobility, and more pronounced semi-metallic properties. However, avoiding excessive thinness can also prevent the quantum confinement effect from reducing conductivity.

[0081] refer to Figure 4 , the current of the diode structure 2 can be read using a test device 400. For example, the device 300 can include a test device 400. The test device 400 can include an ammeter, and the test device 400 is electrically connected to the first electrode 23 and the second electrode 24. The first electrode 23 can be referred to as a negative electrode, and the second electrode 24 can be referred to as an anode.

[0082] refer to Figure 9 , the programmable nonvolatile ferroelectric Schottky diode 100 can be in an initial state. The rectification characteristics of the diode structure 2 are as follows Figure 9 As shown, the horizontal axis represents the scanning voltage applied to the first electrode 23 and the second electrode 24, ranging from -1 volt to 1 volt, for example. The vertical axis on the right is a linear axis, and the vertical axis on the left is a logarithmic axis. Under the linear axis on the right, the current-voltage relationship of the diode structure 2 is reflected as follows: when the voltage is between -1 volt and 0.25 volt, the current is small, and when it exceeds 0.25 volt, the current increases. Under the logarithmic axis on the left, the current-voltage relationship of the same diode structure 2 is reflected as follows: from 0 volt to -1 volt, the current increases and increases more from 0 volt to 1 volt. The rectification ratio of the diode structure 2 is as high as 3×104 The Shockley diode equation is used to fit the 0V to 0.4V interval of the rectification curve in logarithmic coordinates, and the data points are obtained by fitting, and the ideal factor is obtained. , close to an ideal Schottky diode.

[0083] refer to Figure 10 The present application provides a programming method 2000, which is based on the aforementioned programmable non-volatile ferroelectric Schottky diode 100, the aforementioned device 300, or a programmable non-volatile ferroelectric Schottky diode manufactured using the steps of the aforementioned method 1000. The programming method 2000 includes applying a polarization voltage between the conductive layer 11 and the ferroelectric semiconductor layer 21.

[0084] The programming method 2000 can regulate the polarization characteristics of the ferroelectric semiconductor layer 21 , and then regulate the rectification characteristics of the diode structure 2 ; the regulated rectification characteristics can be maintained in the absence of an external voltage.

[0085] Exemplarily, the programming method 2000 includes at least one step from step S210 to step S230 .

[0086] In step S210 , a first polarization voltage may be applied between the conductive layer 11 and the ferroelectric semiconductor layer 21 in response to a first regulation requirement.

[0087] In step S220 , in response to a non-regulation requirement, no polarization voltage is applied between the conductive layer 11 and the ferroelectric semiconductor layer 21 .

[0088] In step S230, in response to the second control requirement, a second polarization voltage may be applied between the conductive layer 11 and the ferroelectric semiconductor layer 21. The first polarization voltage and the second polarization voltage may be +30 volts, +60 volts, -30 volts, or -60 volts, respectively. No polarization voltage may be applied, which may be 0 volts.

[0089] refer to Figure 4 Programming method 2000 can program a programmable nonvolatile ferroelectric Schottky diode 100 according to an exemplary embodiment, wherein the insulating layer 12 is made of SiO2; the conductive layer 11 is made of highly conductive silicon; the ferroelectric semiconductor layer 21 is a few-layer two-dimensional α-In2Se3; and the semi-metallic layer 22 is a few-layer two-dimensional 1T'-MoTe2. The dimension of the two-dimensional α-In2Se3 ferroelectric semiconductor layer 21 along the Z-axis, i.e., its thickness, is approximately 50 nm, while the thickness of the two-dimensional 1T'-MoTe2 semi-metallic layer 22 is approximately 20 nm. The ohmic contact layer is a 10 nm thick chromium layer. The capping layer is a 50 nm thick gold layer. Programmable nonvolatile ferroelectric Schottky diode 100 is easy to implement and has good performance.

[0090] refer to Figure 11, you can test products before and after programming, or test multiple products in different states. Figure 11 The current curves of the diode structure 2 in three states are shown in FIG. Specifically, the diode structure 2 can be in an initial state, a first regulation state in which a negative polarization voltage of -30 volts is applied to the conductive layer 11, and a second regulation state in which a negative polarization voltage of -60 volts is applied to the conductive layer 11. Figure 4 The circuit shown is implemented. Figure 7 and Figure 8 The polarization direction of the two-dimensional α-In2Se3 is downward, and positive polarization charge accumulates at the interface between the SiO2 insulating layer 12 and the two-dimensional α-In2Se3. The energy band of the two-dimensional α-In2Se3 on the side corresponding to the insulating layer 12 bends downward, and the two-dimensional α-In2Se3 exhibits a low-resistance state. The Schottky barrier at the interface between the two-dimensional 1T'-MoTe2 and the two-dimensional α-In2Se3 decreases, and the rectification curve of the diode structure 2 becomes larger than the curve of the initial state. Moreover, due to different degrees of polarization, the barrier changes are also different, and the diode structure 2 exhibits different currents when measured.

[0091] refer to Figure 12 , you can test products before and after programming, or test multiple products in different states. Figure 12 , the current curves of the diode structure 2 in three states are shown. Specifically, the diode structure 2 can be in the initial state, in the third control state where the forward polarization voltage applied to the conductive layer 11 is +30 volts, and in the fourth control state where the forward polarization voltage applied to the conductive layer 11 is +60 volts. Figure 4 The circuit shown is implemented. Figure 5 and Figure 6 The polarization direction of the two-dimensional α-In2Se3 is upward, and negative polarization charges accumulate at the interface between the SiO2 insulating layer 12 and the two-dimensional α-In2Se3. This causes the energy band to bend upward, resulting in a high-resistance state for the two-dimensional α-In2Se3. This increases the Schottky barrier at the interface between the two-dimensional 1T'-MoTe2 and the two-dimensional α-In2Se3, and the rectification curve of diode structure 2 becomes smaller than that of the initial state. Furthermore, due to different degrees of polarization, the barrier changes also vary, resulting in different currents in diode structure 2 when measured.

[0092] refer to Figure 13 In the polarization mode of each horizontal voltage, in addition to the two extreme states of ferroelectric polarization completely upward and completely downward, the diode structure 2 can also form multiple intermediate states through different degrees of polarization. Figure 13 The voltage-current curves on the left side of the logarithm of the five polarization modes are shown, and the intermediate states show obvious differences.

[0093] refer to Figure 14After each polarization voltage is applied, the programmable nonvolatile ferroelectric Schottky diode 100 exhibits a good rectification effect, and the rectification ratio is close to or greater than 4 orders of magnitude.

[0094] refer to Figure 15 , ideality factor of programmable nonvolatile ferroelectric Schottky diode 100 per state They are all close to or less than 2, and the rectification curve performance is excellent, showing nearly ideal Schottky diode characteristics.

[0095] refer to Figure 16 After the polarization voltage applied to the conductive layer 11 and the ferroelectric semiconductor layer 21 is removed, the ferroelectric semiconductor layer 21 exhibits excellent non-volatile characteristics. The current in the diode structure 2 in the fully upward state controlled by the +60V polarization voltage remains stable, while the current in the diode structure 2 in the fully downward state controlled by the -60V polarization voltage remains stable, with a difference between the current values ​​in the two states.

[0096] The programmable nonvolatile ferroelectric Schottky diode 100 according to the embodiment of the present application has at least one of the following technical effects.

[0097] High rectification ratio and near-ideal factor. By optimizing the ferroelectric Schottky interface, the rectification ratio exceeds 4 orders of magnitude and the ideal factor reaches 1.28, maintaining excellent rectification characteristics while ensuring controllability.

[0098] Programmable control of rectification characteristics. By reversing or partially reversing the ferroelectric polarization, the barrier height can be dynamically adjusted, making the rectification curve reversible during use, breaking through the limitations of the fixed rectification characteristics of traditional Schottky diodes.

[0099] Non-volatile storage capability. Because ferroelectric polarization can be maintained for long periods of time without an applied electric field, the regulated rectification characteristics can be stably stored over long periods of time, avoiding the problem of ordinary semiconductor devices returning to their initial state after debiasing.

[0100] Multi-state storage capability. In addition to the two extreme states of ferroelectric polarization ("fully up" and "fully down"), diode structure 2 can also form multiple intermediate states through varying degrees of polarization, expanding storage capacity and making it suitable for analog storage or neuromorphic computing applications. Furthermore, the rectification ratio in each state is close to or greater than 4 orders of magnitude, and the ideality factor is close to or less than 2.

[0101] The technical features of the embodiments disclosed above can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0102] In the embodiments disclosed above, unless otherwise expressly specified and limited, the order of execution of the steps is not limited. For example, the steps may be executed in parallel or in a different order. The substeps of each step may also be executed in an interleaved manner. The various forms of the above-mentioned processes may be used, and steps may be reordered, added, or deleted. As long as the desired results of the technical solutions provided in this application can be achieved, this application is not limited here.

[0103] The embodiments disclosed above merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent protection of the present application. It should be noted that a person skilled in the art could make several variations and improvements without departing from the concept of the present application, all of which fall within the scope of the patent protection claimed by the present application. Therefore, the scope of the patent protection of the present application shall be subject to the appended claims.

Claims

1. A programmable nonvolatile ferroelectric Schottky diode, characterized in that include: a control structure including an insulating layer and a conductive layer; and A diode structure, wherein the diode structure is located on the side of the insulating layer facing away from the conductive layer, the diode structure includes a ferroelectric semiconductor layer and a semi-metal layer, the material of the ferroelectric semiconductor layer includes two-dimensional α-In2Se3, the semi-metal layer Schottky contacts the ferroelectric semiconductor layer, and the material of the semi-metal layer includes two-dimensional 1T'-MoTe2.

2. The programmable nonvolatile ferroelectric Schottky diode according to claim 1, wherein: The thickness of the ferroelectric semiconductor layer is in a range of 30 nm to 50 nm, and the thickness of the semi-metal layer is in a range of 10 nm to 30 nm.

3. The programmable non-volatile ferroelectric Schottky diode according to claim 1, wherein: The material of the insulating layer is SiO2; the material of the conductive layer is high-conductivity silicon; the ferroelectric semiconductor layer is a few-layer two-dimensional α-In2Se3; and the semi-metal layer is a few-layer two-dimensional 1T'-MoTe2.

4. The programmable non-volatile ferroelectric Schottky diode according to claim 1, wherein: The semi-metal layer, the ferroelectric semiconductor layer, the insulating layer and the conductive layer are stacked in sequence; The programmable nonvolatile ferroelectric Schottky diode further includes a first electrode and a second electrode, wherein the first electrode is in ohmic contact with the ferroelectric semiconductor layer, and the second electrode is in ohmic contact with the semi-metal layer.

5. The programmable non-volatile ferroelectric Schottky diode according to claim 4, wherein: At least one of the first electrode and the second electrode is a composite electrode, the composite electrode including an ohmic contact layer and a covering layer, the material of the ohmic contact layer including chromium, and the material of the covering layer including at least one of gold, silver, copper, platinum and palladium.

6. A device, characterized in that include: The programmable non-volatile ferroelectric Schottky diode according to any one of claims 1 to 5; and The control circuit is electrically connected to the conductive layer and the ferroelectric semiconductor layer.

7. A method for manufacturing a programmable nonvolatile ferroelectric Schottky diode, characterized in that include: providing a control structure comprising an insulating layer and a conductive layer; and A diode structure is formed stacked on the control structure, wherein the diode structure is located on the side of the insulating layer facing away from the conductive layer. The steps of forming the diode structure include: achieving Schottky contact between the semi-metal layer and the ferroelectric semiconductor layer; wherein the material of the ferroelectric semiconductor layer includes two-dimensional α-In2Se3, and the material of the semi-metal layer includes two-dimensional 1T'-MoTe2.

8. The method for manufacturing a programmable non-volatile ferroelectric Schottky diode according to claim 7, wherein: The steps of forming the diode structure include: Transferring a few-layer two-dimensional α-In2Se3 onto the insulating layer by mechanical exfoliation to obtain the ferroelectric semiconductor layer; and A few-layer two-dimensional 1T'-MoTe2 is transferred onto the ferroelectric semiconductor layer by mechanical exfoliation.

9. The method for manufacturing a programmable nonvolatile ferroelectric Schottky diode according to claim 7, wherein: Also includes: forming a mask by a laser direct writing exposure process, wherein the mask includes a first pattern corresponding to the ferroelectric semiconductor layer and a second pattern corresponding to the semi-metal layer; forming an ohmic contact layer at the first pattern and the second pattern respectively through a first thermal evaporation process, wherein the material of the ohmic contact layer includes chromium; and A corresponding covering layer is formed on the ohmic contact layer through a second thermal evaporation process, and the material of the covering layer includes at least one of gold, silver, copper, platinum and palladium, wherein the process temperature of the laser direct writing exposure process, the process temperature of the first thermal evaporation process and the process temperature of the second thermal evaporation process are all less than 180°C.

10. A programming method, characterized in that A programmable non-volatile ferroelectric Schottky diode manufactured based on the programmable non-volatile ferroelectric Schottky diode according to any one of claims 1 to 5, or the device according to claim 6, or the steps of the method according to any one of claims 7 to 9, wherein the programming method comprises: A polarization voltage is applied between the conductive layer and the ferroelectric semiconductor layer.

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