Programmable non-volatile ferroelectric Schottky diode and manufacturing method thereof

Abstract

The invention relates to a programmable non-volatile ferroelectric Schottky diode and a manufacturing method thereof. The programmable non-volatile ferroelectric Schottky diode comprises a control structure which comprises an insulating layer and a conductive layer; the diode structure is located on the side, opposite to the conducting layer, of the insulating layer, the diode structure comprises a ferroelectric semiconductor layer and a semimetal layer, the material of the ferroelectric semiconductor layer comprises two-dimensional alpha-In2Se3, the semimetal layer is in Schottky contact with the ferroelectric semiconductor layer, and the material of the semimetal layer comprises two-dimensional 1T '-MoTe2. The programmable non-volatile ferroelectric Schottky diode fills the technical blank of application of ferroelectric materials.

Description

Technical Field

[0001] This application relates to the technical field of ferroelectric semiconductors, and particularly 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 adjustable polarization characteristics, ferroelectric materials show important application prospects in the directions of memory, field-effect transistors, neuromorphic computing, etc.

[0003] Currently, widely studied devices include ferroelectric memories (FeRAM), ferroelectric tunnel junctions (FTJ), and ferroelectric field-effect transistors (FeFET), etc. Ferroelectric materials have shown the advantages of non-volatile storage and adjustable electrical characteristics.

[0004] Although there is a relatively rich research on ferroelectric materials, the application of ferroelectric materials still has room for expansion, and devices of new ferroelectric materials remain to be explored. 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 for the above problems.

[0006] In a first aspect, this 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 located on the side of the insulating layer facing away from the conductive layer. The diode structure includes a ferroelectric semiconductor layer and a semimetal layer. The material of the ferroelectric semiconductor layer includes two-dimensional α-In2Se3, and the semimetal layer is in Schottky contact with the ferroelectric semiconductor layer. The material of the semimetal layer includes two-dimensional 1T’-MoTe2.

[0007] By setting the ferroelectric semiconductor layer of two-dimensional α-In2Se3 and the semimetal layer of two-dimensional 1T’-MoTe2, the formed diode structure is a diode with a Schottky contact of ferroelectric materials. By setting the control structure, it can be used to control the ferroelectric semiconductor layer and then regulate the rectifying characteristics of the Schottky diode structure. The programmable non-volatile ferroelectric Schottky diode fills the technical gap in the application of ferroelectric materials. The programmable non-volatile ferroelectric Schottky diode has the characteristics of a high rectification ratio and a low ideality factor, and can also realize functions such as programmable, non-volatile regulation, and multi-state storage.

[0008] Exemplarily, the thickness range of the ferroelectric semiconductor layer is from 30 nm to 50 nm.

[0009] With such a setting, it can ensure the conductivity of the ferroelectric semiconductor layer and also ensure a strong enough ferroelectricity.

[0010] Exemplarily, the thickness range of the half-metal layer is from 10 nm to 30 nm.

[0011] With such a setting, the half-metal layer has a lower resistivity, a higher carrier mobility, and more obvious half-metallicity, and also avoids the reduction of conductivity caused by the quantum confinement effect.

[0012] In some embodiments, the material of the insulating layer is SiO2; the material of the conductive layer is highly conductive silicon; the ferroelectric semiconductor layer is few-layer two-dimensional α-In2Se3; the half-metal layer is few-layer two-dimensional 1T’-MoTe2.

[0013] With such a setting, the control structure is easy to implement; the diode structure has good performance.

[0014] In some embodiments, the half-metal layer, the ferroelectric semiconductor layer, the insulating layer, and the 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 half-metal layer.

[0015] With such a setting, the programmable non-volatile ferroelectric Schottky diode has good conductivity.

[0016] In some embodiments, at least one of the first electrode and the second electrode is a composite electrode, the composite electrode includes 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 such a setting, the ohmic contact effect achieved by chromium is good, effectively ensuring that in the path of the first electrode, the ferroelectric semiconductor layer, the half-metal layer, and the second electrode, the Schottky barrier comes from the ferroelectric semiconductor layer and the half-metal layer, effectively avoiding the occurrence of a barrier between the metal material and the ferroelectric material, which affects the regulation of the diode structure by the conductive layer; the service lives of the first electrode and the second electrode are good.

[0018] In a second aspect, the present application provides a device, which includes: 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 providing the programmable non-volatile ferroelectric Schottky diode, a rectifying characteristic that can be regulated is achieved. After the device is fabricated, the rectifying characteristic of the device can be dynamically regulated and the regulated characteristic can be maintained.

[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 including an insulating layer and a conductive layer; and forming a diode structure stacked on the control structure, the diode structure being located on a side of the insulating layer facing away from the conductive layer, the step of forming the diode structure including: achieving a Schottky contact between a half-metal layer and a ferroelectric semiconductor layer; wherein the material of the ferroelectric semiconductor layer includes two-dimensional α-In2Se3, and the material of the half-metal layer includes two-dimensional 1T’-MoTe2.

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

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

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

[0024] In some embodiments, the method for manufacturing a programmable non-volatile ferroelectric Schottky diode further includes: forming a mask by laser direct writing exposure, the mask including a first pattern corresponding to the ferroelectric semiconductor layer and a second pattern corresponding to the half-metal layer; forming ohmic contact layers at the first pattern and the second pattern respectively by a first thermal evaporation process, the material of the ohmic contact layer including chromium; and forming corresponding covering layers on the ohmic contact layers by 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 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.

[0025] With such a setting, first electrodes and second electrodes with good electrical performance and long service life can be formed, which 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 programmable non-volatile ferroelectric Schottky diode described above or the programmable non-volatile ferroelectric Schottky diode manufactured by the steps of the device or the method described above. The programming method includes: applying a polarization voltage between the conductive layer and the ferroelectric semiconductor layer.

[0027] With such a setting, the polarization characteristics of the ferroelectric semiconductor layer can be regulated, and then the rectifying characteristics of the diode structure can be regulated; the regulated rectifying characteristics can be maintained without an external voltage. Description of the Drawings

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

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

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

[0031] Figure 4 Schematic circuit diagram of a device and a test device according to one or more embodiments;

[0032] Figure 5 Energy band diagram of a ferroelectric semiconductor layer in a positive voltage regulated state at the interface of an insulating layer according to one or more embodiments;

[0033] Figure 6 Energy band diagram of a ferroelectric semiconductor layer in a positive voltage regulated state at the interface of a half-metal layer according to one or more embodiments;

[0034] Figure 7 Energy band diagram of a ferroelectric semiconductor layer in a negative voltage regulated state at the interface of an insulating layer according to one or more embodiments;

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

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

[0037] Figure 10 Schematic flow block diagram of a programming method according to one or more embodiments;

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

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

[0040] Figure 13 Rectification curve of a diode structure in different regulated states according to one or more embodiments;

[0041] Figure 14 Numerical scatter plot of rectification ratios of a diode structure in different regulated states according to one or more embodiments;

[0042] Figure 15 A scatter plot of the values of the ideality factor of a diode structure according to one or more embodiments in different regulation states;

[0043] Figure 16 A performance retention curve of a diode structure according to one or more embodiments after polarization.

[0044] Description of reference numerals: 1. Control structure; 11. Conductive layer; 12. Insulating layer; 2. Diode structure; 21. Ferroelectric semiconductor layer; 22. Half-metal layer; 23. First electrode; 24. Second electrode;

[0045] 100. Programmable non-volatile ferroelectric Schottky diode; 200. Control circuit; 201. Voltage source; 300. Device; 400. Test device. Detailed implementation manners

[0046] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments of the disclosed implementation manners below.

[0047] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "perpendicular", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0048] In the present application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath", and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0049] In addition, terms such as "first", "second", "third", etc. are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. Exemplarily, the first electrode may also be referred to as the second electrode, and the second electrode may also be referred to as the first electrode. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0050] In the present application, unless otherwise clearly specified and defined, terms such as "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a flexible connection, or a rigid connection along at least one direction; it may be a mechanical connection, or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, or there may be an intermediate medium while being directly connected, and it may also be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly defined. Terms such as "mounted", "arranged", and "fixed" may be understood in a broad sense as connections. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0051] The terms "layer" and "region" used in the present application refer to a part of the material that includes a certain area and has a certain thickness. The layer can extend horizontally, vertically, and / or along a conical surface. The layer can be a region 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. The layer can include multiple layers, which can be multiple stacked layers or multiple layers extending discretely. The shapes of various regions and layers in the drawings, as well as their relative sizes and positional relationships, are only exemplary and may actually deviate due to manufacturing tolerances or technical limitations, and can be adjusted according to actual needs.

[0052] Reference Figure 1 , Figure 1 shows a method 1000 for manufacturing a programmable non-volatile ferroelectric Schottky diode in an embodiment of the present application. In an exemplary embodiment, the method 1000 for manufacturing a programmable non-volatile ferroelectric Schottky diode includes step S110 and step S120.

[0053] Combined Figure 2 shown, step S110, provides a control structure 1. The control structure 1 may include an insulating layer 12 and a conductive layer 11. Exemplarily, 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 high-conductivity silicon layer, specifically, highly doped silicon. The resistivity of the conductive layer 11 is less than 0.005Ω·cm, for example, the high-conductivity silicon layer may be within 0.001Ω·cm to 0.005Ω·cm. The insulating layer 12 may be a silicon dioxide layer.

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

[0056] The method 1000 for manufacturing a programmable non-volatile ferroelectric Schottky diode may further include a step of cleaning the control structure 1. Specifically, the cleaning solution may include at least one of acetone, isopropyl alcohol, and deionized water, and the cleaning may be performed in multiple steps. The cleaning step ensures that the surface of the control structure 1 is clean and free of contamination, especially the surface of the 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 the control structure 1, the few-layer two-dimensional α-In2Se3 can be transferred to the insulating layer 12 by mechanical stripping to obtain the ferroelectric semiconductor layer 21. The transfer setting of the few-layer two-dimensional material is reliable, which helps to ensure the performance of the device. Exemplarily, 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 few-layer two-dimensional 1T'-MoTe2 can be transferred to the ferroelectric semiconductor layer 21 by mechanical stripping to obtain a semi-metal layer 22. The two-dimensional 1T'-MoTe2 material is a semi-metal type two-dimensional material, which can achieve Schottky contact with the two-dimensional α-In2Se3 material. Step S122 can be the step of achieving Schottky contact between the semi-metal layer 22 and the ferroelectric semiconductor layer 21 in step S120. The transfer setting of the few-layer two-dimensional material is reliable, which helps to ensure the performance of the device.

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

[0062] Reference Figure 2 , along the Z-axis direction, a conductive layer 11, an insulating layer 12, a ferroelectric semiconductor layer 21, and a half-metal layer 22 are stacked in sequence from bottom to top. The ferroelectric semiconductor layer 21 extends out of the half-metal layer 22 along the X-axis direction. The half-metal layer 22 may cover a part of the ferroelectric semiconductor layer 21, such that another part of the ferroelectric semiconductor layer 21 is exposed outside the half-metal layer 22.

[0063] The method 1000 for manufacturing a programmable non-volatile ferroelectric Schottky diode may further include step S130 of forming a first electrode 23 and a second electrode 24. The step of forming the first electrode 23 and the step of forming the second electrode 24 may be performed synchronously, and then electrodes with basically the same structure are formed. 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, forming a mask (not shown). Specifically, the mask may be formed by a laser direct writing exposure process. The mask includes a first pattern corresponding to the ferroelectric semiconductor layer 21 and a second pattern corresponding to the half-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, by a first thermal evaporation process, an ohmic contact layer may be formed at the first pattern and the second pattern respectively. The material of the ohmic contact layer is a metal, which may include titanium, nickel, platinum, or chromium. The metal material can be plated on the ferroelectric semiconductor layer 21 and the half-metal layer 22. The ohmic contact layer may be chromium, and the ohmic contact effect is good.

[0067] Exemplarily, the thickness range of the ohmic contact layer is 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, by a second thermal evaporation process, a corresponding covering layer may be formed 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 may be selected from gold, silver, copper, platinum, and palladium.

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

[0070] Step S130 can form the first electrode 23 and the second electrode 24 with good electrical performance and long service life. 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, which can protect the ferroelectric material, especially the two-dimensional α-In2Se3, and avoid phase change.

[0071] Reference Figure 2 and Figure 3 , the method 1000 for manufacturing a programmable non-volatile ferroelectric Schottky diode according to the embodiments of the present application can manufacture the programmable non-volatile ferroelectric Schottky diode 100. The steps of the method 1000 for manufacturing a programmable non-volatile ferroelectric Schottky diode can also be used to manufacture the device 300. This method manufactures new products based on ferroelectric materials.

[0072] Reference Figure 2 , in an exemplary embodiment, the programmable non-volatile ferroelectric Schottky diode 100 provided by the present application 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 half-metal layer 22. The material of the ferroelectric semiconductor layer 21 includes two-dimensional α-In2Se3, and the half-metal layer 22 makes a Schottky contact with the ferroelectric semiconductor layer 21. The material of the half-metal layer 22 includes two-dimensional 1T’-MoTe2.

[0073] Reference Figure 3 , in an exemplary embodiment, the device 300 includes a programmable non-volatile ferroelectric Schottky diode 100. The device 300 may further include a circuit, and the circuit is electrically connected to the conductive layer 11, the ferroelectric semiconductor layer 21, and the half-metal layer 22 respectively. The device 300 may include a control circuit 200, and the control circuit 200 can be used to form the aforementioned circuit. The control circuit 200 is electrically connected to the conductive layer 11; it is also electrically connected to the ferroelectric semiconductor layer 21, for example, through the first electrode 23. The control circuit 200 may include a voltage source 201 (Us) for applying a polarization voltage to regulate the ferroelectric semiconductor layer 21. In addition, the circuit can also apply a scanning voltage to the diode structure 2 for reading the current.

[0074] Once the rectifying characteristics of a traditional Schottky diode are prepared, they are fixed and cannot be dynamically regulated. Although certain semiconductor devices can achieve characteristic changes through means such as electric fields and stresses, most regulations do not have the non-volatility of "remaining after power-off". Once the external bias voltage is removed, the device often returns to its initial state. In addition, the preparation and process integration of many semiconductor devices are more difficult.

[0075] The programmable non-volatile ferroelectric Schottky diode 100 fills a technological gap. By setting the ferroelectric semiconductor layer 21 of two-dimensional α-In2Se3 and the semimetal layer 22 of two-dimensional 1T’-MoTe2, the formed diode structure 2 is a diode with a Schottky contact of ferroelectric material. By setting the control structure 1, it can be used to control the ferroelectric semiconductor layer 21 and then regulate the rectifying characteristics of the Schottky diode structure 2.

[0076] Reference 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 the positive voltage regulation state P up , the programmable non-volatile ferroelectric Schottky diode 100 can also be said to be in the positive voltage regulation state. Taking the Z-axis direction as the up and down direction, when the polarization is upward, the negative polarization charges cause the energy band at the interface of the insulating layer 12 of SiO2 material to bend upward. At this time, the ferroelectric semiconductor layer 21 is in a high-resistance state. When the polarization is upward, it also causes the Schottky barrier to become larger at the interface of the semimetal layer 22 of 1T’-MoTe2 material. Figure 6 In , there may be a van der Waals gap (vdW gap) between 1T’-MoTe2 and α-In2Se3, is the Fermi level, is the conduction band, is the valence band, is the Schottky barrier when the polarization is upward.

[0077] Reference 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 the negative voltage regulation state P down . When the polarization is downward, the polarization charge distribution is opposite to that when the polarization is upward. The positive polarization charges cause the energy band at the interface of the insulating layer 12 to bend downward. When the polarization is downward, it also causes the Schottky barrier to become smaller at the interface of the semimetal layer 22. Figure 8 In , is the Schottky barrier when the polarization is downward.

[0078] The programmable non-volatile ferroelectric Schottky diode 100 has the characteristics of a high rectification ratio and a low ideality factor. At the same time, it can also realize functions such as programmable, non-volatile regulation, and multi-state storage. The programmable non-volatile ferroelectric Schottky diode 100 has broad application prospects in the fields of new memories, reconfigurable circuits, and neuromorphic computing.

[0079] In some embodiments, in the programmable non-volatile ferroelectric Schottky diode 100, the half-metal layer 22, the ferroelectric semiconductor layer 21, the insulating layer 12, and the 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 half-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 good ohmic contact effects with both the ferroelectric semiconductor layer 21 and the half-metal layer 22, effectively ensuring that in the path of the first electrode 23, the ferroelectric semiconductor layer 21, the half-metal layer 22, and the second electrode 24, the Schottky barrier comes from the ferroelectric semiconductor layer 21 and the half-metal layer 22, effectively avoiding the occurrence of a barrier between the metal material and the ferroelectric material, which affects the regulation 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 service lives of the first electrode 23 and the second electrode 24 are good.

[0080] The thickness range of the ferroelectric semiconductor layer 21 is from 30 nm to 50 nm. It will not cause poor conductivity of the diode structure 2 due to the too thick ferroelectric semiconductor layer 21, nor will it be too thin, ensuring the ferroelectricity and the programmable and non-volatile capabilities of the diode structure 2. The thickness range of the half-metal layer 22 is from 10 nm to 30 nm. The thickness of the half-metal layer 22 can affect the electrical properties of the half-metal layer 22. A thinner half-metal layer 22 has a lower resistivity, a higher carrier mobility, and more obvious half-metallicity. However, avoiding being too thin can avoid the reduction of conductivity caused by the quantum confinement effect.

[0081] Reference Figure 4 , the current of the diode structure 2 can be read by using the test device 400. Exemplarily, the device 300 may include the test device 400. The test device 400 may include an ammeter. 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 the negative electrode, and the second electrode 24 can be referred to as the positive electrode.

[0082] Reference Figure 9 , the programmable non-volatile ferroelectric Schottky diode 100 can be in an initial state. The rectifying characteristics of the diode structure 2 are as Figure 9 shown. The abscissa represents the applied sweep voltage between the first electrode 23 and the second electrode 24, and the range is, for example, from -1 V to 1 V. The right ordinate is a linear coordinate, and the left ordinate is a logarithmic coordinate. Under the right linear coordinate, the current-voltage relationship of the diode structure 2 is as follows: the current is small when the voltage is from -1 V to 0.25 V, and the current increases more and more after being greater than 0.25 V. Under the left logarithmic coordinate, the current-voltage relationship of the same diode structure 2 is as follows: the current increases from 0 V to -1 V, and the current increases from 0 V to 1 V and increases more. The rectification ratio of the diode structure 2 is as high as 3×104 Using the Shockley diode equation, the interval from 0 V to 0.4 V of the rectification curve in logarithmic coordinates is fitted to obtain data points and the ideality factor. , close to an ideal Schottky diode.

[0083] Reference Figure 10 , this application provides a programming method 200, which is based on the programmable non-volatile ferroelectric Schottky diode 100 described above, the device 300 described above, or the programmable non-volatile ferroelectric Schottky diode manufactured by the steps of the method 1000 described above. The programming method 200 includes: applying a polarization voltage between the conductive layer 11 and the ferroelectric semiconductor layer 21.

[0084] The programming method 200 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 without an external voltage.

[0085] Exemplarily, the programming method 200 includes at least one of steps S210 to S230.

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

[0087] 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] Step S230, in response to a second regulation requirement, a second polarization voltage is applied between the conductive layer 11 and the ferroelectric semiconductor layer 21. The first polarization voltage and the second polarization voltage can respectively refer to +30 V, +60 V, -30 V or -60 V. Not applying a polarization voltage can mean that the voltage is 0 V.

[0089] Reference Figure 4 , the programming method 200 can program the programmable non-volatile ferroelectric Schottky diode 100 of the exemplary embodiment, wherein the material of the insulating layer 12 is SiO2; the material of the conductive layer 11 is highly conductive silicon; the ferroelectric semiconductor layer 21 is few-layer two-dimensional α-In2Se3; the semimetal layer 22 is few-layer two-dimensional 1T’-MoTe2. The thickness of the ferroelectric semiconductor layer 21 of two-dimensional α-In2Se3 along the Z-axis direction is approximately 50 nm, and the thickness of the semimetal layer 22 of two-dimensional 1T’-MoTe2 is approximately 20 nm. The ohmic contact layer is a 10-nm-thick chromium layer. The covering layer is a 50-nm-thick gold layer. The programmable non-volatile ferroelectric Schottky diode 100 is easy to implement and has good performance.

[0090] Reference Figure 11, it is possible to test the product before and after programming, or to test multiple products in different states. Figure 11 The current curves of the diode structure 2 in three states are shown in Figure 11 . Specifically, the diode structure 2 can be in an initial state, a first regulated state with a negative polarization voltage of -30 V applied to the conductive layer 11, and a second regulated state with a negative polarization voltage of -60 V applied to the conductive layer 11. It can be implemented based on Figure 4 the circuit shown. Refer to Figure 7 and Figure 8 . The polarization direction of two-dimensional α-In2Se3 is downward, and positive polarization charges accumulate at the interface between the insulating layer 12 of the SiO2 material and two-dimensional α-In2Se3. The energy band on the side of two-dimensional α-In2Se3 corresponding to the insulating layer 12 bends downward, and two-dimensional α-In2Se3 is in a low-resistance state. The Schottky barrier at the interface between two-dimensional 1T’-MoTe2 and two-dimensional α-In2Se3 decreases, and the rectification curve of the diode structure 2 becomes larger compared to the curve in the initial state. Moreover, due to different polarization degrees, the resulting barrier changes are also different, and different magnitudes of current are presented when the diode structure 2 is measured.

[0091] Refer to Figure 12 , it is possible to test the product before and after programming, or to test multiple products in different states. Figure 12 The current curves of the diode structure 2 in three states are shown in Figure 12 . Specifically, the diode structure 2 can be in an initial state, a third regulated state with a positive polarization voltage of +30 V applied to the conductive layer 11, and a fourth regulated state with a positive polarization voltage of +60 V applied to the conductive layer 11. It can be implemented based on Figure 4 the circuit shown. Refer to Figure 5 and Figure 6 . The polarization direction of two-dimensional α-In2Se3 is upward, and negative polarization charges accumulate at the interface between the insulating layer 12 of the SiO2 material and two-dimensional α-In2Se3. The energy band bends upward, two-dimensional α-In2Se3 is in a high-resistance state, the Schottky barrier at the interface between two-dimensional 1T’-MoTe2 and two-dimensional α-In2Se3 increases, and the rectification curve of the diode structure 2 becomes smaller compared to the curve in the initial state. Moreover, due to different polarization degrees, the resulting barrier changes are also different, and different magnitudes of current are presented when the diode structure 2 is measured.

[0092] Refer to Figure 13 , in each polarization mode of the horizontal voltage, except for the two extreme states where the ferroelectric polarization is 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 for five polarization modes are shown in Figure 13 , and the intermediate states show obvious differences.

[0093] Refer to Figure 14, for each programmable non-volatile ferroelectric Schottky diode 100 after the action of each polarization voltage, a good rectifying effect is exhibited, and the rectification ratio is close to or greater than 4 orders of magnitude.

[0094] Reference Figure 15 , the ideality factor of the programmable non-volatile ferroelectric Schottky diode 100 in each state is close to or less than 2, the rectifying curve has excellent performance, showing nearly ideal Schottky diode characteristics.

[0095] Reference Figure 16 , after removing the polarization voltage applied to the conductive layer 11 and the ferroelectric semiconductor layer 21, the ferroelectric semiconductor layer 21 exhibits good non-volatile characteristics. The current of the diode structure 2 with a fully upward state regulated by a +60 V polarization voltage can be kept stable, and the current of the diode structure 2 with a fully downward state regulated by a -60 V polarization voltage can be kept stable, and there is a gap between the current values in the two states.

[0096] The programmable non-volatile ferroelectric Schottky diode 100 of the embodiment of the present application has at least one of the following technical effects.

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

[0098] Programmable regulation of rectifying characteristics. Through ferroelectric polarization flipping or partial flipping, dynamic adjustment of the barrier height is realized, enabling reversible regulation of the rectifying curve during use, breaking through the limitation of the fixed rectifying characteristics of traditional Schottky diodes.

[0099] Non-volatile storage ability. Since the ferroelectric polarization can be maintained for a long time without an external electric field, the regulated rectifying characteristics can be stored stably for a long time, avoiding the problem that ordinary semiconductor devices return to the initial state after removing the bias.

[0100] Multistate storage ability. In addition to the two extreme states of "fully upward" and "fully downward" of ferroelectric polarization, the diode structure 2 can also form multiple intermediate states through different degrees of polarization, expanding the storage capacity, and being applicable to analog storage or neuromorphic computing applications. Moreover, the rectification ratio of 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 above-disclosed embodiments can be combined arbitrarily. For the sake of brevity of description, 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, it should be considered to be within the scope described in this specification.

[0102] In the embodiments disclosed above, unless otherwise clearly specified and limited, the execution order of each step is not restricted. For example, steps can be executed in parallel or sequentially in a different order. The sub-steps of each step can also be executed alternately. Various forms of the process described above can be used, and steps can also be reordered, added, or deleted, as long as the desired results of the technical solution provided by this application can be achieved. This application does not impose any restrictions here.

[0103] The embodiments disclosed above only represent several implementation manners of this application. The description is relatively specific and detailed, but it should not be construed as a limitation on the patent protection scope of this application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all fall within the patent protection scope required by this application. Therefore, the patent protection scope of this application shall be subject to the appended claims.

Claims

1. A programmable non-volatile ferroelectric Schottky diode, characterized in that, Comprising: A control structure, including an insulating layer and a conductive layer; And A diode structure, the diode structure being located on a side of the insulating layer facing away from the conductive layer, the diode structure including a ferroelectric semiconductor layer and a half-metal layer, the material of the ferroelectric semiconductor layer including two-dimensional α-In2Se3, the half-metal layer being in Schottky contact with the ferroelectric semiconductor layer, the material of the half-metal layer including two-dimensional 1T’-MoTe2.

2. The programmable non-volatile ferroelectric Schottky diode according to claim 1, wherein The thickness range of the ferroelectric semiconductor layer is from 30 nm to 50 nm, and the thickness range of the half-metal layer is from 10 nm to 30 nm.

3. The programmable non-volatile ferroelectric Schottky diode according to claim 1, characterized in that, The material of the insulating layer is SiO2; the material of the conductive layer is highly conductive silicon; the ferroelectric semiconductor layer is few-layer two-dimensional α-In2Se3; the half-metal layer is few-layer two-dimensional 1T’-MoTe2.

4. The programmable non-volatile ferroelectric Schottky diode according to claim 1, wherein The half-metal layer, the ferroelectric semiconductor layer, the insulating layer and the 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 being in ohmic contact with the ferroelectric semiconductor layer, and the second electrode being in ohmic contact with the half-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. Device, characterized in that, Comprising: The programmable non-volatile ferroelectric Schottky diode according to any one of claims 1 to 5; And A control circuit, electrically connected to the conductive layer and the ferroelectric semiconductor layer.

7. A method for manufacturing a programmable non-volatile ferroelectric Schottky diode, characterized in that, Comprising: Providing a control structure, the control structure including an insulating layer and a conductive layer; And Forming a diode structure stacked on the control structure, the diode structure being located on a side of the insulating layer facing away from the conductive layer, the steps of forming the diode structure including: achieving Schottky contact between a half-metal layer and a ferroelectric semiconductor layer; wherein, the material of the ferroelectric semiconductor layer includes two-dimensional α-In2Se3, and the material of the half-metal layer includes two-dimensional 1T’-MoTe2.

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

9. The method for manufacturing a programmable non-volatile ferroelectric Schottky diode according to claim 7, characterized in that, Further comprising: Forming a mask by laser direct writing exposure process, the mask including a first pattern corresponding to the ferroelectric semiconductor layer and a second pattern corresponding to the half-metal layer; Forming an ohmic contact layer at the first pattern and the second pattern respectively by 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 by 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 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 steps of 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 method according to any one of claims 7 to 9, wherein the programming method comprises: Applying a polarization voltage between the conductive layer and the ferroelectric semiconductor layer.

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