Gating device and preparation method thereof

Abstract

The invention discloses a gating device and a preparation method thereof. The gating device comprises a bottom electrode; the functional layer is located on one side surface of the bottom electrode; the top electrode is located on one side surface of the functional layer away from the bottom electrode; wherein the bottom electrode is made of platinum, the functional layer is made of a carbon-doped germanium telluride film, and the top electrode is made of titanium. Therefore, on the basis of having good compatibility with the phase change memory, the conversion threshold voltage can be reduced, and the conversion voltage fluctuation is relatively small, so that the gating device has good tolerance and consistency; and the power consumption of a peripheral circuit of the integrated circuit can be reduced.

Description

Technical Field

[0001] The present application relates to the field of micro-nanoelectronic technology, and in particular to a gating device and a preparation method thereof. Background Art

[0002] With the development of storage technology, new non-volatile memories have been widely studied and developed. Phase Change Memory (PCM) is one of the new non-volatile memories. It can achieve high integration density through three-dimensional integration, but the problem of crosstalk current will occur in this structure, which will affect the performance of the device and cause misreading of information. To solve this problem, it is particularly important to develop high-performance gating devices; since the bidirectional threshold switch (Ovonic Threshold Switch, OTS) gating device has good compatibility with PCM, it has been widely studied. However, the OTS device in the related technology has the problem of high transition voltage, which brings great trouble to circuit design. Summary of the invention

[0003] The present application proposes a gating device and a preparation method thereof, which can reduce the transition threshold voltage on the basis of having good compatibility with a phase change memory and have a smaller transition voltage fluctuation, so that the gating device has good tolerance and consistency.

[0004] The technical solution of this application is implemented as follows:

[0005] In a first aspect, an embodiment of the present application provides a gating device, the gating device comprising:

[0006] bottom electrode;

[0007] A functional layer, located on a surface of one side of the bottom electrode;

[0008] A top electrode is located on the surface of the functional layer away from the bottom electrode;

[0009] The material of the bottom electrode is platinum, the material of the functional layer is carbon-doped germanium telluride film, and the material of the top electrode is titanium.

[0010] In a second aspect, the present invention provides a preparation method, which comprises:

[0011] Pre-treating the bottom electrode;

[0012] preparing a functional layer on the surface of the bottom electrode;

[0013] A top electrode is prepared on a surface of the functional layer away from the bottom electrode;

[0014] The material of the bottom electrode is platinum, the material of the functional layer is carbon-doped germanium telluride film, and the material of the top electrode is titanium.

[0015] The present application discloses a gating device and a preparation method thereof, wherein the gating device comprises: a bottom electrode; a functional layer located on one side of the bottom electrode; and a top electrode located on the side of the functional layer away from the bottom electrode; wherein the material of the bottom electrode is platinum, the material of the functional layer is a carbon-doped germanium telluride film, and the material of the top electrode is titanium. In this way, on the basis of having good compatibility with phase change memory, the transition threshold voltage can be reduced, and the transition voltage fluctuation is small, so that the gating device has good tolerance and consistency; and for integrated circuits, the power consumption of peripheral circuits can be reduced.

[0016] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not intended to limit the technical solutions of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of a carbon-doped germanium telluride gating device provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of a preparation method provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of an X-ray photoelectron spectroscopy image of a carbon-doped germanium telluride gating device functional layer provided in an embodiment of the present application;

[0020] Figure 4 A schematic diagram of a scanning electron microscope image of a cross section of a carbon-doped germanium telluride gating device provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of low voltage reading of an initial state of a carbon-doped germanium telluride gating device provided in an embodiment of the present application;

[0022] Figure 6 A schematic diagram of an IV curve of a carbon-doped germanium telluride gating device under 10mA current limiting provided in an embodiment of the present application;

[0023] Figure 7 A schematic diagram of the structure of a germanium telluride gating device provided in an embodiment of the present application;

[0024] Figure 8 A schematic diagram of a scanning electron microscope image of a cross section of a germanium telluride gating device provided in an embodiment of the present application;

[0025] Fig. 9 A schematic diagram of low voltage reading of an initial state of a germanium telluride gating device provided in an embodiment of the present application;

[0026] Fig.10 A schematic diagram of a forming process of a germanium telluride gating device provided in an embodiment of the present application;

[0027] Fig.11 A schematic diagram of an IV curve of a germanium telluride gating device under 10mA current limiting provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to enable a more detailed understanding of the features and technical contents of the embodiments of the present application, the implementation of the embodiments of the present application is described in detail below in conjunction with the accompanying drawings. The attached drawings are for reference only and are not used to limit the embodiments of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0030] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0031] It should also be pointed out that the terms "first\second\third" involved in the embodiments of the present application are only used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged in a specific order or sequence where permitted, so that the embodiments of the present application described here can be implemented in an order other than that illustrated or described here.

[0032] In addition, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0033] With the rapid development of science and technology, information technology is leaping forward at an unprecedented speed, and the demand for memory is also increasing, but traditional memory faces huge technical challenges. Therefore, new non-volatile memories have been widely researched and developed, among which phase change memory is one of the new non-volatile memories. It can achieve high integration density through three-dimensional integration, but there will be crosstalk current problems in this structure, which will affect device performance and cause misreading of information. To solve this problem, integrating phase change memory (PCM) and gating devices in series is one of the most effective methods at present. Therefore, it is particularly important to develop high-performance gating devices. Among them, the bidirectional threshold switch (Ovonic Threshold Switch, OTS) gating device has been widely studied due to its good integration characteristics with PCM.

[0034] The following is a brief introduction to the performance parameters of the gating device that measure performance:

[0035] Transition voltage: The transition voltage is mainly divided into threshold voltage V th and holding voltage V hold Among them, V th It means that when voltage is applied to a device, when the voltage increases to a certain value, the device changes from the off state (that is, the device resistance is high resistance) to the on state (that is, the device resistance is low resistance), and the voltage corresponding to the device at this time; V hold It refers to the voltage corresponding to when the device suddenly changes from the on state to the off state when the voltage applied to the device is reduced to a certain value.

[0036] The on-state current refers to the maximum current that can pass through the device when the resistance is low. In the one selector one RRAM (1S1R) structure, the PCM will undergo a material structure transformation during operation, and the amorphization process requires a large drive current. The on-state current of the select device must support the high-low resistance switching of the memory, that is, the writing and erasing of information. Therefore, this parameter should be large enough to drive the working process of the memory. During the test, considering the protection of the device, a limiting current will be applied to the device, that is, the size of the on-state current is the value of the limiting current during the device test.

[0037] The off-state current refers to the current flowing through the device when the device is in the off state with high resistance. In order to reduce the crosstalk current and reduce the impact of the crosstalk effect, this parameter should be small enough.

[0038] Selectivity: Since adjacent memory cells will have leakage current, resulting in voltage drop, crosstalk effect will occur and cause misreading. When the selectivity is large, the leakage current generated to the adjacent cells will be reduced, the voltage drop will also be reduced, and the crosstalk effect will be reduced. There are two ways to read the selectivity ratio. The 1 / 2 reading method is used, that is, the current I (V th ) and the current at half the threshold voltage The ratio is calculated as follows:

[0039]

[0040] In the related technology, the gating devices mainly include Metal Insulator Transition (MIT) gating devices, Field Assisted Super Linear Threshold (FAST) gating devices, OTS gating devices of germanium sulfide (GeS) and OTS gating devices of germanium telluride (GeTe). The following is a brief introduction to these types of gating devices:

[0041] 1. In MIT gating devices, Mott insulators such as niobium dioxide (NbO2) and vanadium dioxide (VO2) have the MIT effect; at low temperatures, the material exhibits an insulating phase with a large resistivity; at high temperatures, the material exhibits a metallic phase with a high conductivity. This type of gating device usually consists of two inert electrodes sandwiching a functional layer. When an external bias is applied, the local contact between the titanium nitride (TiN) bottom electrode and the NbO2 film will generate Joule heat, causing the NbO2 temperature to rise. When the temperature reaches the transition temperature of NbO2, NbO2 will change from the insulating phase to the metallic phase, causing the device current to increase rapidly, thereby driving the gating device from the closed state (abbreviated as "OFF state") to the open state (abbreviated as "ON state"); when the bias decreases, the Joule heat generated will also decrease. At the same time, due to the heat dissipation of the material itself, when the temperature of NbO2 is lower than the transition temperature, NbO2 will change from the metallic phase to the insulating phase, causing the device current to drop sharply, driving the gating tube from the ON state to the OFF state; it can be seen that the MIT gating tube exhibits volatile threshold transition behavior. Although this type of gating device has good threshold transition characteristics, its material system is not well compatible with PCM.

[0042] 2. FAST gating devices use a special insulating superlinear threshold (SLT) material. When the applied voltage reaches the threshold transition voltage, the gating device switches from the OFF state to the ON state. It is worth noting that when the thickness of the intermediate layer increases, the threshold transition voltage of the gating device also increases, indicating that the threshold transition of this type of gating device is driven by an electric field. Although FAST gating devices exhibit excellent gating performance, with very low OFF-state current, extremely high gating ratio, fast switching speed and excellent durability, their material system is not well compatible with PCM.

[0043] 3. GeS's OTS gating device adopts a typical sandwich structure. This material is a sulfur (S) compound medium. Under the drive of an electric field, a volatile threshold transition behavior will occur. With the GeS compound as the intermediate functional layer, when the applied voltage reaches the threshold transition voltage, the device switches from the OFF state to the ON state. When the applied voltage reaches the holding transition voltage, the device switches from the ON state to the OFF state. Although GeS's OTS gating device exhibits excellent gating performance, specifically, it has very low OFF state current, extremely high gating ratio, fast switching speed and excellent durability, it has problems such as excessive transition voltage and complex components, which makes circuit design difficult.

[0044] 4. The GeTe OTS gating device adopts a typical sandwich structure. This material is a germanium (Te) compound medium. Under the drive of the electric field, a volatile threshold transition behavior will occur. With the GeTe compound as the intermediate functional layer, when the applied voltage reaches the threshold transition voltage, the device switches from the OFF state to the ON state. When the applied voltage reaches the holding transition voltage, the device switches from the ON state to the OFF state. Although the Te-based threshold device has a small transition voltage and simple materials, it can effectively solve the problems of the selenium (Se) base, but it also has problems such as low gating ratio and poor tolerance.

[0045] It can be seen that since the material systems of MIT gating devices and FAST gating devices are incompatible with PCM, although they have good threshold transition performance, they are limited in their application to PCM. In contrast, OTS gating devices and PCM have good compatibility characteristics. In related technologies, OTS material systems are mainly studied on Se and tellurium (Te) based materials. Among them, the representative Se-based material is germanium selenide (GeSe), and doping materials based on GeSe have also been widely studied, such as the doping of elements such as nitrogen, silicon, arsenic and antimony to optimize the threshold transition performance of the original device. However, GeSe OTS devices perform well in many performance parameters, but there is a problem of high transition voltage, such as a transition voltage greater than 3 volts (V), which brings great trouble to circuit design. In addition, by doping multiple elements to optimize their performance, the elemental material components are at least quaternary or even quinary, making their composition complicated.

[0046] In short, with the development of storage technology, new non-volatile memories have been widely researched and developed. Among them, PCM is one of the new non-volatile memories. It can achieve high integration density through three-dimensional integration, but the problem of crosstalk current will appear in this structure, which will affect the performance of the device and cause misreading of information. To solve this problem, it is particularly important to develop high-performance gating devices; because the gating devices of OTS have good compatibility with PCM, they have been widely studied. However, the OTS devices in the related technology have the problem of high transition voltage, which brings great trouble to circuit design.

[0047] Based on this, the embodiment of the present application provides a gating device, which can be specifically an OTS gating device of carbon-doped germanium telluride; the gating device includes: a bottom electrode; a functional layer, located on one side of the bottom electrode; and a top electrode, located on the side of the functional layer away from the bottom electrode; wherein the material of the bottom electrode is platinum, the material of the functional layer is a carbon-doped germanium telluride film, and the material of the top electrode is titanium. In this way, on the basis of having good compatibility with phase change memory, the transition threshold voltage can be reduced, and the transition voltage fluctuation is small, so that the gating device has good tolerance and consistency; and for integrated circuits, the power consumption of peripheral circuits can be reduced.

[0048] The present application is further described in detail below through the accompanying drawings and specific embodiments.

[0049] In one embodiment of the present application, Figure 1 A schematic diagram of the structure of a carbon-doped germanium telluride gating device provided in an embodiment of the present application. Figure 1 As shown, the carbon-doped germanium telluride gating device includes:

[0050] bottom electrode;

[0051] A functional layer, located on a surface of one side of the bottom electrode;

[0052] A top electrode is located on the surface of the functional layer away from the bottom electrode;

[0053] The material of the bottom electrode is platinum (Pt), and the material of the functional layer is carbon-doped germanium telluride (GeTe x :C) thin film, the material of the top electrode is titanium (Ti).

[0054] In the embodiments of the present application, the bottom electrode can be called the lower electrode; the top electrode can be called the upper electrode; the functional layer can be called the conversion layer; the gating device can be called a gating tube, or can also be called a gating tube device. It should be noted that the gating device of carbon-doped germanium telluride proposed in the present application belongs to an OTS gating device, which can have good compatibility with PCM in terms of material system.

[0055] In some embodiments, the thickness of the bottom electrode is 150 to 200 nanometers (nm); the shape of the bottom electrode is rectangular, and the side length is 1 to 2 centimeters (cm);

[0056] In some embodiments, the thickness of the functional layer is 61 nm, and the shape of the functional layer is the same as that of the bottom electrode. Here, the thickness of the functional layer can fluctuate within a small range around 61 nm. For example, the thickness of the functional layer can fluctuate within a range of 1 nm. In this case, the thickness of the functional layer can be 60 nm to 62 nm. It should be noted that Figure 1 The shape of the functional layer is the same as that of the bottom electrode, and the side length of the functional layer can also be the same as that of the bottom electrode. Figure 1 Just as an example.

[0057] In some embodiments, the thickness of the top electrode is 0.5 to 1 micrometer (μm); the shape of the top electrode is rectangular or circular, and its side length or diameter is 100 to 900 μm. It should be noted that, Figure 1 The circular top electrode is only an example, and it can also be rectangular, depending on the actual situation.

[0058] In some embodiments, the molar ratio of tellurium, germanium, and carbon in the functional layer is 17.22:80.23:2.55.

[0059] In the embodiment of the present application, in the carbon-doped germanium telluride, the molar percentage of tellurium is 16.72-17.72%, the molar percentage of germanium is 79.73-80.73%, and the molar percentage of carbon is 2.05-3.05%. It should be noted that the corresponding molar percentages of tellurium, germanium and carbon add up to 100%.

[0060] In some embodiments, the carbon-doped germanium telluride gating device further includes a substrate; wherein the substrate is located on a surface of the bottom electrode away from the functional layer.

[0061] In the embodiment of the present application, the substrate may be a silicon (Si) substrate, or a silicon dioxide (SiO2) substrate, or a substrate composed of Si and SiO2. For example, the substrate may be configured with Si on the bottom and SiO2 on the top to provide a better transition through the insulating layer between SiO2 and the substrate and the bottom electrode.

[0062] The embodiment of the present application provides a gating device, which includes: a bottom electrode; a functional layer, located on one side of the bottom electrode; and a top electrode, located on the side of the functional layer away from the bottom electrode; wherein the material of the bottom electrode is platinum, the material of the functional layer is a carbon-doped germanium telluride film, and the material of the top electrode is titanium. In this way, on the basis of having good compatibility with the phase change memory, the transition threshold voltage can be reduced, and the transition voltage fluctuation is small, so that the gating device has good tolerance and consistency; and for integrated circuits, the power consumption of peripheral circuits can be reduced.

[0063] In another embodiment of the present application, Figure 2 The following is a schematic diagram of a preparation method provided in an embodiment of the present application. Here, the preparation method is applied to a gating device of carbon-doped germanium telluride. Figure 2 As shown, the preparation method comprises:

[0064] S201, pre-treating the bottom electrode.

[0065] S202, preparing a functional layer on the surface of the bottom electrode.

[0066] S203, preparing a top electrode on the surface of the functional layer away from the bottom electrode.

[0067] In the embodiment of the present application, the material of the bottom electrode is Pt, the material of the functional layer is a carbon-doped germanium telluride film, and the material of the top electrode is Ti.

[0068] In some embodiments, for step S201, the specific process may include:

[0069] The platinum conductive surface of the platinum substrate was cleaned by scrubbing with anhydrous ethanol, rinsed with deionized water, and then ultrasonically cleaned with deionized water, acetone and anhydrous ethanol for 30 to 40 minutes respectively;

[0070] The cleaned platinum substrate is blown dry, and an insulating tape is attached to one edge of the substrate to form a reserved bottom electrode.

[0071] In the embodiment of the present application, the platinum substrate is cleaned to form a bottom electrode, that is, a Pt bottom electrode is obtained.

[0072] In some embodiments, for step S202, the specific process may include:

[0073] Using germanium telluride and carbon as targets, carbon-doped germanium telluride is deposited on the surface of the bottom electrode by magnetron sputtering;

[0074] The sputtering power of the germanium telluride target is set to 20 to 40 watts (W), and the sputtering power of the carbon target is 3 to 6 W; the sputtering time of the germanium telluride target and the carbon target is 1500 to 2100 seconds.

[0075] In the embodiment of the present application, a carbon-doped germanium telluride thin film is prepared by a magnetron thin film growth method. A germanium telluride target and a carbon target are installed on a magnetron thin film growth device; the Pt bottom electrode obtained in step S201 is placed in the magnetron thin film growth device, the magnetron thin film growth device is turned on, the film growth power of the germanium telluride target and the carbon target is set to 30W and 3W respectively, the film growth time is set to 1800 seconds, and after the deposition is completed, the magnetron thin film growth device is turned off to obtain a carbon-doped germanium telluride functional layer. Figure 3 A schematic diagram of an X-ray photoelectron spectroscopy image of a carbon-doped germanium telluride gating device functional layer provided in an embodiment of the present application. Figure 3 In the three sub-graphs shown, the horizontal axis is the binding energy, which uses electron volts (eV) as the unit; the vertical axis is the intensity, which uses arbitrary units (au), indicating that this intensity is measured in arbitrary units. Figure 3 As shown, Figure 3 The left figure (a) shows the Ge element in the conversion layer. Figure 3 The middle figure (b) shows the Te element in the functional layer. Figure 3 The right figure (c) shows the carbon element in the functional layer, indicating that the conversion layer contains these three elements, indicating that carbon has been successfully doped into the germanium telluride film, thereby obtaining a carbon-doped germanium telluride film.

[0076] In some embodiments, for step S203, the specific process may include:

[0077] Using titanium as a target, a top electrode is prepared on the surface of the functional layer away from the bottom electrode by magnetron sputtering.

[0078] The sputtering power of the metal titanium target is 30 to 50 W, and the sputtering time of the metal titanium target is 1500 to 2100 seconds.

[0079] In the embodiment of the present application, a top electrode is prepared on the surface of a carbon-doped germanium telluride film by a magnetron film growth method. A metal titanium target is installed on a magnetron film growth device; the magnetron film growth device is turned on, and the carbon-doped germanium telluride film obtained in step S202 is placed in the magnetron film growth device, and the film growth power of the metal titanium target is set to 40W, and the film growth time is set to 1800 seconds. After the deposition is completed, the magnetron film growth device is turned off, thereby obtaining a gating device of carbon-doped germanium telluride. Figure 4 A schematic diagram of a scanning electron microscope image of a cross section of a carbon-doped germanium telluride gating device provided in an embodiment of the present application, such as Figure 4 As shown, the scanning electron microscope image shows a three-layer structure, indicating that the three-layer thin films of bottom electrode, functional layer and top electrode have been successfully deposited.

[0080] In some embodiments, both the germanium telluride target and the carbon target can be sputtered using radio frequency magnetron sputtering, and the metal titanium target can be grown using direct current magnetron film growth.

[0081] It should be noted that the magnetron thin film growth method can be a magnetron sputtering method, or it can be called a magnetron sputtering coating technology, so the magnetron thin film growth equipment can also be a magnetron sputtering equipment, the thin film growth power can be called the sputtering power, and the thin film growth time can be called the sputtering time. In addition, radio frequency magnetron sputtering can be called radio frequency magnetron thin film growth, and direct current magnetron sputtering can be called direct current magnetron thin film growth.

[0082] In the embodiment of the present application, after the carbon-doped germanium telluride gating device is prepared, the performance of the gating device is tested using a semiconductor parameter analyzer, as follows:

[0083] The gating device is placed on a probe station, and a voltage-applied probe is used to contact the platinum electrode, and a grounded probe is used to contact the titanium electrode; a low voltage reading is performed on the device to determine its initial resistance state, and a scanning voltage of -200 millivolts (mV) to 200 mV is applied. The initial resistance state of the device is a high resistance state through low voltage reading. Figure 5 Then, a current limit (Icc) of 10 mA and a DC sweep voltage of 0V to 1.5V are applied to test the current-voltage (IV) characteristics of the gate tube. In one sweep cycle, the voltage first increases from 0V to +1.5V, and then gradually sweeps back from +1.5V to 0V, as shown in the figure below. Figure 6 The IV curve shown in Figure 1 shows a typical threshold switching characteristic. Specifically, when the voltage is swept from 0V to +1.5V, the current drops to +1.5V when the current reaches the transition voltage V. th (about 0.65 ~ 0.78V), and reaches the current limit of 10mA. At this time, the conduction device changes from the closed state to the open state. When the voltage is swept back from +1.5V to 0V, the current decreases to the holding voltage V hold(about 0.5-0.6V), at which time the gating device changes from an on state to a closed state, indicating that a gating device with platinum as a bottom electrode, titanium as a top electrode, and a carbon-doped germanium telluride film as a functional layer has been successfully prepared. In addition, the gating device of the embodiment of the present application uses a carbon-doped germanium telluride film as a functional layer, and has a characteristic of not requiring initialization (Forming), referred to as a "Forming-free feature". Since the Forming process is eliminated, the stability and tolerance of the gating tube device are improved, and the high-voltage power supply module and the current limiting module applied to the device in the circuit design are reduced, which greatly simplifies the circuit and reduces the requirements for circuit design.

[0084] The embodiment of the present application provides a preparation method, which uses magnetron sputtering coating technology to successfully dope carbon into germanium telluride film to prepare a carbon-doped germanium telluride gating device, so that it has good compatibility with PCM in terms of material system. Experimental results show that compared with the gating device before doping, the doped device exhibits a significantly increased off-state resistance value and a significantly decreased off-state current; compared with the chalcogenide-doped OTS gating device, the threshold voltage of the gating device proposed in the embodiment of the present application is significantly reduced. Moreover, for integrated circuits, it can reduce the power consumption of peripheral circuits.

[0085] In another embodiment of the present application, Figure 7 A schematic diagram of the composition structure of a germanium telluride gating device provided in an embodiment of the present application. It should be noted that the structure of the germanium telluride gating device is the same as that of the carbon-doped germanium telluride gating device as a comparative example, except that the material of the functional layer of the germanium telluride gating device is different from that of the carbon-doped germanium telluride gating device. Here, in order to distinguish between the two, the germanium telluride gating device is referred to as gating device 1, and the carbon-doped germanium telluride gating device is referred to as gating device 2. Figure 7 As shown, the gating device 1 includes a substrate, a bottom electrode, a functional layer and a top electrode from bottom to top, wherein:

[0086] The material of the bottom electrode is Pt, and the thickness of the bottom electrode is 150 to 200 nm; the bottom electrode is rectangular, and the side length is 1 cm to 2 cm; the material of the functional layer is germanium telluride film, and the thickness of the functional layer is 58 nm, and the shape of the functional layer is the same as that of the bottom electrode; the material of the top electrode is Ti, and the shape of the top electrode is rectangular or circular, and the diameter or side length of the top electrode is 100 to 90000, Figure 7 The top electrode is circular, which is only an example. The substrate is composed of Si and SiO2. The bottom side of the substrate is Si and the top side is SiO2. 2， To achieve a better transition through the SiO2 and the insulating layer between the substrate and the bottom electrode.

[0087] In yet another embodiment of the present application, the present application also provides a method for preparing a germanium telluride gating device, which may include the following steps:

[0088] Pre-treating the bottom electrode;

[0089] preparing a functional layer on the surface of the bottom electrode;

[0090] A top electrode is prepared on a surface of the functional layer away from the bottom electrode;

[0091] The material of the bottom electrode is Pt, the material of the functional layer is germanium telluride film, and the material of the top electrode is Ti.

[0092] In some embodiments, the specific steps for pre-treating the bottom electrode may include:

[0093] The platinum conductive surface of the platinum substrate was wiped clean with anhydrous ethanol, rinsed with deionized water, and then ultrasonically washed with deionized water, acetone and anhydrous ethanol for 30 minutes respectively;

[0094] The cleaned platinum substrate is blown dry, and an insulating tape is attached to one edge of the substrate to form a reserved bottom electrode.

[0095] In some embodiments, the specific steps for preparing the functional layer on the surface of the bottom electrode may include:

[0096] Taking germanium telluride as a target material, the germanium telluride is deposited on the surface of the bottom electrode by magnetron sputtering;

[0097] The sputtering power of the germanium telluride target is set to 20 to 40 W; the sputtering time of the germanium telluride target is 1500 to 2100 seconds.

[0098] In the embodiment of the present application, a germanium telluride thin film is prepared by a magnetron thin film growth method. A germanium telluride target is installed on a magnetron thin film growth device, and the germanium telluride target is grown by radio frequency magnetron thin film. The obtained Pt bottom electrode is placed in the magnetron thin film growth device, the magnetron thin film growth device is turned on, the film growth power of the germanium telluride target is set to 30W, the film growth time is set to 1800 seconds, and after the deposition is completed, the magnetron thin film growth device is turned off to obtain a functional layer of germanium telluride.

[0099] In some embodiments, the specific steps for preparing the top electrode on the surface of the functional layer away from the bottom electrode may include:

[0100] Using titanium as a target, a top electrode is prepared on the surface of the functional layer away from the bottom electrode by magnetron sputtering.

[0101] The sputtering power of the metal titanium target is 30 to 50 W, and the sputtering time of the metal titanium target is 1500 to 2100 seconds.

[0102] In the embodiment of the present application, a top electrode is prepared on the surface of a germanium telluride film by a magnetron film growth method. A metal titanium target is installed on a magnetron film growth device; the magnetron film growth device is turned on, and the obtained germanium telluride film is placed in the magnetron film growth device, and the film growth power of the metal titanium target is set to 40W, and the film growth time is set to 1800 seconds. After the deposition is completed, the magnetron film growth device is turned off, thereby obtaining a gating device of carbon-doped germanium telluride. Figure 8 A schematic diagram of a scanning electron microscope image of a cross section of a germanium telluride gating device provided in an embodiment of the present application, such as Figure 8 As shown, the scanning electron microscope image shows a three-layer structure, indicating that the three-layer thin films of bottom electrode, functional layer and top electrode have been successfully deposited.

[0103] In the embodiment of the present application, after the germanium telluride gating device is prepared, the performance of the gating device is tested using a semiconductor parameter analyzer, as follows:

[0104] Place the gate device 1 on the probe table, touch the platinum electrode with a voltage probe, and touch the titanium electrode with a grounded probe; perform low voltage reading on the gate device 1 to determine its initial resistance state, apply a scanning voltage of -200mV to 200mV, and read the initial resistance state of the device as high resistance state through low voltage reading. Fig. 9 Then, a current limiting voltage (Icc) of 500 microamperes (μA) and a DC scanning voltage of 0V to 6V are applied to form the gate device 1. The forming process of the gate device 1 is as shown in FIG. Fig.10 As shown. Then, a current limit of 10mA and a DC scanning voltage of 0V to 1.5V are applied to test the IV characteristics of the gate device. In one scanning cycle, the voltage first increases from 0V to +1.5V, and then gradually scans back from +1.5V to 0V; the IV curve shows a typical threshold conversion characteristic as shown in Fig.11 As shown in Figure 2, when the voltage is swept from 0V to +1.5V, the current reaches the transition voltage V th When the voltage is swept back from +1.5V to 0V, the current decreases to the holding voltage V hold (about 0.64 ~ 0.7V) decreases sharply, and the gating device changes from the on state to the off state at this time, indicating that the gating device with platinum as the bottom electrode, titanium as the top electrode and germanium telluride film as the functional layer has been successfully prepared.

[0105] In the embodiment of the present application, by comparing the gating device based on carbon-doped germanium telluride and the gating device based on germanium telluride, that is, comparing the gating device 1 and the gating device 2, the following conclusions can be obtained:

[0106] 1. Compared with the first gate device, the off-state resistance of the second gate device is significantly increased, the off-state current is significantly decreased, and the gating ratio of the second gate device is increased to 425% of that of the first gate device.

[0107] 2. Compared with the first gating device, the threshold voltage and holding voltage of the second gating device are reduced, which can alleviate the power consumption of the peripheral circuit for the integrated circuit.

[0108] In another embodiment of the present application, based on the above embodiment, the present application embodiment prepares a gating device 1 and a gating device 2; wherein, the gating device 1 is the gating device of germanium telluride in the above embodiment, and the gating device 2 is the gating device of carbon-doped germanium telluride in the above embodiment. Here, the structures of the gating device 1 and the gating device 2 are the same, and the thickness of each layer of material is basically the same, except that the materials used for the functional layer are different. Taking the gating device 2 as an example, its structure from top to bottom is: top electrode, functional layer, bottom electrode; wherein, the material of the bottom electrode is platinum, with a thickness of 150 to 200nm, a rectangular shape, and the side length of the bottom electrode is 1cm to 2cm; the material of the functional layer is a carbon-doped germanium telluride film with a thickness of 61nm; and the shape of the functional layer is the same as that of the bottom electrode; the material of the top electrode is titanium, with a thickness of 0.5 to 1μm, and the shape of the top electrode is circular, with a diameter of 100 to 900μm. The gating device 1 and the gating device 2 are specifically described below.

[0109] 1. Selection device 1.

[0110] The gate device 1 uses a platinum substrate as the bottom electrode, with a thickness of 200nm, a rectangular shape, and a side length of 1cm to 2cm; uses a germanium telluride film as the functional layer, with a thickness of 58nm and the same shape as the bottom electrode; uses titanium metal as the top electrode, with a circular or rectangular shape, and a diameter or side length of 100 to 900μm. It should be noted that the gate device 1 requires a forming process, and its structure is as follows Figure 7 shown.

[0111] The preparation process of the gating device 1 includes the following steps:

[0112] Step 1: Clean the substrate. Wipe the conductive surface of the platinum with anhydrous ethanol, rinse it with deionized water several times, and then ultrasonically clean it with deionized water, acetone and anhydrous ethanol for 30 minutes; blow dry the platinum substrate, and stick insulating tape on one side of the substrate to reserve the bottom electrode.

[0113] Step 2: Prepare germanium telluride thin film. Prepare germanium telluride thin film by magnetron thin film growth method. The magnetron thin film growth equipment is equipped with germanium telluride target material, and the germanium telluride target material is grown by radio frequency magnetron thin film. The substrate obtained in the first step is placed in the magnetron thin film growth equipment, and the film growth power of the germanium telluride target material is set to 30W, and the film growth time is set to 1800 seconds.

[0114] The third step is to prepare the top electrode. The top electrode is prepared on the surface of the germanium telluride film by the magnetron film growth method. A metal titanium target is installed on the magnetron film growth device, and the metal titanium target is grown by DC magnetron film growth. The germanium telluride film obtained in the second step is placed in the magnetron film growth device, and the film growth power of the metal titanium target is set to 40W, and the film growth time is set to 1800 seconds. The scanning electron microscope image of a cross section of the gating device is shown in FIG. Figure 8 As shown, the image shows a three-layer structure, indicating that the top electrode and functional layers have been successfully deposited.

[0115] Here, after the preparation of the gate device 1 is completed, the performance of the gate device 1 is tested using a semiconductor parameter analyzer, as follows: the gate device 1 is placed on a probe station, a voltage-applied probe contacts the platinum electrode, and a grounded probe contacts the titanium electrode; a low voltage reading is performed on the gate device 1 to determine its initial resistance state, a scanning voltage of -200mV to 200mV is applied, and the initial resistance state of the device is a high resistance state as shown in the low voltage reading. Fig. 9 Then, a current limiting voltage of 500μA and a DC scanning voltage of 0V to 6V are applied to form the gate device 1. The forming of the gate device 1 is shown in FIG. Fig.10 As shown. Then, a current limit of 10mA and a DC scanning voltage of 0V to 1.5V are applied to test the IV characteristics of the gate device. In one scanning cycle, the voltage first increases from 0V to +1.5V, and then gradually scans back from +1.5V to 0V; the IV curve shows a typical threshold conversion characteristic as shown in Fig.11 As shown in Figure 2, when the voltage is swept from 0V to +1.5V, the current reaches the transition voltage V th When the voltage is swept back from +1.5V to 0V, the current decreases to the holding voltage V hold (about 0.64 ~ 0.7V) decreases sharply, and the gating device changes from the on state to the off state at this time, indicating that the gating device with platinum as the bottom electrode, titanium as the top electrode and germanium telluride film as the functional layer has been successfully prepared.

[0116] 2. Select device 2.

[0117] The second gate device uses a platinum substrate as the bottom electrode, with a thickness of 200nm, a rectangular shape, and a side length of 1cm to 2cm; a carbon-doped germanium telluride film is used as the functional layer, with a thickness of 61nm and the same shape as the bottom electrode; and titanium metal is used as the top electrode, with a circular or rectangular shape and a diameter or side length of 100 to 900μm. It should be noted that the second gate device has a Forming-Free feature, and its structure is as follows Figure 1 shown.

[0118] The preparation process of the second gating device includes the following steps:

[0119] Step 1: Wipe the conductive surface of the platinum clean with anhydrous ethanol, rinse it with deionized water for several times, and then ultrasonically wash it with deionized water, acetone and anhydrous ethanol for 30 minutes; blow dry the platinum substrate, stick insulating tape on one side of the substrate, and reserve the bottom electrode.

[0120] The second step is to prepare carbon-doped germanium telluride thin film. Carbon-doped germanium telluride thin film is prepared by magnetron thin film growth method. Install germanium telluride target and carbon target on the magnetron thin film growth equipment, and both germanium telluride target and carbon target can be grown by radio frequency magnetron thin film; place the bottom electrode obtained in the first step in the magnetron thin film growth equipment, set the film growth power of germanium telluride target and carbon target to 30W and 3W respectively, and set the film growth time to 1800 seconds. The X-ray Photoelectron Spectroscopy (XPS) of the functional layer is shown in the figure below. Figure 3 As shown, the XPS graph shows that carbon is successfully doped into the germanium telluride film, and the molar percentages of Ge, Te, and C are approximately 17.22%, 80.23%, and 2.55%, respectively.

[0121] The third step is to prepare the top electrode. The top electrode is prepared on the surface of the carbon-doped germanium telluride film by the magnetron film growth method. A metal titanium target is installed on the magnetron film growth device, and the metal titanium target is grown by DC magnetron film growth; the carbon-doped germanium telluride film of the second step is placed in the magnetron film growth device, and the film growth power of the metal titanium target is set to 40W, and the film growth time is set to 1800 seconds. The scanning electron microscope image of the second cross section of the gating device is shown in Figure 2. Figure 4 As shown, the image shows a three-layer structure, indicating that the top electrode and functional layers have been successfully deposited.

[0122] Here, after the preparation of the second gate device is completed, the performance of the second gate device is tested using a semiconductor parameter analyzer, as follows: the second gate device is placed on a probe station, a voltage-applied probe contacts the platinum electrode, and a grounded probe contacts the titanium electrode; a low voltage reading is performed on the device to determine its initial resistance state, a scanning voltage of -200mV to 200mV is applied, and the initial resistance state of the device is a high resistance state as shown in the low voltage reading. Figure 5 Then, a current limit of 10mA and a DC scanning voltage of 0V to 1.5V are applied to test the IV characteristics of the gate tube. In one scanning cycle, the voltage first increases from 0V to +1.5V, and then gradually scans back from +1.5V to 0V, as shown in the figure. Figure 6 The IV curve shown in Figure 1 shows a typical threshold switching characteristic. Specifically, when the voltage is swept from 0V to +1.5V, the current drops to +1.5V when the current reaches the transition voltage V. thWhen the voltage is swept back from +1.5V to 0V, the current decreases to the holding voltage V hold (about 0.5-0.6V), and the gating device changes from the on state to the off state, indicating that a gating device with platinum as the bottom electrode, titanium as the top electrode and carbon-doped germanium telluride film as the functional layer has been successfully prepared.

[0123] In addition, in the embodiment of the present application, the germanium telluride material system is selected, and the threshold voltage and holding voltage of the gating device are analyzed. Compared with the OTS device of chalcogenide elements in the related art, the device switching voltage of the gating device of the carbon-doped germanium telluride in the embodiment of the present application is greatly reduced, which will greatly reduce the power consumption of the peripheral circuit. Moreover, by doping the germanium telluride with an appropriate concentration of carbon elements, the gating device of the carbon-doped germanium telluride significantly increases the off-state resistance value, significantly decreases the off-state current, and the gating ratio of the device is also greatly increased.

[0124] In the embodiment of the present application, the gating device 1 and the gating device 2 are compared, and the following conclusions are obtained: compared with the gating device 1, the off-state resistance value of the gating device 2 is significantly increased, the off-state current is significantly decreased, and the gating ratio of the gating device 2 is increased to 425% of that of the gating device 1; compared with the gating device 1, the threshold voltage and holding voltage of the gating device 2 are reduced, which can alleviate the power consumption of the peripheral circuit for the integrated circuit.

[0125] The embodiment of the present application provides a gating device based on carbon-doped germanium telluride and a preparation method thereof. The above embodiment is used to elaborate the specific implementation of the above embodiment, from which it can be seen that an OTS gating device with a "sandwich" structure is prepared by magnetron sputtering technology, the material of the top electrode is Ti, the material of the bottom electrode is Pt, and the material of the intermediate functional layer is a carbon-doped germanium telluride film. By doping an appropriate concentration of carbon elements in the germanium telluride material film, an OTS gating device with good compatibility characteristics with PCM is prepared, which solves the compatibility problem between gating tubes of other material systems and PCM, and significantly improves the gating ratio of the device on the basis of the germanium telluride gating device in the related art; and compared with the OTS device doped with chalcogenide elements in the related art, the threshold voltage of the carbon-doped germanium telluride gating device proposed in the present application is significantly reduced, which can reduce the power consumption of the peripheral circuit for integrated circuits.

[0126] It should be noted that, in this application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, product or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, product or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, product or device including the element.

[0127] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0128] The methods disclosed in several method embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments.

[0129] The features disclosed in several product embodiments provided in this application can be arbitrarily combined without conflict to obtain new product embodiments.

[0130] The features disclosed in several method or device embodiments provided in this application can be arbitrarily combined without conflict to obtain new method embodiments or device embodiments.

[0131] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A gating device, characterized in that: The gating device comprises: bottom electrode; A functional layer, located on one surface of the bottom electrode; A top electrode, located on a surface of the functional layer away from the bottom electrode; The material of the bottom electrode is platinum, the material of the functional layer is carbon-doped germanium telluride film, and the material of the top electrode is titanium.

2. The gating device according to claim 1, characterized in that: The thickness of the bottom electrode is 150 to 200 nanometers; the shape of the bottom electrode is rectangular, and the side length is 1 to 2 centimeters.

3. The gating device according to claim 1, characterized in that: The thickness of the functional layer is 61 nanometers; the shape of the functional layer is the same as that of the bottom electrode.

4. The gating device according to claim 1, characterized in that: The thickness of the top electrode is 0.5 to 1 micrometer, and the shape of the top electrode is rectangular or circular, with a side length or diameter of 100 to 900 micrometers.

5. The gating device according to any one of claims 1 to 4, characterized in that: The molar ratio of tellurium, germanium and carbon in the functional layer is 17.22:80.23:2.

55.

6. A preparation method, characterized in that: Applicable to the gating device according to any one of claims 1 to 5, the preparation method comprising: Pre-treating the bottom electrode; Prepare the functional layer on the surface of the bottom electrode; Prepare a top electrode on the surface of the functional layer away from the bottom electrode; The material of the bottom electrode is platinum, the material of the functional layer is carbon-doped germanium telluride film, and the material of the top electrode is titanium.

7. The preparation method according to claim 6, characterized in that: The pre-processing of the bottom electrode comprises: The platinum conductive surface of the platinum substrate was cleaned by scrubbing with anhydrous ethanol, rinsed with deionized water, and then ultrasonically cleaned with deionized water, acetone and anhydrous ethanol for 30 to 40 minutes respectively; The cleaned platinum substrate is blown dry, and an insulating tape is attached to one edge of the substrate to form a reserved bottom electrode.

8. The preparation method according to claim 6, characterized in that: The step of preparing the functional layer on the surface of the bottom electrode comprises: Using germanium telluride and carbon as target materials, a carbon-doped germanium telluride film is deposited on the surface of the bottom electrode by a magnetron sputtering method; Among them, the sputtering power of the germanium telluride target is set to 20 to 40 watts, and the sputtering power of the carbon target is 3 to 6 watts; the sputtering time of the germanium telluride target and the carbon target is 1500 to 2100 seconds.

9. The preparation method according to claim 8, characterized in that: The step of preparing a top electrode on a surface of the functional layer away from the bottom electrode comprises: Using titanium as a target, a top electrode is prepared on the surface of the functional layer away from the bottom electrode by magnetron sputtering; The sputtering power of the metal titanium target is 30 to 50 watts, and the sputtering time of the metal titanium target is 1500 to 2100 seconds.

10. The preparation method according to claim 9, characterized in that: Germanium telluride targets and carbon targets are both produced by radio frequency magnetron sputtering, and metal titanium targets are produced by direct current magnetron sputtering.

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