CN112397648B - Titanium doping-based niobium oxide gate tube and preparation method thereof - Google Patents
Titanium doping-based niobium oxide gate tube and preparation method thereof Download PDFInfo
- Publication number
- CN112397648B CN112397648B CN202011442707.XA CN202011442707A CN112397648B CN 112397648 B CN112397648 B CN 112397648B CN 202011442707 A CN202011442707 A CN 202011442707A CN 112397648 B CN112397648 B CN 112397648B
- Authority
- CN
- China
- Prior art keywords
- titanium
- gate tube
- niobium oxide
- bottom electrode
- conversion layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N70/00—Solid-state devices without a potential-jump barrier or surface barrier, and specially adapted for rectifying, amplifying, oscillating or switching
- H10N70/801—Constructional details of multistable switching devices
- H10N70/881—Switching materials
- H10N70/883—Oxides or nitrides
- H10N70/8833—Binary metal oxides, e.g. TaOx
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N70/00—Solid-state devices without a potential-jump barrier or surface barrier, and specially adapted for rectifying, amplifying, oscillating or switching
- H10N70/011—Manufacture or treatment of multistable switching devices
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N70/00—Solid-state devices without a potential-jump barrier or surface barrier, and specially adapted for rectifying, amplifying, oscillating or switching
- H10N70/011—Manufacture or treatment of multistable switching devices
- H10N70/021—Formation of the switching material, e.g. layer deposition
- H10N70/026—Formation of the switching material, e.g. layer deposition by physical vapor deposition, e.g. sputtering
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N70/00—Solid-state devices without a potential-jump barrier or surface barrier, and specially adapted for rectifying, amplifying, oscillating or switching
- H10N70/801—Constructional details of multistable switching devices
- H10N70/841—Electrodes
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Physical Vapour Deposition (AREA)
Abstract
The invention provides a titanium doping-based niobium oxide gate tube and a preparation method thereof, wherein the gate tube comprises: a bottom electrode; the conversion layer is positioned on one side surface of the bottom electrode; the top electrode is positioned on the surface of one side, away from the bottom electrode, of the conversion layer; wherein the material of the conversion layer is titanium-doped niobium oxide. Compared with the niobium oxide gate tube not doped with titanium, the titanium-doped niobium oxide gate tube needs to be externally added with a Forming voltage of-5.15V, and the gate tube can only show the performance of threshold conversion after the Forming process. The titanium-doped niobium oxide gate tube can directly show the threshold conversion performance without a Forming process, has the Forming-free characteristic, can greatly relieve the design pressure of a peripheral circuit, and protects a device from being damaged by large voltage.
Description
Technical Field
The invention relates to the technical field of information storage, in particular to a titanium doping-based niobium oxide gate tube and a preparation method thereof.
Background
In recent years, with the rise of new technologies such as big data, 5G communication, artificial intelligence, cloud computing and the like, the amount of information required to be stored and read is increasing, and therefore, a memory with better performance is required to meet the requirements of the new technologies on data storage. The mainstream semiconductor memory in commercial use at present is a floating gate structure Flash memory (Flash) memory, however, in recent 30 years, the floating gate Flash memory has not been improved in particular in other aspects except for the reduction in feature size. The characteristic size of the current floating gate flash memory is reduced to a nanometer level, and at the moment, due to the fact that many theoretical and technical limitations are faced, the size is difficult to further reduce; meanwhile, the planar integrated architecture of the system is difficult to further improve the storage density to meet the demand of people in the 21 st century for the amount of stored information. Therefore, it is necessary to develop new memories based on new materials and new structures. The currently developed novel memory represented by a Resistive Random Access Memory (RRAM) based on nonvolatile resistance transformation has a series of advantages of good expandability, low energy consumption, fast switching speed, long endurance time, simple device structure and the like.
However, when a memory is integrated to prepare an array with a high storage density to store a large amount of data, a crosstalk effect is very significant due to interference of adjacent cells in the array, thereby causing data read errors. In order to solve the problem of misreading caused by crosstalk effect, the main solution at present is to integrate the memory and a selector in series. The currently studied selector includes a gate transistor (selector) having a rectifying characteristic, a diode, and a transistor.
The gate tube device is of a two-end structure, the transistor is of a three-end structure, and the structure of the gate tube device is simpler than that of the transistor and good in expandability. The unique bipolar symmetry of the gate tube device, as compared to the diode, allows no polarity limitation in reading and writing data after integration. And the gate device can well control the leakage current, therefore, the gate device is considered as the most promising device to be finally applied in the novel three-dimensional memory stack.
However, most gate devices manufactured by the prior art require a Forming process to convert the device from an initial state to a high-impedance state after the gate device is manufactured, so as to activate the device, and the device exhibits threshold transition based on volatility after activation, so that the gate device has a selective function, which increases the complexity of memory circuit operation. Considering that the size of the current devices is smaller and smaller, the integration level is higher and higher, and if each device needs to apply a large Forming voltage to activate the device, the circuit design is strictly restricted.
Because a large voltage is usually applied to the gate tube in the Forming process, the resistance of the gate tube is unknown changed although the gate tube is activated. And the larger Forming voltage can also cause irreversible damage to the internal structure of the gate tube, possibly reducing the stability and the tolerance of the gate tube, which seriously hinders the wide-range application of the gate tube device. The existence of the Forming process puts higher requirements on the circuit design when the gate tube and the memory are integrated. When a large voltage is applied for Forming, in order to avoid breakdown of the device, current limiting needs to be arranged on the device, an additional high-voltage power supply module and a current limiting module are needed during circuit design, and the circuit design and the device test are heavy burdens.
Based on the technical defects that the prior gate tube device needs a Forming process after being manufactured, the improvement is needed.
Disclosure of Invention
In view of this, the invention provides a niobium oxide gate tube based on titanium doping and a preparation method thereof, so as to solve the technical problem that all gate tube devices in the prior art need to form after being manufactured.
In a first aspect, the present invention provides a titanium doping-based niobium oxide gate tube, including:
a bottom electrode;
the conversion layer is positioned on one side surface of the bottom electrode;
the top electrode is positioned on the surface of one side, away from the bottom electrode, of the conversion layer;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Optionally, the material of the bottom electrode is one of Ti, pt, W or TiN; the top electrode is made of one of Pt or Ti.
Optionally, the thickness of the bottom electrode is 150 to 180nm, the thickness of the conversion layer is 35 to 230nm, and the thickness of the top electrode is 85 to 200nm.
Optionally, in the titanium-doped niobium oxide-based gate tube, the bottom electrode and the conversion layer have the same shape, the bottom electrode is rectangular, and the side length of the bottom electrode is 2 μm to 2cm; the top electrode is rectangular or circular, and the side length or the diameter of the top electrode is 50-300 mu m.
In a second aspect, the invention also provides a preparation method of the titanium-doped niobium oxide gate tube, which comprises the following steps:
providing a bottom electrode;
preparing a conversion layer on the surface of the bottom electrode;
preparing a top electrode on the surface of one side of the conversion layer far away from the bottom electrode;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Optionally, the preparation method of the titanium-doped niobium oxide gate tube includes the following specific steps:
and taking niobium pentoxide, titanium dioxide or metallic titanium as a target material, and depositing on the surface of the bottom electrode by using a magnetron sputtering method to obtain the titanium-doped niobium oxide.
Optionally, in the preparation method of the titanium-doped niobium oxide gate tube, the process conditions controlled by the magnetron sputtering method are as follows: the pressure is 2-6 Torr, the temperature is 280-320K, the sputtering power of the niobium pentoxide target is 50-120W, the sputtering power of the titanium dioxide target is 20-50W or the sputtering power of the metallic titanium target is 15-21W, and the niobium pentoxide target, the titanium dioxide target or the metallic titanium target are sputtered simultaneously.
Optionally, in the preparation method of the titanium-doped niobium oxide gate tube, the top electrode is made of Pt or Ti, and the top electrode is prepared on the surface of the conversion layer on the side away from the bottom electrode by using a magnetron sputtering method with Pt or Ti as a target material.
Optionally, in the preparation method of the titanium-doped niobium oxide gate tube, the process conditions for preparing the top electrode are as follows: the pressure was 4Torr, the temperature was 300K, and the sputtering power was 40 to 100W.
Optionally, in the preparation method of the titanium doping-based niobium oxide gate tube, the niobium pentoxide target material and the titanium dioxide target material are subjected to radio frequency magnetron sputtering, and the metal titanium target material is subjected to direct current sputtering.
Compared with the prior art, the niobium oxide gate tube based on titanium doping has the following beneficial effects:
(1) Compared with the niobium oxide gate tube not doped with titanium, the titanium-doped niobium oxide gate tube needs to be externally added with a Forming voltage of-5.15V, and the gate tube can only show the performance of threshold conversion after the Forming process. The titanium-doped niobium oxide gate tube can directly show the performance of threshold conversion without a Forming process, has the characteristic of Forming-free, can greatly relieve the design pressure of a peripheral circuit, and protects a device from being damaged by large voltage;
(2) Under the condition of the same size, the ON-state current of the titanium-doped gate tube can reach 30mA, while the ON-state current of the non-doped titanium gate tube does not exceed 500 muA, so that the ON-state current density of the titanium-doped gate tube is increased by about 100 times, and the device has overshoot resistance due to large current density.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic structural diagram of a titanium-doped niobium oxide-based gate tube in example 1 of the present invention;
FIG. 2 is a process flow chart of the preparation method of the titanium doped niobium oxide based gate tube in example 1 of the present invention;
FIG. 3 is a schematic structural diagram of a titanium-doped niobium oxide-based gate tube in example 2 of the present invention;
FIG. 4 is an X-ray photoelectron spectrum of a conversion layer of a gate tube prepared in example 1 of the present invention;
FIG. 5 is a cross-sectional scanning electron microscope of a gate tube prepared in example 1 of the present invention;
FIG. 6 is a low voltage read diagram of the initial state of the gate tube prepared in example 1 of the present invention;
FIG. 7 is an I-V curve diagram of a gate tube prepared in example 1 of the present invention;
FIG. 8 is a cross-sectional scanning electron microscope image of a gate tube prepared in example 2 of the present invention;
FIG. 9 is the I-V curve diagram of the gate tube prepared in example 2 of the present invention;
FIG. 10 is a cross-sectional scanning electron microscope image of a gate tube prepared in example 3 of the present invention;
FIG. 11 is the I-V curve of the gate tube prepared in example 3 of the present invention;
FIG. 12 is the I-V curve of the gate tube prepared in example 4 of the present invention;
FIG. 13 is an I-V curve diagram of a gate tube prepared in example 5 of the present invention;
FIG. 14 is a scanning electron microscope image of the cross section of the gate tube prepared in comparative example 1;
FIG. 15 is a schematic diagram of a Forming process of the gate tube prepared in comparative example 1;
FIG. 16 is the I-V curve under the current limit of 300 μ A of the gate tube prepared in comparative example 1;
FIG. 17 is a graph of the I-V curve at 500 μ A restriction for the gate tube prepared in comparative example 1.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Example 1
As shown in fig. 1, the present invention provides a titanium doped niobium oxide gate tube, comprising:
a bottom electrode 1;
the conversion layer 2 is positioned on the surface of one side of the bottom electrode;
the top electrode 3 is positioned on the surface of one side of the conversion layer 2, which is far away from the bottom electrode 1;
wherein the material of the conversion layer 2 is titanium doped niobium oxide.
In the present example, the conversion layer 2 is a titanium-doped niobium oxide (Ti-doped NbO) thin film x ) The niobium oxide film (NbO) x Film) is a compound of niobium and oxygen with a non-stoichiometric ratio, mainly containing Nb 2 O 5 And NbO 2 Wherein Nb 2 O 5 Under the stimulation of large Forming voltage, more oxygen vacancies are generated inside and are gathered together to form a conductive filament, so that the Nb is formed 2 O 5 Exhibits a low resistance state and exhibits conductivity. After the voltage is removed, nb 2 O 5 The conductive filaments in the inner layer are not broken and have nonvolatile properties. When a reverse voltage is applied, the conductive filament consisting of oxygen vacancies is broken due to the drift of oxygen vacancies, and Nb 2 O 5 The film exhibits a high resistance state and exhibits insulation properties. NbO 2 The Mott insulator has phase change characteristics, can change from an insulating tetragonal phase to a metal rutile phase under the action of heat, electricity, light, magnetism and the like, greatly increases the conductivity, changes from the metal rutile phase back to the insulating tetragonal phase after external stimulus is removed, reduces the conductivity and has volatility. In the gate tube, the threshold value conversion of the device under the stimulation of an external voltage depends on NbO 2 Is achieved by the phase change of (1). The reason why the gate tube of the invention can realize the Forming-free (Forming is not needed) is that: existing NbO in the conversion layer of the gate tube 2 The phase transformation region also has Nb 2 O 5 A region of conductive filaments. When Nb 2 O 5 Filament integrity of domains, nbO 2 Gate tubes occur during transition between the insulating tetragonal phase and the metallic rutile phaseA threshold transition. For undoped devices, the initial resistance is very large, nb 2 O 5 The oxygen vacancies in the regions are rare. After the Forming Process, nb 2 O 5 The regions create a plurality of oxygen vacancies and aggregate together to form conductive filaments, giving the gate tube a threshold transition characteristic. And for doped devices, nb 2 O 5 The region can generate a great number of oxygen vacancies due to titanium doping, and when voltage is applied, the oxygen vacancies can move and gather together to form a conductive filament under the action of an electric field, so that an additional Forming process is not needed in Nb 2 O 5 The region creates oxygen vacancies. Therefore, the gating tube device does not need a Forming process and has the Forming-free characteristic.
Specifically, the material of the bottom electrode in the embodiment of the present application is one of Ti, pt, W, or TiN; the material of the top electrode is one of Pt or Ti; specifically, in the embodiment of the present application, the bottom electrode is made of TiN, and the top electrode is made of Pt.
Specifically, in the embodiment of the present application, the thickness of the bottom electrode 1 is 150nm, the shape thereof is rectangular, and the side length is 2 μm; the conversion layer 2 has a thickness of 35nm, a rectangular shape with a side length of 2 μm; the top electrode 3 has a thickness of 200nm and is rectangular in shape with side lengths of 2 μm.
Based on the same inventive concept, the invention also provides a preparation method of the titanium doping-based niobium oxide gate tube, as shown in fig. 2, which comprises the following steps:
s1, providing a bottom electrode;
s2, preparing a conversion layer on the surface of the bottom electrode;
s3, preparing a top electrode on the surface of one side, far away from the bottom electrode, of the conversion layer;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Specifically, in the embodiment of the present application, S1 specifically includes: for the area with TiN bottom electrode of 4.0 μm 2 The surface pretreatment is carried out on the square film-carrying substrate to obtain the bottom electrode, and the pretreatment specifically comprises the following steps: cleaning the substrate with the TiN bottom electrode by using acetone, absolute ethyl alcohol and deionized water in sequence;
specifically, in the embodiment of the present application, S2 specifically includes: a conversion layer is prepared on the surface of a bottom electrode by utilizing a magnetron sputtering method, specifically, a niobium pentoxide target material and a titanium dioxide target material are respectively arranged on a magnetron sputtering device, and argon (Ar) is used as inert gas and is introduced into a vacuum chamber of the magnetron sputtering device. The niobium pentoxide target and the titanium dioxide target are both subjected to radio frequency magnetron sputtering, the substrate with the TiN bottom electrode in the S1 is placed in magnetron sputtering equipment, a magnetron sputtering power supply is started, the system pressure in a vacuum chamber is controlled to be 4Torr, the temperature is controlled to be 300K, the sputtering powers of the niobium pentoxide target and the titanium dioxide target are respectively set to be 120W and 50W, the two targets start sputtering simultaneously, the sputtering time is set to be 650S, and after the deposition is finished, the magnetron sputtering power supply is closed, so that a titanium-doped niobium oxide conversion layer is obtained;
specifically, in the embodiment of the present application, S3 specifically includes: and (2) preparing a top electrode on the surface of the conversion layer of the titanium-doped niobium oxide by utilizing a magnetron sputtering technology, specifically, installing a metal platinum target on a magnetron sputtering device, wherein the metal platinum target adopts a direct-current magnetron sputtering method, placing the conversion layer of the titanium-doped niobium oxide obtained in the step (S2) in the magnetron sputtering device, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power to be 100W and the sputtering time to be 900S, closing the magnetron sputtering power supply after the deposition is finished, and cooling to room temperature to finish the preparation of the platinum top electrode.
Example 2
As shown in fig. 3, the present invention provides a titanium doped niobium oxide gate tube, comprising:
a bottom electrode 1;
the conversion layer 2 is positioned on the surface of one side of the bottom electrode;
the top electrode 3 is positioned on the surface of one side of the conversion layer 2, which is far away from the bottom electrode 1;
wherein the material of the conversion layer 2 is titanium doped niobium oxide.
Specifically, the material of the bottom electrode in the embodiment of the present application is one of Ti, pt, W, or TiN; the top electrode is made of one of Pt or Ti; specifically, in the embodiment of the present application, the material of the bottom electrode is Pt, and the material of the top electrode is Ti.
Specifically, in the embodiment of the present application, the thickness of the bottom electrode 1 is about 180nm, the shape is rectangular, and the side length is 1.5cm; the thickness of the conversion layer 2 is about 130nm, the shape is rectangular, and the side length is 1.5cm; the top electrode 3 has a thickness of about 41nm, is circular in shape and has a diameter of 100 μm, and in the specific embodiment of the present application, the top electrode 3 is distributed on the surface of the conversion layer 2 in an array.
Based on the same invention concept, the invention also provides a preparation method of the titanium-doped niobium oxide gate tube, which comprises the following steps:
s1, providing a bottom electrode;
s2, preparing a conversion layer on the surface of the bottom electrode;
s3, preparing a top electrode on the surface of the conversion layer far away from the bottom electrode;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Specifically, in the embodiment of the present application, S1 specifically includes: firstly, dipping a cotton swab in absolute ethyl alcohol to clean a Pt conductive surface, washing the Pt conductive surface with deionized water for multiple times, and then ultrasonically cleaning the Pt conductive surface with acetone, absolute ethyl alcohol and deionized water for 30 minutes respectively; and drying the cleaned Pt substrate by blowing. Attaching a narrow insulating tape at one side edge of the substrate to form a reserved electrode, namely obtaining a Pt bottom electrode;
specifically, in the embodiment of the present application, S2 specifically includes: a conversion layer is prepared on the surface of a bottom electrode by utilizing a magnetron sputtering method, specifically, a niobium pentoxide target material and a metal titanium target material are respectively arranged on a magnetron sputtering device, and argon (Ar) is used as inert gas and is introduced into a vacuum chamber of the magnetron sputtering device. The method comprises the following steps of (1) performing radio frequency magnetron sputtering on a niobium pentoxide target material, performing direct current sputtering on a metal titanium target material, placing a Pt bottom electrode in S1 in magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, respectively setting the sputtering power of the niobium pentoxide target material and the sputtering power of the metal titanium target material to be 50W and 21W, starting sputtering of the two targets simultaneously, setting the sputtering time to be 1200S, and after deposition is finished, closing the magnetron sputtering power supply to obtain a titanium-doped niobium oxide conversion layer;
specifically, in the embodiment of the present application, S3 specifically includes: and (2) preparing a top electrode on the surface of the conversion layer of the titanium-doped niobium oxide by utilizing a magnetron sputtering technology, specifically, installing a metal titanium target on magnetron sputtering equipment, wherein the metal titanium target adopts a direct-current magnetron sputtering method, placing the conversion layer of the titanium-doped niobium oxide obtained in the step (S2) in the magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power to be 40W and the sputtering time to be 1800S, closing the magnetron sputtering power supply after the deposition is finished, and cooling to room temperature to finish the preparation of the titanium top electrode.
Example 3
The invention provides a titanium doping-based niobium oxide gate tube, which comprises:
a bottom electrode 1;
a conversion layer 2 located on one side surface of the bottom electrode;
the top electrode 3 is positioned on the surface of one side of the conversion layer 2, which is far away from the bottom electrode 1;
wherein the material of the conversion layer 2 is titanium doped niobium oxide.
Specifically, the material of the bottom electrode in the embodiment of the present application is one of Ti, pt, W, or TiN; the top electrode is made of one of Pt or Ti; specifically, in the embodiment of the present application, the material of the bottom electrode is Pt, and the material of the top electrode is Ti.
Specifically, in the embodiment of the present application, the thickness of the bottom electrode 1 is about 160nm, the shape is rectangular, and the side length is 2cm; the thickness of the conversion layer 2 is about 230nm, the shape is rectangular, and the side length is 2cm; the top electrode 3 has a thickness of about 86nm, is circular in shape and has a diameter of 400 μm.
Based on the same invention concept, the invention also provides a preparation method of the titanium-doped niobium oxide gate tube, which comprises the following steps:
s1, providing a bottom electrode;
s2, preparing a conversion layer on the surface of the bottom electrode;
s3, preparing a top electrode on the surface of the conversion layer far away from the bottom electrode;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Specifically, in the embodiment of the present application, S1 specifically includes: firstly, dipping a cotton swab in absolute ethyl alcohol to clean a Pt conductive surface, washing the Pt conductive surface with deionized water for multiple times, and then ultrasonically cleaning the Pt conductive surface with acetone, absolute ethyl alcohol and deionized water for 30 minutes; and drying the cleaned Pt substrate by blowing. Attaching a narrow insulating tape at one side edge of the substrate to form a reserved electrode, namely obtaining a Pt bottom electrode;
specifically, in the embodiment of the present application, S2 specifically includes: a conversion layer is prepared on the surface of a bottom electrode by utilizing a magnetron sputtering method, specifically, a niobium pentoxide target material and a titanium dioxide target material are respectively arranged on a magnetron sputtering device, and argon (Ar) is used as inert gas and is introduced into a vacuum chamber of the magnetron sputtering device. Placing a Pt bottom electrode in the S1 into magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, respectively setting the sputtering power of the niobium pentoxide target and the titanium dioxide target to be 60W and 20W, simultaneously starting sputtering by the two targets, setting the sputtering time to be 3000S, and after the deposition is finished, closing the magnetron sputtering power supply to obtain a titanium-doped niobium oxide conversion layer;
specifically, in the embodiment of the present application, S3 specifically includes: and (2) preparing a top electrode on the surface of the conversion layer of the titanium-doped niobium oxide by utilizing a magnetron sputtering technology, specifically, installing a metal titanium target on magnetron sputtering equipment, wherein the metal titanium target adopts a direct-current magnetron sputtering method, placing the conversion layer of the titanium-doped niobium oxide obtained in the step (S2) in the magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power to be 50W and the sputtering time to be 3000S, closing the magnetron sputtering power supply after the deposition is finished, and cooling to room temperature to finish the preparation of the titanium top electrode.
Example 4
The invention provides a titanium doping-based niobium oxide gate tube, which comprises:
a bottom electrode 1;
the conversion layer 2 is positioned on the surface of one side of the bottom electrode;
the top electrode 3 is positioned on the surface of one side of the conversion layer 2, which is far away from the bottom electrode 1;
wherein the material of the conversion layer 2 is titanium doped niobium oxide.
Specifically, the material of the bottom electrode in the embodiment of the present application is one of Ti, pt, W, or TiN; the top electrode is made of one of Pt or Ti; specifically, in the embodiment of the present application, the material of the bottom electrode is Ti, and the material of the top electrode is Ti.
Specifically, in the embodiment of the present application, the bottom electrode 1 is rectangular, and the side length is 1cm; the conversion layer 2 is rectangular and has a side length of 2cm; the top electrode was rectangular in shape with sides of 100 μm.
Based on the same inventive concept, the invention also provides a preparation method of the titanium doping-based niobium oxide gate tube, which comprises the following steps:
s1, providing a bottom electrode;
s2, preparing a conversion layer on the surface of the bottom electrode;
s3, preparing a top electrode on the surface of one side, far away from the bottom electrode, of the conversion layer;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Specifically, in the embodiment of the present application, S1 specifically includes: taking Pt as a substrate, dipping a cotton swab in absolute ethyl alcohol to clean a Pt conductive surface, washing the Pt conductive surface with deionized water for multiple times, then respectively ultrasonically cleaning the Pt conductive surface with deionized water, acetone and absolute ethyl alcohol for 30 minutes, and drying the cleaned Pt substrate for later use; preparing a bottom electrode on the surface of a Pt substrate by utilizing a magnetron sputtering method, specifically, mounting a metal titanium target on magnetron sputtering equipment, introducing argon (Ar) serving as inert gas into a vacuum chamber of the magnetron sputtering equipment, sputtering the metal titanium target by adopting direct current, placing the Pt substrate in the magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in the vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power of the metal titanium target to be 40W and the sputtering time to be 300s, starting sputtering, closing the magnetron sputtering power supply after deposition is finished, attaching a narrow insulating adhesive tape at one side edge of a metal titanium film obtained by monitoring and controlling sputtering to form a reserved electrode, and thus obtaining the Ti bottom electrode;
specifically, in the embodiment of the present application, S2 specifically includes: a conversion layer is prepared on the surface of a bottom electrode by utilizing a magnetron sputtering method, specifically, a niobium pentoxide target material and a titanium dioxide target material are respectively arranged on a magnetron sputtering device, and argon (Ar) is used as inert gas and is introduced into a vacuum chamber of the magnetron sputtering device. The niobium pentoxide target material and the titanium dioxide target material are both subjected to radio frequency magnetron sputtering, the bottom electrode in the S1 is placed in magnetron sputtering equipment, a magnetron sputtering power supply is started, the system pressure in a vacuum chamber is controlled to be 4Torr, the temperature is controlled to be 300K, the sputtering powers of the niobium pentoxide target material and the titanium dioxide target material are respectively set to be 60W and 20W, the two targets start sputtering simultaneously, the sputtering time is set to be 1200S, and after the deposition is finished, the magnetron sputtering power supply is turned off, so that the titanium-doped niobium oxide conversion layer is obtained;
specifically, in the embodiment of the present application, S3 specifically includes: and (2) preparing a top electrode on the surface of the conversion layer of the titanium-doped niobium oxide by utilizing a magnetron sputtering technology, specifically, installing a metal titanium target on magnetron sputtering equipment, wherein the metal titanium target adopts a direct-current magnetron sputtering method, placing the conversion layer of the titanium-doped niobium oxide obtained in the step (S2) in the magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power to be 40W and the sputtering time to be 1800S, closing the magnetron sputtering power supply after the deposition is finished, and cooling to room temperature to finish the preparation of the titanium top electrode.
Example 5
The invention provides a titanium doping-based niobium oxide gate tube, which comprises:
a bottom electrode 1;
the conversion layer 2 is positioned on the surface of one side of the bottom electrode;
the top electrode 3 is positioned on the surface of one side of the conversion layer 2, which is far away from the bottom electrode 1;
wherein the material of the conversion layer 2 is titanium doped niobium oxide.
Specifically, the material of the bottom electrode in the embodiment of the present application is one of Ti, pt, W, or TiN; the material of the top electrode is one of Pt or Ti; specifically, in the embodiment of the present application, the material of the bottom electrode is W (tungsten), and the material of the top electrode is Ti.
Specifically, in the embodiment of the present application, the bottom electrode 1 is rectangular, and the side length is 2cm; the conversion layer 2 is rectangular and has a side length of 2cm; the top electrode was rectangular in shape with a side length of 900 μm.
Based on the same inventive concept, the invention also provides a preparation method of the titanium doping-based niobium oxide gate tube, which comprises the following steps:
s1, providing a bottom electrode;
s2, preparing a conversion layer on the surface of the bottom electrode;
s3, preparing a top electrode on the surface of the conversion layer far away from the bottom electrode;
wherein the material of the conversion layer is titanium-doped niobium oxide.
Specifically, in the embodiment of the present application, S1 specifically includes: taking Pt as a substrate, dipping a cotton swab in absolute ethyl alcohol to clean a Pt conductive surface, washing the Pt conductive surface with deionized water for multiple times, then ultrasonically cleaning the Pt conductive surface with acetone, absolute ethyl alcohol and deionized water for 30 minutes respectively, and drying the cleaned Pt substrate for later use; preparing a bottom electrode on the surface of a Pt substrate by utilizing a magnetron sputtering method, specifically, mounting a metal tungsten target on magnetron sputtering equipment, introducing argon (Ar) serving as inert gas into a vacuum chamber of the magnetron sputtering equipment, sputtering the metal tungsten target by adopting direct current, placing the Pt substrate in the magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in the vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power of the metal tungsten target to be 30W and the sputtering time to be 300s, starting sputtering, closing the magnetron sputtering power supply after deposition is finished, attaching a narrow insulating adhesive tape at one side edge of a metal tungsten film obtained by monitoring and controlling sputtering to form a reserved electrode, and thus obtaining the W bottom electrode;
specifically, in the embodiment of the present application, S2 specifically includes: a conversion layer is prepared on the surface of a bottom electrode by utilizing a magnetron sputtering method, specifically, a niobium pentoxide target material and a titanium dioxide target material are respectively arranged on a magnetron sputtering device, and argon (Ar) is used as inert gas and is introduced into a vacuum chamber of the magnetron sputtering device. The niobium pentoxide target material and the titanium dioxide target material are both subjected to radio frequency magnetron sputtering, the bottom electrode in the S1 is placed in magnetron sputtering equipment, a magnetron sputtering power supply is started, the system pressure in a vacuum chamber is controlled to be 4Torr, the temperature is controlled to be 300K, the sputtering powers of the niobium pentoxide target material and the titanium dioxide target material are respectively set to be 60W and 20W, the two targets start sputtering simultaneously, the sputtering time is set to be 1200S, and after the deposition is finished, the magnetron sputtering power supply is turned off, so that the titanium-doped niobium oxide conversion layer is obtained;
specifically, in the embodiment of the present application, S3 specifically includes: and (2) preparing a top electrode on the surface of the conversion layer of the titanium-doped niobium oxide by utilizing a magnetron sputtering technology, specifically, installing a metal titanium target on magnetron sputtering equipment, wherein the metal titanium target adopts a direct-current magnetron sputtering method, placing the conversion layer of the titanium-doped niobium oxide obtained in the step (S2) in the magnetron sputtering equipment, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power to be 40W and the sputtering time to be 1800S, closing the magnetron sputtering power supply after the deposition is finished, and cooling to room temperature to finish the preparation of the titanium top electrode.
Comparative example 1
This example provides a niobium oxide gate tube, which has the same structure as the niobium oxide gate tube based on titanium doping in example 1, except that the material of the conversion layer is niobium oxide.
The embodiment of the application also provides a preparation method of the niobium oxide gate tube, which comprises the following steps: the method comprises the following steps:
s1, area of the bottom electrode with TiN is 4.0 μm 2 The surface pretreatment is carried out on the square film-carrying base material to obtain the bottom electrode, and the pretreatment specifically comprises the following steps: cleaning the base material with the TiN bottom electrode by using acetone, absolute ethyl alcohol and deionized water in sequence;
s2, preparing a niobium oxide conversion layer by using a magnetron sputtering method, specifically, installing a niobium pentoxide target on magnetron sputtering equipment, introducing argon (Ar) serving as an inert gas into a vacuum chamber of the magnetron sputtering equipment, performing radio frequency magnetron sputtering on the niobium pentoxide target, placing a bottom electrode in the magnetron sputtering equipment in S1, starting a magnetron sputtering power supply, controlling the system pressure in the vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power of the niobium pentoxide target to be 120W, setting the sputtering time to be 800S, and after deposition is finished, closing the magnetron sputtering power supply to obtain the niobium oxide conversion layer;
and S3, preparing a top electrode on the surface of the niobium oxide conversion layer by utilizing a magnetron sputtering technology, specifically, installing a metal platinum target on magnetron sputtering equipment, placing the niobium oxide conversion layer obtained in the step S2 in the magnetron sputtering equipment by adopting a direct-current magnetron sputtering method, starting a magnetron sputtering power supply, controlling the system pressure in a vacuum chamber to be 4Torr and the temperature to be 300K, setting the sputtering power to be 100W and the sputtering time to be 900S, closing the magnetron sputtering power supply after deposition is finished, and cooling to room temperature to obtain the platinum top electrode.
Performance detection
The conversion layer prepared in example 1 was subjected to X-ray photoelectron spectroscopy (XPS), and the results are shown in FIG. 4, in which a shows Nb 2 O 5 And NbO 2 And experimental (experimental) and Fitting (Fitting) curves, and b in fig. 4 shows Ti 2 O 3 And TiO 2 2 The energy spectrum curve of O is shown in c in figure 4, and as can be seen from figure 4, titanium is successfully doped into the niobium oxide film, and the mass fractions of the three elements of Nb, ti and O are 23.68%, 8.62% and 67.71%, respectively; nb in Nb element 5+ And Nb 4+ The mass fractions of which are 58.89 percent and 41.11 percent respectively, and the Ti element in the Ti element 3+ :Ti 4+ The mass fractions of (a) and (b) were 52.60% and 47.40%, respectively. In the magnetron sputtering process, when argon ions obtain kinetic energy to bombard the niobium pentoxide target under the acceleration of an electric field, the sputtered niobium atoms and oxygen atoms are not in proportion of 2. Similarly, the ratio of the sputtered titanium atoms to the sputtered oxygen atoms is not in accordance with the ratio of Ti to O being 1. Therefore, when the sputtered atoms are deposited on the bottom electrode, nbO is formed due to oxygen deficiency 2 And Ti 2 O 3 So that Nb in the film is Nb 2 O 5 And NbO 2 Is present and Ti is Ti 2 O 3 And TiO 2 Are present.
A cross-sectional Scanning Electron Microscope (SEM) image of the titanium doped niobium oxide gate tube prepared in example 1 is shown in fig. 5, which shows a three-layer structure in fig. 5, indicating that a three-layer film of bottom electrode, switching layer and top electrode has been successfully deposited, wherein the bottom electrode is about 150nm, the switching layer is about 35nm, and the top electrode is about 200nm.
The performance of the titanium-doped niobium oxide-based gate tube prepared in example 1 was tested using an agilent B1500A semiconductor parameter analyzer. Specifically, a titanium-doped niobium oxide gate tube is placed on a probe table, a probe for applying voltage is contacted with a bottom electrode (TiN), and another grounded probe is contacted with a top electrode (Pt). The initial resistance state of the gate tube is determined by reading the gate tube at a low voltage, and applying a scan voltage of-200 mV to obtain an I-V curve as shown in FIG. 6. It can be seen from FIG. 6 that the initial resistance state of the gate tube is a high resistance state. Then, a-3V direct current scanning voltage is added to test the I-V characteristic of the gate tube, as shown in fig. 7, in one scanning period of the voltage, the voltage is gradually increased from 0V to +3V, and then gradually retraced from +3V to 0V; then negative scan is performed, increasing from 0V to-3V and then retracing from-3V to 0V, and the number of scan steps for each part in a period is 101, i.e. the current takes 101 points when the voltage is scanned from 0V to + 3V. The measured I-V curves for 100 cycles are shown in fig. 7, which exhibit typical bipolar threshold switching characteristics. In the process of scanning the voltage from 0 to +3V, when the voltage reaches the threshold voltage V of the forward direction th+ (about 1.2V) the current sharply increases to reach a current limit of 20mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state when the gate tube is changed from an insulating phase to a metal phase; during the process of retracing the voltage from +3V to 0, when the voltage is reduced to the holding voltage V of the positive direction hold+ (about 1.2V) in which the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a positive threshold transition, from the metal phase to the insulating phase. During the voltage scanning from 0 to-3V, when the voltage reaches the negative transition voltage V th- (about-1.2V) the current sharply increases, reaching a current limit of 20mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state; flyback from-3V at voltageIn the process of going to 0, when the voltage is reduced to the negative holding voltage V hold (about-1.2V) when the current sharply decreases, at which point NbO 2 The gate tube transitions from the ON state to the OFF state, which is a negative threshold transition. The gate tube exhibits a threshold transition based on volatility and has very good stability. Meanwhile, when the current limit applied to the gate tube reaches 20mA, the gate tube still can show stable threshold conversion characteristics.
A cross-sectional Scanning Electron Microscope (SEM) image of the titanium doped niobium oxide gate tube prepared in example 2 is shown in FIG. 8, which shows a two-layer structure of the bottom electrode and the conversion layer in FIG. 8, indicating that the bottom electrode, the conversion layer has been successfully deposited, wherein the bottom electrode is about 177nm and the conversion layer is about 131nm.
The performance of the titanium-doped niobium oxide-based gate tube prepared in example 2 was tested using an agilent B1500A semiconductor parameter analyzer. Specifically, the insulating tape on the gate tube is removed, the bottom electrode is exposed and placed on a probe station, the bottom electrode (Pt) is contacted with a probe with a voltage applied, and the top electrode (Ti) is contacted with a probe with a ground. Firstly, low-voltage reading is carried out on the gate tube to judge the initial resistance state of the gate tube, a scanning voltage of-200 mV is added, the initial resistance state of the gate tube is judged to be the high resistance state through the low-voltage reading, then a direct current scanning voltage of-3V is applied to test the I-V characteristic of the gate tube, and as shown in figure 9, in a scanning period of the voltage, the voltage is gradually increased from 0V to +3V, and then the voltage is gradually swept back to 0V from + 3V; following a negative scan, increasing from 0V to-3V and then retracing from-3V to 0V, the number of scan steps per portion of a cycle is 101, i.e. the current takes 101 points when the voltage is swept from 0V to +3V, and the measured I-V curve for 100 cycles is shown in FIG. 9, which shows a typical bipolar threshold switching characteristic. As can be seen from FIG. 9, during the voltage sweep from 0 to +3V, when the voltage reaches the threshold voltage V in the forward direction th+ (about 1.3V) the current increased sharply to reach a current limit of 10mA, at which point NbO 2 The gate tube is changed from an OFF state to an ON state; during the process of flyback from +3V to 0Voltage reduction to a holding voltage V in the forward direction hold+ (about 1.2V) in which the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a positive threshold transition, from the metal phase to the insulating phase. During the voltage scanning from 0 to-3V, when the voltage reaches the negative transition voltage V th- (about-1.3V) the current sharply increases to reach a current limit of 10mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state; during the process of flyback from-3V to 0, when the voltage is reduced to negative, the holding voltage V hold (about-1.2V) when the current sharply decreases, at which point NbO 2 The gate tube transitions from the ON state to the OFF state, which is a negative threshold transition. The gate tube has the characteristic of volatile resistance, adopts a titanium-doped niobium oxide film as a conversion layer, and has the Forming-free characteristic.
A cross-sectional Scanning Electron Microscope (SEM) image of the titanium doped niobium oxide gate tube prepared in example 3 is shown in FIG. 10. The bottom, conversion layer and top electrode three-layer structure is shown in FIG. 10, indicating that the bottom, conversion and top electrodes have been successfully deposited, wherein the bottom electrode is about 158nm, the conversion layer is about 229nm and the top electrode is about 86.3nm.
The performance of the titanium-doped niobium oxide-based gate tube prepared in example 3 is tested by using an agilent B1500A semiconductor parameter analyzer, specifically, the insulating tape on the gate tube is removed, the bottom electrode is exposed and placed on a probe table, a probe with a voltage is used to contact the bottom electrode (Pt), a grounded probe is used to contact the top electrode (Ti), the gate tube is read at a low voltage to determine the initial resistance state, a-200 mV scan voltage is added, the initial resistance state of the gate tube is determined to be the high resistance state by reading at the low voltage, and then a-2V dc scan voltage is applied to test the I-V characteristic of the gate tube, as shown in fig. 11, the voltage is gradually increased from 0V to +2V and then gradually swept back from +2V to 0V in one scan period of the voltage; then, negative scan is performed, increasing from 0V to-2V, and then retracing from-2V to 0V, and the number of scanning steps in each part of one period is 101, i.e. the voltage is scanned from 0V to 0VThe current at +23V takes 101 points, and the measured I-V curve of 100 cycles is shown in FIG. 11. As can be seen from FIG. 11, the I-V curve shows the typical bipolar threshold switching characteristic when the voltage reaches the forward threshold voltage V during the voltage sweep from 0 to +2V th+ (about 1.2V) the current increased sharply to reach a current limit of 5mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state when the gate tube is changed from an insulating phase to a metal phase; during the process of retracing the voltage from +2V to 0, when the voltage is reduced to the holding voltage V of the positive direction hold+ (about 0.9V) in which the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a positive threshold transition, from the metal phase to the insulating phase. During the voltage sweep from 0 to-2V, the transition voltage V when the voltage reaches the negative direction th- (about-1.2V) the current sharply increased to reach a current limit of 5mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state when the gate tube is changed from an insulating phase to a metal phase; during the process of retracing the voltage from-2V to 0, when the voltage is reduced to the negative direction, the holding voltage V hold (about-0.9V) when the current sharply decreases, in which case NbO 2 The gate tube is switched from the ON state to the OFF state, which is a negative threshold transition, from the metal phase to the insulating phase. The gate tube has the characteristic of volatile resistance, adopts a titanium-doped niobium oxide film as a conversion layer, and has the Forming-free characteristic.
Testing the performance of the titanium-doped niobium oxide gate tube prepared in example 4 by using an Agilent B1500A semiconductor parameter analyzer, placing the gate tube on a probe station, contacting a bottom electrode (Ti) with a probe with a voltage, contacting a top electrode (Ti) with a grounded probe, reading the gate tube at a low voltage to judge the initial resistance state, adding a scanning voltage of-200 mV, judging that the initial resistance state of the gate tube is the high resistance state by reading the low voltage, and applying a direct current scanning voltage of-2V to test the I-V characteristic of the gate tube, wherein the voltage is gradually increased from 0V to +2V and then gradually retraces from +2V to 0V in a scanning period of the voltage as shown in FIG. 12; then, negative direction scanning is performed, increasing from 0V to-2V, and then retracing from-2V to 0V, wherein the scanning step number of each part in one period is 101, namely, the voltage is scanned from 0V to +2VThe measured I-V curve is shown in FIG. 12 at 101 points, and it can be seen from FIG. 12 that the I-V curve shows a typical bipolar threshold transition characteristic when the voltage reaches the forward threshold voltage V during the voltage sweep from 0 to +2V th+ (about 0.7V) the current sharply increased to reach a current limit of 7mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state when the gate tube is changed from an insulating phase to a metal phase; during the process of retracing the voltage from +2V to 0, when the voltage is reduced to the holding voltage V of the positive direction hold+ (about 0.7V) in which the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a positive threshold transition, from the metal phase to the insulating phase. During the voltage sweep from 0 to-2V, the transition voltage V when the voltage reaches the negative direction th- (about-0.7V) the current increased sharply to reach a current limit of 7mA, at which point NbO 2 The gate tube is changed from an OFF state to an ON state when the gate tube is changed from an insulating phase to a metal phase; during the process of flyback from-2V to 0, when the voltage is reduced to negative, the holding voltage V hold (about-0.7V) when the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a negative threshold transition. The gate tube has the characteristic of volatile resistance, adopts a titanium-doped niobium oxide film as a conversion layer, and has the Forming-free characteristic.
An Agilent B1500A semiconductor parameter analyzer is used for testing the performance of the titanium-doped niobium oxide-based gate tube prepared in the embodiment 5, firstly, the gate tube is placed on a probe station, a probe with voltage is used for contacting a bottom electrode (W), a grounded probe is used for contacting a top electrode (Ti), low-voltage reading is firstly carried out on the gate tube to judge the initial resistance state of the gate tube, a scanning voltage of-200 mV is added, the initial resistance state of the gate tube is judged to be the high resistance state through the low-voltage reading, then a direct-current scanning voltage of-2V is applied to test the I-V characteristic of the gate tube, as shown in figure 13, in one scanning period of the voltage, the voltage is firstly gradually increased from 0V to +2V, and then gradually retraces from +2V to 0V; then negative-going scanning is carried out, increasing from 0V to-2V, and retracing from-2V to 0V, the number of scanning steps in each part of a period is 101, namely, the current takes 101 points when the voltage is scanned from 0V to +2V,the measured I-V curves are shown in FIG. 13. As can be seen from FIG. 13, the I-V curves exhibit a typical bipolar threshold switching characteristic when the voltage reaches the forward threshold voltage V during the voltage sweep from 0 to +2V th+ (about 1.1V) the current sharply increases to reach a current limit of 10mA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state; during the process of retracing the voltage from +2V to 0, when the voltage is reduced to the holding voltage V of the positive direction hold+ (about 0.9V) in which the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a positive threshold transition, from the metal phase to the insulating phase. During the voltage scanning from 0 to-2V, when the voltage reaches the negative transition voltage V th- (about-1.0V) the current increased sharply to reach a current limit of 10mA, at which point NbO 2 The gate tube is changed from an OFF state to an ON state; during the process of flyback from-2V to 0, when the voltage is reduced to negative, the holding voltage V hold (about-0.9V) the current decreases sharply, while NbO 2 The gate tube transitions from the ON state to the OFF state, which is a negative threshold transition. The gate tube has the characteristic of volatile resistance, adopts a titanium-doped niobium oxide film as a conversion layer, and has the Forming-free characteristic.
A cross-sectional Scanning Electron Microscope (SEM) image of the niobium oxide gate tube prepared in comparative example 1 is shown in fig. 14, and a three-layer structure of a bottom electrode, a conversion layer, and a top electrode is shown in fig. 14, indicating that the bottom electrode, the conversion layer, and the top electrode have been successfully deposited, wherein the bottom electrode is about 150nm, the conversion layer is about 35nm, and the top electrode is about 200nm.
The performance of the niobium oxide gate tube prepared in the comparative example 1 was tested by using an Agilent B1500A semiconductor parameter analyzer. Concretely, firstly, placing the probe on a probe station, contacting the probe with applied voltage with a bottom electrode (TiN), contacting the other grounded probe with a top electrode (Pt), firstly, reading the low voltage of the gate tube to judge the initial resistance state, adding a scanning voltage of-200 mV, the initial resistance of the gate tube is extremely large, the whole test circuit is nearly broken, and then applying a scanning voltage of-200 mVA scan voltage of 0V to-7V with a current limit of 500 μ A is applied to form the gate tube, as shown in FIG. 15. When the voltage increases to-5.15V, the current of the gate tube sharply increases to reach the limit of 500 muA, which also means the Forming voltage (V) of the gate tube Forming ) is-5.15V. Then, a-2V direct-current scanning voltage is added to test the I-V characteristic of the gate tube, as shown in fig. 16, in one scanning period of the voltage, the voltage is gradually increased from 0V to +2V, and then gradually retraced from +2V to 0V; a negative scan is then performed, increasing from 0V to-2V, and then retracing from-2V to 0V. The number of scanning steps in each part of a period is 101, i.e. the current takes 101 points when the voltage is scanned from 0V to +2V, and the I-V curve of 100 cycles measured by applying a current limit of 300 μ a during the dc scanning is shown in fig. 16, and as can be seen from fig. 16, the I-V curve also exhibits a typical bipolar threshold switching characteristic. During the voltage scanning from 0 to +2V, when the voltage reaches the threshold voltage V of the forward direction th+ (about 0.9V) the current increased sharply to reach a current limit of 300 muA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state; during the process of retracing the voltage from +2V to 0, when the voltage is reduced to the holding voltage V of the positive direction hold+ (about 0.9V) in which the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a positive threshold transition, from the metal phase to the insulating phase. During the voltage sweep from 0 to-2V, the transition voltage V when the voltage reaches the negative direction th- (about-0.9V) the current increased sharply to reach a current limit of 300 muA, at which time NbO 2 The gate tube is changed from an OFF state to an ON state; during the process of retracing the voltage from-2V to 0, when the voltage is reduced to the negative direction, the holding voltage V hold (about-0.9V) when the current sharply decreases, in which case NbO 2 The gate tube transitions from the ON state to the OFF state, which is a negative threshold transition.
To investigate whether the gate tube prepared in comparative example 1 can normally operate at a high current limit, the current limit was increased to 500 μ a during the dc scan, and the measured I-V curve for 100 cycles is shown in fig. 17. As shown in fig. 17, the gate tube has failed to make a threshold transition, and thus it can be seen that too much restriction causes damage to the gate tube. Therefore, the maximum current limit that the undoped titanium niobium oxide gate tube can endure does not exceed 500 muA.
By comparing the titanium-doped niobium oxide gas pipe prepared in example 1 with the niobium oxide gas pipe prepared in comparative example 1, it can be seen that:
1. for the niobium oxide gate tube which is not doped with titanium in the comparative example 1, a voltage which is more than-5.15V needs to be added to the gate tube to enable the gate tube to undergo the Forming process, and the gate tube can show the threshold conversion performance only through the Forming process, while for the niobium oxide gate tube which is doped with titanium in the example 1, the threshold conversion performance can be directly shown without the Forming process, and the niobium oxide gate tube has the characteristics of Forming-free, so that the design pressure of a peripheral circuit can be greatly relieved, and a device is protected from being damaged by large voltage;
2. under the condition of the same size, the ON-state current of the titanium-doped gate tube in the example 1 can reach 30mA, while the ON-state current of the non-doped gate tube in the comparative example 1 does not exceed 500 muA, so that the ON-state current density of the titanium-doped gate tube is increased by about 100 times, and the device has overshoot resistance due to large current density.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (7)
1. A preparation method of a titanium-doped niobium oxide gate tube is characterized by comprising the following steps:
providing a bottom electrode;
preparing a conversion layer on the surface of the bottom electrode;
preparing a top electrode on the surface of one side of the conversion layer far away from the bottom electrode;
wherein the material of the conversion layer is titanium-doped niobium oxide;
the preparation of the conversion layer on the surface of the bottom electrode specifically comprises the following steps:
taking niobium pentoxide, titanium dioxide or metallic titanium as a target material, and depositing on the surface of the bottom electrode by a magnetron sputtering method to obtain titanium-doped niobium oxide;
the technological conditions controlled by the magnetron sputtering method are as follows: the pressure is 2 to 6Torr, the temperature is 280 to 320K, the sputtering power of the niobium pentoxide target is 50 to 120W, the sputtering power of the titanium dioxide target is 20 to 50W or the sputtering power of the metallic titanium target is 15 to 21W, and the niobium pentoxide target, the titanium dioxide target or the metallic titanium target are sputtered simultaneously.
2. The method for preparing the niobium oxide gate tube based on titanium doping according to claim 1, wherein the material of the bottom electrode is one of Ti, pt, W or TiN; the top electrode is made of one of Pt or Ti.
3. The method for preparing a titanium-doped niobium oxide gate tube as claimed in claim 1, wherein the thickness of the bottom electrode is 150 to 180nm, the thickness of the conversion layer is 35 to 230nm, and the thickness of the top electrode is 85 to 200nm.
4. The method for preparing the titanium-doped niobium oxide gate tube as claimed in claim 1, wherein the bottom electrode and the conversion layer have the same shape, the bottom electrode is rectangular, and the side length of the bottom electrode is 2 μm-2 cm; the top electrode is rectangular or circular, and the side length or the diameter of the top electrode is 50-300 mu m.
5. The method for preparing the niobium oxide gate tube based on titanium doping according to claim 1, wherein the material of the top electrode is Pt or Ti, and the top electrode is prepared on the surface of the conversion layer away from the bottom electrode by a magnetron sputtering method by using Pt or Ti as a target material.
6. The method for preparing the titanium-doped niobium oxide gate tube as claimed in claim 5, wherein the process conditions for preparing the top electrode are as follows: the pressure was 4Torr, the temperature was 300K, and the sputtering power was 40 to 100W.
7. The method for preparing the titanium doping-based niobium oxide gate tube as claimed in claim 1, wherein the niobium pentoxide target material and the titanium dioxide target material are subjected to radio frequency magnetron sputtering, and the metal titanium target material is subjected to direct current sputtering.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011442707.XA CN112397648B (en) | 2020-12-11 | 2020-12-11 | Titanium doping-based niobium oxide gate tube and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011442707.XA CN112397648B (en) | 2020-12-11 | 2020-12-11 | Titanium doping-based niobium oxide gate tube and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112397648A CN112397648A (en) | 2021-02-23 |
| CN112397648B true CN112397648B (en) | 2023-04-07 |
Family
ID=74625699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011442707.XA Active CN112397648B (en) | 2020-12-11 | 2020-12-11 | Titanium doping-based niobium oxide gate tube and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112397648B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106856221A (en) * | 2015-12-09 | 2017-06-16 | 爱思开海力士有限公司 | Switching device and the resistive random access memory including its alternatively device |
| CN108258115A (en) * | 2018-03-16 | 2018-07-06 | 湖北大学 | A kind of 1S1R devices and its manufacturing method based on niobium oxide gate tube and zirconium oxide change resistance layer |
| CN108539014A (en) * | 2018-04-27 | 2018-09-14 | 湖北大学 | A kind of gating device of oxide and preparation method thereof based on niobium |
-
2020
- 2020-12-11 CN CN202011442707.XA patent/CN112397648B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106856221A (en) * | 2015-12-09 | 2017-06-16 | 爱思开海力士有限公司 | Switching device and the resistive random access memory including its alternatively device |
| CN108258115A (en) * | 2018-03-16 | 2018-07-06 | 湖北大学 | A kind of 1S1R devices and its manufacturing method based on niobium oxide gate tube and zirconium oxide change resistance layer |
| CN108539014A (en) * | 2018-04-27 | 2018-09-14 | 湖北大学 | A kind of gating device of oxide and preparation method thereof based on niobium |
Non-Patent Citations (1)
| Title |
|---|
| Ti-Doped GaOx Resistive Switching Memory with Self-Rectifying Behavior by Using NbOx/Pt Bilayers;Ju Hyun Park;《Applied Materials & Interfaces》;20171115;正文第2、6页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112397648A (en) | 2021-02-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Gao et al. | Forming-free and self-rectifying resistive switching of the simple Pt/TaO x/n-Si structure for access device-free high-density memory application | |
| Xu et al. | Bipolar switching behavior in TiN/ZnO/Pt resistive nonvolatile memory with fast switching and long retention | |
| CN108831992B (en) | Resistive random access memory with hafnium-doped zinc oxide resistive layer and preparation method thereof | |
| EP3602561B1 (en) | A switching resistor and method of making such a device | |
| Molina-Reyes et al. | Understanding the resistive switching phenomena of stacked Al/Al 2 O 3/Al thin films from the dynamics of conductive filaments | |
| RU2468471C1 (en) | Method of obtainment of nonvolatile storage element | |
| Napolean et al. | Electroforming atmospheric temperature and annealing effects on Pt/HfO 2/TiO 2/HfO 2/Pt resistive random access memory cell | |
| CN112397648B (en) | Titanium doping-based niobium oxide gate tube and preparation method thereof | |
| Liu et al. | Memristive properties of transparent $({\rm La},\,{\rm Sr}){\rm MnO} _ {3} $ thin films deposited on ITO glass at room temperature | |
| Chiu | Resistance switching characteristics in ZnO-based nonvolatile memory devices | |
| CN101577311A (en) | One-time programming memory and manufacturing method thereof | |
| CN113066927B (en) | Titanium-doped niobium oxide-based 1S1R device and preparation method thereof | |
| Wang et al. | Uniform and electroforming-free resistive memory devices based on solution-processed triple-layered NiO/Al 2 O 3 thin films | |
| CN108232011B (en) | Amorphous strontium titanate thin-film device and preparation method thereof | |
| Wang et al. | Solution processed resistive random access memory devices for transparent solid-state circuit systems | |
| CN112885869A (en) | 1S1R device based on metallic intercalation and preparation method thereof | |
| CN112885868A (en) | 1S1R device based on niobium oxide gate tube and preparation method thereof | |
| KR101009441B1 (en) | Fabrication method of room temperature processed thin film structure multi-layered with metal oxide for high device yield resistive random access memory device | |
| CN101969100A (en) | Nonvolatile resistance-variable storage and preparation method thereof | |
| CN111223986A (en) | Silver intercalation gating device based on hafnium oxide transition layer and manufacturing method thereof | |
| CN105098065A (en) | Preparation method for memory cell of resistive random access memory and product thereof | |
| Chen et al. | HfOx Thin Films for Resistive Memory Device by Use of Atomic Layer Deposition | |
| KR100963828B1 (en) | Thin film structure for resistive random access memory device having narrow set voltage window and the fabrication method thereof | |
| CN111564555B (en) | Resistive random access memory for improving working stability and memory window and preparation method thereof | |
| Wang et al. | Effects of electrode on resistance switching properties of ZnMn 2 O 4 films deposited by magnetron sputtering |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |