CN110890280B - A method for preparing an oxide semiconductor Schottky diode using a palladium/palladium oxide double-layer Schottky electrode - Google Patents

Abstract

The invention relates to a method for preparing an oxide semiconductor Schottky diode by utilizing a palladium/palladium oxide double-layer Schottky electrode, which sequentially comprises a substrate, an active layer and Pd/PdO from bottom to top _X Double-layer structure Pd/PdO _X The double-layer structure sequentially comprises Pd oxide PdO from bottom to top _x Metal Pd, comprising the following steps: (1) growing an ohmic electrode on a substrate; (2) growing an active layer; (3) Pd/PdO formation on active layer using magnetron sputtering _X A double layer structure; (4) annealing under low temperature conditions. The invention can prepare the semiconductor film material which is similar to the target material in composition, compact and good in uniformity, can control the oxidation degree of the Schottky electrode and regulate and control the interface oxygen concentration by controlling the gas atmosphere of the sputtering chamber, can be compatible with various flexible plastic substrates, can be deposited in a large area at low cost, and is beneficial to the industrial conversion and popularization of the oxide semiconductor Schottky diode.

Description

A method of preparing oxide semiconductor Schottky electrodes using palladium/palladium oxide double-layer Schottky electrodes Terki diode method

Technical field

The invention relates to a method for preparing an oxide semiconductor Schottky diode using a palladium/palladium oxide double-layer Schottky electrode, and belongs to the technical field of semiconductor materials and devices.

Background technique

In the 21st century, mankind has entered an era of rapid development of information technology. As one of the important ways of information exchange, flat panel display has also entered the fast lane of development. Thin film transistor (TFT), as the core component of switches and drives, has also been proposed. High-standard requirements, such as higher mobility, low-temperature or even room-temperature processing to be compatible with flexible substrates such as plastics and paper, visible light transparency, etc. Traditional silicon-based devices are no longer able to meet today's needs for flexible and transparent electronics due to complex preparation processes, high process temperatures, difficulty in achieving flexibility, high cost, and opacity.

In recent years, transparent oxide semiconductors represented by indium gallium zinc oxide In-Ga-Zn-O (IGZO) have been favored by researchers at home and abroad. They have high mobility (~10-100cm ² /Vs), The wide bandgap makes it transparent to visible light, can be processed on flexible substrates at room temperature, and can be uniformly filmed over a large area. Like transistors, diodes are also basic components in semiconductor circuits. High-performance Schottky diodes play a vital role in radio frequency ID tags, solar cells, amplifier circuits and logic circuits. Schottky diodes (SBDs) utilize the Schottky barrier formed when metal contacts a semiconductor. This barrier determines its current transmission and capacitance characteristics. Compared with diodes of other structures, Schottky diodes have two main advantages: first, Schottky diodes have small turn-on voltage and on-resistance, making it easier to reduce device power consumption; second, Schottky diodes carry most current There is no minority carrier injection process due to carrier transmission, so its switching speed is fast and it can be used in (ultra) high-frequency applications.

At present, the research on oxide semiconductor Schottky diodes is still in its infancy, and there are few related literature reports at home and abroad. The Japanese Honson group prepared Pt-IGZO Schottky diodes by the PLD method, and then annealed them at high temperature at 200°C to obtain Superior performance (ideality factor 1.04; barrier height 1.2eV; rectification ratio 10 ⁸ ) [DHLee, K.Nomura, T.Kamiya, and H.Hosono, IEEE Electron.Dev.Lett., 32, 1695-1697( 2011).]. The PLD method is difficult to apply in industrial production due to its high preparation cost, and the preparation method requires post-annealing at a high temperature of 200°C, which far exceeds the temperature tolerance of most flexible substrates and greatly limits the application of IGZO SBD in flexible and Application prospects of wearable electronic products. The patent applicant team has developed Pd-IGZO flexible Schottky diodes with excellent DC and high-frequency performance on flexible PET plastic substrates using a non-annealing room temperature process from 2015 to 2019. The DC performance can achieve an ideal factor of 1.09 , switch ratio 2×10 ⁷ [Lulu Du, Jiawei Zhang, Yunpeng Li, Mingsheng Xu, Qingpu Wang and Aimin Song, IEEE Transactions on Electron Devices, 4326-4333 (2018).], high frequency performance can achieve a cutoff of 6.25GHz Frequency [Zhang, J., Li, Y., Zhang, B. et al. Flexible indium–gallium–zinc–oxide Schottky diode operating beyond 2.45GHz. Nat Commun 6, 7561 (2015)], breaking the boundaries of flexible plastic electronics at that time Highest frequency recorded. However, this process must first prepare the Pd Schottky electrode and perform oxygen treatment on the Pd electrode. In actual circuit applications, in order to avoid the impact of other early processes on the Schottky interface, it is usually hoped that the Schottky interface Preparation as a later process.

At present, IGZO Schottky diodes still face many problems: First, it is difficult to obtain a stable and high-quality Schottky junction with IGZO as the semiconductor active layer. This is mainly because the oxide semiconductor has many defects such as oxygen vacancies. , its Schottky interface is very sensitive to the process. Second, the process for preparing IGZO Schottky diodes often requires higher temperature annealing, which limits its process integration and its development in fields such as flexible electronics to a certain extent. Third, the preparation process requires oxygen-rich treatment of the Schottky interface, making it difficult to use the Schottky electrode as the last step of the process. The Schottky electrode is very sensitive to later processes (such as atmosphere, annealing, etc.), so it is difficult to This limits its application in circuit integration to a great extent.

Contents of the invention

In view of the shortcomings of the existing technology, the present invention provides a method for preparing an indium gallium zinc oxide Schottky diode using double-layer palladium oxide contact. This process can realize the preparation of the Schottky electrode as the finishing step in the preparation process. .

Sputtering a Pd/ _PdO A stable and high-performance Schottky diode was prepared, laying the foundation for its application in flexible integrated circuits.

Terminology explanation:

Pd/ _PdO , on the one hand, it enhances the oxygen content of IGZO at the interface, and on the other hand, it increases the work function of Pd; the gas atmosphere deposited on the non-contact surface is pure argon gas, which is conducive to the formation of Pd metal.

The technical solution of the present invention is:

A method for preparing an oxide semiconductor Schottky diode by contacting a sputtered Pd/ _PdO /PdO _X double-layer structure, _the value range of X is 0<X<1, the Pd/ _PdO

(1) Sequentially grow the ohmic electrode and deposit the active layer on the substrate;

(2) Use magnetron sputtering to generate the Pd/PdO _x double-layer structure on the active layer, including the following steps:

A. Put the sample and Pd target into the sputtering chamber and evacuate;

B. Set the sputtering power to 30-100W, and pass in an argon-oxygen gas mixture with an _O2 content of 2.5%-35%. This ratio is the volume ratio of _O2 in the argon-oxygen gas mixture, and maintain the sputtering chamber. The working pressure of the chamber is 3.45-4.00mTorr, and the oxide PdO _x is generated on the active layer with a thickness of 5-20nm;

C. Set the sputtering power to 30-100W, pass in pure Ar, keep the working pressure of the sputtering chamber at 3.55-4.10mTorr, and generate the metal Pd of 20-100nm on the oxide PdO _X ;

(3) Anneal at 50-200°C for 30-90 minutes to obtain.

The present invention adopts the preparation process of magnetron sputtering method, which can prepare semiconductor thin film materials with similar composition to the target material, denseness and good uniformity. By controlling the gas atmosphere of the sputtering chamber, the oxidation degree of the Schottky electrode can be controlled. By controlling the interfacial oxygen concentration, this process is compatible with a variety of flexible plastic substrates (such as PET, PEN, PI, etc.), can be deposited on a large area and at low cost, and is conducive to the industrial transformation and promotion of oxide semiconductor Schottky diodes.

Depositing palladium oxide on the contact layer of the oxide semiconductor Schottky diode first fills the oxygen vacancy defects at the interface, reducing the carrier concentration at the interface, reducing the interface band gap state density and the resulting Fermi level spike. The pinning effect is conducive to the formation of high-quality Schottky contacts; second, the work function of palladium oxide is greater than that of metal palladium, which can form a larger Schottky barrier. On the non-contact upper layer, metal palladium is sputtered, which not only helps reduce the contact resistance between the probe and the metal during testing, but also facilitates probe testing. The present invention uses the magnetron sputtering method to grow a Pd/ _PdO diode.

According to the preferred embodiment of the present invention, the oxide semiconductor Schottky diode is an indium gallium zinc oxide Schottky diode. In step B, the sputtering power is set to 40W, and argon oxygen with an O ₂ content of 25% is introduced. Mix the gas, adjust the working pressure of the sputtering chamber to 3.46mTorr, sputter for 90 seconds, and generate the oxide PdO _X with a thickness of 5 nm on the active layer.

The palladium oxide prepared with the above optimal value contacts the IGZO layer to form a high barrier and a good Schottky contact close to 1 (1.03). Working principle: Palladium oxide is deposited on the IGZO contact layer to fill the interface. The oxygen vacancy defect can significantly reduce the interface state density, thus weakening the Fermi level pinning effect caused by the interface state. Second, the work function of palladium oxide is greater than that of metal palladium, which can form a larger Schottky barrier.

According to the preferred embodiment of the present invention, the oxide semiconductor Schottky diode is an indium gallium zinc oxide Schottky diode. In step C, the sputtering power is set to 40W, pure Ar is introduced, and the operation of the sputtering chamber is adjusted. The gas pressure was 3.75 mTorr, and the metal Pd was formed on the oxide PdO _X with a thickness of 45 nm after sputtering for 10 minutes.

Continuing to deposit metal Pd on the oxide _PdO

According to the preferred embodiment of the present invention, the oxide semiconductor Schottky diode is an indium gallium zinc oxide Schottky diode. In the step (3), a Hotplate is used to anneal at 100°C for 60 minutes in an air environment.

After air annealing at 100°C, the oxygen vacancy concentration of the IGZO layer is reduced, thereby reducing the carrier concentration at the contact surface between the IGZO layer and the _PdO Within the scope, its future application in the field of flexible wearable electronics has broad prospects.

According to the preferred embodiment of the present invention, in the step (1), an electron beam evaporation coating method is used to grow a Ti film on the substrate as the ohmic electrode, including the following steps:

D. Place the substrate and Ti metal source into the electron beam evaporation chamber and evacuate;

E. Evaporate a Ti film with a thickness of 30-100 nm on the substrate.

Further preferably, in step E, a Ti film with a thickness of 50 nm is evaporated on the substrate.

It has good adhesion to the substrate and its roughness is at the atomic level, which is conducive to the formation of ohmic contact.

According to the preferred embodiment of the present invention, the oxide semiconductor Schottky diode is an indium gallium zinc oxide Schottky diode. In the step (1), a magnetron sputtering method is used to grow an IGZO film on the ohmic electrode as The active layer includes the following steps:

F. Put the Ti electrode sample and IGZO ceramic target into the sputtering chamber and evacuate;

G. Set the sputtering power to 50-100W, pass in an argon _- oxygen mixture with an O2 content of 0%-5%, adjust the working pressure of the sputtering chamber to 3.30-4.00mTorr, and sputter for 35 minutes, 43 seconds to 107 minutes. , that is, an IGZO film with a thickness of approximately 50 to 200 nm is obtained.

Suitable growth conditions effectively obtain an IGZO film with a smooth and uniform surface, making it easy to prepare good Schottky contacts.

Further preferably, in the step G, the sputtering power is set to 70W, the O ₂ content is 2.5% argon-oxygen mixture, the working pressure of the sputtering chamber is adjusted to 3.58mTorr, and the sputtering is performed for 71 minutes and 25 seconds, that is, IGZO film with a thickness of 100nm.

Depositing IGZO under the condition of an argon-oxygen mixture with an _O2 content of 2.5% can effectively reduce the oxygen vacancy defects in the IGZO layer, reduce the carriers generated by the oxygen vacancy defects, and make it easier to form a good Schottky contact at the interface.

According to the preferred embodiment of the present invention, the oxide semiconductor Schottky diode is an indium gallium zinc oxide Schottky diode, the substrate is 100-300nm polished SiO ₂ /P ⁺ -Si, and the surface of the substrate has been Polishing makes the surface nearly atomically rough, which is beneficial to the formation of a good Schottky junction. The ohmic electrode is a Ti film of 30-100nm, the active layer is an IGZO film of 50-200nm, _the oxide _PdO The metal Pd is 20-100nm Pd.

Further preferably, the substrate is 100nm polished SiO ₂ /P ⁺ -Si, the ohmic electrode is a 50nm Ti film, the active layer is a 100nm IGZO film, and the oxide _PdO 5nm PdO _X , and the metal Pd is 45nm Pd.

Choosing a 100nm thick IGZO layer satisfies the intrinsic depletion region width of the Schottky diode and can form a better Schottky junction. The 5nm PdOx and 45nm Pd can both form a sufficient oxide layer at the interface and make it easier to establish a Schottky barrier. , and can provide enough thickness for probe testing without damaging the device.

According to the preferred embodiment of the present invention, cleaning the substrate before step (1) means: ultrasonic cleaning with Decon at a power of 90W for 5 minutes, ultrasonic cleaning with deionized water at a power of 90W for 10 minutes, and acetone with Ultrasonic cleaning at 90W power for 5 minutes, ultrasonic cleaning at 90W power with ethanol for 5 minutes, blow dry with nitrogen and set aside.

The beneficial effects of the present invention are:

1. The method of the present invention prepares stable and high-performance Schottky diodes by exploring and optimizing the magnetron sputtering Pd/PdO _X double-layer structure and IGZO air annealing at low temperature (100°C). This method is simple, efficient, easy to repeat, and suitable for industrial large-area production.

2. The Schottky diode prepared by the method of the present invention has excellent electrical properties: ideality factor close to 1 (1.03), high switching current ratio (3×10 ⁷ ), small series resistance (250mΩ·cm ² ), High potential barrier (0.85eV) and high reverse breakdown voltage (11-14V). These excellent electrical properties can be deposited on a large scale by magnetron sputtering and obtained under low temperature (100°C) annealing conditions, making the Schottky diodes prepared by this method have broad application prospects in large-scale flexible integrated circuits in the future. .

Description of drawings

Figure 1 is the AFM image of IGZO film;

Figure 2 is a schematic structural diagram of IGZO SBD;

Figure 3 is a schematic diagram of the J-V curve of IGZO SBD;

Figure 4 is a schematic diagram of the A ² /C ² -V curve of IGZO SBD;

Figure 5 is a schematic diagram of the breakdown curve of IGZO SBD.

Detailed ways

The present invention will be further limited below with reference to the accompanying drawings and examples of the description, but is not limited thereto.

Example 1

A method for preparing an indium gallium zinc oxide Schottky diode using a double-layer sputtering Pd/ _PdO layer, Pd/ _{PdO X} double-layer structure, _the value range of X is 0-1, the Pd/PdO :

(1) Sequentially grow ohmic electrodes and deposit active layers on the substrate;

(2) Use magnetron sputtering to generate a Pd/PdO _x double-layer structure on the active layer, including the following steps:

A. Put the sample and Pd target into the sputtering chamber and evacuate;

B. Set the sputtering power to 30-100W, and pass in an argon-oxygen gas mixture with an _O2 content of 2.5%-35%. This ratio is the volume ratio of _O2 in the argon-oxygen gas mixture, and maintain the sputtering chamber. The working pressure of the chamber is 3.45-4.00mTorr, and 5-20nm oxide PdO _X is generated on the active layer;

C. Set the sputtering power to 30-100W, pass in pure Ar, keep the working pressure of the sputtering chamber at 3.55-4.10mTorr, and generate 20-100nm metal Pd on the oxide PdO _X ;

(3) Anneal at 50-200°C for 30-90 minutes to obtain.

The present invention adopts the preparation process of magnetron sputtering method, which can prepare semiconductor thin film materials with similar composition to the target material, denseness and good uniformity. By controlling the gas atmosphere of the sputtering chamber, the oxidation degree of the Schottky electrode can be controlled. By controlling the interfacial oxygen concentration, this process is compatible with a variety of flexible plastic substrates (such as PET, PEN, PI, etc.), can be deposited on a large area and at low cost, and is conducive to the industrial transformation and promotion of oxide semiconductor Schottky diodes.

Depositing palladium oxide on the contact layer of the oxide semiconductor Schottky diode first fills the oxygen vacancy defects at the interface, reducing the carrier concentration at the interface, reducing the interface band gap state density and the resulting Fermi level spike. The pinning effect is conducive to the formation of high-quality Schottky contacts; second, the work function of palladium oxide is greater than that of metal palladium, which can form a larger Schottky barrier. On the non-contact upper layer, metal palladium is sputtered, which not only helps reduce the contact resistance between the probe and the metal during testing, but also facilitates probe testing. The present invention uses the magnetron sputtering method to grow a Pd/ _PdO diode.

Example 2

According to a method for preparing an indium gallium zinc oxide Schottky diode using double-layer palladium oxide contact as described in Example 1, the difference is that:

In step (1), an electron beam evaporation coating method is used to grow a Ti film on the substrate as an ohmic electrode, including the following steps:

D. Place the substrate and Ti metal source into the electron beam evaporation chamber and evacuate;

E. Evaporate a Ti film with a thickness of 30-100nm on the substrate.

In step (1), a magnetron sputtering method is used to grow an IGZO film as the active layer on the ohmic electrode, including the following steps:

F. Place the Ti electrode sample and IGZO ceramic target into the sputtering chamber and evacuate;

G. Set the sputtering power to 50-100W, pass in an argon _- oxygen mixture with an O2 content of 0%-5%, adjust the working pressure of the sputtering chamber to 3.30-4.00mTorr, and sputter for 35 minutes, 43 seconds to 107 minutes. , that is, an IGZO film with a thickness of approximately 50 to 200 nm is obtained.

The substrate is polished SiO ₂ /P ⁺ -Si with a thickness of 100-300 nm. The surface of the substrate has been polished and the surface is nearly atomically rough, which is conducive to the formation of a good Schottky junction. The ohmic electrode is a Ti film of 30-100nm, the active layer is an IGZO film of 50-200nm, _the oxide _PdO The metal Pd is 20-100nm Pd.

Example 3

According to a method of preparing an indium gallium zinc oxide Schottky diode by sputtering a Pd/ _PdO

In step E, a Ti film with a thickness of 50 nm is evaporated on the substrate. It has good adhesion to the substrate and its roughness is at the atomic level, which is conducive to the formation of ohmic contact.

In step G, set the sputtering power to 70W, pass in the argon-oxygen mixture with an _O2 content of 2.5%, adjust the working pressure of the sputtering chamber to 3.58mTorr, and sputter for 71 minutes and 25 seconds to obtain an IGZO film with a thickness of 100nm. .

Depositing IGZO under the condition of an argon-oxygen mixture with an _O2 content of 2.5% can effectively reduce the oxygen vacancy defects in the IGZO layer, reduce the carriers generated by the oxygen vacancy defects, and make it easier to form a good Schottky contact at the interface.

In step B, set the sputtering power to 40W, pass in an argon-oxygen mixture with an _O2 content of 25%, adjust the working pressure of the sputtering chamber to 3.46mTorr, sputter for 90s, and generate on the active layer Oxide PdO _X with a thickness of 5 nm.

The palladium oxide prepared with the above optimal value contacts the IGZO layer to form a high barrier and a good Schottky contact close to 1 (1.03). Working principle: Deposit palladium oxide with the IGZO contact layer to fill the interface. The oxygen vacancy defect reduces the carrier concentration at the interface, reduces the Schottky interface state density and the resulting Fermi pinning effect, which is more conducive to the formation of high-quality Schottky contacts. Secondly, the palladium oxide The work function is larger than that of metallic palladium and can form a larger Schottky barrier.

In step C, set the sputtering power to 40W, pass in pure Ar, adjust the working pressure of the sputtering chamber to 3.75mTorr, sputter for 10 minutes, and generate metallic Pd with a thickness of 45nm on the oxide PdO _X. Continuing to deposit Pd metal on the Pd metal oxide will not only reduce the contact resistance between the probe and the metal during testing, but also facilitate probe testing.

In step (3), use Hotplate to anneal at 100°C for 60 minutes in an air environment. After air annealing at 100°C, the oxygen vacancy concentration of the IGZO layer is reduced, thereby reducing the carrier concentration at the contact surface between the IGZO layer and the _PdO Within the scope, its future application in the field of flexible wearable electronics has broad prospects.

The substrate is 100nm polished SiO ₂ /P ⁺ -Si, the ohmic electrode is 50nm Ti film, the active layer is 100nm _IGZO film, the oxide _PdO The AFM image of the IGZO film is shown in Figure 1. As can be seen from Figure 1, the surface roughness of the active layer of the sputtered IGZO film is 1.07nm, which better reflects the process versatility of this method for preparing high-performance Schottky diodes.

Choosing a 100nm thick IGZO layer satisfies the intrinsic depletion region width of the Schottky diode and can form a better Schottky junction. The 5nm PdOx and 45nm Pd can both form a sufficient oxide layer at the interface and make it easier to establish a Schottky barrier. , and can provide enough thickness for probe testing without damaging the device.

Detect, analyze and characterize the surface morphology and electrical properties of the magnetron sputtered double-layer _PdO The AgilentB2900 semiconductor analyzer and Agilent E4980A LCR Mater were used to test the electrical performance of the IGZO Schottky diode.

The JV curve of the indium gallium zinc oxide Schottky diode prepared in this embodiment is shown in Figure 3; the abscissa is the voltage applied on the Schottky electrode of the Schottky diode, and the ordinate is the current density (current divided by Schottky Base junction area), it can be seen from Figure 3 that the IGZO SBD prepared in this embodiment exhibits excellent rectification characteristics, with a current switching ratio of 10 ⁷ and a maximum conduction current density of 2.5A·cm ^-2 at a forward voltage of 1V. .

The A ² /C ² -V curve of the indium gallium zinc oxide Schottky diode prepared in this embodiment is shown in Figure 4; the abscissa is the voltage applied on the Schottky electrode of the Schottky diode, and the ordinate is the Schottky Base area squared divided by Schottky capacitance squared. As can be seen from Figure 4, the IGZO SBD prepared in this embodiment has a larger A ² /C ² value, which means that the device has fewer interface defects.

The breakdown curve of the indium gallium zinc oxide Schottky diode prepared in this embodiment is shown in Figure 5; the abscissa is the voltage applied on the Schottky electrode of the Schottky diode, and the ordinate is the current. It can be seen from Figure 5 that the breakdown voltage is 12V, which reflects the good Schottky junction quality.

Table 1 shows various characteristic parameters of the IGZO SBD prepared in this embodiment. IGZO SBD exhibits excellent electrical properties, with low ideality factor (1.03), high rectification ratio (3.0×10 ⁷ ), and low series resistance. (250.3mΩ·cm ² ), high JV curve barrier height 0.85eV), high CV curve barrier height (0.97eV), low background doping concentration (7.12×10 ¹⁶ cm ^-3 ), and high Breakdown voltage (-12.15V).

Table 1

Claims (9)

1. Pd/PdO sputtering method _X The method for preparing the oxide semiconductor Schottky diode by the double-layer structure contact is characterized in that the oxide semiconductor Schottky diode is an indium gallium zinc oxide Schottky diode, and the oxide semiconductor Schottky diode sequentially comprises a substrate, an ohmic electrode, an active layer and Pd/PdO from bottom to top _X Double-layer structure, X is 0 in value range<X<1，Pd/PdO _X The double-layer structure sequentially comprises oxide PdO from bottom to top _X Metal Pd, comprising the following steps:

(1) Sequentially growing the ohmic electrode and depositing the active layer on the substrate;

(2) Generating the Pd/PdO on the active layer using magnetron sputtering _X The double-layer structure comprises the following steps:

A. placing the substrate and Pd target material which are generated in the step (1) and deposit the active layer into a sputtering chamber, and vacuumizing;

B. setting the sputtering power to30-100W, let in O ₂ Argon-oxygen mixture with the content of 2.5-35 percent is introduced into the argon-oxygen mixture to form O ₂ The volume ratio of the oxide PdO is kept between 3.45 and 4.00mTorr, and 5 to 20nm of oxide PdO is generated on the active layer _X ；

C. Setting sputtering power to be 30-100W, introducing pure Ar, keeping the working air pressure of a sputtering chamber to be 3.55-4.10mTorr, and forming the oxide PdO _X Generating 20-100nm of the metal Pd;

(3) Annealing for 60min at 100deg.C by using Hotplate under air environment.

2. A method according to claim 1 using sputtered Pd/PdO _X A method for preparing an oxide semiconductor Schottky diode by double-layer structure contact is characterized in that in the step B, sputtering power is set to be 40W, and O is introduced ₂ Regulating the working pressure of a sputtering chamber to 3.46mTorr by using an argon-oxygen mixture gas with the content of 25 percent, sputtering for 90 seconds, and generating the oxide PdO with the thickness of 5nm on the active layer _X 。

3. A method according to claim 1 using sputtered Pd/PdO _X The method for preparing the oxide semiconductor Schottky diode by the double-layer structure contact is characterized in that in the step C, the sputtering power is set to be 40W, pure Ar is introduced, the working pressure of a sputtering chamber is regulated to be 3.75mTorr, the sputtering is carried out for 10min, and the oxide PdO is obtained _X The metal Pd with the thickness of 45nm is generated.

4. A method according to claim 1 using sputtered Pd/PdO _X The method for preparing the oxide semiconductor Schottky diode by the double-layer structure contact is characterized in that in the step (1), a Ti film is grown on the substrate by using an electron beam evaporation coating method as the ohmic electrode, and the method comprises the following steps:

D. placing a substrate and a Ti metal source into an electron beam evaporation chamber, and vacuumizing;

E. evaporating a Ti film with the thickness of 30-100nm on the substrate.

5. A method according to claim 4, wherein the Pd/PdO is sputtered _X The method for preparing the oxide semiconductor Schottky diode by the double-layer structure contact is characterized in that in the step E, a Ti film with the thickness of 50nm is evaporated on the substrate.

6. A method according to claim 4, wherein the Pd/PdO is sputtered _X The method for preparing the oxide semiconductor schottky diode by the double-layer structure contact is characterized in that in the step (1), an IGZO film is grown on the ohmic electrode by using a magnetron sputtering method as the active layer, and the method comprises the following steps:

F. placing the Ti film and the IGZO ceramic target into a sputtering chamber, and vacuumizing;

G. setting the sputtering power to 50-100W, introducing O ₂ And regulating the working pressure of a sputtering chamber to 3.30-4.00mTorr by using an argon-oxygen mixed gas with the content of 0-5%, and sputtering for 35 minutes, 43 seconds and 107 minutes to obtain the IGZO film with the thickness of 50-200 nm.

7. A method according to claim 6 using sputtered Pd/PdO _X A method for preparing an oxide semiconductor Schottky diode by double-layer structure contact is characterized in that in the step G, sputtering power is set to be 70W, and O is introduced ₂ And regulating the working pressure of a sputtering chamber to 3.58mTorr by using an argon-oxygen mixed gas with the content of 2.5%, and sputtering for 71 minutes and 25 seconds to obtain the IGZO film with the thickness of 100 nm.

8. A method according to claim 1 using sputtered Pd/PdO _X A method for preparing an oxide semiconductor Schottky diode by double-layer structure contact is characterized in that the substrate is polished SiO of 100-300nm ₂ /P ⁺ Si, the ohmic electrode is a Ti film of 30-100nm, the active layer is an IGZO film of 50-200nm, the oxide PdO _X PdO of 5-20nm _x The metal Pd is 20-100nm Pd.

9. A method according to any one of claims 1-8 using sputtered Pd/PdO _X A method for preparing an oxide semiconductor Schottky diode by double-layer structure contact is characterized in that the substrate is polished SiO of 100nm ₂ /P ⁺ Si, the ohmic electrode is a 50nm Ti film, the active layer is a 100nm IGZO film, the oxide PdO _X PdO at 5nm _X The metal Pd is 45nm Pd.