Method for preparing high-quality corner two-dimensional n-type semiconductor electronic device

Abstract

The invention discloses a method for preparing a high-quality corner two-dimensional n-type semiconductor electronic device, and the method comprises the steps: picking up a hexagonal boron nitride BN and a corner double-layer n-type TMDc Van der Waals heterojunction through a PPC thin film, and overturning and placing the hexagonal boron nitride BN and the corner double-layer n-type TMDc Van der Waals heterojunction at the center of a dry silicon wafer; carrying out annealing treatment in an ultrahigh vacuum environment; introducing a thin layer h-BN, and forming a Hall bar geometric structure through an etching process; depositing a bismuth and gold metal layer on the surface of the corner double-layer n-type TMDc of the thin layer h-BN by adopting electron beam photoetching and electron beam evaporation technologies; the other thin layer h-BN is picked up and released to the deposited metal electrode; depositing a metal layer on the surface of the device by adopting electron beam photoetching and electron beam evaporation technologies, and preparing a top gate structure of a Hall bar channel; the super-clean Van der Waals interface is constructed, so that the contact resistance of the two-dimensional semiconductor is remarkably reduced, and the super-high carrier mobility is realized.

Description

Technical Field

[0001] The present invention relates to a method for preparing electronic devices, and particularly to a method for preparing high-quality corner two-dimensional n-type semiconductor electronic devices. Background Art

[0002] The preparation quality of electronic devices is one of the key factors affecting their performance. From the perspective of device processes, constructing a super-clean van der Waals interface, reducing the contact resistance of two-dimensional semiconductors, and achieving ultra-high mobility are crucial for the preparation of high-performance devices.

[0003] Especially in the research of two-dimensional n-type corner TMDs, most current research methods mainly rely on optical methods, supplemented by scanning probe techniques for local electrical measurements. Overall, the electrical transport research of corner TMDc is still limited by the device quality. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to improve the quality of corner two-dimensional n-type semiconductor electronic devices.

[0005] Technical Solution: The method of the present invention includes the following steps:

[0006] S1. Pick up hexagonal boron nitride BN and a corner bilayer n-type TMDc van der Waals heterojunction, and place it upside down on a dry silicon wafer;

[0007] S2. Perform annealing treatment in an ultra-high vacuum environment;

[0008] S3. Introduce a thin layer of h-BN, pick up the thin layer of h-BN, release it onto the surface of the corner bilayer n-type TMDc, and perform annealing treatment in an ultra-high vacuum environment;

[0009] S4. Deposit a metal layer on the surface of the corner bilayer n-type TMDc of the thin layer of h-BN to construct a contact;

[0010] S5. Pick up another thin layer of h-BN and release it onto the deposited metal electrode;

[0011] S6. Deposit a metal layer on the device surface to prepare a top-gate structure of a Hall bar channel.

[0012] Preferably, in S1, a PPC thin film is used to pick up the hexagonal boron nitride BN and the corner bilayer n-type TMDc van der Waals heterojunction.

[0013] Preferably, S1 includes: sequentially picking up the hexagonal boron nitride BN, first picking up half of the corner bilayer n-type TMDc van der Waals heterojunction, rotating the angle θ, and then picking up the other half, and placing it upside down at the center of the dry silicon wafer.

[0014] Preferably, the ultra-high vacuum environment is 8.5E-7 hPa.

[0015] Preferably, the annealing treatment is carried out at a temperature of 350 °C and maintained for 30 minutes.

[0016] Preferably, after introducing a thin layer of h-BN in S3, a Hall bar geometry structure is formed.

[0017] Preferably, the Hall bar geometry structure is formed by an etching process.

[0018] Preferably, the metal layer is deposited by electron beam lithography and electron beam evaporation techniques.

[0019] Preferably, the metal layer is composed of bismuth and gold.

[0020] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: 1. By constructing an ultra-clean van der Waals interface, the quality of the twisted electron device is improved; 2. By contacting gold or bismuth with two-dimensional materials, the contact resistance is reduced and the carrier mobility is increased; 2. The preparation method is simple and efficient, with excellent operability and repeatability, showing broad application prospects in the field of twisted two-dimensional n-type semiconductor electronics. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the preparation of a high-quality twisted two-dimensional semiconductor electronic device according to the present invention;

[0022] Figure 2 Schematic diagram of the cross-sectional TEM of the ultra-clean van der Waals heterojunction of the twisted device according to the present invention;

[0023] Figure 3 Schematic diagram of the contact resistance of the twisted two-dimensional semiconductor electronic device according to the present invention;

[0024] Figure 4 Schematic diagram of the Hall mobility of the twisted two-dimensional semiconductor electronic device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] The polyacrylate carbonate PPC film is a flexible material that can deform under external stress without destroying its atomic structure; in addition, the polyacrylate carbonate PPC film also has adhesiveness, and its adhesion characteristics are significantly affected by temperature. At low temperatures, the adhesiveness of the polyacrylate carbonate PPC film increases and can be used to pick up materials from a silicon wafer; at high temperatures, the adhesiveness of the polyacrylate carbonate PPC film decreases, thus realizing the precise release and transfer of materials.

[0027] Such asFigure 1 As shown, a method for fabricating a high-quality two-dimensional n-type semiconductor electronic device with a corner is as follows:

[0028] S1. Select a monolayer transition metal chalcogenide TMDc material with adjacent crystal orientations being the same. Use a polyacrylate carbonate PPC film to pick up hexagonal boron nitride BN with a thickness of about 30 nm. First, pick up half of the corner double-layer n-type TMDc van der Waals heterojunction, then rotate by the required angle θ, and then pick up the other half of the TMDc and flip it and place it at the center of a dry silicon wafer.

[0029] S2. Anneal in an ultra-high vacuum environment of 8.5E-7 hPa at a temperature of 350 °C and hold for 30 minutes to improve the interface quality and remove organic residues.

[0030] S3. Introduce a thin layer of h-BN with a thickness of 5 - 8 nm, form a Hall bar geometry through an etching process, use a new polyacrylate carbonate PPC film to pick up this thin layer of h-BN, release it onto the surface of the corner double-layer n-type TMDc, and perform an annealing treatment in an ultra-high vacuum environment of 8.5E-7 hPa to optimize the interface quality.

[0031] S4. Adopt electron beam lithography and electron beam evaporation techniques to deposit a bismuth / gold (Bi / Au, 6 / 10 nm) metal layer on the surface of the corner double-layer n-type TMDc of the thin layer of h-BN. First, evaporate Bi, and then immediately evaporate Au to construct a high-quality metal / semiconductor contact.

[0032] S5. Pick up another thin layer of h-BN with a thickness of 20 - 30 nm and release it onto the deposited Bi / Au metal electrode to effectively protect the Bi metal from oxidation and at the same time provide an ideal interface condition for the preparation of the subsequent top gate.

[0033] S6. Adopt electron beam lithography and electron beam evaporation techniques to deposit a metal layer on the surface of the semiconductor electronic device to realize the connection of the Bi / Au electrodes and simultaneously define the top gate structure of the Hall bar channel to ensure the stability and functional integrity of the device.

[0034] By characterizing the device interface through a transmission electron microscope (TEM), it can be found that the fabricated electronic device has an ultra-clean van der Waals interface, as Figure 2 shown. In addition, by performing electrical measurements at low temperature (1.5 K), the contact resistance of the two-dimensional semiconductor is significantly reduced, as Figure 3 shown. And an ultra-high carrier mobility is achieved, as Figure 4 shown.

Claims

1. A method for fabricating a high-quality two-dimensional n-type semiconductor electronic device with a corner, characterized in that, It includes the following steps: S1. Pick up hexagonal boron nitride (BN) and a twisted bilayer n-type TMDc van der Waals heterojunction, turn it over and place it on a dry silicon wafer; S2. Perform annealing treatment in an ultra-high vacuum environment; S3. Introduce a thin layer of h-BN, pick up the thin layer of h-BN, release it onto the surface of the twisted bilayer n-type TMDc, and perform annealing treatment in an ultra-high vacuum environment; S4. Deposit a metal layer on the surface of the twisted bilayer n-type TMDc with the thin layer of h-BN to construct a contact; S5. Pick up another thin layer of h-BN and release it onto the deposited metal electrode; S6. Deposit a metal layer on the device surface to prepare the top gate structure of the Hall bar channel.

2. The method according to claim 1, characterized in that In S1, a PPC thin film is used to pick up the hexagonal boron nitride (BN) and the twisted bilayer n-type TMDc van der Waals heterojunction.

3. The method according to claim 1, wherein S1 includes: sequentially pick up the hexagonal boron nitride (BN), first pick up half of the twisted bilayer n-type TMDc van der Waals heterojunction, rotate the angle θ and then pick up the other half, and turn it over and place it at the center of the dry silicon wafer.

4. The method according to claim 1, wherein The ultra-high vacuum environment is 8.5E-7 hPa.

5. The method according to claim 1, characterized in that For the annealing treatment, anneal at a temperature of 350 °C and hold for 30 minutes.

6. The method according to claim 1, wherein After introducing the thin layer of h-BN in S3, a Hall bar geometry structure is formed.

7. The method according to claim 6, wherein The Hall bar geometry structure is formed by an etching process.

8. The method according to claim 1, wherein The metal layer is deposited by electron beam lithography and electron beam evaporation techniques.

9. The method according to claim 1, characterized in that The metal layer is composed of bismuth and gold.

10. The method according to claim 9, characterized in that, First, evaporate bismuth, and then evaporate gold to form the deposited metal layer.

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