Phase-change-regulated Van der Waals junction type transistor infrared detection chip and preparation method and application of phase-change-regulated Van der Waals junction type transistor infrared detection chip

Abstract

The invention relates to a phase change regulation and control Van der Waals junction type transistor infrared detection chip and a preparation method and application thereof. The unit structure of the Van der Waals junction type transistor infrared detection chip comprises a two-dimensional material layer, a metal electrode, a vanadium dioxide micro-nano structure, an electrical channel and a CMOS reading circuit from top to bottom. The metal electrode comprises a metal grid electrode, an auxiliary electrode, a metal source electrode and a metal drain electrode; two ends of the vanadium dioxide micro-nano structure are respectively connected with the metal grid electrode and the auxiliary electrode, and two ends of the two-dimensional material layer are respectively connected with the metal source electrode and the metal drain electrode; and the electrical channel is connected with the metal electrode and the CMOS reading circuit on the substrate. According to the infrared detection chip prepared by the invention, the response speed of a device is remarkably improved, the response range is widened, ultra-sensitive detection is realized, a self-powered infrared detection chip can be realized, and the infrared detection chip has important significance for reducing the power consumption and the cost of the device.

Description

Technical Field

[0001] The present invention belongs to the field of semiconductor device photoelectric infrared detection, and particularly relates to a phase-change controlled van der Waals junction transistor infrared detection chip, and a preparation method and application thereof. Background Art

[0002] Infrared detection technology is widely used in the military field and the national economy. It can ensure stable observation results under harsh weather conditions and plays a key role in aerospace, optical communications, industrial control, near-infrared imaging and other fields. Traditional infrared detection devices are difficult to further optimize in terms of performance indicators such as responsiveness, response speed and detection wavelength, and there are problems such as the need for low-temperature refrigeration, large size and difficulty in integration, and high cost. Therefore, it is necessary to use new principles and technologies to develop high-performance infrared detectors and chips.

[0003] Two-dimensional materials have unique optical and electrical properties because of their ultra-thin materials with only atomic layer thickness and no dangling bonds. They have broad application prospects in the fields of electronics and optoelectronics, especially room temperature infrared detection, which will significantly reduce the complexity and cost of photoelectric detection systems. In addition, two-dimensional materials have high carrier mobility characteristics, which enables photogenerated carriers to be quickly transmitted and collected inside the material, and is expected to improve performance parameters such as the response speed and sensitivity of photodetectors. The optoelectronic properties of two-dimensional materials can also be tuned in a variety of ways, making it possible to achieve wide spectrum detection. Although two-dimensional materials have excellent optoelectronic properties, there are still some bottlenecks in the process of practical application. At the contact interface between two-dimensional materials and other materials, due to the charge capture caused by the surface state, a part of the photogenerated carriers are captured by the trap state, thereby reducing the carrier collection efficiency. This will not only increase the power consumption of the device, but also prolong the detector response time, limiting the rapid response capability of the photodetector. For some common two-dimensional materials, such as molybdenum disulfide, their intrinsic band gap makes them have good photoelectric properties in the visible light or near-infrared bands, but they cannot respond in the mid-infrared and far-infrared bands. It is necessary to control the band gap of the material through complex energy band engineering and other means, but these methods often have certain technical difficulties and limitations, which restricts the widespread application of two-dimensional materials in the field of infrared photoelectric detection. Summary of the invention

[0004] The purpose of the present invention is to provide a phase change controlled van der Waals junction transistor infrared detection chip and its preparation method and application, so as to solve the problems of low responsiveness and detection rate, long response time and low temperature refrigeration required in existing infrared detectors.

[0005] The present invention provides a phase-change-controlled van der Waals junction transistor infrared detection chip, whose unit structure comprises from top to bottom a two-dimensional material layer, a metal electrode, a vanadium dioxide micro-nano structure, an electrical channel, and a CMOS (Complementary Metal-Oxide-Semiconductor) readout circuit; the metal electrode comprises a metal gate, an auxiliary electrode, a metal source and a metal drain; the two ends of the vanadium dioxide micro-nano structure are respectively connected to the metal gate and the auxiliary electrode, and the two ends of the two-dimensional material layer are respectively connected to the metal source and the metal drain; the electrical channel connects the metal electrode and the CMOS readout circuit on the substrate.

[0006] Preferably, the material of the two-dimensional material layer includes any one of an n-type semiconductor or a p-type semiconductor, and its thickness ranges from 0.3 to 100 nm, the length ranges from 1 to 500 μm, and the width ranges from 100 nm to 20 μm; the preparation method of the two-dimensional material layer includes any one of mechanical exfoliation, chemical vapor deposition, liquid phase exfoliation or molecular beam epitaxy.

[0007] More preferably, the n-type semiconductor includes any one of molybdenum disulfide (MoS2), platinum selenide (PtSe2), tungsten diselenide (WSe2), tin disulfide (SnS2), indium selenide (InSe), tungsten disulfide (WS2), molybdenum ditelluride (MoTe2), tin diselenide (SnSe2), zinc oxide (ZnO), and gallium arsenide (GaAs); the p-type semiconductor includes any one of black phosphorus (BP), tellurium (Te), germanium selenide (GeSe), tungsten selenide (WSe2), gallium selenide (GaSe), and gallium arsenide (GaAs).

[0008] Preferably, the metal electrodes have a thickness ranging from 50 to 200 nm, a length ranging from 50 to 5000 μm, and a width ranging from 100 nm to 50 μm.

[0009] Preferably, the material of the metal gate and the auxiliary electrode includes one or more of gold, silver, copper, and chromium; the material selection of the metal source and the metal drain is based on the material of the two-dimensional material layer. When the two-dimensional material layer is an n-type semiconductor, the metal source and the metal drain are low work function metals, including one or more of aluminum, titanium, and scandium; when the two-dimensional material layer is a p-type semiconductor, the metal source and the metal drain are high work function metals, including one or more of gold, silver, platinum, and nickel.

[0010] Preferably, the material of the vanadium dioxide micro-nanostructure is vanadium dioxide, the shape is rectangular, the length ranges from 1 to 500 μm, and the width ranges from 100 nm to 20 μm.

[0011] Preferably, the CMOS readout circuit is engraved in the substrate, which obtains the detector output signal and converts it into an electrical signal for subsequent processing; the substrate is connected to the electron transmission orbit in the two-dimensional material layer through an electrical channel to realize the transmission of signals and energy; the material of the substrate includes any one of Si, sapphire, polyethylene terephthalate (PET) or polyimide (PI); the material of the electrical channel includes any one of indium, gold, silver or aluminum.

[0012] The present invention provides an application of the above-mentioned phase change-controlled van der Waals junction transistor infrared detection chip in the field of photoelectric detection.

[0013] The present invention also provides a method for preparing the above-mentioned phase change-controlled van der Waals junction transistor infrared detection chip, comprising the following steps: S1: prepare substrate; S2: Carve out a CMOS readout circuit on the substrate; S3: Preparation of vanadium dioxide micro-nanostructures on substrates; S4: photolithography a metal electrode pattern on the substrate on which the vanadium dioxide micro-nano structure is prepared, and a metal electrode is prepared and peeled off, so that the two ends of the vanadium dioxide micro-nano structure are respectively connected to a metal gate and an auxiliary electrode, and a metal source and a metal drain are prepared at the same time; S5: preparing a two-dimensional material layer, and transferring it onto the vanadium dioxide micro-nanostructure to form a heterojunction, so that two ends of the two-dimensional material layer are in contact with the metal source and the metal drain respectively; S6: Photolithography patterning is performed on the substrate, and then metal is deposited as electrical channels.

[0014] Preferably, in step S2, when the CMOS readout circuit is engraved on the rigid substrate (Si or sapphire), the conventional CMOS integrated circuit manufacturing process is adopted, and when the CMOS readout circuit is engraved on the flexible substrate (PET or PI), the printed electronic process is adopted; in step S3, the preparation method of the vanadium dioxide micro-nano structure includes a top-down method or a bottom-up method; wherein the top-down method is to prepare a vanadium dioxide film on the substrate, and then obtain the vanadium dioxide micro-nano structure by photolithography and etching, including but not limited to any one of magnetron sputtering method or laser pulse deposition method; the bottom-up method To directly grow vanadium dioxide micro-nanostructures, including but not limited to any one of hydrothermal method or chemical vapor deposition method; the photolithography method in step S4 includes but is not limited to any one of ultraviolet lithography or electron beam lithography; the preparation process of the metal electrode includes any one of electron beam evaporation, magnetron sputtering or thermal evaporation; the preparation method of the two-dimensional material layer in step S5 includes but is not limited to any one of mechanical stripping method, liquid phase stripping method, chemical vapor deposition method, and its transfer method includes but is not limited to any one of dry transfer or wet transfer using viscoelastic polydimethylsiloxane (PDMS) polymer film.

[0015] More preferably, the mechanical stripping method mainly uses an adhesive tape to repeatedly strip the bulk material into thin layers, and the stripped thin layer material can be directly transferred to a target substrate and directly contacted with a metal to construct a specific device.

[0016] Transistors based on hybrid heterojunctions composed of two-dimensional materials and phase-change vanadium dioxide materials have characteristics such as low subthreshold swing and high carrier mobility, and can achieve fast and ultra-sensitive response in the subthreshold region of the device. When a source-drain bias is applied, the heterojunction interface forms a built-in electric field due to the band bending. By applying a certain negative gate voltage, the two-dimensional material channel can be pinched off, and the device is in the cut-off state. When infrared light is irradiated to the surface of the device, due to the photothermoelectric effect, VO2 changes from semiconductor properties to metallic properties, thereby regulating the depletion region in the two-dimensional material channel, and the device changes from the off state to the on state. Therefore, sensitive response to room temperature infrared light can be achieved according to the change of source-drain current, which has the advantage of high signal-to-noise ratio, and the light response speed of the device is determined by the switching speed of the transistor, achieving fast response. When no bias is applied, due to the built-in electric field at both ends of the two-dimensional material and the interface of the phase change material, self-powered response can also be achieved. By arraying the above-mentioned unit devices and connecting them to the readout circuit, infrared imaging function can be realized.

[0017] Beneficial Effects

[0018] (1) The present invention proposes a new type of dielectric layer-free transistor structure composed of a hybrid heterojunction of phase change material and two-dimensional semiconductor material, which solves the problem of slow response speed (milliseconds to seconds) caused by interface charge traps. The response time of the device is no longer determined by the lifetime of photogenerated carriers, but depends on the switching speed of the device (nanoseconds to microseconds). This junction transistor has an extremely fast switching speed due to its excellent subthreshold swing, so it can significantly improve the response speed of the device. In addition, the device has the advantage of low dark current in the subthreshold region, achieving ultra-sensitive detection, and solving the problem that the metal-oxide field effect transistor structure in the prior art cannot solve the contradiction between device responsiveness and response speed.

[0019] (2) The response wavelength of two-dimensional material photon detectors is limited by the band gap, especially for semiconductors with large intrinsic band gaps, infrared light detection cannot be achieved. Although vanadium dioxide can be used for infrared detection, its response mechanism is a thermal effect, so the response time is in the order of milliseconds to seconds. The present invention proposes to perform infrared detection by regulating the built-in electric field of the hybrid heterojunction. This new response mechanism breaks through the limitation of the semiconductor band gap of traditional photon detectors, broadens the response range, and utilizes the formation of type II contact and Schottky contact with two-dimensional materials before and after the VO2 phase transition, which is expected to achieve effective resolution of wavelength and light power.

[0020] (3) The junction field effect transistor proposed in the present invention has the advantage of low power consumption. In the subthreshold region, only a very small gate voltage is required to cut off the device. Moreover, by utilizing the built-in electric field at the interface of vanadium dioxide and two-dimensional materials, the detector can operate under zero bias, thus realizing a self-powered infrared detection chip, which is of great significance for reducing device power consumption and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front view of the structure of the van der Waals junction transistor infrared detection chip controlled by phase change of the present invention.

[0022] Figure 2 It is a side view of the unit structure of the van der Waals junction transistor infrared detection chip controlled by phase change of the present invention.

[0023] Figure 3 This is a simulation diagram of changing the gate voltage of the phase-change-controlled van der Waals junction transistor infrared detection chip of the present invention.

[0024] Figure 4 The photocurrent diagram (V DS =1V).

[0025] Figure 5 It is a response time diagram of the phase change-controlled van der Waals junction transistor infrared detection chip of the present invention.

[0026] Figure numerals: 1-two-dimensional material layer, 21-metal gate, 22-auxiliary electrode, 23-metal source, 24-metal drain, 3-vanadium dioxide micro-nanostructure, 4-electrical channel, 5-CMOS readout circuit. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0028] Example

[0029] This embodiment provides a phase-change controlled van der Waals junction transistor infrared detection chip, such as Figure 1 , Figure 2 As shown, the unit structure of the van der Waals junction transistor infrared detection chip includes a two-dimensional material layer 1, a metal electrode, a vanadium dioxide micro-nano structure 3, an electrical channel 4 and a CMOS readout circuit 5 from top to bottom; the metal electrode includes a metal gate 21, an auxiliary electrode 22, a metal source 23 and a metal drain 24; the two ends of the vanadium dioxide micro-nano structure 3 are respectively connected to the metal gate 21 and the auxiliary electrode 22, and the two ends of the two-dimensional material layer 1 are respectively connected to the metal source 23 and the metal drain 24; the electrical channel 4 connects the metal electrode and the CMOS readout circuit 5 on the substrate.

[0030] The method for preparing the above-mentioned phase change-controlled van der Waals junction transistor infrared detection chip comprises the following steps:

[0031] S1: Prepare substrate: Use acetone and isopropanol solutions to ultrasonically clean the silicon wafer with a 300 nm oxide layer for 15 min, and then blow dry with inert gas such as nitrogen; S2: Carve out a CMOS readout circuit on the substrate 5: Form the circuit on the silicon wafer by oxidation, photolithography, etching, and ion implantation in sequence; S3: preparing vanadium dioxide micro-nanostructure 3 on the substrate by UV lithography, magnetron sputtering and thermal oxidation in sequence; S4: A metal electrode pattern is prepared on the substrate by ultraviolet lithography, with a channel width of 5 μm, and then a metal electrode is deposited by electron beam evaporation, the electrode includes 5 nm chromium and 70 nm gold (chromium is used as an adhesion layer to prevent gold from falling off), and finally the excess photoresist is removed by acetone stripping, so that the two ends of the vanadium dioxide micro-nanostructure 3 are connected to the metal gate 21 and the auxiliary electrode 22 respectively; at the same time, a 70 nm titanium metal electrode is prepared as the metal source 23 and the metal drain 24; S5: The two-dimensional material layer 1 is made of molybdenum disulfide material and prepared by mechanical stripping: 3M tape is used to repeatedly strip the molybdenum disulfide crystal material, and a few layers of molybdenum disulfide material of appropriate size are selected through an optical microscope; the molybdenum disulfide is transferred to the top of the vanadium dioxide micro-nanostructure 3 by PDMS dry transfer, and a heterojunction is formed at the junction, and the two ends of the molybdenum disulfide two-dimensional material layer 1 are in contact with the metal source 23 and the metal drain 24 respectively; S6: The substrate is patterned by photolithography, and then metal indium is deposited as an electrical channel 4 to connect the metal electrode and the CMOS readout circuit 5.

[0032] When no current is applied, vanadium dioxide is in a semiconductor state. At this time, the electron-hole pairs generated by light-excited vanadium dioxide are effectively separated under the action of the built-in electric field formed with molybdenum disulfide. Under the regulation of vanadium dioxide, the conductivity of molybdenum disulfide is regulated by changing the length of the depletion layer in the molybdenum disulfide channel, so that its threshold voltage moves laterally. The smaller the incident light power, the greater the responsivity, and the responsivity can reach 10 during operation. 3 A / W, indicating that the device can detect near-infrared light with ultra-sensitivity. When vanadium dioxide changes from a semiconductor state to a metallic state, the electrically driven phase change response time is in the order of microseconds to milliseconds. Compared with the two-dimensional material photodetector, which usually has a response time of seconds, the response speed can be increased by more than three orders of magnitude.

[0033] Set the corresponding parameters in the TCAD simulation software and simulate the above transistor structure. Figure 3 It can be seen from the simulation results that when the heterojunction is not formed, the electron concentration of the MOS2 channel is determined by the semiconductor doping concentration, which is specified as 10 18 cm -3 , as a PN junction is formed between the contact interface of VO2 and MOS2, when a gate voltage (V G ) is equal to 0V, due to the bending of the energy band, a depletion layer of a certain width is formed. Although the channel electron concentration decreases, the device is still in the on state; when V G When V is less than 0, the PN junction between the gate and the channel will be reverse biased. According to the characteristics of the PN junction, the reverse bias voltage will cause the depletion layer to widen, and the electron concentration in the MoS2 channel will further decrease, resulting in a decrease in conductivity. When the absolute value of the negative voltage applied to the gate continues to increase, the depletion layer will further widen and the conductive channel will further narrow. It can be seen from the figure that when V G When it decreases to -0.7 V, the depletion layer almost occupies the conductive channel, and the electron concentration reaches the minimum corresponding to the cut-off state, at which time the channel current is almost zero. Therefore, the electron concentration and the width of the depletion layer in the channel can be controlled by changing the gate voltage, thereby controlling the current size and realizing the characteristics of controlling the transistor switch.

[0034] Figure 4 is the drain-source voltage V DS =1V, the device is tested under dark and light conditions. From the figure, it can be seen that the device exhibits very low subthreshold swing, very low threshold voltage, and the switch ratio can reach nearly 4 orders of magnitude. When illuminated, the photocurrent increases significantly. In the subthreshold region, the device has the advantages of low dark current, large switch ratio, and high device sensitivity.

[0035] Figure 5 This is the light response time diagram of the above-mentioned phase change-controlled van der Waals junction transistor infrared detection chip. The rise time is the time for the normalized photocurrent to increase from 10% to 90%, and the fall time is the time for the normalized photocurrent to decrease from 90% to 10%. It can be seen from the figure that the device has a microsecond response speed (7μs, 10μs).

Claims

1. A phase-change controlled van der Waals junction transistor infrared detection chip, characterized in that: The unit structure of the van der Waals junction transistor infrared detection chip comprises, from top to bottom, a two-dimensional material layer (1), a metal electrode, a vanadium dioxide micro-nano structure (3), an electrical channel (4), and a CMOS readout circuit (5); the metal electrode comprises a metal gate (21), an auxiliary electrode (22), a metal source electrode (23), and a metal drain electrode (24); the two ends of the vanadium dioxide micro-nano structure (3) are respectively connected to the metal gate electrode (21) and the auxiliary electrode (22), and the two ends of the two-dimensional material layer (1) are respectively connected to the metal source electrode (23) and the metal drain electrode (24); the electrical channel (4) connects the metal electrode and the CMOS readout circuit (5) on the substrate.

2. The phase-change controlled van der Waals junction transistor infrared detection chip according to claim 1, characterized in that: The material of the two-dimensional material layer (1) includes any one of an n-type semiconductor or a p-type semiconductor, and has a thickness range of 0.3 to 100 nm, a length range of 1 to 500 μm, and a width range of 100 nm to 20 μm; the preparation method of the two-dimensional material layer (1) includes any one of a mechanical exfoliation method, a chemical vapor deposition method, a liquid phase exfoliation method, or a molecular beam epitaxy method.

3. The phase change controlled van der Waals junction transistor infrared detection chip according to claim 2, characterized in that: The n-type semiconductor includes any one of molybdenum disulfide, platinum selenide, tungsten diselenide, tin disulfide, indium selenide, tungsten disulfide, molybdenum ditelluride, tin diselenide, zinc oxide, and gallium arsenide; the p-type semiconductor includes any one of black phosphorus, tellurium, germanium selenide, tungsten selenide, gallium selenide, and gallium arsenide.

4. The phase-change controlled van der Waals junction transistor infrared detection chip according to claim 1, characterized in that: The thickness of the metal electrodes ranges from 50 to 200 nm, the length ranges from 50 to 5000 μm, and the width ranges from 100 nm to 50 μm.

5. The phase change controlled van der Waals junction transistor infrared detection chip according to claim 1, characterized in that: The materials of the metal gate (21) and the auxiliary electrode (22) include one or more of gold, silver, copper, and chromium; the materials of the metal source (23) and the metal drain (24) are selected based on the material of the two-dimensional material layer (1); when the two-dimensional material layer (1) is an n-type semiconductor, the metal source (23) and the metal drain (24) are low-work-function metals, including one or more of aluminum, titanium, and scandium; when the two-dimensional material layer (1) is a p-type semiconductor, the metal source (23) and the metal drain (24) are high-work-function metals, including one or more of gold, silver, platinum, and nickel.

6. The phase-change controlled van der Waals junction transistor infrared detection chip according to claim 1, characterized in that: The material of the vanadium dioxide micro-nanostructure (3) is vanadium dioxide, the shape is rectangular, the length range is 1-500 μm, and the width range is 100 nm-20 μm.

7. The phase change controlled van der Waals junction transistor infrared detection chip according to claim 1, characterized in that: The CMOS readout circuit (5) is engraved in the substrate, and acquires the detector output signal and converts it into an electrical signal for subsequent processing; the substrate is connected to the electron transmission track in the two-dimensional material layer (1) through an electrical channel (4) to achieve signal and energy transmission; the material of the substrate includes any one of Si, sapphire, polyethylene terephthalate or polyimide; the material of the electrical channel (4) includes any one of indium, gold, silver or aluminum.

8. Application of the phase change controlled van der Waals junction transistor infrared detection chip according to any one of claims 1 to 7 in the field of photoelectric detection.

9. A method for preparing a phase-change controlled van der Waals junction transistor infrared detection chip, comprising the following steps: S1: prepare substrate; S2: Carving out a CMOS readout circuit on the substrate (5); S3: Preparation of vanadium dioxide micro-nanostructures on substrates (3); S4: photolithography of a metal electrode pattern on the substrate on which the vanadium dioxide micro-nanostructure (3) is prepared, and a metal electrode is prepared and peeled off, so that the two ends of the vanadium dioxide micro-nanostructure (3) are respectively connected to a metal gate (21) and an auxiliary electrode (22), and a metal source electrode (23) and a metal drain electrode (24) are prepared at the same time; S5: preparing a two-dimensional material layer (1) and transferring it onto the vanadium dioxide micro-nanostructure (3) to form a heterojunction, so that two ends of the two-dimensional material layer (1) are in contact with the metal source electrode (23) and the metal drain electrode (24) respectively; S6: Photolithographic patterning is performed on the substrate, and then metal is deposited as electrical channels (4).

10. The method for preparing the phase-change controlled van der Waals junction transistor infrared detection chip according to claim 9, characterized in that: In the step S2, when the CMOS readout circuit (5) is engraved on the rigid substrate, a conventional CMOS integrated circuit manufacturing process is used; when the CMOS readout circuit (5) is engraved on the flexible substrate, a printed electronics process is used; in the step S3, the method for preparing the vanadium dioxide micro-nano structure (3) includes a top-down method or a bottom-up method; wherein the top-down method is to prepare a vanadium dioxide film on a substrate, and then obtain the vanadium dioxide micro-nano structure (3) by photolithography and etching, including any one of a magnetron sputtering method and a laser pulse deposition method; and the bottom-up method is to prepare a vanadium dioxide film on a substrate, and then obtain the vanadium dioxide micro-nano structure (3) by photolithography and etching. To directly grow the vanadium dioxide micro-nanostructure (3), a hydrothermal method or a chemical vapor deposition method is included; the photolithography method in step S4 includes any one of ultraviolet photolithography or electron beam photolithography; the preparation process of the metal electrode includes any one of electron beam evaporation, magnetron sputtering or thermal evaporation; the preparation method of the two-dimensional material layer (1) in step S5 includes any one of mechanical stripping, liquid phase stripping, and chemical vapor deposition, and the transfer method includes any one of dry transfer or wet transfer using a viscoelastic polydimethylsiloxane polymer film.

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