An ultraviolet photomemristor and its fabrication method

Abstract

This invention relates to the field of semiconductor ultraviolet photoresist technology, specifically providing an ultraviolet photoresist and its fabrication method. The ultraviolet photoresist of this invention includes a substrate, an AlGaN photosensitive channel layer, a source electrode, a drain electrode, an AlScN electroresistive layer, and a top electrode. The AlGaN photosensitive channel layer serves as the light absorption region of the detector, forming a space charge region, which generates photogenerated carriers under illumination, changing the conductivity and thus altering the voltage division across the AlScN electroresist. Because the MSM-type AlGaN detector and the AlScN memristor form a series structure, the voltage across the AlScN increases under illumination, while the voltage required for polarization reversal decreases. Due to the symmetrical structure of the MSM-type AlGaN detector, the polarization reversal voltage of the AlScN memristor after illumination also exhibits good symmetry. This phenomenon of optical signal-controlled polarization reversal voltage can be used to achieve light-enhanced or light-suppressed ultraviolet photoresist.

Description

Technical Field

[0001] This invention relates to the field of semiconductor ultraviolet photomemristor technology, and in particular to an ultraviolet photomemristor and its fabrication method. Background Technology

[0002] AlGaN, with its bandgap of 3.4–6.2 eV varying with Al composition, covers a detection wavelength range of 200 nm–400 nm, making it a highly suitable semiconductor material for fabricating ultraviolet optoelectronic devices and holding immense promise for ultraviolet detection applications. AlScN, an emerging III-V group semiconductor ferroelectric material, has a hexagonal wurtzite crystal structure. In terms of growth, AlScN has a bandgap in the range of 4.0–6.2 eV, and high-quality material growth can be achieved by adjusting the Sc composition to match the lattice of nitride semiconductors. In terms of performance, its piezoelectric coefficient is four times that of AlN, and its spontaneous polarization coefficient is twice that of AlN. AlScN not only possesses a strong depolarization electric field within the thin film, but also exhibits potential for application in memristors because its polarization direction can be controlled by the direction of an applied electric field, resulting in different IV characteristics under different polarizations. AlScN materials possess unique advantages such as high remanent polarization, high coercivity, high Curie temperature, and compatibility with mainstream CMOS processes, enabling applications in harsh environments and making them a preferred material for fabricating memristor devices. In terms of device fabrication, AlScN is compatible with existing AlGaN-based process systems, facilitating integration into existing AlGaN-based technologies. Therefore, the combination of AlScN memristors and nitride semiconductors has broad application prospects in the field of ultraviolet optoelectronic memristors. However, current AlScN polarization reversal methods rely on an external electric field (electrical writing), and due to their strong coercivity and wide bandgap, AlScN memristors cannot be polarized by illumination.

[0003] Given that current AlScN memristors have issues with coercive field strength and wide bandgap, limiting their application to electrical memristors to optical memristors, improvements are necessary. Summary of the Invention

[0004] The purpose of this invention is to address the problem that AlScN memristors, with their strong coercive field and wide bandgap, can only achieve electrical memristivity and not optical memristivity. This invention proposes an ultraviolet (UV) photoelectric memristor and its fabrication method. The UV photoelectric memristor of this invention is suitable for UV signal detection in the light absorption region of various AlGaN compositions (detection cutoff wavelength of 200-365 nm). The AlScN electrical memristor can switch between high and low resistance states via electrical signal control. Furthermore, the MSM-type symmetrical UV detection structure of AlGaN generates a large number of photogenerated carriers under illumination, altering its conductivity and thus reducing the polarization reversal voltage of the AlScN electrical memristor. Therefore, UV photoelectric memristors with enhanced or suppressed light can be achieved through voltage control. This integrated device method realizes a sensing-storage-computing function.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides an ultraviolet photomemristor, comprising:

[0007] Substrate;

[0008] An AlGaN photosensitive channel layer is located on the surface of the substrate;

[0009] The AlGaN photosensitive channel layer has a source electrode and a drain electrode on both sides of the surface away from the substrate, respectively;

[0010] An AlScN memristor layer is located on the surface of the source electrode or drain electrode away from the substrate;

[0011] The top electrode is located on the surface of the AlScN memristor layer away from the substrate.

[0012] Preferably, a buffer layer is further provided between the substrate and the AlGaN photosensitive channel layer, and the two sides of the buffer layer are respectively attached to the substrate and the AlGaN photosensitive channel layer.

[0013] Preferably, the AlGaN photosensitive channel layer is undoped Al. x Ga 1-x N photosensitive channel layer, 0.75≥x≥0.65.

[0014] Preferably, the AlScN memristor layer is Al 1-y Sc y N-type memristor layer, 0.5≥y≥0.05.

[0015] Preferably, the substrate is a heterogeneous substrate or a homogeneous substrate;

[0016] The heterogeneous substrate includes any one of sapphire substrate, silicon carbide substrate, and silicon substrate;

[0017] Homogeneous substrates include GaN substrates or AlN substrates;

[0018] And / or, the materials of the source electrode and the drain electrode include at least one of Pt, Ti, Al, Ni, and Au;

[0019] And / or, the material of the top electrode includes at least one of Pt, Ti, Al, Ni, Au, and Ag;

[0020] And / or, the buffer layer is an AlN buffer layer or a GaN buffer layer.

[0021] Preferably, the thickness of the AlGaN photosensitive channel layer is 1~100 nm;

[0022] And / or, the thickness of the AlScN memristor layer is 1~100 nm;

[0023] And / or, the thickness of the source electrode and the drain electrode is 200~400 nm;

[0024] And / or, the thickness of the top electrode is 200~400 nm.

[0025] Secondly, the present invention also provides a method for fabricating the aforementioned ultraviolet photomemristor, comprising the following steps:

[0026] Epitaxial growth of a buffer layer on the substrate;

[0027] An AlGaN photosensitive channel layer is deposited on the buffer layer;

[0028] Source and drain electrodes are deposited on the AlGaN photosensitive channel layer;

[0029] An AlScN memristor layer is deposited on the source electrode or drain electrode;

[0030] A top electrode is deposited on the AlScN memristor layer.

[0031] Preferably, a source electrode and a drain electrode are deposited on the AlGaN photosensitive channel layer, specifically including:

[0032] Photoresist mask patterns for source and drain electrodes are prepared on the AlGaN photosensitive channel layer. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode pattern area is retained. Then, source and drain electrode materials are deposited on the photoresist mask pattern. The photoresist and the electrode material covering its surface are then removed. Finally, annealing is performed to form the source and drain electrodes.

[0033] Preferably, an AlScN memristor layer is deposited on the source electrode or drain electrode, specifically including:

[0034] An AlScN material layer is grown on a substrate on which active and drain electrodes are fabricated.

[0035] A SiO2 mask layer is grown on the AlScN material layer. The mesa pattern of the AlScN memristor layer is photolithographically formed on the SiO2 mask layer. The SiO2 mask layer in the non-mesa area is etched away. The area without the SiO2 mask layer is etched until the AlScN material layer is completely removed. The AlScN memristor layer is obtained by removing the SiO2 mask layer in the mesa area.

[0036] Preferably, depositing a top electrode on the AlScN memristor layer specifically includes:

[0037] A photoresist mask pattern for the top electrode is prepared on the AlScN memristor layer. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode area is retained. Then, the top electrode material is deposited on the photoresist mask pattern by vapor deposition. The photoresist and the electrode material covering its surface are removed. Finally, the top electrode is obtained by annealing.

[0038] The ultraviolet photomemristor of the present invention has the following advantages over the prior art:

[0039] The ultraviolet photomemristor of the present invention includes a substrate, an AlGaN photosensitive channel layer, a source electrode, a drain electrode, an AlScN memristor layer, and a top electrode. The source electrode and drain electrode are located on opposite sides of the surface of the AlGaN photosensitive channel layer, and the AlScN memristor layer can be located on either the surface of the source electrode or the surface of the drain electrode. The top electrode is located on the surface of the AlScN memristor layer. The AlGaN photosensitive channel layer serves as the light absorption region of the detector, forming a space charge region, which generates photogenerated carriers under illumination, changing the conductivity and thus altering the conductivity at both ends of the AlScN memristor. Voltage division effect; the top electrode is located on the surface of the AlScN memristor layer, forming an AlScN memristor; since the MSM-type AlGaN detector and the AlScN memristor form a series structure, the voltage across the AlScN increases under illumination, and the voltage required for the device to achieve polarization reversal decreases; due to the symmetrical structure of the MSM-type AlGaN detector, the polarization reversal voltage of the AlScN memristor after illumination also has good symmetry, and this phenomenon of optical signal modulation of polarization reversal voltage can be used to realize ultraviolet photomemristors with light enhancement or light suppression. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of the ultraviolet photomemristor of the present invention;

[0042] Figure 2 This is a flowchart of the fabrication method of the ultraviolet photomemristor of the present invention. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this invention, it should be understood that the orientation or positional relationship indicated by terms such as "above" is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, or the orientation or positional relationship in which those skilled in the art are usually understood. It is only for the convenience of describing this invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0046] The following provides a detailed description of each example. It should be noted that the order of description of the embodiments below is not intended to limit the preferred order of the embodiments. Furthermore, in the description of this application, the term "comprising" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single digits within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0047] This invention provides an ultraviolet photomemristor, such as... Figure 1 As shown, it includes:

[0048] Substrate 1;

[0049] AlGaN photosensitive channel layer 3 is located on the surface of substrate 1;

[0050] Source electrode 4 and drain electrode 5 are respectively provided on both sides of the surface of AlGaN photosensitive channel layer 3 away from substrate 1;

[0051] AlScN memristor layer 6 is located on the surface of the source electrode 4 or drain electrode 5 away from the substrate 1;

[0052] The top electrode 7 is located on the surface of the AlScN memristor layer 6 away from the substrate 1.

[0053] The ultraviolet photoresistor of this invention includes a substrate 1, an AlGaN photosensitive channel layer 3, a source electrode 4, a drain electrode 5, an AlScN electroresistive layer 6, and a top electrode 7. The source electrode 4 and drain electrode 5 are located on opposite sides of the surface of the AlGaN photosensitive channel layer 3. The AlScN electroresistive layer 6 can be located on either the surface of the source electrode 4 or the surface of the drain electrode 5. The top electrode 7 is located on the surface of the AlScN electroresistive layer 6. AlScN, as a nitride semiconductor ferroelectric material, has the characteristic of changing its polarization direction with the direction of the applied electric field, and it has unique advantages such as high remanent polarization intensity, high coercive field strength, and high Curie temperature. Because the change in the polarization direction of AlScN changes the potential barrier height at its interface with the metal electrode, it affects the different transport properties of charge carriers. The device exhibits different conduction states under different polarizations, which can be used for non-volatile memory applications. AlGaN, as a good ultraviolet detection material, can generate a large number of photogenerated charge carriers under ultraviolet light irradiation, thus changing its conductivity. Furthermore, AlScN material can be prepared by magnetron sputtering, which is compatible with CMOS processes. Therefore, integrating the AlGaN MSM ultraviolet detector structure with the AlScN memristor allows for the control of AlScN polarization reversal voltage changes by ultraviolet light, thereby achieving ultraviolet photomemristor functionality. This structure has broad application prospects in ultraviolet AlGaN-based non-volatile ultraviolet photomemristors.

[0054] This invention combines the ultraviolet detection capability of AlGaN material with the non-volatile memory storage function of AlScN material's ferroelectric properties, enabling the integration of an AlGaN ultraviolet detector and an AlScN memristor into a series structure. Utilizing the photoconductivity of the AlGaN detector under illumination, which generates a large number of photogenerated carriers, the external bias voltage required for polarization reversal of the AlScN memristor is correspondingly reduced, thus enabling photoelectrically modulated ultraviolet memristor devices. Furthermore, because the growth and fabrication methods of AlScN material are compatible with CMOS processes, the AlScN memristor can be directly integrated into the electrode region of the AlGaN ultraviolet detector, forming a series integrated structure.

[0055] This invention designs a device that combines the ultraviolet detection capability of AlGaN with the non-volatile memory of AlScN. By adjusting the conductivity of the AlGaN ultraviolet detection region through optical signal modulation, the voltage division of the AlScN memristor in the integrated device changes with light intensity, reducing the overall device voltage required for polarization reversal. By setting the voltage, an opto-memristor device capable of light enhancement or light suppression driven by optical signal can be realized, providing an effective solution for integrated ultraviolet sensing and computing.

[0056] In the ultraviolet photomemristor of this invention, the source electrode 4 and drain electrode 5 are located on opposite sides of the surface of the AlGaN photosensitive channel layer 3, forming a Schottky contact. The AlGaN photosensitive channel layer 3 serves as the light absorption region of the detector, forming a space charge region, which generates photogenerated carriers under illumination, changing the conductivity and thus altering the voltage division across the AlScN memristor. The top electrode 7 is located on the surface of the AlScN memristor layer 6, forming the AlScN memristor. Because the MSM-type (metal-semiconductor-metal) AlGaN detector and the AlScN memristor form a series structure, the voltage across the AlScN increases under illumination, and the voltage required for polarization reversal decreases. Due to the symmetrical structure of the MSM-type AlGaN detector, the polarization reversal voltage of the AlScN memristor after illumination also exhibits good symmetry. This phenomenon of optical signal-controlled polarization reversal voltage can be used to realize photosynaptic devices with light enhancement or light suppression.

[0057] In some embodiments, a buffer layer 2 is further provided between the substrate 1 and the AlGaN photosensitive channel layer 3, with both sides of the buffer layer 2 respectively attached to the substrate 1 and the AlGaN photosensitive channel layer 3. The buffer layer 2 releases the stress caused by the lattice mismatch between the substrate 1 and the AlGaN photosensitive channel layer 3, as well as the thermal stress caused by the mismatch in the coefficient of thermal expansion.

[0058] In some embodiments, the AlGaN photosensitive channel layer 3 is an undoped Al x Ga 1-x N photosensitive channel layer, 0.75≥x≥0.65.

[0059] In some embodiments, the AlScN memristor layer 6 is Al 1-y Sc y N-type memristor layer, 0.5≥y≥0.05.

[0060] In some embodiments, substrate 1 is a heterogeneous substrate or a homogeneous substrate;

[0061] Heterogeneous substrates include any one of sapphire substrates, silicon carbide substrates, and silicon substrates;

[0062] Homogeneous substrates include GaN substrates or AlN substrates.

[0063] In some embodiments, the source electrode 4 and the drain electrode 5 are Schottky electrodes, and the material of the source electrode 4 and the drain electrode 5 includes at least one of Pt, Ti, Al, Ni, and Au; that is, the source electrode 4 and the drain electrode 5 are any one of Pt, Ti, Al, Ni, and Au, or an alloy of two or more of Pt, Ti, Al, Ni, and Au; preferably, the source electrode 4 and the drain electrode 5 are made of the same material.

[0064] In some embodiments, the top electrode 7 is a Schottky electrode, and the material of the top electrode 7 includes at least one of Pt, Ti, Al, Ni, Au, and Ag; that is, the material of the top electrode 7 is any one of Pt, Ni, Al, Ti, Ag, or Au, or an alloy of two or more of Pt, Ti, Al, Ni, Ag, and Au.

[0065] In some embodiments, the buffer layer 2 is an AlN buffer layer or a GaN buffer layer; the thickness of the buffer layer 2 is 100nm~300nm, specifically, the thickness of the buffer layer 2 can be 100nm, 200nm or 300nm.

[0066] In some embodiments, the thickness of the AlGaN photosensitive channel layer 3 is 1~100 nm. Specifically, the thickness of the AlGaN photosensitive channel layer 3 can be 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0067] In some embodiments, the thickness of the AlScN memristor layer 6 is 1~100 nm. Specifically, the thickness of the AlScN memristor layer 6 can be 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, or 100 nm.

[0068] In some embodiments, the thickness of the source electrode 4 and the drain electrode 5 is 200~400 nm; specifically, the thickness of the source electrode 4 and the drain electrode 5 can be 200 nm, 300 nm, or 400 nm, and preferably, the thickness of the source electrode 4 and the drain electrode 5 is the same.

[0069] In some embodiments, the thickness of the top electrode 7 is 200~400 nm. Specifically, the thickness of the top electrode 7 can be 200 nm, 300 nm, or 400 nm.

[0070] Based on the same inventive concept, this invention also provides a method for preparing the aforementioned ultraviolet photomemristor, such as... Figure 2 As shown, it includes the following steps:

[0071] S1. Epitaxially grow a buffer layer on the substrate;

[0072] S2. An AlGaN photosensitive channel layer is deposited on the buffer layer;

[0073] S3. Deposit source and drain electrodes on the AlGaN photosensitive channel layer;

[0074] S4. Deposit an AlScN memristor layer on the source or drain electrode;

[0075] S5. A top electrode is deposited on the AlScN memristor layer.

[0076] In some embodiments, step S3, which involves depositing source and drain electrodes on the AlGaN photosensitive channel layer, specifically includes:

[0077] Photoresist mask patterns for source and drain electrodes are fabricated on an AlGaN photosensitive channel layer using photolithography. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode pattern area is retained. Then, source and drain electrode materials are deposited on the photoresist mask pattern by vapor deposition. The photoresist and the electrode material covering its surface are then removed using lift-off technology. Finally, annealing is performed to form the source and drain electrodes.

[0078] In some embodiments, step S4, which involves depositing an AlScN memristor layer on the source or drain electrode, specifically includes:

[0079] An AlScN material layer is grown on a substrate on which active and drain electrodes are fabricated.

[0080] A SiO2 mask layer is grown on the AlScN material layer using PECVD technology. The AlScN memristor layer mesa pattern is then etched on the SiO2 mask layer using photolithography. The SiO2 mask layer in the non-mesa areas that are not covered by photoresist is removed using RIE (Reactive Ion Etching) technology. The areas not covered by the SiO2 mask layer are then etched using ICP (Inductively Coupled Plasma) technology until the AlScN material layer is completely removed. The AlScN memristor layer is obtained by removing the SiO2 mask layer in the mesa areas.

[0081] In some embodiments, the deposition of the top electrode on the AlScN memristor layer in step S5 specifically includes:

[0082] A photoresist mask pattern for the top electrode is prepared on an AlScN memristor layer using photolithography. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode area is retained. Then, the top electrode material is deposited on the photoresist mask pattern by vapor deposition. The photoresist and the electrode material covering its surface are then removed using lift-off technology. Finally, the top electrode is obtained by annealing.

[0083] In some embodiments, the method for depositing and forming the AlGaN photosensitive channel layer on the buffer layer in step S2 is MOCVD, and the method for growing the AlScN material is any one of MOCVD, MBE, and magnetron sputtering.

[0084] In some embodiments, in steps S3 and S5, photolithography is used, and the selection of positive and negative photoresists is determined according to the design of the photomask pattern window, so that the photoresist in the electrode pattern area is removed after development, while the photoresist in the non-electrode area is retained.

[0085] In some embodiments, in step S4, photolithography is used, and the selection of positive and negative photoresists is determined according to the design of the photomask pattern window, so that the photoresist in the surface area is retained after development, and the photoresist in the non-surface area is removed.

[0086] In some embodiments, in steps S3 and S5, the method used for evaporating the source electrode, drain electrode material, and top electrode material is electron beam evaporation or thermal evaporation technology.

[0087] In some embodiments, in steps S3 and S5, the photoresist is dissolved using Lift Off technology, and the dissolving solution is either acetone solution or photoresist remover.

[0088] In some embodiments, in steps S3 and S5, the annealing process is performed by annealing the source electrode, drain electrode, and top electrode in a nitrogen atmosphere using a rapid annealing furnace, wherein the annealing temperature and time are determined by the electrode material. For example, when the source electrode, drain electrode, and top electrode are Pt, the annealing temperature is 400~600℃ and the annealing time is 20~40min; when the source electrode, drain electrode, and top electrode are Ti, the annealing temperature is 300~500℃ and the annealing time is 15~30min; when the source electrode, drain electrode, and top electrode are Al, the annealing temperature is 300~450℃ and the annealing time is 15~30min; when the source electrode, drain electrode, and top electrode are Ni, the annealing temperature is 300~500℃ and the annealing time is 15~30min; when the source electrode, drain electrode, and top electrode are Au, the annealing temperature is 200~400℃ and the annealing time is 10~20min; when the source electrode, drain electrode, and top electrode are Ag, the annealing temperature is 200~350℃ and the annealing time is 10~20min.

[0089] In some embodiments, the buffer layer is an AlN buffer layer, which is deposited using ammonia and an aluminum source as raw materials. The aluminum source is preferably an organoaluminum compound, more preferably trimethylaluminum. The deposition conditions of the AlN buffer layer are preferably 920–1000°C and 40–150 mbar, and more preferably 940–960°C and 60–80 mbar.

[0090] In some embodiments, an AlGaN photosensitive channel layer is deposited on a buffer layer using the MOCVD method. The specific process conditions are as follows: the growth temperature is maintained at 1000~1050℃, the hydrogen flow rate is 1500~1600 sccm, the ammonia flow rate is 1500~1600 sccm, and an aluminum source (trimethylaluminum) with a flow rate of 65~75 μmol / min and a gallium source (trimethylgallium) with a flow rate of 25~35 μmol / min are introduced into the reaction chamber to grow the AlGaN photosensitive channel layer.

[0091] In some embodiments, AlScN materials are grown using the MOCVD method. The specific process conditions are as follows: the growth temperature is maintained at 1000~1050℃, the hydrogen flow rate is 1400~1500 sccm, the ammonia flow rate is 1500~1600 sccm, and an aluminum source (trimethylaluminum) and an organic scandium source (such as tris(dimethylamino)scandium) with a flow rate of 50~95 μmol / min and a flow rate of 5~50 μmol / min are introduced into the reaction chamber to obtain an AlScN material layer.

[0092] The following detailed embodiments further illustrate the ultraviolet photomemristor and its fabrication method of this application. This section further explains the invention in conjunction with specific embodiments, but should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in the art.

[0093] Example 1

[0094] This application provides an ultraviolet photomemristor, comprising:

[0095] Substrate;

[0096] A buffer layer is located on the substrate surface;

[0097] The AlGaN photosensitive channel layer is located in the buffer layer away from the substrate surface;

[0098] The AlGaN photosensitive channel layer has a source electrode and a drain electrode on both sides of the surface away from the substrate, respectively;

[0099] An AlScN memristor layer is located on the surface of the source electrode away from the substrate;

[0100] The top electrode is located on the surface of the AlScN memristor layer away from the substrate;

[0101] The buffer layer is an AlN buffer layer with a thickness of 200nm;

[0102] The AlGaN photosensitive channel layer is made of undoped Al. x Ga 1-x The photosensitive channel layer has an N-type photosensitive layer, x=0.7, and the AlGaN photosensitive channel layer has a thickness of 45nm.

[0103] The AlScN memristor layer is Al 1-y Sc y N-type memristor layer, y=0.45, AlScN memristor layer thickness is 60nm;

[0104] The substrate is a sapphire substrate;

[0105] The source and drain electrodes are made of Ti, and their thickness is 280 nm.

[0106] The top electrode is made of Ni and has a thickness of 320 nm.

[0107] The fabrication method of the ultraviolet photomemristor in Example 1 above includes the following steps:

[0108] S1. An AlN buffer layer was epitaxially grown on the substrate using the MOCVD method. The specific process conditions were as follows: the growth temperature was maintained at 1000℃, the hydrogen flow rate was 1500 sccm, the ammonia flow rate was 1500 sccm, and an aluminum source (trimethylaluminum) with a flow rate of 60 μmol / min was introduced into the reaction chamber to grow the AlN buffer layer.

[0109] S2. An AlGaN photosensitive channel layer is deposited on the buffer layer using the MOCVD method. The specific process conditions are as follows: the growth temperature is maintained at 1000℃, the hydrogen flow rate is 1500 sccm, the ammonia flow rate is 1500 sccm, and an aluminum source (trimethylaluminum) with a flow rate of 70 μmol / min and a gallium source (trimethylgallium) with a flow rate of 30 μmol / min are introduced into the reaction chamber to grow the AlGaN photosensitive channel layer.

[0110] S3. Depositing source and drain electrodes on the AlGaN photosensitive channel layer, specifically including: preparing photoresist mask patterns for source and drain electrodes on the AlGaN photosensitive channel layer using photolithography; removing the photoresist in the electrode pattern area after development, while retaining the photoresist in the non-electrode pattern area; then depositing source and drain electrode materials on the photoresist mask pattern by evaporation; removing the photoresist and the electrode material covering its surface using lift-off technology; and finally performing annealing to form the source and drain electrodes; wherein, the source electrode Ti and drain electrode Ti are prepared by electron beam evaporation, with an annealing temperature of 320℃ and an annealing time of 20min;

[0111] S4. Depositing and forming an AlScN memristor layer on the source or drain electrode, specifically including:

[0112] An AlScN material layer is grown on a substrate on which active and drain electrodes are fabricated.

[0113] A SiO2 mask layer is grown on the AlScN material layer using PECVD technology. The AlScN memristor layer mesa pattern is then etched on the SiO2 mask layer using photolithography. The SiO2 mask layer in the non-mesa area is etched away using RIE technology. The area without the SiO2 mask layer is then etched away using ICP technology until the AlScN material layer is completely removed. The AlScN memristor layer is obtained by removing the SiO2 mask layer in the mesa area.

[0114] AlScN material layers were grown using the MOCVD method. The specific process conditions were as follows: the growth temperature was maintained at 1000℃, the hydrogen flow rate was 1400 sccm, the ammonia flow rate was 1500 sccm, and an aluminum source (trimethylaluminum) with a flow rate of 55 μmol / min and an organic scandium source (tris(dimethylamino)scandium) with a flow rate of 45 μmol / min were introduced into the reaction chamber to obtain the AlScN material layer.

[0115] S5. A top electrode is deposited on the AlScN memristor layer. Specifically, a photoresist mask pattern for the top electrode is prepared on the AlScN memristor layer using photolithography. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode area is retained. Then, the top electrode material is deposited on the photoresist mask pattern by evaporation. Next, the photoresist and the electrode material covering its surface are removed using lift-off technology. Finally, the top electrode is annealed to obtain the top electrode. The top electrode Ni is prepared by electron beam evaporation at an annealing temperature of 400℃ for 15 minutes.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ultraviolet photomemristor, characterized in that, include: Substrate; An AlGaN photosensitive channel layer is located on the surface of the substrate; The AlGaN photosensitive channel layer has a source electrode and a drain electrode on both sides of the surface away from the substrate, respectively; An AlScN memristor layer is located on the surface of the source electrode or drain electrode away from the substrate; The top electrode is located on the surface of the AlScN memristor layer away from the substrate; The AlGaN photosensitive channel layer, source electrode, and drain electrode form an MSM-type symmetrical ultraviolet detection structure. The AlScN memristor layer is directly integrated into the electrode region of the MSM-type symmetrical ultraviolet detection structure to form a series integrated structure.

2. The ultraviolet photomemristor as described in claim 1, characterized in that, A buffer layer is also provided between the substrate and the AlGaN photosensitive channel layer, and the two sides of the buffer layer are respectively attached to the substrate and the AlGaN photosensitive channel layer.

3. The ultraviolet photomemristor as described in claim 1, characterized in that, The AlGaN photosensitive channel layer is made of undoped Al. x Ga 1-x N photosensitive channel layer, 0.75≥x≥0.

65.

4. The ultraviolet photomemristor as described in claim 1, characterized in that, The AlScN memristor layer is Al 1-y Sc y N-type memristor layer, 0.5≥y≥0.

05.

5. The ultraviolet photomemristor as described in claim 2, characterized in that, The substrate is a heterogeneous substrate or a homogeneous substrate; The heterogeneous substrate includes any one of sapphire substrate, silicon carbide substrate, and silicon substrate; Homogeneous substrates include GaN substrates or AlN substrates; And / or, the materials of the source electrode and the drain electrode include at least one of Pt, Ti, Al, Ni, and Au; And / or, the material of the top electrode includes at least one of Pt, Ti, Al, Ni, Au, and Ag; And / or, the buffer layer is an AlN buffer layer or a GaN buffer layer.

6. The ultraviolet photomemristor as described in claim 2, characterized in that, The thickness of the AlGaN photosensitive channel layer is 1~100 nm; And / or, the thickness of the AlScN memristor layer is 1~100 nm; And / or, the thickness of the source electrode and the drain electrode is 200~400 nm; And / or, the thickness of the top electrode is 200~400 nm.

7. A method for fabricating an ultraviolet photomemristor as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Epitaxial growth of a buffer layer on the substrate; An AlGaN photosensitive channel layer is deposited on the buffer layer; Source and drain electrodes are deposited on the AlGaN photosensitive channel layer; An AlScN memristor layer is deposited on the source electrode or drain electrode; A top electrode is deposited on the AlScN memristor layer.

8. The method for fabricating an ultraviolet photomemristor as described in claim 7, characterized in that, The source electrode and drain electrode are deposited on the AlGaN photosensitive channel layer, specifically including: Photoresist mask patterns for source and drain electrodes are prepared on the AlGaN photosensitive channel layer. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode pattern area is retained. Then, source and drain electrode materials are deposited on the photoresist mask pattern. The photoresist and the electrode material covering its surface are then removed. Finally, annealing is performed to form the source and drain electrodes.

9. The method for fabricating an ultraviolet photomemristor as described in claim 7, characterized in that, An AlScN memristor layer is deposited on the source electrode or drain electrode, specifically including: An AlScN material layer is grown on a substrate on which active and drain electrodes are fabricated. A SiO2 mask layer is grown on the AlScN material layer. The mesa pattern of the AlScN memristor layer is photolithographically formed on the SiO2 mask layer. The SiO2 mask layer in the non-mesa area is etched away. The area without the SiO2 mask layer is etched until the AlScN material layer is completely removed. The AlScN memristor layer is obtained by removing the SiO2 mask layer in the mesa area.

10. The method for fabricating an ultraviolet photomemristor as described in claim 7, characterized in that, The deposition of the top electrode on the AlScN memristor layer specifically includes: A photoresist mask pattern for the top electrode is prepared on the AlScN memristor layer. After development, the photoresist in the electrode pattern area is removed, while the photoresist in the non-electrode area is retained. Then, the top electrode material is deposited on the photoresist mask pattern by vapor deposition. The photoresist and the electrode material covering its surface are removed. Finally, the top electrode is obtained by annealing.

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