阅读说明：本技术 一种光电突触器件及其应用 (Photoelectric synapse device and application thereof ) 是由 朱锐 梁会力 王燕 刘尧平 梅增霞 于 2021-05-17 设计创作，主要内容包括：本申请提供一种光电突触器件及其应用,属于人工突触技术领域。光电突触器件包括多个电性连接的光电突触元器件。每个光电突触元器件包括层叠设置的基片、非晶氧化镓层以及收集电极,非晶氧化镓层与收集电极相邻设置,非晶氧化镓层中氧空位浓度的控制可通过在0～0.2sccm的氧流量条件下磁控溅射沉积得以实现。光电突触器件具备较稳定的突触性能和较低的突触触发能耗；光电突触器件用作模拟生物突触行为的器件在人工神经网络硬件中的应用,能以较低能耗执行突触事件；光电突触器件用作图像处理的器件在图像传感设备中的应用,能有效实现抑噪。(The application provides a photoelectric synapse device and application thereof, and belongs to the technical field of artificial synapses. The optoelectronic synapse device comprises a plurality of electrically connected optoelectronic synapse elements. Each photoelectric synapse component comprises a substrate, an amorphous gallium oxide layer and a collecting electrode which are arranged in a stacked mode, wherein the amorphous gallium oxide layer and the collecting electrode are arranged adjacently, and the concentration of oxygen vacancies in the amorphous gallium oxide layer can be controlled through magnetron sputtering deposition under the condition of oxygen flow of 0-0.2 sccm. The photoelectric synapse device has stable synapse performance and low synapse triggering energy consumption; the photoelectric synapse device is used for simulating the application of a biological synapse behavior device in artificial neural network hardware, and can execute synapse events with lower energy consumption; the photoelectric synapse device is used as an image processing device in image sensing equipment, and can effectively realize noise suppression.)

1. The photoelectric synapse device is characterized by comprising a plurality of photoelectric synapse components electrically connected, wherein each photoelectric synapse component comprises a substrate, an amorphous gallium oxide layer and a collecting electrode which are arranged in a stacked mode, the amorphous gallium oxide layer is adjacent to the collecting electrode, and the concentration of oxygen vacancies in the amorphous gallium oxide layer can be controlled through magnetron sputtering deposition under the condition of oxygen flow of 0-0.2 sccm.

2. The optoelectronic synapse device of claim 1, further comprising a plurality of switching elements, wherein any two adjacent optoelectronic synapse elements are electrically connected in an electrical connection direction.

3. The optoelectronic synapse device of claim 2, wherein a plurality of the optoelectronic synapse elements are arranged in an array, each row of the optoelectronic synapse elements is arranged along a first predetermined direction, and each column of the optoelectronic synapse elements is arranged along a second predetermined direction;

the optoelectronic synapse device having a plurality of row lines and a plurality of column lines, each of the row lines extending in the first predetermined direction and each of the column lines extending in the second predetermined direction;

and two ends of each switch component are connected to the same row line, one end of each photosynaptic component is connected to one row line, and the other end of each photosynaptic component is connected to one column line.

4. The optoelectronic synapse device of claim 3, wherein the plurality of switching elements are arranged in an array, each row of the switching elements is spaced apart along the first predetermined direction and connected to a same row line, and each column of the switching elements is spaced apart along the second predetermined direction;

in the first preset direction, the photoelectric synapse elements and the switch elements are distributed alternately; in the second preset direction, a plurality of rows of the photoelectric synapse elements and a plurality of rows of the switch elements are alternately distributed;

and the anode and the cathode of each switch component are respectively connected with the anodes of the two photoelectric synapse components in the same row in the two adjacent columns at the two sides of the switch component.

5. Use of an optoelectronic synapse device as claimed in any one of claims 1-4 as a device for simulating biological synapse behavior in artificial neural network hardware.

6. The use according to claim 5,

adopting a pulse light source with the wavelength of 200-280 nm as an input light source; optionally, a pulse light source with the wavelength of 254nm is adopted as an input light source;

and/or the reading voltage applied on the collecting electrode is less than or equal to 0.2V; optionally, the read voltage applied on the collection electrode is 0.2V.

7. Use according to claim 5 or 6, characterized in that the neurosynaptic short-range plastic behaviour is achieved under first preset conditions;

the first preset condition includes: the pulse width is 100ms, and the optical power density is 1 muW/cm²。

8. Use according to claim 5 or 6, characterized in that the plastic behavior of the neuronal synaptic length is achieved under second preset conditions;

the second preset condition includes: the pulse width is 100ms, and the optical power density is 5-50 μ W/cm²(ii) a Optionally, the optical power density is 5 μ W/cm²；

Or, the second preset condition includes: the pulse width is 5s, and the optical power density is 1-50 μ W/cm²；

Or, the second preset condition includes: the pulse width is 100ms, the number of pulses is multiple, the pulse interval is 1s, and the optical power density is 1-50 muW/cm²。

9. Use according to claim 5 or 6, characterized in that the double-pulse facilitation action is effected under third preset conditions;

the third preset condition includes: the pulse width is 100ms, the pulse interval is 1-10 s, and the optical power density is 1-50 μ W/cm²。

10. Use of an optoelectronic synapse device as claimed in any one of claims 1-4 as an image processing device in an image sensing apparatus.

Technical Field

The application relates to the technical field of artificial synapses, in particular to a photoelectric synapse device and application thereof.

Background

Neurons are the fundamental unit of human brain function, and synapses are the important structures of neurons for signal transmission and information exchange. Each synapse may not only perform computation and storage simultaneously, but may also efficiently process large amounts of information in parallel. More importantly, the energy consumption for triggering synaptic events is only 1-100 fJ. Therefore, the function and performance of the simulated human brain synapse are the cornerstones for constructing the neuromorphic calculation in the mass data age.

In recent years, optoelectronic synapse devices stimulated by light have become important in the synapse field. On one hand, compared with electrical input, the non-contact optical input has the advantages of large bandwidth, low crosstalk, no RC delay and the like; on the other hand, more than 70% of the information perceived by people from the outside comes from vision, and the optoelectronic synapse device is the necessary basis for simulating human vision.

Low energy consumption is one of the greatest advantages expected of synaptic devices, however, most of the optoelectronic synaptic devices reported today mainly focus on the simulation of synaptic plasticity and neglect the implementation of low energy consumption. Achieving low power consumption remains a challenge for optoelectronic synapse devices.

Disclosure of Invention

The present application is directed to a photo-synapse device and an application thereof, where the photo-synapse device has a stable synapse performance and a low synapse triggering energy consumption.

The embodiment of the application is realized as follows:

in a first aspect, an embodiment of the present application provides an optoelectronic synapse device comprising: the photoelectric synapse device comprises a plurality of photoelectric synapse devices which are electrically connected, wherein each photoelectric synapse device comprises a substrate, an amorphous gallium oxide layer and a collecting electrode which are arranged in a stacked mode, the amorphous gallium oxide layer and the collecting electrode are arranged in an adjacent mode, and the concentration of oxygen vacancies in the amorphous gallium oxide layer can be controlled through magnetron sputtering deposition under the condition of oxygen flow of 0-0.2 sccm.

In a second aspect, embodiments of the present application provide an application of the optoelectronic synapse device as provided in the first aspect as a device for simulating biological synapse behavior in artificial neural network hardware.

In a third aspect, embodiments of the present application provide an application of the optoelectronic synapse device as provided in the embodiments of the first aspect as a device for image processing in an image sensing apparatus.

The photoelectric synapse device and the application thereof provided by the embodiment of the application have the beneficial effects that:

according to the photoelectric synapse device, the amorphous gallium oxide layer can generate migration of oxygen vacancies during ionization and has a high deionization potential barrier, so that the photoelectric synapse device has stable synapse performance. A high-barrier Schottky contact is formed between the amorphous gallium oxide layer and the collecting electrode, so that lower dark current can be obtained; a large number of oxygen vacancies exist in the amorphous gallium oxide layer, and the oxygen vacancies are ionized after absorbing ultraviolet light and migrate under an electric field, so that a Schottky barrier is reduced, a large photocurrent gain can be generated, and high responsivity can be provided, therefore, the photoelectric synapse device can realize synapse performance under the condition of weak light, namely, the photoelectric synapse device has low synapse triggering energy consumption.

The application of the photoelectric synapse device in simulating biological synapse behaviors in artificial neural network hardware can execute synapse events with lower energy consumption and can realize a neural computation task with lower energy consumption.

According to the application of the photoelectric synapse device in image processing in the image sensing equipment, as the photoelectric synapse device has stable synapse performance, the synapse current corresponding to weak noise light can be quickly recovered to the synapse current level corresponding to the dark state after exposure, and the synapse current corresponding to strong useful signal light can be kept higher than the synapse current level corresponding to the dark state after exposure, so that noise suppression can be effectively realized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained from the drawings without inventive effort.

FIG. 1 is a schematic circuit diagram of an optoelectronic synapse device according to an embodiment of the present disclosure;

FIG. 2 is a schematic structural diagram of a first optoelectronic synapse element as provided in the present application at a first viewing angle;

FIG. 3 is a schematic structural diagram of a second optoelectronic synapse element as claimed in the present application at a first viewing angle;

FIG. 4 is a schematic structural diagram of a first optoelectronic synapse element at a second viewing angle in accordance with an embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a switch component provided in an embodiment of the present application;

FIG. 6 is a schematic diagram of a partial structure of an optoelectronic synapse device according to an embodiment of the present disclosure;

FIG. 7 shows the optical synapse device in example 1 with a reading voltage of 10V, a pulse width of 20s, and an optical power density of 150 μ W/cm²Under the excitation of single 254nm pulse light;

FIG. 8 shows that the optoelectronic synapse device provided in embodiment 1 of the present application has a reading voltage of 0.2V, a pulse width of 100ms, and optical power densities of 1 μ W/cm²、5μW/cm²、10μW/cm²And 50. mu.W/cm²A synaptic current test graph under single 254nm pulse light excitation;

FIG. 9 shows the optical synapse devices in example 1 with a read voltage of 0.2V, a pulse width of 5s, and optical power densities of 1, 5, 10 and 50 μ W/cm²A synaptic current test graph under single 254nm pulse light excitation;

FIG. 10 shows the optoelectronic synapse device in example 1 with a read voltage of 0.2V, a pulse width of 100ms, a pulse spacing of 1s, and optical power densities of 1, 5, 10 and 50 μ W/cm²The synaptic current test chart under the excitation of 10 continuous 254nm pulse lights;

FIG. 11 is a diagram of a photoelectric synapse as provided in example 1 of the present applicationThe read voltage of the component is 0.2V, the pulse width is 100ms, the pulse interval is 1s, and the optical power density is 50 muW/cm²The double-pulse facilitated state test chart under the excitation of 2 continuous 254nm pulse lights;

FIG. 12 shows that the optoelectronic synapse device provided in embodiment 1 of the present application has a read voltage of 0.2V, a pulse width of 100ms, a pulse interval of 1, 5, and 10s, and an optical power density of 1, 5, 10, and 50 μ W/cm²The double-pulse facilitation index statistical chart under the excitation of 2 continuous 254nm pulse lights;

fig. 13 is a trend graph of contrast along with signal processing time corresponding to different light intensity signals when the optoelectronic synapse component provided in embodiment 1 is applied to a visual sensing device.

Icon: 100-a photovoltaic synapse device; 10-an optoelectronic synapse element; 11-a substrate; 12-an amorphous gallium oxide layer; 13-a collecting electrode; 131-a first electrode; 132 a second electrode; 20-a switching element; 21-a substrate layer; 22-a gate electrode; 23-insulating dielectric layer; 24-a channel layer; 251-a drain electrode; 252-a source electrode; 30-row line; 40-column line; a-a first preset direction; b-a second predetermined direction.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

It should be noted that "and/or" in the present application, such as "feature 1 and/or feature 2" refers to "feature 1" alone, "feature 2" alone, and "feature 1" plus "feature 2" alone.

In addition, in the description of the present application, unless otherwise specified, "plural" in "plural", "plural rows" and "plural columns" and the like means including a number of 2 and a number exceeding 2; the range of "numerical value a to numerical value b" includes both values "a" and "b", and "unit of measure" in "numerical value a to numerical value b + unit of measure" represents both "unit of measure" of "numerical value a" and "numerical value b".

The optoelectronic synapse device 100 of the present application and the application thereof are described in detail below.

In a photovoltaic synapse, low energy consumption requires a material with low dark current, while a material with a pronounced response to low light is required. In current photoelectric synapses, photosensitive materials mainly include IGZO, ZnO, perovskite materials, organic materials, and the like, and the energy consumption for triggering a synaptic event is usually hundreds to thousands of picojoules (pJ), and can only reach about 10pJ at the lowest.

The inventors have found that amorphous gallium oxide has a larger band gap (4.9eV) compared to current photosensitive materials, which is advantageous for reducing dark current. Meanwhile, under specific conditions, the amorphous gallium oxide also has higher light responsivity and sensitivity. Therefore, the amorphous gallium oxide material is used as a photosensitive material, and ultraviolet light sensitive to the amorphous gallium oxide is used as an excitation light source, so that the amorphous gallium oxide material has great potential for further reducing synapse energy consumption in the preparation of photoelectric synapses.

Referring to fig. 1-4, in a first aspect, an embodiment of the present application provides an optoelectronic synapse device 100 comprising: the photoelectric synapse device comprises a plurality of photoelectric synapse devices 10 which are electrically connected, wherein each photoelectric synapse device 10 comprises a substrate 11, an amorphous gallium oxide layer 12 and a collecting electrode 13 which are arranged in a stacked mode, the amorphous gallium oxide layer 12 and the collecting electrode 13 are arranged adjacently, and oxygen vacancies of the amorphous gallium oxide layer 12 can be obtained through magnetron sputtering deposition under the condition of oxygen flow of 0-0.2 sccm.

As an example, in the optoelectronic synapse device 100, a plurality of optoelectronic synapse elements 10 share a substrate 11.

Because a large number of oxygen vacancies exist in the amorphous gallium oxide layer 12, the amorphous gallium oxide layer 12 can generate oxygen vacancy migration during ionization and has a high deionization barrier, so that the photoelectric synapse device 100 has a stable synapse performance.

Since the amorphous gallium oxide has a wide band gap and a high barrier schottky contact is formed between the amorphous gallium oxide layer 12 and the collecting electrode 13, a low dark current can be obtained. The large number of oxygen vacancies present in the amorphous gallium oxide layer 12 ionize upon absorption of uv light and migrate under the electric field, causing the schottky barrier to be lowered, thereby enabling a large photocurrent gain to be generated and providing a high responsivity. Therefore, the optoelectronic synapse device 100 may achieve synapse performance under low light conditions, i.e., has lower synapse triggering energy consumption.

In the optoelectronic synapse device 100 provided herein, the optoelectronic synapse component 10 has a low synapse triggering energy consumption. Under the standard that the length of an active layer of the optoelectronic synapse component 10 is 5 micrometers and the width thereof is 5 micrometers, pulsed light excitation is performed under specific conditions, energy consumption for triggering a synapse event can be reduced to 136fJ (flying joule), the optoelectronic synapse component 100 is applied to artificial neural network hardware to simulate biological synapse behavior, synapse events can be executed with low energy consumption, and a neural computation task with low energy consumption can be realized.

In the optoelectronic synapse device 100 provided by the present application, the optoelectronic synapse element 10 has a stable synapse performance, a synapse current corresponding to a weaker noise light may quickly return to a synapse current level corresponding to a dark state after exposure, and a synapse current corresponding to a stronger useful signal light may keep higher than the synapse current level corresponding to the dark state after exposure, which may effectively implement noise suppression.

It should be noted that, in the present application, the concentration of oxygen vacancies in the amorphous gallium oxide layer 12 can be obtained by magnetron sputtering deposition under the condition of specific oxygen flow rate, and is used for limiting the concentration of oxygen vacancies in the amorphous gallium oxide layer 12. Thus, in the present application, the amorphous gallium oxide layer 12 is not limited to being deposited by magnetron sputtering under specific oxygen flow conditions, and may be grown in a manner known in the art so long as the same concentration of oxygen vacancies is obtained.

As an example, the amorphous gallium oxide layer 12 may be magnetron sputter deposited at an oxygen flow rate of 0-0.2 sccm, such as, but not limited to, any one of 0sccm, 0.05sccm, 0.1sccm, 0.15sccm, and 0.2sccm, or a range therebetween.

It is contemplated that the more oxygen vacancies in the deposited amorphous gallium oxide layer 12 at lower oxygen flux concentrations results in a higher responsivity and thus lower power consumption of the device.

As an example, the amorphous gallium oxide layer 12 is prepared at an oxygen flow rate of 0 sccm.

The substrate 11, the amorphous gallium oxide layer 12, and the collecting electrode 13 in the optoelectronic synapse component 10 are not particularly limited, and may be arranged in a semiconductor device known in the art.

Regarding the selection of the arrangement of the structures in the optoelectronic synapse component 10:

in the first example, as shown in fig. 2, the substrate 11, the amorphous gallium oxide layer 12, and the collecting electrode 13 are sequentially stacked.

In the second example, as shown in fig. 3, the substrate 11, the amorphous gallium oxide layer 12, and the collecting electrode 13 are sequentially stacked.

With respect to substrate 11, in some alternative embodiments, substrate 11 may be selected to be a rigid material or a flexible material. Wherein the rigid material comprises any one or more of silicon material, sapphire and quartz glass; the flexible material includes any one or more of polyethylene naphthalate (PEN), polyethylene terephthalate (PET), Polyimide (PI), polymethyl methacrylate (PMMA), Polydimethylsiloxane (PDMS), polyvinyl chloride (PVC), Polycarbonate (PC), Polystyrene (PS), and flexible glass.

The inventor researches and discovers that when the substrate 11 is a flexible substrate 11 made of an organic material, gas in the environment can be adsorbed, and deformation caused by thermal effect exists in the subsequent preparation process, so that the overall performance of the component can be influenced to a certain extent.

In order to effectively improve the above problem of the substrate 11, the surface of the substrate 11 is optionally covered with a coating layer made of, for example, alumina.

With respect to the amorphous gallium oxide layer 12, in some alternative embodiments, the thickness of the amorphous gallium oxide layer 12 is 0.06 to 0.2 μm, such as, but not limited to, any one of 0.06 μm, 0.08 μm, 0.1 μm, 0.12 μm, 0.14 μm, 0.16 μm, 0.18 μm, and 0.2 μm, or a range therebetween.

With respect to the collecting electrode 13, it has a first electrode 131 and a second electrode distributed at intervals, and the first electrode 131 and the second electrode are optionally ring electrodes, interdigital electrodes, sheet electrodes or other realizable shapes.

As an example, as shown in fig. 4, the first electrode 131 and the second electrode are interdigital electrodes. The fingers of the first electrode 131 and the fingers of the second electrode are alternately arranged at intervals in a predetermined direction. The widths of the fingers of the first electrode 131 and the fingers of the second electrode in the predetermined direction and the pitch between the fingers are not limited as long as a short circuit is not generated between the first electrode 131 and the second electrode, which is alternatively 5 to 10 μm, or 5 to 7 μm, for example, 5 μm.

In some alternative embodiments, the collecting electrode 13 is a high work function electrode, and the collecting electrode 13 includes a high work function electrode material. As an example, the work function of the high work function electrode material is 4.5eV or more, and the high work function electrode material is, for example, one of ITO, Au, Pt, Pd and MXene.

Further, the thickness of the collecting electrode 13 is 0.01 to 0.3 μm, such as but not limited to any one of 0.01 μm, 0.05 μm, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm and 0.3 μm or a range value therebetween.

Taking the optoelectronic synapse component 10 shown in fig. 2 as an example, an exemplary method for manufacturing the optoelectronic synapse component 10 is as follows:

pretreatment of the substrate 11: taking a glass sheet as an example, the glass sheet is sequentially subjected to ultrasonic treatment in acetone, alcohol and deionized water for 5 minutes respectively, and is dried by nitrogen. The other substrates 11 are correspondingly pretreated to obtain clean and flat substrates 11.

Preparing amorphous gallium oxide on the surface of the pretreated substrate 11: the amorphous gallium oxide is prepared by a vacuum deposition mode or a normal pressure preparation mode. Wherein the vacuum deposition mode comprises magnetron sputtering, atomic layer deposition, electron beam deposition, laser pulse deposition, thermal evaporation and chemical vapor deposition, and the deposition temperature is-20 to 450 ℃; the normal pressure preparation mode comprises normal pressure chemical vapor deposition, spin coating, drop coating, spray coating, printing and printing modes.

In the preparation process, oxygen vacancies with specific concentration are introduced into the amorphous gallium oxide by changing the growth atmosphere, temperature or precursor components and the like. Taking magnetron sputtering of amorphous gallium oxide as an example, on one hand, a large amount of oxygen vacancies can be obtained through the sputtering atmosphere of pure argon; on the other hand, more oxygen vacancies can be obtained by co-sputtering gallium oxide with other metals (e.g., chromium).

Preparing a collecting electrode 13 on the surface of the amorphous gallium oxide: the structure of the collecting electrode 13 is photoetched on the amorphous gallium oxide by adopting ultraviolet exposure, development and fixing technology, then the amorphous gallium oxide is placed into a vacuum chamber to deposit electrode material, then the residual photoresist and the electrode material attached to the photoresist are removed, the electrode material in the photoetching pattern area is reserved, and the collecting electrode 13, namely the first electrode 131 and the second electrode, is formed. Or, depositing electrode material in a vacuum chamber, photoetching the electrode to form a structure of the collecting electrode 13 by adopting ultraviolet exposure, development and fixing technologies, etching by using electrode etching liquid, and finally removing photoresist to finish the patterning of the electrode. Alternatively, the collecting electrode 13 may be directly formed on the amorphous gallium oxide layer 12 by means of masking, screen printing, ink jet printing, or the like.

It is contemplated that when only a plurality of optoelectronic synapse elements 10 are provided in an optoelectronic synapse device 100, the array may exhibit crosstalk. In some exemplary embodiments, the optoelectronic synapse device 100 further comprises a plurality of switching elements 20, wherein any two optoelectronic synapse elements 10 adjacent to each other in the electrical connection direction are electrically connected to the switching elements 20, and the switching elements 20 separate any two optoelectronic synapse elements 10 adjacent to each other in the electrical connection direction, which may effectively improve crosstalk in the array.

In the present application, the electrical connection direction refers to the circuit transmission direction of each series circuit. For example, when a first optoelectronic synapse element 10 and a second optoelectronic synapse element 10 are connected in series, a switching element 20 is disposed between the first optoelectronic synapse element 10 and the second optoelectronic synapse element 10; when the first optoelectronic synapse element 10 is connected in parallel with the second optoelectronic synapse element 10, no switching element 20 is required between the first optoelectronic synapse element 10 and the second optoelectronic synapse element 10.

It is to be understood that, in the present application, the switching component 20 only has to have a switching function, and may select a switching structure known in the art, and may be selected as a diode or a transistor, such as a field effect diode or a MOS transistor.

In some exemplary embodiments, the switching component 20 is a field effect diode. As shown in fig. 5, the field effect diode includes a substrate layer 21, a gate electrode 22, an insulating medium layer 23, a channel layer 24, a source electrode 252 and a drain electrode 251, wherein the gate electrode 22 is disposed on the surface of the substrate layer 21, the insulating medium layer 23 is disposed on the surface of the gate electrode 22, the channel layer 24 is disposed on the surface of the insulating medium layer 23, and the source electrode 252 and the drain electrode 251 are both disposed on the surface of the channel layer 24.

As an example, the substrate 11 of the optoelectronic synapse component 10 and the substrate layer 21 of the switch component 20 are the same structural layer, that is, in the optoelectronic synapse device 100, a plurality of optoelectronic synapse components 10 and a plurality of switch components 20 share one substrate structure.

Taking the switching component 20 shown in fig. 5 as an example, an exemplary method for manufacturing the switching component 20 is as follows:

and (3) preprocessing the substrate layer 21 in a mode consistent with the preprocessing mode of the substrate 11 during the preparation of the photoelectric synapse component 10.

Preparing a gate electrode 22 on the surface of the pretreated substrate layer 21 and patterning: and placing the substrate layer 21 into a vacuum chamber to deposit an electrode material, and photoetching the shape of the gate electrode 22 by adopting ultraviolet exposure, development, fixation, etching and dissolution technology.

Preparing an insulating dielectric layer 23 on the surface of the gate electrode 22: an insulating dielectric layer 23 is deposited on the surface of the gate electrode 22 by sputtering or atomic layer deposition.

Preparing a channel layer 24 on the surface of the insulating medium layer 23: and preparing a channel layer 24 on the surface of the insulating medium layer 23 by magnetron sputtering, pulsed laser deposition or spin coating.

Patterning of the insulating medium layer 23 and the channel layer 24: and respectively patterning the channel layer 24 and the insulating medium layer 23 by adopting a photoetching and etching method.

Preparing and patterning a source electrode 252 and a drain electrode 251 on the surface of the channel layer 24: the source electrode 252 and the drain electrode 251 are formed on the surface of the channel layer 24 by ultraviolet exposure, development and fixing, the channel layer is placed in a vacuum chamber to deposit electrode material, then the residual photoresist and the electrode material attached to the photoresist are removed, the electrode material in the photoetching pattern area is reserved, and the source electrode 252 and the drain electrode 251 are formed. Or, depositing electrode material in a vacuum chamber, then photoetching the structures of the source electrode 252 and the drain electrode 251 on the electrode by adopting ultraviolet exposure, development and fixing technologies, then etching by using electrode etching liquid, and finally removing the photoresist to finish the patterning of the electrode. Alternatively, the source electrode 252 and the drain electrode 251 may be directly formed by a mask, screen printing, inkjet printing, or the like.

It is understood that, in the present application, the arrangement of the optoelectronic synapse component 10 and the switch component 20 is not limited, as long as the electrical connection requirement can be satisfied.

In some exemplary embodiments, a plurality of optoelectronic synapse elements 10 are distributed in an array; in the first preset direction a, the plurality of optoelectronic synapse components 10 are divided into a plurality of rows; in the second predetermined direction B, the plurality of optoelectronic synapse elements 10 are divided into a plurality of rows. Each row of the optoelectronic synapse elements 10 is distributed along a first predetermined direction a, and each column of the optoelectronic synapse elements 10 is distributed along a second predetermined direction B.

Optionally, the optoelectronic synapse device 100 has a plurality of row lines 30 and a plurality of column lines 40, each row line 30 extending in a first predetermined direction a, each column line 40 extending in a second predetermined direction B. Both ends of each switching element 20 are connected to the same row line 30, and one end of each photosynaptic element is connected to one row line 30 and the other end is connected to one column line 40.

Further, the plurality of switch components 20 are distributed in an array, each row of switch components 20 is distributed at intervals along the first preset direction a and connected to the same row line 30, and each column of switch components 20 is distributed at intervals along the second preset direction B. In a first preset direction A, a plurality of rows of photoelectric synapse components 10 and a plurality of rows of switch components 20 are alternately distributed; in the second predetermined direction B, the plurality of rows of optoelectronic synapse elements 10 and the plurality of rows of switching elements 20 are alternately arranged. The positive electrode and the negative electrode of each switching element 20 are respectively connected with the positive electrodes of two photoelectric synapse elements 10 in the same row in two adjacent columns at two sides of the switching element.

Referring to fig. 6, as an example, in the embodiment where the switching device 20 is configured as a field effect diode, the first electrode 131 of the optoelectronic synapse device 10 is electrically connected to the drain electrode 251 of the field effect diode on the column line 30, and the second electrode 132 of the optoelectronic synapse device 10 is directly connected to the column line 40.

The above arrangement of the optoelectronic synapse elements 10 and the switching elements 20 may form a plurality of optoelectronic synapse elements 10 and switching elements 20 on the same substrate structure as shown in fig. 1, and then form the row lines 30 and the column lines 40 for circuit connection when the optoelectronic synapse device 100 is manufactured. Wherein, the row lines 30 and the column lines 40 are insulated and separated by preparing an insulating layer (such as alumina).

In a second aspect, embodiments of the present application provide an application of the optoelectronic synapse device 100 as provided in the first aspect, as a device for simulating biological synapse behavior, in artificial neural network hardware.

The optoelectronic synapse device 100 provided by the present application may be capable of better simulating biological synapse behaviors including short-range plastic behaviors of neurosynaptic, long-range plastic behaviors of neurosynaptic, and double-pulse facilitated behaviors due to the relatively stable synapse performance of the optoelectronic synapse component 10. Meanwhile, since the optoelectronic synapse element 10 can execute synapse events with lower energy consumption, a lower energy consumption neural computation task can be realized.

It will be appreciated that in the present application, the excitation light source and the read voltage may be selected according to requirements known in the art.

In some optional embodiments, a pulsed light source with a wavelength of 200-280 nm is used as the input light source, for example, a pulsed light source with a wavelength of 254nm is used as the input light source. The pulse light source has good matching with the band gap of the amorphous gallium oxide material, and can well stimulate the optoelectronic synapse component 10 to simulate biological synapse behavior. Meanwhile, an input light source required by the wavelength is convenient to provide, and the excitation energy is insufficient due to overlarge wavelength.

Considering that the smaller the reading voltage applied to the first electrode 131 and the second electrode of the collecting electrode 13, the smaller the power consumption, in some alternative embodiments, the reading voltage applied to the collecting electrode 13 is ≦ 0.2V.

Further, it is considered that the smaller the reading voltage is, the smaller the responsiveness is, and the higher responsiveness is advantageous to ensure that the synaptic performance is better achieved under the synaptic test condition. As an example, the reading voltage applied to the collecting electrode 13 is 0.2V, which can ensure both reduction of power consumption and higher responsivity.

Considering that different biological synapse behaviors need different excitation conditions when the optoelectronic synapse component 10 is used to simulate the biological synapse behaviors, in order to better satisfy the simulation requirements, appropriate excitation conditions need to be selected for the different biological synapse behaviors.

With respect to the neurosynaptic short-range plastic behavior, in some alternative embodiments, the neurosynaptic short-range plastic behavior is achieved under a first preset condition.

The first preset condition includes: the pulse width is 100ms, and the optical power density is 1 muW/cm²。

With respect to the plastic behavior of the synaptic length, in some alternative embodiments, the plastic behavior of the synaptic length is achieved under a second preset condition.

As a first example, the second preset condition includes: the pulse width is 100ms, and the optical power density is 5-50 μ W/cm². Optionally, the optical power density is 5 μ W/cm²、10μW/cm²And 50. mu.W/cm²Or any range value therebetween.

As a second example, theThe second preset condition comprises: the pulse width is 5s, and the optical power density is 1-50 μ W/cm². Optionally, the optical power density is 5 μ W/cm²、10μW/cm²And 50. mu.W/cm²Or any range value therebetween.

As a third example, the second preset condition includes: the pulse width is 100ms, the number of pulses is multiple, the pulse interval is 1s, and the optical power density is 1-50 muW/cm². Optionally, the number of pulses is 10, and the optical power density is 5 μ W/cm²、10μW/cm²And 50. mu.W/cm²Or any range value therebetween.

In some exemplary embodiments, when the optoelectronic synapse device 100 is used to simulate biological synaptic behavior, the short-range plastic behavior of the synapse is converted to long-range plastic behavior of the synapse by increasing the pulse width and/or increasing the number of pulses.

With respect to the double pulse facilitation behavior, in some alternative embodiments, the double pulse facilitation behavior is achieved under a third preset condition.

The third preset condition includes: the pulse width is 100ms, the pulse interval is 1-10 s, and the optical power density is 1-50 μ W/cm². Optionally, the pulse spacing is any one of 1s, 5s and 10s or a range between any two, and the optical power density is 5 μ W/cm²、10μW/cm²And 50. mu.W/cm²Or any range value therebetween.

In some exemplary embodiments, the double pulse facilitation index is reduced by increasing the pulse spacing when using the optoelectronic synapse device 100 to mimic biological synapse behavior.

In a third aspect, embodiments of the present application provide an application of the optoelectronic synapse device 100 as provided in the first aspect as an image processing device for image processing in an image sensing apparatus. The image sensing device is, for example, a vision sensing device or an image recognition device.

In the optoelectronic synapse device 100 provided by the present application, since the optoelectronic synapse element 10 has a stable synapse performance, a synapse current corresponding to a weaker noise light may quickly return to a synapse current level corresponding to a dark state after exposure, and a synapse current corresponding to a stronger useful signal light may be kept higher than the synapse current level corresponding to the dark state after exposure, so that noise suppression may be effectively achieved, and image preprocessing with enhanced contrast may be simultaneously achieved. The image after the preprocessing is taken as an input layer of image recognition, so that the efficiency of image recognition can be greatly improved.

As an example, when the optical power density of the target noise is 1 μ W/cm²Then, the optoelectronic synapse component 10 is selected to have the following optoelectronic synapse properties: 1 μ W/cm²The light source corresponding to the synaptic current can quickly return to the level of the synaptic current corresponding to the dark state after the exposure is finished, and the intensity is higher than 1 muW/cm²The light source can maintain a higher level of synaptic current after exposure than the light source in the dark state. The photoelectric synapse performance of the photoelectric synapse component 10 may be adjusted by adjusting the area of the photoelectric synapse component 10, the oxygen vacancy concentration of the amorphous gallium oxide layer 12, and the like.

The features and properties of the present application are described in further detail below with reference to examples.

Example 1

An optoelectronic synapse device comprises a plurality of electrically connected optoelectronic synapse elements. The preparation method of the photoelectric synapse component comprises the following steps:

s1, ultrasonically cleaning a quartz substrate by sequentially adopting acetone, alcohol and deionized water, and drying by using dry high-purity nitrogen.

S2, placing the blow-dried quartz glass substrate into a magnetron sputtering cavity, starting a vacuum pump to pump the vacuum cavity to be in background vacuum, introducing 10sccm argon to start brightness, and depositing a 90nm amorphous gallium oxide film rich in oxygen vacancies by using a gallium oxide ceramic target under the condition of not introducing oxygen.

S3, placing the quartz glass substrate with the prepared amorphous gallium oxide into a magnetron sputtering cavity for sputtering a metal electrode, and sputtering Au with the thickness of 50nm under the atmosphere of pure argon. And then, a series of processes of gluing, pre-baking, exposure, post-baking, developing, etching and dissolving-out are adopted to finish the patterning of the Au electrode to form a collecting electrode, and the photoelectric synapse component is obtained.

The structure of the optoelectronic synapse element is shown in fig. 2 and 4. Wherein, the front-end interdigital structures in the collecting electrode structure are alternately distributed at intervals along a preset direction, and the parameters of the interdigital structures are as follows: in a preset direction, the line width of each interdigital is 5um, and the distance between the interdigital is 5 um; in the direction perpendicular to the preset direction, the length of each interdigital is 100 um; the fingers are 10 pairs.

Example 2

An optoelectronic synapse device as in example 1 differing only in that: in the preparation method of the photoelectric synapse component, a substrate made of PEN is adopted; after drying the substrate, preparing a layer of Al on the substrate in an atomic layer deposition system₂O₃And (4) coating.

Example 3

An optoelectronic synapse device as in example 1 differing only in that: in the preparation method of the photoelectric synapse component, amorphous gallium oxide is prepared by adopting a pulsed laser deposition method. Wherein the deposition atmosphere is unchanged, and the target material is Ga with the purity of 99.999 percent₂O₃The ceramic target was a 248nm KrF excimer laser with a pulse energy of 300mJ and a pulse frequency of 10 Hz.

Example 4

An optoelectronic synapse device as in example 1 differing only in that: in the preparation method of the photoelectric synapse component, amorphous gallium oxide is prepared by adopting a plasma enhanced chemical vapor deposition method. The amorphous gallium oxide rich in oxygen vacancies is obtained by using trimethyl gallium as a gallium source and carbon dioxide as an oxidant and regulating the relative contents of trimethyl gallium and carbon dioxide.

Example 5

A method for fabricating an optoelectronic synapse device for forming an array of optoelectronic synapses in circuit connection and arrangement as shown in FIG. 1, comprising:

s1, ultrasonically cleaning a quartz substrate by sequentially adopting acetone, alcohol and deionized water, and drying by using dry high-purity nitrogen.

S2, placing the blow-dried quartz glass substrate into a magnetron sputtering cavity, starting a vacuum pump to pump the vacuum cavity to be in background vacuum, introducing 10sccm argon to start brightness, and depositing a 50nm Cr gate electrode by using a Cr target. And then, a series of processes of coating, prebaking, exposing, postbaking, developing, etching and dissolving are adopted to complete the patterning of the Cr gate electrode.

Then preparing an alumina insulating medium layer with the thickness of 50nm by using an ALD method at the temperature of 200 ℃, wherein an aluminum source is trimethyl aluminum, and an oxygen source is water. And then preparing an IGZO channel layer with the thickness of 40nm by using a magnetron sputtering method under the temperature condition of 100 ℃. And then patterning the aluminum oxide insulating medium layer and the IGZO channel layer by photoetching and etching respectively. Wherein, the etching liquid of the aluminum oxide insulating medium layer is NaOH, and the etching liquid of the IGZO channel layer is hydrochloric acid.

And then, preparing the shapes of a source electrode and a drain electrode by using a photoetching method, continuously depositing Ti with the thickness of 40nm and Au with the thickness of 20nm in a magnetron sputtering cavity, and then, realizing the imaging of the source electrode and the drain electrode by using a stripping process to obtain the switch component.

S3, sputtering and depositing an amorphous gallium oxide film which is rich in oxygen vacancy and has the thickness of 90nm by using a gallium oxide ceramic target in a pure Ar atmosphere, and patterning by using a photoetching and etching method, wherein an etching solution is an alkaline developing solution. Au was then sputtered to a thickness of 50nm under a pure argon atmosphere. And then, a series of processes of gluing, pre-baking, exposure, post-baking, developing, etching and dissolving-out are adopted to finish the patterning of the Au electrode to form a collecting electrode, and the photoelectric synapse component is obtained.

S4, preparing an aluminum oxide insulating medium layer with the thickness of 100nm by adopting an ALD method at the temperature of 200 ℃, wherein an aluminum source is trimethyl aluminum, and an oxygen source is water. And patterning by photoetching and etching methods to form through holes for connecting the first electrode of the collecting electrode, the drain electrode and the source electrode. Then sputtering Cr and patterning to complete the arrangement of the row lines.

S5, preparing an aluminum oxide insulating medium layer with the thickness of 100nm by adopting an ALD method at the temperature of 200 ℃, wherein an aluminum source is trimethyl aluminum, and an oxygen source is water. The second electrode, which is also patterned by photolithography and etching, is provided with a via hole for connecting the collecting electrode. Cr is subsequently sputtered and patterned to complete the arrangement of the column lines.

Test examples

(1) The photoelectric synapse component prepared in example 1 was read at a voltage of 10V, a pulse width of 20s, and an optical power density of 150 μ W/cm²The persistent photoconduction under single 254nm pulsed light excitation was tested and the results are shown in figure 7.

As can be seen from fig. 7, the photo-synaptic device prepared in example 1 can increase the photo-current to mA level under illumination, which corresponds to high responsivity. After the pulsed light is removed, the current is maintained at a level much higher than the dark current even after 1000s has elapsed. It can be seen that the optoelectronic synapse component prepared in example 1 has high responsivity and long-term continuous photoconduction, and can provide guarantee for stable synapse performance under synapse test conditions.

(2) The photoelectric synapse device prepared in example 1 was read at a voltage of 0.2V, a pulse width of 100ms, and an optical power density of 1 μ W/cm²、5μW/cm²、10μW/cm²And 50. mu.W/cm²The synaptic current under single 254nm pulsed light excitation was tested, and the test results are shown in fig. 8.

As can be seen from FIG. 8, under the excitation of a single 254nm pulse light with a read voltage of 0.2V and a pulse width of 100ms, the optical power density is 1 μ W/cm²And when the pulse is finished, the synaptic current quickly returns to a level close to a dark state, which shows that the photoelectric synaptic component can better realize the short-range plastic behavior of the nerve synapse under the condition.

It can also be seen from FIG. 8 that the optical power densities are 5 μ W/cm under single 254nm pulsed optical excitation with a read voltage of 0.2V and a pulse width of 100ms²、10μW/cm²And 50. mu.W/cm²In time, the synaptic current is also maintained at a level which is obviously higher than the dark-state current after the pulse is finished, which shows that the photoelectric synaptic component can better realize the plastic behavior of the long-range of the nerve synapse under the condition.

At a read voltage of 0.2V and a pulse widthIs 100ms and the optical power density is 5 muW/cm respectively²And under the excitation of single 254nm pulse light, calculating the energy consumption for triggering a synaptic event. The length of an active layer of the device is 5 micrometers, the width of the active layer of the device is 5 micrometers, the energy consumption of light is calculated according to a formula 1, the energy consumption of electricity is calculated according to a formula 2, and the total energy consumption is the sum of the energy consumption of light and the energy consumption of electricity.

Equation 1: e_l＝PSΔt。

Equation 2: ee is approximately equal to V_readI_peakΔt。

Where P is the optical power density, S is the effective illumination area of the device, Δ t is the pulse width, V_readWherein is the read voltage, I_peakIs the peak current under optical excitation.

In equation 2, approximately equal means that when the time integration result is obtained, a rectangular region close to the time integration curve is obtained on the time integration curve, and the area of the rectangular region is obtained as the time integration result.

The calculated electric energy consumption is 11fJ, the light energy consumption is 125fJ, and the total energy consumption is 136 fJ. Therefore, the energy consumption of the photoelectric synapse element under the excitation condition basically reaches a low energy consumption level comparable to that of biological synapse.

(3) The photoelectric synapse device prepared in example 1 was tested at a read voltage of 0.2V, a pulse width of 5s, and optical power densities of 1, 5, 10, and 50 μ W/cm²The synaptic current under single 254nm pulsed light excitation was tested, and the test results are shown in fig. 9.

As can be seen from fig. 9, the optoelectronic synapse element can achieve a long-range plastic behavior of the synapse under the above conditions.

Further, the optical power densities were 1. mu.W/cm, respectively²It can also be seen that by increasing the pulse width, the short-range synaptic plasticity can be effectively converted to long-range synaptic plasticity.

(4) The photoelectric synapse device prepared in example 1 was read at a voltage of 0.2V, a pulse width of 100ms, a pulse spacing of 1s, and optical power densities of 1, 5, 10, and 50 μ W/cm²10 continuous 254nm pulsed lightsThe synaptic current under excitation was tested and the results are shown in FIG. 10.

As can be seen from fig. 10, by increasing the number of pulses, the synaptic current is significantly increased, and the optoelectronic synapse device can better realize the plastic behavior of the synapse length under the above conditions.

Further, the optical power densities were 1. mu.W/cm, respectively²It can also be seen that by increasing the number of pulses, short-range synaptic plasticity can be efficiently converted to long-range synaptic plasticity.

(5) The photoelectric synapse device prepared in example 1 was read at a voltage of 0.2V, a pulse width of 100ms, a pulse interval of 1s, and an optical power density of 50 μ W/cm²The two-pulse facilitated state under the excitation of 2 continuous 254nm pulse lights is tested, and the test result is shown in fig. 11. Wherein PPF is double pulse facilitation index, and PPF is A₂/A₁。

The photoelectric synapse device prepared in example 1 was read at a voltage of 0.2V, a pulse width of 100ms, a pulse interval of 1, 5, and 10s, and an optical power density of 1, 5, 10, and 50 μ W/cm²The double-pulse facilitation state under the excitation of 2 continuous 254nm pulse lights is tested, and then the double-pulse facilitation indexes are counted, and the statistical result is shown in fig. 12.

As can be seen from FIGS. 11 and 12, the dipulse facilitation index decreases with increasing pulse spacing, and the optoelectronic synapse device can achieve the dipulse facilitation under the above conditions.

(6) The optoelectronic synapse device manufactured in example 1 is applied to a visual sensing device, and the variation trend of the corresponding contrast with the signal processing time under different light intensity signals is counted, and the result of the statistical trend is shown in fig. 13.

Will correspond to 1. mu.W/cm²Will correspond to 5, and 10. mu.W/cm as noise signals²Wherein each calculation of the contrast corresponds to a current of "0" and an optical power density of 10. mu.W/cm in a dark state²The corresponding current is "1" for normalization.

For a common CCD camera, since the photocurrent does not change with time, the contrast ratio will remain unchanged and the contrast ratio of the noise signal will not decrease.

As can be seen from FIG. 13, the optical power density is 1. mu.W/cm²The contrast of the noise signal is continuously reduced with the increase of the processing time, and after the processing of 40s, the contrast is changed from the original 0.28 to 0.06, namely, the contrast of the noise signal is reduced by more than 4 times. While the contrast of other useful image signals with higher optical power densities fluctuates only to a small extent over the entire time range. Therefore, the photoelectric synapse component can well realize noise suppression preprocessing of the image.

The embodiments described above are some, but not all embodiments of the present application. The detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.