CN111863777A - A low-noise single-sided integrated injectable biological photoelectrode microprobe and preparation method - Google Patents

Abstract

The invention discloses a low-noise single-side integrated micro probe capable of being injected with a biological photoelectric electrode and a preparation method thereof. By using the invention, the interference of electromagnetic radiation to the photoelectrode can be inhibited, thereby obtaining a biological signal with higher quality. The invention is a low-noise single-side integrated injectable biological photoelectrode microprobe and a preparation method thereof, and can be widely applied to the field of semiconductor chips in life science.

Description

A low-noise single-sided integrated injectable biological photoelectrode microprobe and preparation method

technical field

The invention relates to the field of life science semiconductor chips, in particular to a low-noise single-sided integrated injectable biological photoelectrode microprobe and a preparation method.

Background technique

Optogenetic tools need to have both the function of specifically targeting light regulation and recording of neural signals, which are defined as photoelectrodes. Photoelectrodes can be divided into two types: coupled light source type and injection light source type. Coupled light source photoelectrodes are bound by optical fibers, laser sources, and external coupling devices, which limit the development of wireless and intelligent photoelectrodes. It has become an inevitable development trend of optogenetic tools. When the light source driving module injected into the light source photoelectrode works, the injected current will bring electromagnetic radiation interference and power frequency noise to the recording of biological signals. The suppression and elimination of electromagnetic radiation interference is one of the difficulties that photoelectrodes must solve, and it has a crucial impact on improving the quality of collected biological signals.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problems, the purpose of the present invention is to provide a low-noise single-sided integrated injectable biological photoelectrode microprobe and a preparation method, which can be used in an injection light source type photoelectrode with high resolution, high optical power density, small size, Based on the advantages of low power consumption, the recording quality of biological signals is further optimized.

The first technical solution adopted by the present invention is: a low-noise single-sided integrated injectable biological photoelectrode microprobe, comprising a light-emitting diode structure, a recording electrode and an electromagnetic shielding structure, and the light-emitting diode structure includes a substrate from bottom to top material, n-type gallium nitride, active layer, p-type gallium nitride, transparent conductive layer, insulating isolation layer, insulating passivation layer, the insulating isolation layer is provided with a light-emitting diode anode structure and a light-emitting diode cathode structure, so The electromagnetic shielding structure is composed of an electromagnetic shielding layer structure and a ground wire half-enclosed structure.

Further, the light-emitting diode anode structure includes a light-emitting diode anode electrode, a light-emitting diode anode wire, and a light-emitting diode anode pad, and the light-emitting diode cathode structure includes a light-emitting diode cathode, a light-emitting diode cathode wire, and a light-emitting diode cathode pad, and the recording The electrode structure includes a recording electrode, a recording electrode wire, and a recording electrode pad.

Further, an anode window and a cathode window are provided on the insulating isolation layer.

Further, the anode window is provided with a light-emitting diode anode electrode, the insulating isolation layer is provided with a light-emitting diode anode wire and a light-emitting diode anode pad, and the light-emitting diode anode electrode passes through the light-emitting diode anode wire and the light-emitting diode anode pad. connect.

Further, the cathode window is provided with a light-emitting diode cathode electrode, the insulating isolation layer is provided with a light-emitting diode cathode wire and a light-emitting diode cathode pad, and the light-emitting diode cathode electrode passes through the light-emitting diode cathode wire and the light-emitting diode cathode pad. connect.

Further, a recording electrode, a recording electrode wire and a recording electrode pad are arranged on the insulating isolation layer, and the recording electrode is connected to the recording electrode pad through the recording electrode wire.

Further, the insulating passivation layer is provided with an anode pad window, a cathode pad window, a recording electrode window and a recording electrode pad window.

The second technical solution adopted by the present invention is: a preparation method of a low-noise single-sided integrated injectable biological photoelectrode microprobe, comprising the above steps:

Growing n-type gallium nitride, active layer and p-type gallium nitride in sequence on sapphire substrate;

Through photolithography and magnetron sputtering process, indium tin oxide transparent conductive layer is prepared in high vacuum argon atmosphere;

The transparent conductive layer of indium tin oxide is patterned through a lift-off process to prepare a transparent anode and an electromagnetic shielding layer of the light-emitting diode;

A good ohmic contact is formed between the transparent conductive layer of indium tin oxide and p-type gallium nitride by rapid thermal annealing process;

Through photolithography and dry etching process, the epitaxial wafer is etched to n-type gallium nitride under the condition of Cl ₂ and BCl ₃ gas environment;

High temperature activated active layer;

By photolithography and plasma-enhanced chemical vapor deposition process, silicon dioxide isolation layer was prepared in the gas environment of SiH ₄ and N ₂ O, high vacuum and 350 ℃ high temperature environment, and etched with buffer oxide by wet etching process The etching solution patterned the silicon dioxide isolation layer to prepare a cathode window and an anode window;

Through photolithography and electron beam evaporation processes, metal thin films are prepared in a high vacuum environment, and the metal thin films are patterned by a lift-off process to prepare LED anode electrodes, LED anode wires, LED anode pads, and LED cathode electrodes. , LED cathode wires, LED cathode pads, recording electrodes, recording electrode wires and recording electrode pads;

By photolithography and plasma enhanced chemical vapor deposition process, silicon dioxide passivation layer was prepared in the gas environment of SiH ₄ and N ₂ O, high vacuum and 350℃ high temperature environment, and the buffer oxide was prepared by wet etching process The etching solution patterned the silicon dioxide isolation layer to prepare an anode pad window, a cathode pad window, a recording electrode window and a recording electrode pad window

Further, the metal thin film adopts a titanium metal thin film of 50 nm or a gold metal thin film of 150 nm.

The beneficial effects of the invention are as follows: on the one hand, a layer of transparent conductive film is prepared on the n-type gallium nitride as the electromagnetic shielding structure of the whole photoelectrode to prevent it from being affected by external electromagnetic interference; The ground wire of the light-emitting diode can be used not only as the cathode of the light-emitting diode, but also as a shielding structure to protect the recording electrode wire from being affected by electromagnetic interference. It is also possible to use the through-hole structure to lead the electromagnetic shielding layer of the transparent conductive film to the insulating isolation layer as the ground. The wire semi-surrounding structure protects the recording electrode from interference by electromagnetic shielding. When the light emitting diode is working, the structure can shield the interference of the injection current of the light emitting diode and the external electrical signal to the recording electrode, reduce the noise size when the recording electrode is working, and improve the quality of the collected biological signal.

Description of drawings

1 is a device structure diagram of a low-noise single-sided integrated injectable biological photoelectrode microprobe of the present invention;

2 is a perspective view of a low-noise single-sided integrated injectable biological photoelectrode microprobe device structure of the present invention after etching the mesa and preparing the transparent electrode;

3 is a perspective view of a low-noise single-sided integrated injectable biological photoelectrode microprobe device structure of the present invention after preparing an insulating isolation layer;

4 is a perspective view of a low-noise single-sided integrated injectable biological photoelectrode microprobe device structure of the present invention after preparing an insulating passivation layer.

FIG. 5 is a flow chart showing the steps of a method for preparing a low-noise single-sided integrated injectable biological photoelectrode microprobe according to the present invention.

Reference signs: 1. sapphire substrate; 2. n-type gallium nitride; 3. active layer; 4. p-type gallium nitride; 5. transparent conductive layer of indium tin oxide; 6. silicon dioxide isolation layer; 7 , anode window; 8, cathode window; 9, LED anode electrode; 10, recording electrode; 11, LED cathode electrode; 12, recording electrode wire; 13, LED anode wire; 14, LED cathode wire; 15, recording electrode pad; 16, LED cathode pad; 17, LED anode pad; 18, silicon dioxide passivation layer; 19, recording electrode window; 20, recording electrode pad window; 21, anode pad window ; 22. Cathode pad window.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The numbers of the steps in the following embodiments are only set for the convenience of description, and the sequence between the steps is not limited in any way, and the execution sequence of each step in the embodiments can be adapted according to the understanding of those skilled in the art Sexual adjustment.

As shown in FIG. 1, the present invention provides a low-noise single-sided integrated injectable biological photoelectrode microprobe, including a light-emitting diode structure, a recording electrode structure and an electromagnetic shielding structure, and the light-emitting diode structure includes a sapphire liner from bottom to top Bottom 1, n-type gallium nitride 2, active layer 3, p-type gallium nitride 4, indium tin oxide transparent conductive layer 5, silicon dioxide isolation layer 6, silicon dioxide passivation layer 18, the silicon dioxide The isolation layer 6 is provided with a light-emitting diode anode structure and a light-emitting diode cathode structure, and the electromagnetic shielding structure is composed of an electromagnetic shielding layer structure and a ground wire half-enclosed structure.

As shown in FIG. 2 , the epitaxial structure of the gallium nitride epitaxial wafer is: sapphire substrate 1 , n-type gallium nitride 2 , active layer 3 , and p-type gallium nitride 4 . The mesa is etched to the n-type gallium nitride 2 , and the indium tin oxide transparent conductive layer 5 is prepared on the p-type gallium nitride 4 and the n-type gallium nitride 2 . The transparent conductive layer 5 prepared on the p-type gallium nitride 4 is used as the anode of the light-emitting diode structure. Although the transparent electrode can increase the light transmittance while increasing the current injection area, it is inconvenient to lead out long leads and pads, so some The area is set aside for preparing the anode of the metal structure; the indium tin oxide transparent conductive layer 5 is prepared on the n-type gallium nitride 2 as the electromagnetic shielding structure of the whole photoelectrode.

Specifically, the electromagnetic shielding structure is composed of an electromagnetic shielding layer structure and a ground wire semi-enclosed structure. On the one hand, a layer of indium tin oxide transparent conductive film is prepared on the n-type gallium nitride 2, which is used as the electromagnetic shielding structure of the entire photoelectrode to prevent its Affected by external electromagnetic interference; on the other hand, the ground wire of the light-emitting diode is not only used as the cathode of the light-emitting diode, but also as a shielding structure to protect the recording electrode wire from being affected by electromagnetic interference, or use a through-hole structure. The electromagnetic shielding layer of the indium tin oxide transparent conductive film is led to the silicon dioxide isolation layer 6 as a semi-surrounding structure of the ground wire to protect the recording electrode from being interfered by the electromagnetic shielding. When the light emitting diode is working, the structure can shield the interference of the injection current of the light emitting diode and the external electrical signal to the recording electrode, reduce the noise size when the recording electrode is working, and improve the quality of the collected biological signal.

Further as a preferred embodiment of the method, the LED anode structure includes LED anode electrode 9, LED anode wire 13, LED anode pad 17, and the LED cathode structure includes LED cathode 11, LED cathode Wires 14 , light-emitting diode cathode pads 16 , and the recording electrode structure includes recording electrodes 10 , recording electrode wires 12 , and recording electrode pads 15 .

As shown in FIG. 4 , on the basis of FIG. 3 , titanium/gold (50/150 nm) was used to prepare the anode, cathode and recording electrode structures of the light emitting diode structure. Specifically, the anode of the LED includes: LED anode electrode 9, LED anode wire 13, LED anode pad 17; the cathode of the LED includes: LED cathode electrode 11, LED cathode wire 14, LED cathode welding The disk 16 ; the recording electrode structure includes: the recording electrode 10 , the recording electrode wire 12 , and the recording electrode pad 15 . The cathode wire of the light emitting diode partially surrounds the recording electrode wire, which can effectively suppress the electromagnetic interference caused by the injection current of the anode of the light emitting diode.

As a further preferred embodiment of the method, the silicon dioxide isolation layer 6 is provided with an anode window 7 and a cathode window 8 .

As shown in FIG. 3 , the silicon dioxide isolation layer 6 is prepared on the basis of FIG. 2 , in order to prevent the leakage problem caused by the subsequently prepared long leads, and the preparation of the long leads facilitates the subsequent encapsulation of the device. The silicon dioxide isolation layer 6 is etched, an anode window 7 structure is prepared for the anode metal of the light emitting diode structure, and a cathode window structure 8 is prepared for the cathode metal of the light emitting diode structure.

Further as a preferred embodiment of this method, the anode window 7 is provided with a light-emitting diode anode electrode 9, the silicon dioxide isolation layer 6 is provided with a light-emitting diode anode wire 13 and a light-emitting diode anode pad 17, the light-emitting diode The anode electrode 9 is connected to the LED anode pad 17 through the LED anode wire 13 .

Further as a preferred embodiment of the method, the cathode window is provided with a light-emitting diode cathode electrode 11, the silicon dioxide isolation layer 6 is provided with a light-emitting diode cathode lead 14 and a light-emitting diode cathode pad 16, the light-emitting diode cathode The electrode 11 is connected to the LED cathode pad 16 through the LED cathode wire 14 .

Further as a preferred embodiment of this method, the silicon dioxide isolation layer is provided with a recording electrode 10 , a recording electrode wire 12 and a recording electrode pad 15 , and the recording electrode 10 is connected to the recording electrode pad 15 through the recording electrode wire 12 .

As a further preferred embodiment of the method, the silicon dioxide passivation layer 18 is provided with an anode pad window 21 , a cathode pad window 22 , a recording electrode window 19 and a recording electrode pad window 20 .

As shown in FIG. 1, a silicon dioxide passivation layer 18 is prepared on the basis of FIG. 4, in order to protect the anode electrode 9, cathode electrode 11, anode wire 13, cathode wire 14 of the light emitting diode structure, and the recording electrode structure. The recording electrode 10 prevents the leakage of electricity from these structures when the photoelectrode is in the electrolyte solution, which affects the normal operation of the photoelectrode. Etch the silicon dioxide passivation layer 18, prepare the anode pad window 21 and the cathode pad window 22 for the anode pad and the cathode pad of the light emitting diode structure, and prepare the recording electrode window 19 and the recording electrode pad window for the recording electrode structure 20. The preparation of these window structures enables the photoelectrode to work normally in an electrolyte environment, which facilitates subsequent testing and packaging work in the laboratory.

As shown in Figure 2, a preparation method of a low-noise single-sided integrated injectable bio-photoelectrode microprobe includes the following steps:

S1, sequentially growing n-type gallium nitride, active layer and p-type gallium nitride on the sapphire substrate;

S2, prepare the transparent conductive layer of indium tin oxide in a high vacuum argon atmosphere by photolithography and magnetron sputtering;

S3, patterning the indium tin oxide transparent conductive layer through a peeling process to prepare a transparent anode and an electromagnetic shielding layer of the light-emitting diode;

S4. A good ohmic contact is formed between the indium tin oxide transparent conductive layer thin film and the p-type gallium nitride through a rapid thermal annealing process;

S5. Etch the epitaxial wafer to n-type gallium nitride under the condition that the gas environment is Cl ₂ and BCl ₃ through photolithography and dry etching processes;

S6. High temperature activates the active layer;

S7. Prepare a silicon dioxide isolation layer in a gas environment of SiH ₄ and N ₂ O, high vacuum and a high temperature environment of 350°C by photolithography and plasma enhanced chemical vapor deposition process, and use a wet etching process to use buffer oxidation The silicon dioxide isolation layer is patterned with an etching solution to prepare a cathode window and an anode window;

S8. Prepare a metal film in a high vacuum environment through photolithography and electron beam evaporation processes, and pattern the metal film by a lift-off process to prepare an LED anode electrode, an LED anode wire, an LED anode pad, and a LED Cathode electrode, LED cathode wire, LED cathode pad, recording electrode, recording electrode wire and recording electrode pad;

S9. Prepare a silicon dioxide passivation layer in a gas environment of SiH ₄ and N ₂ O, a high vacuum and a high temperature environment of 350°C through photolithography and plasma enhanced chemical vapor deposition process, and use a wet etching process to use a buffer The oxide etching solution patterned the silicon dioxide isolation layer to prepare an anode pad window, a cathode pad window, a recording electrode window and a recording electrode pad window.

As a further preferred embodiment of the method, the metal thin film is a titanium metal thin film with a thickness of 50 nm or a gold metal thin film with a thickness of 150 nm.

The contents in the above method embodiments are all applicable to the present system embodiments, the specific functions implemented by the present system embodiments are the same as the above method embodiments, and the beneficial effects achieved are also the same as those achieved by the above method embodiments.

The above is a specific description of the preferred implementation of the present invention, but the present invention is not limited to the described embodiments, and those skilled in the art can make various equivalent deformations or replacements without departing from the spirit of the present invention. , these equivalent modifications or substitutions are all included within the scope defined by the claims of the present application.

Claims (9)

1. a low-noise single-sided integrated injectable biological photoelectrode microprobe is characterized in that, comprising a light-emitting diode structure, a recording electrode and an electromagnetic shielding structure, and the light-emitting diode structure comprises substrate material, n-type nitrogen from bottom to top Gallium oxide, active layer, p-type gallium nitride, transparent conductive layer, insulating isolation layer, insulating passivation layer, the insulating isolation layer is provided with a light-emitting diode anode structure and a light-emitting diode cathode structure, and the electromagnetic shielding structure is composed of The electromagnetic shielding layer structure and the ground wire semi-enclosed structure are formed. 2 . The low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 1 , wherein the LED anode structure comprises a LED anode electrode, a LED anode wire, and a LED anode pad. 3 . The light-emitting diode cathode structure includes a light-emitting diode cathode, a light-emitting diode cathode wire, and a light-emitting diode cathode pad, and the recording electrode structure includes a recording electrode, a recording electrode wire, and a recording electrode pad. 3 . The low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 2 , wherein an anode window and a cathode window are provided on the insulating isolation layer. 4 . 4 . The low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 3 , wherein the anode window is provided with a light-emitting diode anode electrode, and the insulating isolation layer is provided with a light-emitting diode. 5 . Anode wires and LED anode pads, the LED anode electrodes are connected to the LED anode pads through the LED anode wires. 5 . The low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 4 , wherein the cathode window is provided with a light-emitting diode cathode electrode, and the insulating isolation layer is provided with a light-emitting diode. 6 . Cathode wires and LED cathode pads, the LED cathode electrodes are connected to the LED cathode pads through the LED cathode wires. 6. The low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 5, wherein the insulating isolation layer is provided with a recording electrode, a recording electrode lead and a recording electrode pad, and the The recording electrodes are connected to the recording electrode pads through the recording electrode wires. 7. The low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 6, wherein the insulating passivation layer is provided with an anode pad window, a cathode pad window, a recording electrode window and a Record electrode pad window. 8. A method for preparing a low-noise single-sided integrated injectable biological photoelectrode microprobe, comprising the following steps: Growing n-type gallium nitride, active layer and p-type gallium nitride in sequence on sapphire substrate; Through photolithography and magnetron sputtering process, indium tin oxide transparent conductive layer is prepared in high vacuum argon atmosphere; The transparent conductive layer of indium tin oxide is patterned through a lift-off process to prepare a transparent anode and an electromagnetic shielding layer of the light-emitting diode; A good ohmic contact is formed between the transparent conductive layer of indium tin oxide and p-type gallium nitride by rapid thermal annealing process; Through photolithography and dry etching process, the epitaxial wafer is etched to n-type gallium nitride under the condition of Cl ₂ and BCl ₃ gas environment; High temperature activated active layer; By photolithography and plasma-enhanced chemical vapor deposition process, silicon dioxide isolation layer was prepared in the gas environment of SiH ₄ and N ₂ O, high vacuum and 350 ℃ high temperature environment, and etched with buffer oxide by wet etching process The etching solution patterned the silicon dioxide isolation layer to prepare a cathode window and an anode window; Through photolithography and electron beam evaporation processes, metal thin films are prepared in a high vacuum environment, and the metal thin films are patterned by a lift-off process to prepare recording electrodes, recording electrode wires, recording electrode pads, LED anode electrodes, and LED anodes. Wires, LED anode pads, LED cathode electrodes, LED cathode wires and LED cathode pads; By photolithography and plasma enhanced chemical vapor deposition process, silicon dioxide passivation layer was prepared in the gas environment of SiH ₄ and N ₂ O, high vacuum and 350℃ high temperature environment, and the buffer oxide was prepared by wet etching process The etching solution patterned the silicon dioxide isolation layer to prepare an anode pad window, a cathode pad window, a recording electrode window and a recording electrode pad window. 9 . The method for preparing a low-noise single-sided integrated injectable biological photoelectrode microprobe according to claim 8 , wherein the metal film is a 50 nm titanium metal film or a 150 nm gold metal film. 10 .

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