Fluid gate dielectric diamond field effect transistor and preparation method thereof

Abstract

The invention provides a fluid gate dielectric diamond field effect transistor and a preparation method thereof, and the fluid gate dielectric diamond field effect transistor comprises a diamond substrate, a source electrode, a drain electrode, a dielectric layer, a thickened source electrode, a thickened drain electrode, and a gate electrode. The upper side of the diamond substrate is provided with a conducting channel formed on a hydrogen terminal surface and an oxygen terminal surface; the source electrode and the drain electrode are separately arranged on the upper side of the diamond substrate at intervals; the dielectric layer is laid on the upper side of the diamond substrate and covers the source electrode and the drain electrode, a micro-channel is formed in the lower side of the dielectric layer, and the micro-channel is communicated with the conductive channel; the thickened source electrode and the thickened drain electrode are respectively arranged on the upper side of the dielectric layer and respectively penetrate through the dielectric layer to be connected with the source electrode and the drain electrode; the gate electrode is arranged on the upper side of the dielectric layer; the preparation method is used for preparing the fluid gate dielectric diamond field effect transistor. The fluid gate dielectric diamond field effect transistor provided by the invention can effectively improve the sensitivity of biological detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of biochips, and particularly relates to a fluid-gated dielectric diamond field-effect transistor and a preparation method thereof. Background Art

[0002] Current biochips have been widely used in biological detection. The core principle of biochips is based on molecular recognition and signal conversion. Currently, mainly, but the biocompatibility of silicon materials is not high enough, and the detection sensitivity is lower compared with traditional biosensors. Summary of the Invention

[0003] The present invention provides a fluid-gated dielectric diamond field-effect transistor and a preparation method thereof, aiming to solve the technical problems raised in the above background art.

[0004] To achieve the above object, the technical solution adopted by the present invention is:

[0005] In a first aspect, an embodiment of the present invention provides a fluid-gated dielectric diamond field-effect transistor, including:

[0006] A diamond substrate, on the upper side of which there are a conductive channel formed by a hydrogen-terminated surface and an oxygen-terminated surface;

[0007] A source electrode and a drain electrode, which are respectively arranged at intervals on the upper side of the diamond substrate, are connected to the conductive channel and conductively cooperate with it;

[0008] A dielectric layer, which is laid on the upper side of the diamond substrate and covers the source electrode and the drain electrode. A microchannel is opened on the lower side of the dielectric layer, and the microchannel is arranged between the source electrode and the drain electrode and communicated with the conductive channel;

[0009] A thickened source electrode and a thickened drain electrode, which are respectively arranged on the upper side of the dielectric layer and respectively pass through the dielectric layer to be connected to the source electrode and the drain electrode; and

[0010] A gate electrode, which is arranged on the upper side of the dielectric layer and is arranged between the thickened source electrode and the thickened drain electrode and connected to the dielectric layer.

[0011] In combination with the first aspect, in a possible implementation manner of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the materials of the source electrode and the drain electrode are one of Ti, Al, Pt, Ni, Au, and Ir.

[0012] In combination with the first aspect, in a possible implementation manner of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the materials of the source electrode and the drain electrode are a combination of several of Ti, Al, Pt, Ni, Au, and Ir.

[0013] Combined with the first aspect, in a possible implementation of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the material of the dielectric layer is MoO 3 、Al 2 O 3 、HfO 2 、TiO 2 、SiN x 、SiO 2 or AlN.

[0014] Combined with the first aspect, in a possible implementation of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, a group-mounting surface is provided on the surface of the microchannel or the bottom surface of the conductive channel, and the group-mounting surface is used to mount different groups.

[0015] Combined with the first aspect, in a possible implementation of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the group-mounting surface is a hydrogen-terminated surface, an oxygen-terminated surface, an amino-terminated surface or a halogen-terminated surface.

[0016] In a second aspect, an embodiment of the present invention provides a method for manufacturing a fluid-gated dielectric diamond field-effect transistor, including the following steps:

[0017] S01, forming a hydrogen-terminated layer on a diamond substrate to form hydrogen-terminated diamond;

[0018] S02, lithographically exposing the active region and protecting the active region with a photoresist; then, treating the surface of the hydrogen-terminated diamond to form an oxygen-terminated surface to achieve device isolation;

[0019] S03, lithographically exposing the source electrode and drain electrode windows, depositing metal, stripping the photoresist in steps S02 and S03 to form the source electrode and drain electrode, and forming a conductive channel between the source electrode and the drain electrode; then, through annealing, forming an ohmic contact;

[0020] S05, using a photoresist for lithography so that the photoresist serves as a sacrificial layer to protect the conductive channel region, and the sacrificial layer is spaced apart from the source electrode and the drain electrode;

[0021] S06, generating a dielectric layer on the upper side of the hydrogen-terminated diamond to cover the source electrode, the drain electrode and the sacrificial layer; and stripping and removing the photoresist sacrificial layer to form a microchannel;

[0022] S07, lithographically exposing a gate window on the surface of the dielectric layer, depositing gate metal to form a gate electrode;

[0023] S08. Lithographically pattern the source and drain electrode windows on the dielectric layer, etch the dielectric layer, and deposit metal to complete electrode thickening and interconnection, forming a thick source electrode and a thick drain electrode.

[0024] Combined with the second aspect, in a possible implementation manner of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, in step S01, the hydrogen termination layer is epitaxially formed on the diamond substrate using a microwave plasma chemical vapor deposition system or the hydrogen termination layer is formed by hydrogen plasma treatment, and the thickness of the hydrogen termination layer is 1 nm to 1 mm.

[0025] Combined with the second aspect, in a possible implementation manner of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, between steps S03 and S05, there is also step S04 of treating the surface of the conductive channel to form a group-anchoring surface for anchoring different target groups.

[0026] Combined with the second aspect, in a possible implementation manner of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, in step S04, the surface of the conductive channel is treated with oxygen plasma or ozone to form an oxygen-terminated surface, placed in an ammonia atmosphere, and irradiated with ultraviolet light to form an amino-terminated surface on the surface of the conductive channel, or placed in a halogen atmosphere, and heated or irradiated with light to form a halogen-terminated surface on the surface of the conductive channel.

[0027] The beneficial effects of the fluid-gated dielectric diamond field-effect transistor provided by the present invention are as follows: Compared with the prior art, for the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the surface of the conductive channel is a carbon-hydrogen bond, the microchannel is connected to the conductive channel. During detection, when a biological solution flows through the microchannel, the biological solution flowing in the microchannel will flow through the conductive channel, and different pH values of the passing biological solution can cause changes in the resistance between the source electrode and the drain electrode, so that the detection of the acidity and alkalinity of the biological solution can be realized. Moreover, since the diamond substrate, as a carbon-based material, has good biocompatibility, it can effectively improve the detection sensitivity.

[0028] The beneficial effects of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention are as follows: Compared with the prior art, for the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the prepared transistor is provided with a microchannel connected to the conductive channel. The biological solution flowing in the microchannel will flow through the conductive channel, and different pH values of the passing biological solution can cause changes in the resistance between the source electrode and the drain electrode, so that the detection of the acidity and alkalinity of the biological solution can be realized. Moreover, since the diamond substrate, as a carbon-based material, has good biocompatibility, it can effectively improve the detection sensitivity. Description of the Drawings

[0029] Figure 1 Schematic diagram of the preparation process flow of the fluid-gate dielectric diamond field-effect transistor provided in the first embodiment of the present invention;

[0030] Figure 2 Schematic diagram of the preparation process flow of the fluid-gate dielectric diamond field-effect transistor provided in the second embodiment of the present invention;

[0031] Description of the reference numerals:

[0032] 10. Diamond substrate; 11. Hydrogen-terminated surface; 12. Oxygen-terminated surface; 13. Conductive channel;

[0033] 21. Source electrode; 22. Thick source electrode; 23. Drain electrode; 24. Thick drain electrode; 30. Dielectric layer;

[0034] 40. Sacrificial layer; 50. Microchannel; 60. Gate electrode; 70. Group-mounted surface. Detailed implementation manners

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present application and its application or use. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0037] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless otherwise clearly specified in the context, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "comprise" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0038] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0039] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation terms such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom", etc., are usually based on the orientation or positional relationships shown in the drawings. It is only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation terms do not indicate and 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 on the protection scope of the present application; the orientation terms "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0040] For the convenience of description, spatial relative terms such as "above...", "over...", "on the upper surface of...", "above", etc., can be used here to describe the spatial positional relationships of one device or feature shown in the drawings with other devices or features. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation described in the drawings of the device. For example, if the device in the drawing is inverted, the device described as "above other devices or structures" or "over other devices or structures" will then be positioned as "below other devices or structures" or "under other devices or structures". Thus, the exemplary term "above..." can include both the orientations of "above..." and "below...". The device can also be positioned in other different ways, and corresponding interpretations should be made for the spatial relative descriptions used here.

[0041] In addition, it should be noted that the use of terms such as "first", "second", etc. to limit components is only for the convenience of distinguishing the corresponding components. Without otherwise stating, the above terms have no special meanings. Therefore, it should not be construed as a limitation on the protection scope of the present application.

[0042] Embodiment 1:

[0043] Please refer to Figure 1 , and now the fluid-gated dielectric diamond field-effect transistor provided by the embodiment of the present invention will be described. The fluid-gated dielectric diamond field-effect transistor includes a diamond substrate 10, a source electrode 21, a drain electrode 23, a dielectric layer 30, a thickened source electrode 22, a thickened drain electrode 24, and a gate electrode 60. A conductive channel 13 formed by a hydrogen-terminated surface 11 and an oxygen-terminated surface 12 are provided on the upper side of the diamond substrate 10; the source electrode 21 and the drain electrode 23 are respectively arranged at intervals on the upper side of the diamond substrate 10, connected to the conductive channel 13 and conductively cooperated; the dielectric layer 30 is laid on the upper side of the diamond substrate 10 and covers the source electrode 21 and the drain electrode 23. A microchannel 50 is provided on the lower side of the dielectric layer 30. The microchannel 50 is arranged between the source electrode 21 and the drain electrode 23 and communicated with the conductive channel 13; the thickened source electrode 22 and the thickened drain electrode 24 are respectively arranged on the upper side of the dielectric layer 30 and respectively pass through the dielectric layer 30 to be connected to the source electrode 21 and the drain electrode 23; the gate electrode 60 is arranged on the upper side of the dielectric layer 30 and is arranged between the thickened source electrode 22 and the thickened drain electrode 24 and connected to the dielectric layer 30.

[0044] Specifically, the bottom of the microchannel 50 is the surface of the conductive channel 13. The conductive channel 13 on the surface of the diamond substrate 10 in the diamond field-effect transistor (FET) mainly depends on the two-dimensional hole gas formed by the surface termination treatment technology.

[0045] The hydrogen termination treatment makes the diamond surface form a negative electron affinity. When contacting with water vapor or an oxide layer in the air, the gas molecules adsorbed on the surface (such as oxygen and carbon dioxide) act as electron acceptors, causing the valence band electrons of the diamond to transition to the adsorption layer, thereby forming a high-concentration two-dimensional hole gas (2DHG) at a depth of about 10 nm below the surface.

[0046] Specifically, in a specific implementation manner of the fluid-gated dielectric diamond field-effect transistor provided by the embodiment of the present invention, the materials of the source electrode 21 and the drain electrode 23 are one of Ti, Al, Pt, Ni, Au, and Ir.

[0047] Specifically, in a specific implementation manner of the fluid-gated dielectric diamond field-effect transistor provided by the embodiment of the present invention, the materials of the source electrode 21 and the drain electrode 23 are a combination of several of Ti, Al, Pt, Ni, Au, and Ir, formed with or without high-temperature annealing.

[0048] In a specific implementation manner of the fluid-gated dielectric diamond field-effect transistor provided by the embodiment of the present invention, the material of the dielectric layer 30 is MoO 3 , Al 2 O 3 、HfO 2 、TiO 2 、SiN x, SiO 2 or AlN.

[0049] The beneficial effects of the fluid-gate dielectric diamond field-effect transistor provided by the embodiments of the present invention are as follows: Compared with the prior art, in the fluid-gate dielectric diamond field-effect transistor provided by the embodiments of the present invention, the surface of the conductive channel 13 is a carbon-hydrogen bond, and the microchannel 50 is communicated with the conductive channel 13. During detection, a biological solution is made to flow through the microchannel 50, and the biological solution flowing in the microchannel 50 will flow through the conductive channel 13. Different pH values of the passing biological solution can cause changes in the resistance between the source electrode 21 and the drain electrode 23, so that the detection of the acidity and alkalinity of the biological solution can be realized. Moreover, since the diamond substrate 10, as a carbon-based material, has good biocompatibility, the detection sensitivity can be effectively improved.

[0050] Based on the same inventive concept, the embodiments of the present invention also provide a preparation method of a fluid-gate dielectric diamond field-effect transistor, including the following steps:

[0051] S01, epitaxially grow a 5-nm high-quality hydrogen-terminated layer on the diamond substrate 10 using a microwave plasma chemical vapor deposition system, such as Figure 1 a, form hydrogen-terminated diamond;

[0052] S02, use a positive photoresist to cover the active area through steps such as spin coating, pre-baking, exposure, development, and hard baking, and protect the active area through the photoresist; then, treat the surface of the hydrogen-terminated diamond. After oxygen plasma treatment for 10-20 minutes, the surface of the hydrogen-terminated diamond is oxidized into an oxygen-terminated surface to form the oxygen-terminated surface 12, realizing device isolation;

[0053] S03, use a positive or negative photoresist to lithograph the source electrode and drain electrode windows through steps such as spin coating, pre-baking, exposure, post-baking, and development, and use electron beam evaporation to deposit Ti / Au (30 / 500 nm). The metal material and thickness can be set according to actual situations and needs. After stripping the photoresist in steps S02 and S03, the source electrode 21 and the drain electrode 23 are formed, and a conductive channel 13 is formed between the source electrode 21 and the drain electrode 23; then, high-temperature annealing in hydrogen is carried out to form an ohmic contact, such as Figure 1 b;

[0054] S05, use a positive high-temperature-resistant photoresist to lithograph a pattern through steps such as spin coating, pre-baking, exposure, development, and hard baking to cover a partial area of the conductive channel 13, and use the photoresist as a sacrificial layer 40 to protect the area of the conductive channel 13. The sacrificial layer 40 is spaced from the source electrode 21 and the drain electrode 23, such as Figure 1 c;

[0055] S06. Using an atomic layer deposition system, grow a 100-nm aluminum oxide dielectric (the thickness can be set according to actual conditions and needs) at 70 - 80 °C to cover the source electrode 21, drain electrode 23, and sacrificial layer 40, as shown in Figure 1 d; Growing the dielectric at a low temperature can protect the photoresist of the sacrificial layer 40 in step S05 from being damaged as much as possible; then strip and remove the photoresist sacrificial layer 40 to form the microchannel 50, as shown in Figure 1 e;

[0056] S07. Use positive or negative photoresist, and through steps such as spin coating, pre-baking, exposure, post-baking, and development, photolithograph a gate window on the surface of the dielectric layer 30, then magnetron sputter or electron beam evaporate and deposit Al / Au (100 / 500 nm) as the gate metal (the metal material and thickness can be set according to actual conditions and needs), and then strip and remove the photoresist to form the gate electrode 60, as shown in Figure 1 f;

[0057] S08. Use positive photoresist and through steps such as spin coating, pre-baking, exposure, development, and hard baking, photolithograph source and drain electrode windows on the dielectric layer 30, use a dry etching process, etch the dielectric layer 30 through chlorine gas, argon gas, or boron trichloride to expose the source electrode 21 and drain electrode 23, and deposit metal to complete electrode thickening and interconnection to form the thick source electrode 22 and thick drain electrode 24, as shown in Figure 1 h.

[0058] It should be noted that for the fluid-gated dielectric diamond field-effect transistor prepared by the above method, the surface of the microchannel 50 is a hydrogen-terminated surface 11, which has hydrophobicity. Since it shows different resistance values for the acidity and alkalinity of the surface biological solution, it can be used to detect the pH value.

[0059] The beneficial effects of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention are as follows: Compared with the prior art, for the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the present invention, the prepared transistor is provided with a microchannel 50 connected to the conductive channel 13. The biological solution flowing in the microchannel 50 will flow through the conductive channel 13, and different pH values of the passing biological solution can cause changes in the resistance between the source electrode 21 and the drain electrode 23, so that the detection of the acidity and alkalinity of the biological solution can be realized; and because the diamond substrate 10, as a carbon-based material, has good biocompatibility, it can effectively improve the detection sensitivity.

[0060] As shown in Figure 1 and Figure 2As shown, in a specific implementation manner of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the embodiment of the present invention, in step S01, a hydrogen-terminated layer is epitaxially formed on the diamond substrate 10 using a microwave plasma chemical vapor deposition system or a hydrogen-terminated layer is formed by hydrogen plasma treatment, and the thickness of the hydrogen-terminated layer is 1 nm to 1 mm.

[0061] As Figure 1 and Figure 2 shown, in a specific implementation manner of the preparation method of the fluid-gated dielectric diamond field-effect transistor provided by the embodiment of the present invention, in step S03, the ohmic contact is prepared using one or a combination of Ti, Al, Pt, Ni, Au, Ir, etc., and is formed with or without high-temperature alloy annealing.

[0062] In step S05, a sacrificial layer 40 can also be selected from media, metals, etc. that can be selectively removed.

[0063] In step S06, the dielectric layer 30 can be prepared by processes such as thermal evaporation, electron beam evaporation, magnetron sputtering, or atomic layer deposition; the material of the dielectric layer 30 can be MoO 3 , Al 2 O 3 , HfO 2 , TiO 2 , SiN x , SiO 2 or AlN, etc.

[0064] Furthermore, multiple fluid-gated dielectric diamond field-effect transistors are prepared on the same chip, and different molecules can be simultaneously detected through different surface treatments, thereby improving the sensitivity and detection efficiency.

[0065] Example 2:

[0066] Please refer to Figure 2, the fluid-gated dielectric diamond field-effect transistor provided by the embodiments of the present invention will now be described. The fluid-gated dielectric diamond field-effect transistor includes a diamond substrate 10, a source electrode 21, a drain electrode 23, a dielectric layer 30, a thickened source electrode 22, a thickened drain electrode 24, and a gate electrode 60. On the upper side of the diamond substrate 10, there is a conductive channel 13 formed by a hydrogen-terminated surface 11 and an oxygen-terminated surface 12; the source electrode 21 and the drain electrode 23 are respectively arranged at intervals on the upper side of the diamond substrate 10, connected to the conductive channel 13 and electrically cooperating; the dielectric layer 30 is laid on the upper side of the diamond substrate 10 and covers the source electrode 21 and the drain electrode 23. A microchannel 50 is opened on the lower side of the dielectric layer 30. The microchannel 50 is arranged between the source electrode 21 and the drain electrode 23 and communicates with the conductive channel 13; the thickened source electrode 22 and the thickened drain electrode 24 are respectively arranged on the upper side of the dielectric layer 30 and respectively pass through the dielectric layer 30 to be connected to the source electrode 21 and the drain electrode 23; the gate electrode 60 is arranged on the upper side of the dielectric layer 30 and is arranged between the thickened source electrode 22 and the thickened drain electrode 24 and connected to the dielectric layer 30. A group attachment surface 70 is provided on the surface of the microchannel 50 or the bottom surface of the conductive channel 13. The group attachment surface 70 is used to attach different groups to detect the concentrations of different biological groups in a biological solution.

[0067] Specifically, the bottom of the microchannel 50 is the surface of the conductive channel 13. The conductive channel 13 on the surface of the diamond substrate 10 in the diamond field-effect transistor (FET) mainly depends on the two-dimensional hole gas formed by the surface termination treatment technology.

[0068] The hydrogen termination treatment makes the diamond surface form a negative electron affinity. When contacting with water vapor or an oxide layer in the air, the gas molecules adsorbed on the surface (such as oxygen and carbon dioxide) act as electron acceptors, causing the valence band electrons of the diamond to transition to the adsorption layer, thereby forming a high-concentration two-dimensional hole gas (2DHG) at a depth of about 10 nm below the surface.

[0069] Preferably, a group attachment surface 70 is provided on the bottom surface of the conductive channel 13.

[0070] Specifically, in a specific implementation manner of the fluid-gated dielectric diamond field-effect transistor provided by the embodiments of the present invention, the group attachment surface 70 is a hydrogen-terminated surface 11, an oxygen-terminated surface 12, an amino-terminated surface, or a halogen-terminated surface.

[0071] The hydrogen-terminated surface is treated with oxygen plasma or ozone to form an oxygen-terminated surface, which can bind to the ε-amino group of lysine in a biological solution, etc.; the hydrogen-terminated diamond surface is placed in an ammonia atmosphere and irradiated with ultraviolet light to form an amino-terminated surface; by heating or irradiating in a halogen atmosphere, a halogen-terminated surface can be formed, which can bind to biological groups after halogenation reaction; organic biomolecules (such as DNA fragments, proteins, etc.) can also be introduced by reacting with active functional groups introduced on the diamond surface, or directly introduced by photochemical, thermochemical or electrochemical methods, etc., to bind to different biological groups.

[0072] Specifically, in a specific embodiment of the fluid-gate dielectric diamond field-effect transistor provided in the embodiments of the present invention, the materials of the source electrode 21 and the drain electrode 23 are one of Ti, Al, Pt, Ni, Au, and Ir.

[0073] Specifically, in a specific embodiment of the fluid-gate dielectric diamond field-effect transistor provided in the embodiments of the present invention, the materials of the source electrode 21 and the drain electrode 23 are a combination of several of Ti, Al, Pt, Ni, Au, and Ir, formed with or without high-temperature annealing.

[0074] In a specific embodiment of the fluid-gate dielectric diamond field-effect transistor provided in the embodiments of the present invention, the material of the dielectric layer 30 is MoO 3 , Al 2 O 3 , HfO 2 , TiO 2 , SiN x , SiO 2 or AlN, etc.

[0075] The beneficial effects of the fluid-gate dielectric diamond field-effect transistor provided in the embodiments of the present invention are as follows: Compared with the prior art, in the fluid-gate dielectric diamond field-effect transistor provided in the embodiments of the present invention, the surface of the conductive channel 13 is surface-modified to form a group-mounted surface 70, which can adsorb different biological groups. The microchannel 50 is connected to the conductive channel 13. During detection, the biological solution is made to flow through the microchannel 50, and the biological groups in the biological solution bind to the group-mounted surface 70, changing the resistance between the source electrode 21 and the drain electrode 23. Then, by detecting the change in current between the source electrode 21 and the drain electrode 23, or directly detecting the change in resistance between the source electrode 21 and the drain electrode 23, the quantity or concentration of the corresponding biological groups in the biological solution is detected. Moreover, since the diamond substrate 10, as a carbon-based material, has good biocompatibility, the detection sensitivity can be effectively improved.

[0076] Based on the same inventive concept, an embodiment of the present invention further provides a method for preparing a fluid grid dielectric diamond field effect transistor, including the following steps:

[0077] S01, epitaxially grow a 5-nm high-quality hydrogen-terminated layer on a diamond substrate 10 using a microwave plasma chemical vapor deposition system to form a hydrogen-terminated diamond, as shown in Figure 2 a;

[0078] S02, use a positive photoresist to cover the active region through steps such as spin coating, pre-baking, exposure, development, and hard baking, and protect the active region through the photoresist; then, treat the surface of the hydrogen-terminated diamond, perform oxygen plasma treatment for 10-20 minutes, and the surface of the hydrogen-terminated diamond is oxidized into an oxygen-terminated surface to form an oxygen-terminated surface 12, realizing device isolation;

[0079] S03, use a positive or negative photoresist to photolithograph source electrode and drain electrode windows through steps such as spin coating, pre-baking, exposure, post-baking, and development, and use electron beam evaporation to deposit Ti / Au (30 / 500 nm). The metal material and thickness can be set according to actual situations and needs. After stripping the photoresist in steps S02 and S03, a source electrode 21 and a drain electrode 23 are formed, and a conductive channel 13 is formed between the source electrode 21 and the drain electrode 23; then, perform high-temperature annealing in hydrogen to form an ohmic contact, as shown in Figure 2 b;

[0080] S04, treat the surface of the conductive channel 13 to form a group-mounted surface 70, as shown in Figure 2 c, for mounting different target groups; by performing different treatments on the surface, different group-mounted surfaces 70 can be obtained, such as a hydrogen-terminated surface 11, an oxygen-terminated surface 12, an amino-terminated surface, or a halogen-terminated surface, etc.;

[0081] Specifically, the surface of the conductive channel 13 is treated with oxygen plasma or ozone to form an oxygen-terminated surface 12; or placed in an ammonia atmosphere and irradiated with ultraviolet light to form an amino-terminated surface on the surface of the conductive channel 13; or placed in a halogen atmosphere and heated or irradiated with light to form a halogen-terminated surface on the surface of the conductive channel 13; it can also react with active functional groups introduced on the diamond surface to introduce organic biomolecules, or directly introduce them through photochemical, thermochemical, or electrochemical methods, etc.;

[0082] S05, use a positive high-temperature-resistant photoresist to photolithograph a pattern through steps such as spin coating, pre-baking, exposure, development, and hard baking, covering a part of the region of the conductive channel 13, and use the photoresist as a sacrificial layer 40 to protect the region of the conductive channel 13. The sacrificial layer 40 is spaced from the source electrode 21 and the drain electrode 23, as shown in Figure 2 d;

[0083] S06. Using an atomic layer deposition system, grow a 130 nm alumina dielectric (the thickness can be set according to actual conditions and requirements) at 70 - 80 °C to cover the source electrode 21, drain electrode 23, and sacrificial layer 40, as Figure 2 e; Growing the dielectric at a low temperature can protect the photoresist of the sacrificial layer 40 in step S05 from being damaged as much as possible; then strip and remove the photoresist sacrificial layer 40 to form the microchannel 50, as Figure 2 f;

[0084] S07. Using positive or negative photoresist, through steps such as spin coating, pre-baking, exposure, post-baking, and development, photolithograph a gate window on the surface of the dielectric layer 30, then magnetron sputter or electron beam evaporate and deposit Al / Au (100 / 500 nm) as the gate metal (the metal material and thickness can be set according to actual conditions and requirements), and then strip and remove the photoresist to form the gate electrode 60, as Figure 2 h;

[0085] S08. Using positive photoresist, through steps such as spin coating, pre-baking, exposure, development, and hard baking, photolithograph source and drain electrode windows on the dielectric layer 30, use a dry etching process to etch the dielectric layer 30 through chlorine gas, argon gas, or boron trichloride to expose the source electrode 21 and drain electrode 23, and deposit metal to complete electrode thickening and interconnection to form a thick source electrode 22 and a thick drain electrode 24, as Figure 2 i.

[0086] The beneficial effects of the preparation method of the fluid gate dielectric diamond field effect transistor provided by the present invention are as follows: Compared with the prior art, in the preparation method of the fluid gate dielectric diamond field effect transistor provided by the present invention, the prepared transistor is provided with a microchannel 50 communicating with the conductive channel 13. The biological solution flowing in the microchannel 50 will flow through the conductive channel 13. The surface of the conductive channel 13 is surface-modified to form a group-mounted surface 70, which can adsorb different biological groups. The microchannel 50 communicates with the conductive channel 13. During detection, the biological solution is made to flow through the microchannel 50, and the biological groups in the biological solution bind to the group-mounted surface 70, changing the resistance value between the source electrode 21 and the drain electrode 23. Then, by detecting the change in the current between the source electrode 21 and the drain electrode 23, or directly detecting the change in the resistance value between the source electrode 21 and the drain electrode 23, the quantity or concentration of the corresponding biological groups in the biological solution is detected. Moreover, since the diamond substrate 10, as a carbon-based material, has good biocompatibility, it can effectively improve the detection sensitivity.

[0087] As Figure 1 and Figure 2As shown, in a specific embodiment of the method for preparing a fluid-gate dielectric diamond field-effect transistor provided by an embodiment of the present invention, in step S01, a hydrogen-terminated layer is epitaxially formed on a diamond substrate 10 using a microwave plasma chemical vapor deposition system or a hydrogen-terminated layer is formed by hydrogen plasma treatment, and the thickness of the hydrogen-terminated layer is 1 nm to 1 mm.

[0088] As Figure 1 and Figure 2 shown, in a specific embodiment of the method for preparing a fluid-gate dielectric diamond field-effect transistor provided by an embodiment of the present invention, in step S03, the ohmic contact is prepared using one or a combination of Ti, Al, Pt, Ni, Au, Ir, etc., and is formed with or without high-temperature alloy annealing.

[0089] In step S05, a medium, metal, etc. that can be selectively removed can also be selected as the sacrificial layer 40.

[0090] In step S06, the dielectric layer 30 can be prepared by processes such as thermal evaporation, electron beam evaporation, magnetron sputtering, or atomic layer deposition; the material of the dielectric layer 30 can be MoO 3 , Al 2 O 3 , HfO 2 , TiO 2 , SiN x , SiO 2 or AlN, etc.

[0091] Furthermore, multiple fluid-gate dielectric diamond field-effect transistors are prepared on the same chip, and different molecules are simultaneously detected through different surface treatments, thereby improving the sensitivity and detection efficiency.

[0092] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A fluid gate dielectric diamond field effect transistor, characterized in that: include: A diamond substrate having a conductive channel formed by a hydrogen termination surface and an oxygen termination surface on its upper side; A source electrode and a drain electrode are respectively arranged on the upper side of the diamond substrate at intervals, connected to the conductive channel and conductively matched; A dielectric layer is laid on the upper side of the diamond substrate and covers the source electrode and the drain electrode, and a microchannel is opened on the lower side of the dielectric layer, the microchannel is arranged between the source electrode and the drain electrode and communicates with the conductive channel; A thickened source electrode and a thickened drain electrode, which are respectively arranged on the upper side of the dielectric layer and respectively pass through the dielectric layer to be connected to the source electrode and the drain electrode; as well as The gate electrode is disposed on the upper side of the dielectric layer and between the thickened source electrode and the thickened drain electrode to be connected to the dielectric layer.

2. The fluid gate dielectric diamond field effect transistor according to claim 1, characterized in that: The source electrode and the drain electrode are made of one of Ti, Al, Pt, Ni, Au and Ir.

3. The fluid gate dielectric diamond field effect transistor according to claim 1, characterized in that: The material of the source electrode and the drain electrode is a combination of Ti, Al, Pt, Ni, Au and Ir.

4. The fluid gate dielectric diamond field effect transistor according to claim 1, characterized in that: The material of the dielectric layer is MoO3, Al2O3, HfO2, TiO2, SiNx, SiO2 or AlN.

5. The fluid gate dielectric diamond field effect transistor according to claim 1, characterized in that: The surface of the microchannel or the bottom surface of the conductive channel is provided with a group mounting surface, and the group mounting surface is used to mount different groups.

6. The fluid gate dielectric diamond field effect transistor according to claim 5, characterized in that: The group mounting surface is a hydrogen terminal surface, an oxygen terminal surface, an amino terminal surface or a halogen terminal surface.

7. A method for preparing a fluid gate dielectric diamond field effect transistor, characterized in that: The following steps are involved: S01, forming a hydrogen-terminated layer on a diamond substrate to form hydrogen-terminated diamond; S02, photolithography to form an active area, and protecting the active area with a photoresist; then, treating the hydrogen-terminated diamond surface to form an oxygen-terminated surface to achieve device isolation; S03, photolithography to form source electrode and drain electrode windows, and deposit metal, and after stripping the photoresist in steps S02 and S03, form a source electrode and a drain electrode, and form a conductive channel between the source electrode and the drain electrode; After annealing, an ohmic contact is formed; S05, performing photolithography using a photoresist, so that the photoresist serves as a sacrificial layer to protect a conductive channel region, wherein the sacrificial layer is spaced apart from the source electrode and the drain electrode; S06, generating a dielectric layer on the upper side of the hydrogen terminal diamond to cover the source electrode, the drain electrode and the sacrificial layer; and stripping and removing the photoresist sacrificial layer to form a microchannel; S07, photolithography a gate window on the surface of the dielectric layer, depositing a gate metal to form a gate electrode; S08, photolithography source electrode and drain electrode windows in the dielectric layer, etching the dielectric layer, and depositing metal to complete electrode thickening and interconnection to form thick source electrode and thick drain electrode.

8. The method for preparing a fluid gate dielectric diamond field effect transistor according to claim 7, characterized in that: In step S01, the hydrogen termination layer is epitaxially formed on a diamond substrate using a microwave plasma chemical vapor deposition system or is formed by hydrogen plasma treatment, and the thickness of the hydrogen termination layer is 1 nm to 1 mm.

9. The method for preparing a fluid gate dielectric diamond field effect transistor according to claim 7, characterized in that: There is also a step S04 between steps S03 and S05, in which the surface of the conductive channel is processed to form a group mounting surface for mounting different target groups.

10. The method for preparing a fluid gate dielectric diamond field effect transistor according to claim 9, characterized in that: In step S04, the surface of the conductive channel is treated with oxygen plasma or ozone to form an oxygen-terminated surface, placed in an ammonia atmosphere, and exposed to ultraviolet light to form an amino-terminated surface on the surface of the conductive channel, or placed in a halogen atmosphere and heated or exposed to light to form a halogen-terminated surface on the surface of the conductive channel.

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