Hydrogen terminal diamond field effect transistor structure and electronic device

Abstract

The utility model relates to the technical field of diamond field effect transistors, in particular to a hydrogen terminal diamond field effect transistor structure, which comprises a diamond substrate, a boss is arranged on the diamond substrate, and diamond drift regions with the thickness of 0.5-1.5 microns are arranged on two sides of the boss. The voltage withstanding characteristic of the device can be adjusted by setting diamond drift regions with different thicknesses; a nitrogen-doped single crystal diamond layer is arranged on a boss; hydrogen terminal diamond layers are arranged on the nitrogen-doped single crystal diamond layer and the diamond drift region, so that the diamond drift region and the hydrogen terminal diamond layers are divided into different layers of diamond structures, and a device breakdown electric field can be adjusted by adjusting the thickness of the diamond drift region when a crystal tube structure is designed; therefore, the requirement of higher device performance is met. The problems that in the prior art, the thickness of a drift region of a vertical field effect transistor cannot be adjusted, and device performance with higher requirements cannot be met are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of diamond field effect transistors, specifically to a hydrogen-terminated diamond field effect transistor structure and an electronic device, in particular to a vertical hydrogen-terminated diamond field effect transistor structure and an electronic device with adjustable drift region thickness. Background Art

[0002] Diamond materials have many excellent properties, such as good light transmittance, strong resistance to radiation damage, large breakdown electric field, high thermal conductivity, high carrier mobility, good biocompatibility, etc., which makes it have broad application prospects in optical window materials, coating materials, biomedicine, and especially in the field of electronic devices. The main method for growing single crystal diamond is microwave plasma chemical vapor deposition (MPCVD), but the current growth of single crystal diamond faces the problem of low quality and small area. In terms of diamond devices, since the activation energy of conventional dopants in diamond is too large, it will lead to doping failure. Fortunately, there is a layer of two-dimensional hole gas (2DHG) on the surface of hydrogen-terminated diamond, and the concentration and mobility can reach 10 13 / cm 2 and 1~200 cm 2 / Vs, hydrogen-terminated diamond can be used to make electronic devices. The thickness of the hydrogen-terminated diamond layer in a typical hydrogen-terminated diamond electronic device is about 200nm.

[0003] The use of a vertical field-effect transistor (FET) structure can effectively increase the breakdown electric field of hydrogen-terminated diamond FETs, thereby improving the device's output power. This is primarily due to the vertical FET's drift region's ability to effectively carry the device voltage, with drift regions of varying thicknesses having varying voltage-carrying capabilities. However, in conventional hydrogen-terminated diamond FETs, the drift region and hydrogen-terminated diamond layer are constructed from the same diamond layer. This makes it impossible to adjust the drift region thickness, and thus the device's breakdown electric field, making it impossible to meet higher device performance requirements. Utility Model Content

[0004] Aiming at the problem in the prior art that the thickness of the drift region of a vertical field effect transistor cannot be adjusted and that higher device performance requirements cannot be met, the utility model provides a hydrogen-terminated diamond field effect transistor structure and an electronic device.

[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0006] The utility model provides a hydrogen-terminated diamond field-effect transistor structure, comprising a diamond substrate, wherein a boss is provided on the diamond substrate, and diamond drift regions are provided on the diamond substrate on both sides of the boss; a nitrogen-doped single-crystal diamond layer is provided on the boss; a hydrogen-terminated diamond layer is provided on both the nitrogen-doped single-crystal diamond layer and the deposited diamond drift region; a dielectric layer is provided above the deposited hydrogen-terminated diamond layer, and the dielectric layer wraps the hydrogen-terminated diamond layer and is connected to the diamond substrates on both sides of the boss; a gate is provided on the dielectric layer, wherein the thickness of the diamond drift region is 0.5 to 1.5 μm.

[0007] Furthermore, it also includes a source electrode, which passes through the dielectric layer and connects to the hydrogen-terminated diamond layer.

[0008] Furthermore, a drain is provided at the bottom of the diamond substrate.

[0009] Preferably, the drain electrode is a Ti metal layer, a Pt metal layer and an Au metal layer sequentially arranged on the bottom of the diamond substrate.

[0010] Preferably, the thickness ratio of the Ti metal layer, the Pt metal layer and the Au metal layer is 2:3:10.

[0011] Preferably, the diamond substrate is doped with boron at a concentration of Heavily boron-doped p-type single crystal diamond substrate.

[0012] Preferably, the boss is a circular boss with a boss diameter of 90 to 110 μm and a boss height of 3.5 to 5 μm.

[0013] Preferably, the dielectric layer is an Al2O3 dielectric layer.

[0014] Preferably, the gate is an Au gate.

[0015] An electronic device comprises the above-mentioned hydrogen-terminated diamond field-effect transistor structure.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The utility model discloses a hydrogen-terminated diamond field-effect transistor structure, which includes a diamond substrate. A boss is provided on the diamond substrate, and diamond drift regions with a thickness of 0.5 to 1.5 μm are provided on both sides of the boss. The voltage resistance characteristics of the device can be adjusted by setting diamond drift regions of different thicknesses. A nitrogen-doped single-crystal diamond layer is provided on the boss; and a hydrogen-terminated diamond layer is provided on both the nitrogen-doped single-crystal diamond layer and the diamond drift region, thereby forming a diamond structure in which the diamond drift region and the hydrogen-terminated diamond layer are divided into different layers. Therefore, when designing a crystal tube structure, the breakdown electric field of the device can be adjusted by adjusting the thickness of the diamond drift region, thereby meeting higher device performance requirements.

[0018] It also includes a source electrode, which passes through the dielectric layer and connects to the hydrogen-terminated diamond layer. The source electrode can be used as a source of input signals to provide carriers such as electrons or holes to the transistor to form current.

[0019] A drain is provided at the bottom of the diamond substrate, which is the output end of the transistor structure and is responsible for collecting carriers injected from the source and transmitted through the channel.

[0020] The drain is a Ti metal layer, a Pt metal layer and an Au metal layer sequentially arranged at the bottom of the diamond substrate, wherein the Ti metal layer has good adhesion and can be firmly attached to the diamond substrate to ensure the stability of the drain structure, and has strong bonding force, which helps to prevent the phenomenon of falling off or delamination in subsequent processes or during use. The Pt metal layer has a low resistivity and can reduce the resistance of the drain. It has excellent electrical conductivity and can effectively transmit current, improve the current transmission efficiency of the transistor, and ensure that the drain operates normally in the transistor. In addition, Pt also has good oxidation resistance and corrosion resistance, can maintain stable performance in harsh environments, help to extend the service life of the transistor, and improve its reliability and stability. The Au metal layer has good weldability and machinability, is easy to connect and package with other electronic components, can adapt to the requirements of various packaging processes, and ensure the reliable connection of the transistor with other circuits.

[0021] The gate is an Au gate, which not only has excellent electrical conductivity, but also has good chemical stability, welding and machinability, and can significantly improve the performance and service life of the transistor.

[0022] The utility model provides an electronic device including the above-mentioned hydrogen-terminated diamond field-effect transistor structure. The electronic device has faster response speed and working efficiency, higher energy utilization rate, better stability and reliability, and better application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1This is a schematic diagram of a hydrogen-terminated diamond field-effect transistor structure of the present utility model.

[0024] Figure 2 This is a diamond substrate structure diagram in the structure diagram of the preparation process of a hydrogen-terminated diamond field-effect transistor of the present invention.

[0025] Figure 3 This is a structural diagram of the preparation process of a hydrogen-terminated diamond field-effect transistor of the utility model, and a structural diagram after preparing a nitrogen-doped single crystal diamond layer.

[0026] Figure 4 This is a structural diagram of the preparation process of a hydrogen-terminated diamond field-effect transistor of the utility model after the drain electrode is prepared.

[0027] Figure 5 This is a structural diagram of the hydrogen-terminated diamond field-effect transistor after etching the boss in the structural diagram of the preparation process of the utility model.

[0028] Figure 6 This is a structural diagram of the preparation process of a hydrogen-terminated diamond field-effect transistor of the utility model, and a structural diagram after the diamond drift region is prepared.

[0029] Figure 7 This is a structural diagram of the preparation process of a hydrogen-terminated diamond field-effect transistor of the utility model, and a structural diagram after preparation of a hydrogen-terminated diamond layer.

[0030] Figure 8 This is a structural diagram of the preparation process of a hydrogen-terminated diamond field-effect transistor of the utility model after the source electrode is prepared.

[0031] Figure 9 This is a structural diagram of the hydrogen-terminated diamond field-effect transistor preparation process in the utility model, after the dielectric layer is prepared.

[0032] Figure 10 This is a structural diagram of the hydrogen-terminated diamond field-effect transistor preparation process of the utility model, in which the overall hydrogen-terminated diamond field-effect transistor structure is prepared.

[0033] Among them, 1 is a diamond substrate, 2 is a nitrogen-doped single crystal diamond layer, 3 is a drain, 4 is a diamond drift region, 5 is a hydrogen-terminated diamond layer, 6 is a source, 7 is a dielectric layer, and 8 is a gate. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0035] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0036] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0037] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear to indicate an orientation or positional relationship, they are based on the orientation or positional relationship shown in the accompanying drawings, or are the orientation or positional relationship in which the product of the present invention is typically placed when in use. These terms are used solely to facilitate the description of the present invention and to simplify the description. They do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0040] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain rather than limit the present invention.

[0041] See also Figure 1 The utility model discloses a hydrogen-terminated diamond field effect transistor structure, comprising a drain 3, on which a diamond substrate 1 is arranged. The diamond substrate 1 is a heavily boron-doped p-type single crystal diamond substrate. The boron doping concentration of the heavily boron-doped p-type single crystal diamond substrate is , preferably , further preferably ; The diamond substrate 1 is provided with a boss, which is a circular boss with a boss diameter of 90 to 110 μm, preferably 100 to 110 μm, more preferably 100 μm, and a boss height of 3.5 to 5 μm, preferably 3.5 to 4 μm, more preferably 4 μm; a diamond drift region 4 and a hydrogen-terminated diamond layer 5 are sequentially provided on the diamond substrate 1 on both sides of the boss, and the thickness of the diamond drift region 4 is 0.5 to 1.5 μm; a nitrogen-doped single-crystal diamond layer 2 is wrapped on the boss, and the nitrogen impurity concentration of the nitrogen-doped single-crystal diamond layer 2 is greater than The hydrogen-terminated diamond layer 5 wraps the doped single-crystal diamond layer 2; the outside of the deposited hydrogen-terminated diamond layer 5 is wrapped with a dielectric layer 7, and a gate 8 and a source 6 are provided on the dielectric layer 7. The source 6 passes through the dielectric layer 7 and connects to the hydrogen-terminated diamond layer 5. The source 6 is a Ti metal layer, a Pt metal layer and an Au metal layer sequentially provided on the hydrogen-terminated diamond layer 5. The thickness ratio of the Ti metal layer, the Pt metal layer and the Au metal layer is 2:3:10; the drain 3 is a Ti metal layer, a Pt metal layer and an Au metal layer sequentially provided at the bottom of the diamond substrate 1. The thickness ratio of the Ti metal layer, the Pt metal layer and the Au metal layer is 2:3:10. Preferably, the thicknesses of the Ti metal layer, the Pt metal layer and the Au metal layer are 20nm, 30nm and 100nm respectively. The gate 8 is an Au gate.

[0042] The preparation method of the above hydrogen-terminated diamond field-effect transistor structure is as follows:

[0043] See also Figure 2 First, the heavily boron-doped p-type single crystal diamond substrate 1 is cleaned with acid and alkali to remove the non-diamond phase on the substrate surface; The heavily boron-doped p-type single crystal diamond is used as the diamond substrate 1, wherein the boron impurity concentration is The pickling acid is a mixture of 98% sulfuric acid and 67% nitric acid in a volume ratio of 1:1. The pickling temperature is 100°C for 1 hour. Then, a mixture of 5% sodium hydroxide solution and 36% hydrogen peroxide solution in a volume ratio of 5:3 is heated to 60°C and cleaned for 1 hour to complete the acid-base cleaning of the diamond substrate 1.

[0044] Then, see Figure 3 Epitaxially growing a nitrogen-doped single-crystal diamond layer 2 on the cleaned diamond substrate 1 to block leakage between the diamond drift region 4 and the diamond substrate 1, the thickness of the nitrogen-doped single-crystal diamond layer 2 being 2.5 to 4 μm, preferably 3 μm, under the following growth conditions: 1000 sccm of hydrogen, 20 sccm of methane, 2 sccm of nitrogen, a pressure of 100 Torr, and a temperature of 1000°C;

[0045] See also Figure 4 , depositing a drain electrode 3 on the back side of the diamond substrate 1, and using electron beam deposition technology to deposit a Ti metal layer, a Pt metal layer and an Au metal layer on the back side of the diamond substrate 1, with thicknesses of 20 nm, 30 nm and 100 nm respectively, at room temperature;

[0046] See also Figure 5 The nitrogen-doped single-crystal diamond layer 2 and the diamond substrate 1 are patterned using inductively coupled plasma etching. The surface of the nitrogen-doped single-crystal diamond layer 2 is etched using photolithography and ICP techniques to form a raised mesa. The upper surface of the mesa is circular, preferably with a diameter of 100 μm and a height of 4 μm, and the mesa area is larger than the area of ​​the source electrode 6.

[0047] See also Figure 6 The growth of the diamond drift region 4 is achieved by photolithography, metal deposition, and microwave plasma chemical vapor deposition technology. The preferred thickness is 1 μm. In the actual preparation process, the thickness of the diamond drift region 4 can be adjusted according to demand, thereby achieving the effect of adjusting the breakdown electric field of the device.

[0048] See also Figure 7 The selective growth of the hydrogen-terminated diamond layer 5 is achieved using photolithography, metal deposition, and MPCVD techniques. Specifically, Au is used as a mask to cover the area shown in the figure. The Au mask is then washed away with potassium iodide, and the hydrogen-terminated diamond layer 5 is deposited, covering the mesa of the nitrogen-doped single-crystal diamond layer 2 and a portion of the heavily boron-doped p-type single-crystal diamond substrate 1.

[0049] See also Figure 8 , Ti, Pt and Au metal layers are deposited on the surface of the nitrogen-doped single crystal diamond layer 5 as the source electrode 6 using electron beam deposition technology, with thicknesses of 20, 30 and 100 nm respectively, and the deposition temperature is room temperature.

[0050] See also Figure 9 , depositing a dielectric layer 7 on the hydrogen-terminated diamond layer 5 so that the deposited dielectric layer 7 wraps the hydrogen-terminated diamond layer 5; the dielectric layer 7 is an Al2O3 dielectric layer,

[0051] See also Figure 10 Finally, a gate electrode 8 is deposited on the dielectric layer 7. The Au gate electrode 8 has a gate length of 9 to 11 μm, preferably 10 μm, to complete the device preparation.

[0052] An electronic device comprising the above-mentioned hydrogen-terminated diamond field-effect transistor structure has faster response speed and working efficiency, higher energy utilization rate, better stability and reliability, and better application prospects.

[0053] In summary, the present invention provides a hydrogen-terminated diamond field-effect transistor structure and an electronic device. By arranging a boss on a diamond substrate 1 and arranging a diamond drift region 4 with a thickness of 0.5 to 1.5 μm on both sides of the boss, the voltage resistance characteristics of the device can be adjusted by setting diamond drift regions of different thicknesses. When designing the transistor structure, the breakdown electric field of the device can be adjusted by adjusting the thickness of the diamond drift region, so that it can meet higher device performance requirements.

[0054] The above description is merely a preferred embodiment of the present invention and is not intended to impose any limitation on the technical solution of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can also be subjected to several simple modifications and replacements, and these modifications and replacements are also within the scope of protection covered by the claims.

Claims

1. A hydrogen-terminated diamond field-effect transistor structure, characterized in that: The present invention comprises a diamond substrate (1), wherein a boss is provided on the diamond substrate (1), and diamond drift regions (4) are provided on the diamond substrate (1) on both sides of the boss; a nitrogen-doped single crystal diamond layer (2) is provided on the boss; a hydrogen-terminated diamond layer (5) is provided on both the nitrogen-doped single crystal diamond layer (2) and the deposited diamond drift region (4); a dielectric layer (7) is provided above the deposited hydrogen-terminated diamond layer (5), and the dielectric layer (7) wraps the hydrogen-terminated diamond layer (5) and is connected to the diamond substrate (1) on both sides of the boss; a gate (8) is provided on the dielectric layer (7), wherein the thickness of the diamond drift region (4) is 0.5 to 1.5 μm.

2. The hydrogen-terminated diamond field-effect transistor structure according to claim 1, characterized in that It also includes a source electrode (6), which passes through the dielectric layer (7) and is connected to the hydrogen-terminated diamond layer (5).

3. The hydrogen-terminated diamond field-effect transistor structure according to claim 1, characterized in that: A drain (3) is provided at the bottom of the diamond substrate (1).

4. The hydrogen-terminated diamond field-effect transistor structure according to claim 3, characterized in that: The drain electrode (3) is a Ti metal layer, a Pt metal layer and an Au metal layer which are sequentially arranged on the bottom of the diamond substrate (1).

5. The hydrogen-terminated diamond field-effect transistor structure according to claim 4, characterized in that: The thickness ratio of the Ti metal layer, the Pt metal layer and the Au metal layer is 2:3:

10.

6. The hydrogen-terminated diamond field-effect transistor structure according to claim 1, wherein: The boss is a circular boss with a boss diameter of 90 to 110 μm and a boss height of 3.5 to 5 μm.

7. The hydrogen-terminated diamond field-effect transistor structure according to claim 1, wherein: The dielectric layer (7) is an Al2O3 dielectric layer.

8. The hydrogen-terminated diamond field-effect transistor structure according to any one of claims 1 to 7, characterized in that: The gate (8) is an Au gate.

9. An electronic device, characterized in that: The invention comprises the hydrogen-terminated diamond field-effect transistor structure according to any one of claims 1 to 8.

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