Vertical hydrogen terminal diamond field effect transistor and electronic device
By designing a vertical hydrogen-terminated diamond field-effect transistor structure, the problem of low output current density of high-power FETs was solved, the device power was increased without affecting the output current density, and the stability and performance of the device were improved.
Patent Information
- Application Number
- CN202422516326.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-17
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2034-10-17
AI Technical Summary
Existing high-power field-effect transistors (FETs) have low output current density and cannot effectively increase the power of electronic devices. Existing methods also lead to degradation of the concentration and mobility of hydrogen-terminated diamond holes.
A vertical hydrogen-terminated diamond field-effect transistor structure is adopted, including setting a boss, a nitrogen-doped single-crystal diamond layer and a source electrode on a diamond substrate, and improving the surface stability through the hydrogen-terminated diamond layer and the dielectric layer. Combined with a heavily boron-doped p-type single-crystal diamond substrate, Ti, Pt and Au drain-source structure, the electric field distribution is optimized and the internal structure is protected.
The switching ratio and transconductance of the transistor are improved, the breakdown voltage and output power are increased, while maintaining good chemical and thermal stability, thereby enhancing the reliability and stability of the device.
Smart Images
Figure CN223310192U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of diamond field effect transistor preparation, in particular to a vertical hydrogen-terminated diamond field effect transistor and an electronic device. Background Art
[0002] With the rapid development of social economy and science and technology, high-power field-effect transistors (FETs), as the core of power electronic devices, play a vital role in high-tech industries such as aerospace and 5G communications. Diamond, as a new type of ultra-wide bandgap semiconductor material, has excellent properties such as large bandgap width, high carrier mobility, large breakdown electric field, and high thermal conductivity compared to other semiconductor materials. It is expected to break through the technical bottlenecks faced by existing high-power FETs. When the diamond surface is hydrogen-terminated, after being placed in the air for a period of time, a natural two-dimensional hole gas layer will be formed on the diamond surface, and its in-plane hole concentration can reach 10 13 cm -2 The hole mobility is generally 30 to 500 cm 2 / Vs, high-power FETs can be prepared using hydrogen-terminated diamond.
[0003] In order to improve the output power of planar hydrogen-terminated diamond FETs, it is necessary to increase their breakdown voltage. Generally, methods such as partially oxygen-terminating the channel of the hydrogen-terminated diamond or adding a passivation layer are used to increase the breakdown voltage. However, studies have shown that these methods will cause the hole concentration and mobility of the hydrogen-terminated diamond to degrade, thereby reducing the output current density of the device and failing to achieve power improvement. Utility Model Content
[0004] In view of the problem in the prior art that high-power field-effect transistors have low output current density and cannot effectively improve the power of electronic devices, the utility model provides a vertical hydrogen-terminated diamond field-effect transistor 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 vertical hydrogen-terminated diamond field-effect transistor, comprising a diamond substrate, wherein a boss is provided on the diamond substrate, and a nitrogen-doped single-crystal diamond layer and a source electrode are sequentially provided on the boss; a hydrogen-terminated diamond layer and a dielectric layer are also provided on the diamond substrate, wherein the hydrogen-terminated diamond layer wraps the nitrogen-doped single-crystal diamond layer, and the dielectric layer wraps the hydrogen-terminated diamond layer, and a gate is further provided on the dielectric layer; and a drain electrode is provided at the bottom of the diamond substrate.
[0007] Furthermore, the diamond substrate is doped with boron at a concentration greater than Heavily boron-doped p-type single crystal diamond substrate.
[0008] Preferably, the diamond substrate is doped with boron at a concentration of Heavily boron-doped p-type single crystal diamond substrate.
[0009] Preferably, the drain electrode comprises Ti, Pt and Au in a thickness ratio of 2:3:10.
[0010] Preferably, the source electrode comprises Ti, Pt and Au with a thickness ratio of 2:3:10.
[0011] Preferably, the cross-sectional area of the boss is larger than the cross-sectional area of the source.
[0012] Preferably, the nitrogen-doped single crystal diamond layer has a nitrogen doping concentration greater than Nitrogen-doped single-crystal diamond layer.
[0013] Preferably, the dielectric layer is an Al2O3 layer.
[0014] Preferably, the gate is an Au gate.
[0015] An electronic device comprises the vertical hydrogen-terminated diamond field-effect transistor.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] The utility model discloses a vertical hydrogen-terminated diamond field-effect transistor, comprising a diamond substrate. By arranging a boss on the substrate and sequentially arranging a nitrogen-doped single-crystal diamond layer and a source electrode on the boss, the three-dimensional structure of the transistor is increased, the electric field distribution is optimized, and the device performance is improved. By arranging the hydrogen-terminated diamond layer and the dielectric layer, the stability of the diamond surface can be improved, the surface state density can be reduced, thereby improving the switching ratio and transconductance of the transistor, and effectively improving the breakdown voltage of the device. While achieving an increase in the output power of the device without affecting the output current density of the device, the hydrogen-terminated diamond layer also has good chemical stability and thermal stability, and can maintain the device performance in harsh environments. The dielectric layer is wrapped around the hydrogen-terminated diamond layer to play an isolation and protection role, and can prevent the external environment from interfering with the internal structure of the transistor, thereby improving the reliability and stability of the device. Finally, the switching function of the transistor is realized by arranging the gate, drain and source electrodes.
[0018] The diamond substrate is a heavily boron-doped p-type single crystal diamond substrate, and the boron doping concentration of the heavily boron-doped p-type single crystal diamond substrate is greater than The diamond substrate has low resistivity, high stability and high corrosion resistance, which can improve the electrical performance, service life and operational stability of electronic devices to a certain extent.
[0019] The drain and source both include Ti, Pt and Au with a thickness ratio of 2:3:10. The Ti metal layer has good adhesion and can be firmly attached to the diamond substrate, ensuring the stability of the drain structure, and has strong bonding force, which helps to prevent falling off or delamination during subsequent processes or use. The Pt metal layer has a low resistivity, can reduce the resistance of the drain, has excellent electrical conductivity, 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 reliable connection of the transistor with other circuits.
[0020] An electronic device comprising the vertical hydrogen-terminated diamond field-effect transistor has faster response speed and working efficiency, higher energy utilization, better stability and higher output power. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a schematic diagram of a vertical hydrogen-terminated diamond field-effect transistor of the present invention.
[0022] Figure 2 This is a diamond substrate structure diagram in the preparation process structure diagram of a vertical hydrogen-terminated diamond field-effect transistor of the present invention.
[0023] Figure 3 This is a structural diagram of the preparation process of a vertical hydrogen-terminated diamond field-effect transistor of the utility model, and a structural diagram after preparing a nitrogen-doped single-crystal diamond layer.
[0024] Figure 4 This is a structural diagram of the vertical hydrogen-terminated diamond field-effect transistor preparation process after drain electrode preparation in the structural diagram of the utility model.
[0025] Figure 5 This is a structural diagram of the vertical hydrogen-terminated diamond field-effect transistor after etching the boss in the structural diagram of the preparation process of the utility model.
[0026] Figure 6 This is a structural diagram of the preparation process of a vertical hydrogen-terminated diamond field-effect transistor of the utility model after the source electrode is prepared.
[0027] Figure 7 This is a structural diagram of the vertical hydrogen-terminated diamond field-effect transistor preparation process diagram of the utility model after the hydrogen-terminated diamond layer is prepared.
[0028] Figure 8 This is a structural diagram of the vertical hydrogen-terminated diamond field-effect transistor preparation process in the utility model, and a structural diagram after the dielectric layer is prepared.
[0029] Figure 9 This is a structural diagram of the vertical 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.
[0030] Among them, 1 is a diamond substrate, 2 is a nitrogen-doped single crystal diamond layer, 3 is a drain, 4 is a source, 5 is a hydrogen-terminated diamond layer, 6 is a dielectric layer, and 7 is a gate. DETAILED DESCRIPTION
[0031] 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.
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] 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.
[0037] 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.
[0038] See also Figure 1 The utility model discloses a vertical hydrogen-terminated diamond field-effect transistor, comprising a diamond substrate 1, a nitrogen-doped single-crystal diamond layer 2, a drain 3, a source 4, a diamond layer 5, a dielectric layer 6 and a gate 7;
[0039] The diamond substrate 1 is a heavily boron-doped p-type single crystal diamond substrate, and the boron doping concentration of the heavily boron-doped p-type single crystal diamond substrate is greater than , preferably, greater than , further preferably, greater than Less than , most preferably, The diamond substrate 1 is provided with a boss, the boss diameter is 95 to 110 μm, more preferably 100 μm, the boss height is 3.5 to 5 μm, preferably 3.5 to 4 μm, more preferably 4 μm;
[0040] The nitrogen-doped single crystal diamond layer 2 is arranged on the boss, and the nitrogen-doped single crystal diamond layer 2 has a nitrogen doping concentration greater than ;
[0041] The drain electrode 3 is provided at the bottom of the diamond substrate 1 and comprises Ti, Pt and Au with a thickness ratio of 2:3:10. Preferably, the thicknesses of Ti, Pt and Au are 20 nm, 30 nm and 100 nm respectively.
[0042] The hydrogen-terminated diamond layer 5 wraps the nitrogen-doped single crystal diamond layer 2;
[0043] The dielectric layer 6 is wrapped around the hydrogen-terminated diamond layer 5, and is preferably Al2O3;
[0044] The source electrode 4 includes Ti, Pt and Au with a thickness ratio of 2:3:10, and the source electrode 4 is connected to the nitrogen-doped single crystal diamond layer 2 through the hydrogen-terminated diamond layer 5 and the dielectric layer 6;
[0045] The gate 7 is made of Au and is disposed on the dielectric layer 6 .
[0046] The preparation method of the above hydrogen-terminated diamond field-effect transistor structure is as follows:
[0047] 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.
[0048] See also Figure 3 Epitaxially grow a nitrogen-doped single-crystal diamond layer 2 on the cleaned diamond substrate 1 to block leakage between the source electrode 4 and the diamond substrate 1. The thickness of the nitrogen-doped single-crystal diamond layer 2 is 2.5 to 4 μm, preferably 3 μm. The growth conditions are: 1000 sccm of hydrogen, 20 sccm of methane, 2 sccm of nitrogen, a pressure of 100 Torr, and a temperature of 1000°C.
[0049] 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;
[0050] 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.
[0051] See also Figure 6, using electron beam deposition technology to deposit Ti, Pt and Au metal layers as source electrodes 4 on the surface of the nitrogen-doped single crystal diamond layer 2, with thicknesses of 20, 30 and 100 nm respectively, at room temperature;
[0052] 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.
[0053] See also Figure 8 , depositing a dielectric layer 6 on the hydrogen-terminated diamond layer 5 so that the deposited dielectric layer 6 wraps the hydrogen-terminated diamond layer 5; the dielectric layer 6 is an Al2O3 dielectric layer,
[0054] See also Figure 9 Finally, a gate 7 is deposited on the dielectric layer 6. The Au gate 7 has a gate length of 9 to 11 μm, preferably 10 μm, to complete the device preparation.
[0055] An electronic device comprising the vertical hydrogen-terminated diamond field-effect transistor has faster response speed and working efficiency, higher energy utilization, better stability and higher output power.
[0056] In summary, the present invention provides a vertical hydrogen-terminated diamond field-effect transistor and electronic device, including a diamond substrate 1. By arranging a boss on the substrate 1 and arranging a nitrogen-doped single-crystal diamond layer 2 and a source electrode 4 in sequence on the boss, it is beneficial to increase the three-dimensional structure of the transistor, optimize the electric field distribution, and improve the device performance. By arranging a hydrogen-terminated diamond layer 5 and a dielectric layer 6, the stability of the diamond surface can be improved, the surface state density can be reduced, thereby improving the switching ratio and transconductance of the transistor, and effectively improving the device breakdown voltage. While achieving the improvement of the device output power without affecting the output current density of the device, the hydrogen-terminated diamond layer 5 also has good chemical stability and thermal stability, and can maintain the device performance in harsh environments. The dielectric layer 6 is wrapped around the hydrogen-terminated diamond layer 5 to play an isolation and protection role, which can prevent the external environment from interfering with the internal structure of the transistor, and improve the reliability and stability of the device. Finally, through the arrangement of the gate, drain and source, the switching function of the transistor is realized, making it have higher application value and potential.
[0057] 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 vertical hydrogen-terminated diamond field-effect transistor, characterized in that: The present invention comprises a diamond substrate (1), wherein a boss is provided on the diamond substrate (1), and a nitrogen-doped single crystal diamond layer (2) and a source electrode (4) are sequentially provided on the boss; a hydrogen-terminated diamond layer (5) and a dielectric layer (6) are also provided on the diamond substrate (1), wherein the hydrogen-terminated diamond layer (5) wraps the nitrogen-doped single crystal diamond layer (2), and the dielectric layer (6) wraps the hydrogen-terminated diamond layer (5); a gate electrode (7) is also provided on the dielectric layer (6), and a drain electrode (3) is provided at the bottom of the diamond substrate (1).
2. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The diamond substrate (1) is doped with boron at a concentration greater than Heavily boron-doped p-type single crystal diamond substrate.
3. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The diamond substrate (1) is doped with boron at a concentration of Heavily boron-doped p-type single crystal diamond substrate.
4. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The drain (3) comprises Ti, Pt and Au with a thickness ratio of 2:3:
10.
5. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The source electrode (4) comprises Ti, Pt and Au with a thickness ratio of 2:3:
10.
6. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The cross-sectional area of the boss is larger than the cross-sectional area of the source (4).
7. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The nitrogen-doped single crystal diamond layer (2) has a nitrogen doping concentration greater than Nitrogen-doped single-crystal diamond layer.
8. The vertical hydrogen-terminated diamond field-effect transistor according to claim 1, characterized in that: The dielectric layer (6) is an Al2O3 layer.
9. The vertical hydrogen-terminated diamond field-effect transistor according to any one of claims 1 to 8, characterized in that: The gate (7) is an Au gate.
10. An electronic device, characterized in that: The invention comprises a vertical hydrogen-terminated diamond field-effect transistor according to any one of claims 1 to 9.