A high current high voltage diamond diode and a method of manufacturing the same

Abstract

The present application relates to a kind of high-voltage diamond diode of large current and its manufacturing method, profile structure is based on substrate diamond (1) as bottom, based on substrate diamond (1) upper surface local setting a type doped diamond (2), further in the upper surface of a type doped diamond (2), and substrate diamond (1) upper surface layout a type conducting channel (7), then in a type conducting channel (7) corresponding a type doped diamond (2) position area local setting barrier adjustment layer (6), finally setting first electrode (4), second electrode (5), and dielectric layer (3), constitute high-voltage, large current density diamond diode, solve the problem such as low voltage, low current density of traditional power diamond schottky diode, and propose manufacturing method, innovation design manufacturing process sequence, reduce leakage current and process difficulty, the designed diamond diode effectively improves actual work efficiency.

Description

Technical Field

[0001] This invention relates to a high-current, high-voltage diamond diode and its manufacturing method, belonging to the field of semiconductor device structure design and manufacturing technology. Background Technology

[0002] In the current development of the semiconductor industry, diamond, as a fourth-generation semiconductor, has great application prospects. Diamond Schottky diodes (SBDs) are of great significance in extreme environments such as high power, high temperature, high frequency and high radiation due to their excellent characteristics such as high breakdown voltage, high thermal conductivity, high carrier mobility, low leakage current, high temperature stability and radiation resistance.

[0003] Schottky diodes operate based on the unidirectional conductivity of Schottky contacts, which are formed by creating a metal-semiconductor interface on the semiconductor surface. This interface has a potential barrier that allows current to flow under forward bias but blocks it under reverse bias. Under forward bias, the Fermi level on the metal side is raised, lowering the barrier height, allowing electrons to be injected from the metal into the diamond, forming a current. This current primarily consists of the drift and diffusion of majority carriers (holes). Under reverse bias, the Fermi level on the metal side is lowered, increasing the barrier height, making it difficult for electrons to be injected from the semiconductor into the metal, thus preventing current flow.

[0004] The working principle of hydrogen-terminated diamond (HTD) is based on the bonding of hydrogen atoms with carbon atoms on the diamond surface, forming stable CH bonds. This surface treatment not only reduces the surface state density but also significantly improves the surface conductivity. The low electron affinity of the hydrogen-terminated surface makes it easier for electrons to be adsorbed, thus forming a high-density two-dimensional hole gas (2DHG) on the surface. These holes have high mobility and can move rapidly under the influence of an electric field, achieving efficient current transmission. In addition, the high mobility of the hydrogen-terminated surface makes the device perform well in high-frequency and high-power applications. However, the hydrogen-terminated surface has poor stability under high temperature and high radiation environments, which can easily lead to performance degradation. Furthermore, due to the limitations of the diamond n-type doping process, the diamond pn junction manufacturing process is difficult, which greatly limits the breakdown voltage performance. In addition, the low process precision of traditional diamond SBD devices makes it difficult to control the thickness and doping concentration of the p-type epitaxial layer. Traditional diamond SBD devices also suffer from problems such as uneven Schottky barrier layer and large leakage current. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high-current, high-voltage diamond diode, which innovatively improves the voltage withstand capability, reduces leakage current, and has better process compatibility with diamond field-effect transistor (FET) devices.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention designs a high-current, high-voltage diamond diode, based on a cubic design with a cross-sectional structure penetrating its two opposite sides as shown below, or based on a circular top-view geometry, with a cross-sectional structure along its radius as shown below; The structure includes a substrate diamond, a type-1 doped diamond, a dielectric layer, a first electrode, and a second electrode. The substrate diamond is located at the bottom of the cross-sectional structure, and its two sides are defined as side A and side B, respectively. The type-1 doped diamond is disposed on a local segment of the upper surface of the substrate diamond starting from side A. This local segment of the upper surface of the type-1 doped diamond starting from side A is processed to form a barrier adjustment layer. The non-type-1 doped diamond area on the upper surface of the substrate diamond, as well as the exposed surface of the type-1 doped diamond, are processed to form a type-1 conductive channel. The first electrode is disposed on a local segment of the upper surface of the type-1 conductive channel starting from side B, and forms an ohmic contact with the type-1 conductive channel. The second electrode is disposed on a local segment of the upper surface of the barrier adjustment layer starting from side A, and forms a Schottky contact or a semiconductor heterojunction with the barrier adjustment layer. The dielectric layer covers the upper surface of the barrier adjustment layer and the upper surface of the type-1 conductive channel disposed between the first electrode and the second electrode, and its two sides are respectively connected to the first electrode and the second electrode they face. If the geometry is a circular top-view projection, the side of the cross-section structure corresponding to side A corresponds to the center of the circular top-view projection, and the side of the cross-section structure corresponding to side B corresponds to the outer perimeter of the circular top-view projection.

[0007] As a preferred technical solution of the present invention: the type-1 doped diamond includes an upper type-1 doped diamond and a lower type-1 doped diamond made of the same material. In the cross-sectional structure, the lower type-1 doped diamond is embedded in a local segment of the type-1 doped diamond on the upper surface of the substrate diamond, and the upper surface of the lower type-1 doped diamond is flush with the upper surface of the substrate diamond. The upper type-1 doped diamond is disposed on the upper surface of the lower type-1 doped diamond, and the end of the upper type-1 doped diamond corresponding to side A is flush with the end of the lower type-1 doped diamond corresponding to side A in the vertical direction. The upper surface of the upper type-1 doped diamond constitutes the upper surface of the type-1 doped diamond.

[0008] As a preferred technical solution of the present invention: the type-1 doped diamond includes a lower type-1 doped diamond. In the cross-sectional structure, the lower type-1 doped diamond is embedded in a local segment of the type-1 doped diamond on the upper surface of the substrate diamond, and the upper surface of the lower type-1 doped diamond is flush with the upper surface of the substrate diamond. The upper surface of the lower type-1 doped diamond constitutes the upper surface of the type-1 doped diamond.

[0009] As a preferred technical solution of the present invention: the depth of the lower type I doped diamond is greater than the depth of the type I conductive channel.

[0010] As a preferred technical solution of the present invention: the type-1 doped diamond includes an upper type-1 doped diamond. In the cross-sectional structure, the upper type-1 doped diamond is disposed on a local segment of the type-1 doped diamond on the upper surface of the substrate diamond, and the upper surface of the upper type-1 doped diamond constitutes the upper surface of the type-1 doped diamond.

[0011] As a preferred technical solution of the present invention, it further includes any one of a metal carbide layer, a type-1 doped diamond embedding layer, and a type-1 doped diamond epitaxial layer; Among them, a type-doped diamond embedding layer is disposed on a local segment of a type-conductive channel corresponding to the lower part of the first electrode, and an ohmic contact is formed by the contact between the first electrode and the type-doped diamond embedding layer region. A metal carbide layer is disposed on a type-1 conductive channel at a local segment position corresponding to the first electrode, and an ohmic contact is formed between the first electrode and the diamond substrate through the metal carbide layer. A type-doped diamond epitaxial layer is disposed on a local segment of the upper surface of a type-conductive channel corresponding to the lower part of the first electrode, and an ohmic contact is formed by the contact between the first electrode and the type-doped diamond epitaxial layer.

[0012] Corresponding to the above, the technical problem that this invention also needs to solve is to provide a manufacturing method for a high-current, high-voltage diamond diode, with an innovative design of the manufacturing process sequence, so that the designed diamond diode can improve the actual working efficiency.

[0013] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention designs a method for manufacturing a high-current, high-voltage diamond diode, comprising the following steps: Step A. Growing diamond substrate; Step B. Process a type-doped diamond onto the surface of the diamond substrate; Step C. For the upper surface of the substrate diamond and the exposed surface of the type-1 doped diamond, a terminal treatment is performed to form a type-1 conductive channel; Step D. Deposit metal on the upper surface of the overall device, then remove the metal in a local area on the upper surface of the type I doped diamond to expose the underlying type I conductive channel, and then perform a termination treatment on the exposed type I conductive channel area to form a barrier conditioning layer; Step E. Deposit metal on the upper surface of a type-1 conductive channel, and then etch away the excess metal to form the first electrode of an ohmic contact; Step F. Deposit dielectric material on the upper surface of the entire device, and then remove dielectric material from local areas on the upper surface of the first electrode and the barrier adjustment layer to form a dielectric layer; Step G. Deposit metal on the upper surface of the overall device, then remove excess metal, and form a second electrode in a local segment on the upper surface of the barrier adjustment layer to realize a Schottky contact or a semiconductor heterojunction.

[0014] As a preferred technical solution of the present invention: in step B, based on the upper surface of the substrate diamond, a lower layer of type I doped diamond is formed by ion implantation, thereby realizing the generation of type I doped diamond; Alternatively, trenches can be etched on the upper surface of the diamond substrate, and a lower layer of type-1 doped diamond can be formed in the trenches through secondary epitaxial growth, thereby achieving the generation of type-1 doped diamond.

[0015] As a preferred technical solution of the present invention: in step A, the growth process of the substrate diamond is any one of MPCVD, HFCVD, and HTHP, and the growth crystal orientation includes, but is not limited to, 100, 110, and 111. The etching of the trenches on the diamond surface of the substrate is any one of reactive ion etching, electron cyclotron resonance etching, and laser etching; the termination process of the type-1 conductive channel is any one of H termination process and Si termination process. The terminal treatment of the barrier modulation layer can be any one of surface terminal treatment, asymmetric deposition of high and low barrier metals, or optical modulation of Schottky barrier height.

[0016] As a preferred technical solution of the present invention: the type-1 doped diamond is p-type doped; the conductivity type of the type-1 conductive channel is p-type; the first electrode is a material capable of forming an ohmic contact; the second electrode is a material capable of forming a Schottky contact or a semiconductor heterojunction with the barrier adjustment layer; and the dielectric layer is an insulating dielectric material capable of forming a passivation effect.

[0017] The high-current, high-voltage diamond diode and its manufacturing method described in this invention have the following technical advantages compared with the prior art: (1) This invention designs a high-current, high-voltage diamond diode and its manufacturing method. The cross-sectional structure is based on a diamond substrate. A type-doped diamond is locally set on the upper surface of the diamond substrate. A type-conductive channel is further arranged on the upper surface of the type-doped diamond and the upper surface of the diamond substrate. Then, a barrier adjustment layer is locally set in the area corresponding to the type-doped diamond position of the type-conductive channel. Finally, a first electrode, a second electrode, and a dielectric layer are set to form a diamond diode with high voltage and high current density. This invention solves the problems of low voltage and low current density of traditional power diamond Schottky diodes. Furthermore, it proposes a manufacturing method and innovatively designs the manufacturing process sequence to reduce leakage current and process difficulty. The designed diamond diode effectively improves the actual working efficiency. (2) Traditional transverse diamond SBD devices have long transmission paths and many defects in the p-type doped region, resulting in limited current density and uneven transverse electric field distribution, leading to low breakdown voltage performance. This invention is designed to conduct electricity through hydrogen-terminated channels. By reducing electron affinity through the surface channel of the hydrogen terminator, a high concentration of 2DHG is formed on the diamond surface, which greatly improves carrier mobility and thus significantly increases current density. Furthermore, the surface passivation of the hydrogen terminator can reduce the interface trap density and effectively suppress electric field concentration, thereby greatly improving the breakdown voltage performance of the device. (3) The performance of traditional diamond SBD devices depends on the precise control of the concentration and thickness of p-type secondary epitaxy. However, excessively high p-type secondary epitaxy concentration can lead to enhanced impurity scattering, thereby reducing the on-resistance. It may also lead to increased lattice damage or the formation of compensating defect centers. These defects can trap carriers, reduce the carrier concentration, and increase the on-resistance. In addition, excessively high p-type secondary epitaxy thickness will increase the bulk resistance, thereby increasing the on-resistance. However, excessively low thickness may lead to punch-through and a surge in leakage current. This invention uses a hydrogen-terminated conductive channel as the conductive path, eliminating the influence of deviations in secondary epitaxy concentration and thickness on device performance. Moreover, the defects of type I doped diamond in this invention have minimal impact on the electrical performance of the device. Thus, without reducing device performance, the process difficulty of secondary epitaxy is reduced, and the process cost is greatly reduced. (4) Traditional diamond SBD devices form ohmic contacts with metal by p-type heavy doping of diamond, which is difficult to process. In this invention, the metal is deposited directly to form a Schottky contact with the hydrogen terminal conductive channel, which greatly reduces the difficulty of the process, the barrier height and the ohmic contact resistance. (5) The present invention uses a dielectric layer with passivation function, which can effectively protect the hydrogen terminal conductive channel, prevent hydrogen desorption at high temperature, and improve device stability; moreover, the Schottky junction capacitance can be adjusted by designing the dielectric layer thickness and dielectric constant, thereby reducing switching losses. (6) The core of current diamond field-effect transistor (FET) manufacturing processes is highly dependent on precise surface termination treatment (such as hydrogen termination to induce two-dimensional hole gas 2DHG, or oxygen termination to achieve insulating / semi-insulating surfaces). The device manufacturing process adopted in this invention has significantly higher compatibility with the aforementioned mainstream diamond FET processes in key process steps (especially surface treatment, thin film deposition, and patterning), compared to the typical process of traditional diamond Schottky barrier diodes (SBDs) (which usually do not involve or rely less on such precise surface termination control). This compatibility is reflected in the sharing of similar process modules (such as hydrogen plasma treatment, atomic layer deposition (ALD), and specific metallization processes) and material systems (such as gate dielectric, passivation layer, and ohmic contact metal). Therefore, the device structure of this invention can be seamlessly integrated into existing diamond FET manufacturing platforms without introducing disruptive process changes or additional complex steps, thereby significantly reducing the technical difficulty and manufacturing cost of monolithic integration of heterogeneous devices (diodes and transistors) on a single diamond wafer or chip, and providing convenient conditions for building more functional diamond-based integrated circuits. Attached Figure Description

[0018] Figures 1(a), 1(b), and 1(c) are schematic diagrams of three sub-implementations of the first type of embodiment of the high-current, high-voltage diamond diode designed in this invention; Figure 2 This is a schematic diagram of a second type of embodiment of the high-current, high-voltage diamond diode designed in this invention; Figure 3 This is a schematic diagram of the third type of embodiment of the high-current, high-voltage diamond diode designed in this invention. Figure 4 This is a flowchart of the manufacturing method of the high-current, high-voltage diamond diode designed in this invention; Figure 5 This is a state diagram of step A in the manufacturing method of the high-current, high-voltage diamond diode of the present invention. Figure 6 This is a state diagram of step B in the manufacturing method of the high-current, high-voltage diamond diode of the present invention. Figure 7 This is a state diagram of step C in the manufacturing method of the high-current, high-voltage diamond diode designed in this invention. Figure 8 This is a state diagram of step E in the manufacturing method of the high-current, high-voltage diamond diode designed in this invention. Figure 9 This is a state diagram of step F in the manufacturing method of the high-current, high-voltage diamond diode designed in this invention.

[0019] Among them, 1. substrate diamond, 2. type I doped diamond, 2-1. upper type I doped diamond, 2-2. lower type I doped diamond, 3. dielectric layer, 4. first electrode, 5. second electrode, 6. barrier adjustment layer, 7. type I conductive channel. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0021] This invention designs a high-current, high-voltage diamond diode. In practical applications, it is specifically divided into two categories: a cubic diamond diode and a circular top-view projection diamond diode. The specific designs for the two types of structures are as follows: for the cubic structure, the cross-sectional structure that runs through its two opposite sides is designed as follows; and for the geometric body based on the circular top-view projection, the cross-sectional structure along its radius is designed as follows.

[0022] The cross-sectional structure includes a substrate diamond 1, a type-1 doped diamond 2, a dielectric layer 3, a first electrode 4, and a second electrode 5. The substrate diamond 1 is located at the bottom of the cross-sectional structure, and its two sides are defined as side A and side B, respectively. The type-1 doped diamond 2 is disposed on a local segment of the upper surface of the substrate diamond 1 starting from side A. This local segment of the upper surface of the type-1 doped diamond 2, starting from side A, is processed to form a barrier conditioning layer 6. The areas on the upper surface of the substrate diamond 1 where the type-1 doped diamond 2 is not disposed, as well as the exposed surface of the type-1 doped diamond 2, are all treated... The process forms a conductive channel 7; a first electrode 4 is disposed on a partial section of the upper surface of the conductive channel 7 starting from its B-side end, and the first electrode 4 forms an ohmic contact with the conductive channel 7; a second electrode 5 is disposed on a partial section of the upper surface of the barrier adjustment layer 6 starting from its A-side end, and the second electrode 5 forms a Schottky contact or a semiconductor heterojunction with the barrier adjustment layer 6; a dielectric layer 3 covers the upper surface of the barrier adjustment layer 6 and the upper surface of the conductive channel 7 disposed between the first electrode 4 and the second electrode 5, and the two sides of the dielectric layer 3 are respectively connected to the first electrode 4 and the second electrode 5 facing it.

[0023] Traditional lateral diamond SBD devices suffer from limited current density and uneven lateral electric field distribution due to long transmission paths and numerous defects in the p-type doped region, resulting in low breakdown voltage performance. This invention employs a hydrogen-terminated channel for conduction. By reducing electron affinity through the surface channel of the hydrogen terminator, a high concentration of 2DHG is formed on the diamond surface, significantly improving carrier mobility and thus dramatically increasing current density. Furthermore, the surface passivation of the hydrogen terminator reduces interface trap density, effectively suppressing electric field concentration and significantly enhancing the device's breakdown voltage performance.

[0024] Furthermore, the performance of traditional diamond SBD devices relies on precise control of the concentration and thickness of the p-type secondary epitaxial layer. However, excessively high p-type secondary epitaxial layer concentration can lead to enhanced impurity scattering, thereby reducing on-resistance and potentially causing exacerbated lattice damage or the formation of compensating defect centers. These defects trap charge carriers, reducing carrier concentration and increasing on-resistance. Conversely, excessively high p-type secondary epitaxial layer thickness increases bulk resistance, thus increasing on-resistance, while insufficient thickness can lead to punch-through and a surge in leakage current. This invention uses a hydrogen-terminated conductive channel as the conductive path, eliminating the impact of deviations in secondary epitaxial layer concentration and thickness on device performance. Moreover, the defects of type I doped diamond 2 in this invention have minimal impact on the electrical performance of the device. Therefore, without reducing device performance, the process difficulty of secondary epitaxy is reduced, significantly lowering process costs.

[0025] Regarding the designed cross-sectional structure, if the diamond diode is a geometric body with a circular top view, then the side of the cross-sectional structure corresponding to side A corresponds to the center position of the circular top view, and the side of the cross-sectional structure corresponding to side B corresponds to the outer perimeter of the circular top view.

[0026] Regarding the above-mentioned design of the type-doped diamond 2 based on the partial segment of the upper surface of the substrate diamond 1 starting from its A-side end, three specific embodiments are designed in practical applications. In the first embodiment, the type-doped diamond 2 is designed to include an upper type-doped diamond 2-1 and a lower type-doped diamond 2-2 made of the same material. In the cross-sectional structure, the lower type-doped diamond 2-2 is embedded in the partial segment of the type-doped diamond 2 on the upper surface of the substrate diamond 1, and the upper surface of the lower type-doped diamond 2-2 is flush with the upper surface of the substrate diamond 1. The upper type-doped diamond 2-1 is disposed on the upper surface of the lower type-doped diamond 2-2, and the end of the upper type-doped diamond 2-1 corresponding to the A-side is flush with the end of the lower type-doped diamond 2-2 corresponding to the A-side in the vertical direction. The upper surface of the upper type-doped diamond 2-1 constitutes the upper surface of the type-doped diamond 2.

[0027] Regarding the first type of embodiment described above, the present invention further considers three sub-embodiments. The first sub-embodiment is shown in Figure 1(a), where the width of the upper type-1 doped diamond 2-1 is designed to be the same as the width of the lower type-1 doped diamond 2-2. The second sub-embodiment is shown in Figure 1(b), where the width of the upper type-1 doped diamond 2-1 is designed to be greater than the width of the lower type-1 doped diamond 2-2. In this case, the type-1 conductive channel 7 covers the upper surface of the substrate diamond 1, a portion of the upper right surface of the upper type-1 doped diamond 2-1, and the right surface. The third sub-embodiment is shown in Figure 1(c), where the width of the upper type-1 doped diamond 2-1 is designed to be less than the width of the lower type-1 doped diamond 2-2. In this case, the type-1 conductive channel 7 covers the upper surface of the substrate diamond 1, the upper surface of a portion of the right side of the lower type-1 doped diamond 2-2, and the upper surface of a portion of the right side of the upper type-1 doped diamond 2-1 and the right surface.

[0028] The second type of implementation, for example Figure 2 As shown, the design of a type-doped diamond 2 includes a lower type-doped diamond 2-2. In the cross-sectional structure, the lower type-doped diamond 2-2 is embedded in a local segment of the type-doped diamond 2 on the upper surface of the substrate diamond 1, and the upper surface of the lower type-doped diamond 2-2 is flush with the upper surface of the substrate diamond 1. The upper surface of the lower type-doped diamond 2-2 constitutes the upper surface of the type-doped diamond 2.

[0029] Regarding the lower type I doped diamond 2-2 involved in both the first and second type embodiments mentioned above, in practical applications, the depth of the lower type I doped diamond 2-2 is further designed to be greater than the depth of the type I conductive channel 7.

[0030] The third type of implementation, for example Figure 3 As shown, the design of a type-doped diamond 2 includes an upper type-doped diamond 2-1. In the cross-sectional structure, the upper type-doped diamond 2-1 is disposed on a local section of the type-doped diamond 2 on the upper surface of the substrate diamond 1, and the upper surface of the upper type-doped diamond 2-1 constitutes the upper surface of the type-doped diamond 2.

[0031] The design involves a first electrode 4 disposed on a local segment of the upper surface of a type-1 conductive channel 7 starting from its B-side end. The first electrode 4 and the type-1 conductive channel 7 form an ohmic contact. In practical applications, it is also possible to further design any one of a metal carbide layer, a type-1 doped diamond embedded layer, or a type-1 doped diamond epitaxial layer. The type-1 doped diamond embedded layer is disposed on the type-1 conductive channel 7 at a local segment position corresponding to the lower part of the first electrode 4, and an ohmic contact is formed by the contact between the first electrode 4 and the area of ​​the type-1 doped diamond embedded layer. A metal carbide layer is disposed on a type-1 conductive channel 7 at a local segment position corresponding to the lower part of the first electrode 4, and an ohmic contact is formed between the first electrode 4 and the substrate diamond 1 through the metal carbide layer. A type-doped diamond epitaxial layer is disposed on a local segment of the upper surface of a type-conductive channel 7 corresponding to the lower part of the first electrode 4, and an ohmic contact is formed by the contact between the first electrode 4 and the type-doped diamond epitaxial layer.

[0032] In practical applications, the high-current, high-voltage diamond diodes designed above can be further improved by adding an field plate to enhance their voltage withstand capability.

[0033] For the high-current, high-voltage diamond diode designed above, in practical applications, this invention further specifies a corresponding manufacturing method, as follows: Figure 4 As shown, perform steps A through G as follows.

[0034] Step A. Grow the substrate diamond 1 using any one of the growth processes: MPCVD, HFCVD, or HTHP. The crystal orientation of the growth is including, but is not limited to, 100, 110, and 111. In practical applications, high-purity single-crystal silicon or diamond is selected, cleaned, dried, and polished. Diamond is then deposited in an H2 / CH4 atmosphere with a certain flux of N2. After deposition, in-situ annealing in H2 plasma forms the substrate diamond 1. Figure 5 As shown.

[0035] Step B. For the upper surface of the substrate diamond 1, a type I doped diamond 2, specifically p-type doped, is fabricated, with typical doping elements being B, Al, Be, etc. If the type I doped diamond 2 has a lower type I doped diamond 2-2, it is formed by ion implantation, or by using a single gas (O2, CF4, Ar, etc.) or a mixture of gases to etch trenches through reactive ion etching, electron cyclotron resonance etching, or laser etching, and then forming the lower type I doped diamond 2-2 within the trenches through secondary epitaxial growth. This process achieves the formation of the type I doped diamond 2. Figure 6 As shown; in application, ensure that the depth of the lower type I doped diamond 2-2 is greater than the depth of the type I conductive channel 7 to form good contact.

[0036] In practical applications, if the type-1 doped diamond 2 also includes an upper type-1 doped diamond 2-1, then a type-1 doped diamond is first grown on the upper surface of the lower type-1 doped diamond 2-2 through secondary epitaxial growth. Then, the excess type-1 doped diamond on the surface of the substrate diamond 1 is removed by etching or stripping processes, thereby forming an upper type-1 doped diamond 2-1 on the upper surface of the type-1 doped diamond 2-2, thus constituting a type-1 doped diamond 2 having an upper type-1 doped diamond 2-1 and a lower type-1 doped diamond 2-2. In practical applications, if the type-1 doped diamond 2 only includes the upper type-1 doped diamond 2-1, then the type-1 doped diamond is first grown on the upper surface of the substrate diamond 1 through secondary epitaxial growth, and then the excess type-1 doped diamond on the surface of the substrate diamond 1 is removed by etching or stripping processes, thereby forming the upper type-1 doped diamond 2-1 on the upper surface of the substrate diamond 1, thus constituting a type-1 doped diamond 2 that only has the upper type-1 doped diamond 2-1.

[0037] Step C. On the upper surface of the substrate diamond 1 and the exposed surface of the type-1 doped diamond 2, in an H2 plasma atmosphere, a type-1 conductive channel 7 with p-type conductivity is formed by either H-termination processing or Si-termination processing. Figure 7 As shown.

[0038] Traditional diamond SBD devices form ohmic contacts with metal by p-type heavy doping of diamond, which is difficult to process. This invention forms Schottky contacts directly with hydrogen-terminated conductive channels by depositing metal, which greatly reduces the difficulty of the process, the barrier height and the ohmic contact resistance.

[0039] Diamond terminal treatment is a surface treatment process that achieves dangling bond saturation and property control through surface atomic bond reconstruction. Commonly used terminal treatment processes can achieve surface treatment effects for various elements, including H-terminal treatment, Si-terminal treatment, O-terminal treatment, and F-terminal treatment. Specific implementation methods include plasma treatment, gas atmosphere treatment, surface deposition, and chemical reagent treatment. H-terminal treatment forms CH-C bonds, inducing surface p-type conductivity (two-dimensional hole gas) and generating negative electron affinity, achieving superior performance such as high carrier mobility and high current density. Si-terminal treatment constructs a C-Si covalent interface, providing a heterogeneous integration platform with low interface state density and high thermal conductivity transport channels, serving power electronic heat dissipation and diamond-silicon heterojunction devices. O-terminal treatment and F-terminal treatment achieve surface barrier control by adjusting the material's surface affinity. Terminal treatment processes optimize material functionality and power device performance through surface electronic structure reconstruction and interface band engineering.

[0040] Step D. Deposit metal on the upper surface of the overall device, and then use processes such as etching, wet etching, and stripping to remove the metal in a local area on the upper surface of the type I doped diamond 2, exposing the type I conductive channel 7 underneath. Then, for the exposed type I conductive channel 7 area, form a barrier adjustment layer 6 by any of the following termination processes: surface termination treatment, asymmetric deposition of high and low barrier metals, and optical modulation of Schottky barrier height.

[0041] Step E. Deposit metal on the upper surface of the conductive channel 7, then etch away the excess metal to form the first electrode 4 of the ohmic contact, as shown below. Figure 8 As shown, in practical applications, the first electrode 4 is manufactured from a material that can form an ohmic contact, such as one or more of Au, Pt, Ti, and Mo.

[0042] Step F. Deposit dielectric material on the upper surface of the entire device, then remove dielectric material from local areas on the upper surface of the first electrode 4 and the barrier adjustment layer 6 to form dielectric layer 3, such as... Figure 9 As shown.

[0043] Step G. Deposit metal on the upper surface of the overall device, then remove excess metal, and form a second electrode 5 in a local segment on the upper surface of the barrier adjustment layer 6 to realize a Schottky contact or a semiconductor heterojunction.

[0044] As shown in Figure 1(a), in practical applications, the second electrode 5 is made of a material that can form a Schottky contact or a semiconductor heterojunction with the barrier adjustment layer 6, such as Au, Ti, Al, W, etc.; and regarding the dielectric layer 3, an insulating dielectric material that can form a passivation effect is used, such as Al2O3, HfO2, Si3N4. The dielectric layer 3 with a passivation effect can effectively protect the hydrogen terminal conductive channel, prevent hydrogen desorption at high temperatures, and improve device stability; moreover, the Schottky junction capacitance can be adjusted by designing the dielectric layer thickness and dielectric constant, thereby reducing switching losses.

[0045] The core of current diamond field-effect transistor (FET) manufacturing processes heavily relies on precise surface termination treatments (such as hydrogen termination to induce two-dimensional hole gas 2DHG, or oxygen termination to achieve insulating / semi-insulating surfaces). The device manufacturing process employed in this invention, compared to the typical process of traditional diamond Schottky barrier diodes (SBDs) (which typically do not involve or rely less on such precise surface termination control), exhibits significantly higher compatibility with the aforementioned mainstream diamond FET processes in key process steps (especially surface treatment, thin film deposition, and patterning). This compatibility is reflected in the sharing of similar process modules (such as hydrogen plasma treatment, atomic layer deposition (ALD), and specific metallization processes) and material systems (such as gate dielectric, passivation layer, and ohmic contact metal). Therefore, the device structure of this invention can be seamlessly integrated into existing diamond FET manufacturing platforms without introducing disruptive process changes or additional complex steps. This significantly reduces the technical difficulty and manufacturing cost of monolithic integration of heterogeneous devices (diodes and transistors) on a single diamond wafer or chip, providing convenient conditions for constructing more functional diamond-based integrated circuits.

[0046] The high-current, high-voltage diamond diode and its manufacturing method described above have the following cross-sectional structure: a diamond substrate 1 is used as the base, and a type-doped diamond 2 is locally disposed on the upper surface of the diamond substrate 1. A type-conductive channel 7 is further arranged on the upper surface of the type-doped diamond 2 and the upper surface of the diamond substrate 1. Then, a barrier adjustment layer 6 is locally disposed in the region of the type-doped diamond 2 corresponding to the location of the type-doped diamond 2 in the type-conductive channel 7. Finally, a first electrode 4, a second electrode 5, and a dielectric layer 3 are disposed to form a diamond diode with high voltage and high current density. This solves the problems of low voltage and low current density of traditional power diamond Schottky diodes. Furthermore, a manufacturing method is proposed, and the manufacturing process sequence is innovatively designed to reduce leakage current and process difficulty. The designed diamond diode effectively improves the actual working efficiency.

[0047] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A high current high voltage diamond diode, characterized by: The cross-sectional structure of a cube that runs through its two opposite sides is as follows, or the cross-sectional structure along its radius is as follows, based on the geometry of a circular top-view projection. The structure includes a substrate diamond (1), a type-doped diamond (2), a dielectric layer (3), a first electrode (4), and a second electrode (5). The substrate diamond (1) is located at the bottom of the cross-sectional structure, and the two sides of the substrate diamond (1) are defined as side A and side B, respectively. The type-doped diamond (2) is formed on a local segment of the upper surface of the substrate diamond (1) starting from its side A end. The local segment of the upper surface of the type-doped diamond (2) starting from its side A end is processed to form a barrier adjustment layer (6). The area on the upper surface of the substrate diamond (1) where the type-doped diamond (2) is not located, as well as the exposed surface of the type-doped diamond (2), are all processed to form a barrier adjustment layer (6). A conductive channel (7) is formed; a first electrode (4) is disposed on a local section of the upper surface of the conductive channel (7) starting from its B-side end, and the first electrode (4) forms an ohmic contact with the conductive channel (7); a second electrode (5) is disposed on a local section of the upper surface of the barrier adjustment layer (6) starting from its A-side end, and the second electrode (5) forms a Schottky contact or a semiconductor heterojunction with the barrier adjustment layer (6); a dielectric layer (3) covers the upper surface of the barrier adjustment layer (6) and the upper surface of the conductive channel (7) disposed between the first electrode (4) and the second electrode (5), and the two sides of the dielectric layer (3) are respectively connected to the first electrode (4) and the second electrode (5) facing it. If the geometry is a circular top-view projection, the side of the cross-section structure corresponding to side A corresponds to the center of the circular top-view projection, and the side of the cross-section structure corresponding to side B corresponds to the outer perimeter of the circular top-view projection. Type I doped diamond (2) includes an upper type I doped diamond (2-1) and a lower type I doped diamond (2-2) made of the same material. In the cross-sectional structure, the lower type I doped diamond (2-2) is embedded in a local section of the type I doped diamond (2) on the upper surface of the substrate diamond (1), and the upper surface of the lower type I doped diamond (2-2) is flush with the upper surface of the substrate diamond (1). The upper type I doped diamond (2-1) is set on the upper surface of the lower type I doped diamond (2-2), and the end of the upper type I doped diamond (2-1) corresponding to side A is flush with the end of the lower type I doped diamond (2-2) corresponding to side A in the vertical direction. The upper surface of the upper type I doped diamond (2-1) constitutes the upper surface of the type I doped diamond (2).

2. The high current high voltage diamond diode according to claim 1, wherein: The type-1 doped diamond (2) includes a lower type-1 doped diamond (2-2). In the cross-sectional structure, the lower type-1 doped diamond (2-2) is embedded in a local segment of the type-1 doped diamond (2) on the upper surface of the substrate diamond (1), and the upper surface of the lower type-1 doped diamond (2-2) is flush with the upper surface of the substrate diamond (1). The upper surface of the lower type-1 doped diamond (2-2) constitutes the upper surface of the type-1 doped diamond (2).

3. The high-current high-voltage diamond diode according to claim 1 or 2, characterized in that: The depth of the lower type I doped diamond (2-2) is greater than the depth of the type I conductive channel (7).

4. The high-current, high-voltage diamond diode according to claim 1, characterized in that: The type-doped diamond (2) includes an upper type-doped diamond (2-1). In the cross-sectional structure, the upper type-doped diamond (2-1) is disposed on a local section of the type-doped diamond (2) on the upper surface of the substrate diamond (1), and the upper surface of the upper type-doped diamond (2-1) constitutes the upper surface of the type-doped diamond (2).

5. The high-current, high-voltage diamond diode according to claim 1, characterized in that: It also includes any one of the following: metal carbide layer, type I doped diamond embedded layer, and type I doped diamond epitaxial layer; Among them, a type-doped diamond embedding layer is disposed on a type-conductive channel (7) at a local segment position corresponding to the first electrode (4), and an ohmic contact is formed by the first electrode (4) and the type-doped diamond embedding layer region. A metal carbide layer is disposed on a type-1 conductive channel (7) at a local segment position corresponding to the first electrode (4), and an ohmic contact is formed between the first electrode (4) and the substrate diamond (1) through the metal carbide layer. A type-doped diamond epitaxial layer is disposed on the upper surface of a type-conductive channel (7) at a local segment position corresponding to the first electrode (4), and an ohmic contact is formed by the contact between the first electrode (4) and the type-doped diamond epitaxial layer.

6. A method for manufacturing a high-current, high-voltage diamond diode as described in claim 1 or 2, characterized in that, Includes the following steps: Step A. Growing diamond substrate (1); Step B. On the upper surface of the substrate diamond (1), a type-doped diamond (2) is generated. Step C. For the upper surface of the substrate diamond (1) and the exposed surface of the type-doped diamond (2), a terminal treatment is performed to form a type-conductive channel (7). Step D. Deposit metal on the upper surface of the overall device, then remove the metal in a local area on the upper surface of the type-1 doped diamond (2) to expose the underlying type-1 conductive channel (7), and then perform a termination process on the exposed type-1 conductive channel (7) area to form a barrier conditioning layer (6). Step E. Deposit metal on the upper surface of a type-1 conductive channel (7), and then etch the excess metal to form the first electrode (4) of the ohmic contact. Step F. Deposit dielectric on the upper surface of the entire device, and then remove dielectric from the local area of ​​the upper surface of the first electrode (4) and the barrier adjustment layer (6) to form a dielectric layer (3). Step G. Deposit metal on the upper surface of the overall device, then remove excess metal, and form a second electrode (5) on a local segment of the upper surface of the barrier adjustment layer (6) to realize Schottky contact or semiconductor heterojunction.

7. The method for manufacturing a high-current, high-voltage diamond diode according to claim 6, characterized in that: In step B, based on the upper surface of the substrate diamond (1), a lower layer of type I doped diamond (2-2) is formed by ion implantation, thereby realizing the generation of type I doped diamond (2); Alternatively, trenches can be etched on the upper surface of the substrate diamond (1), and a lower layer of type-1 doped diamond (2-2) can be formed in the trenches through secondary epitaxial growth, thereby realizing the generation of type-1 doped diamond (2).

8. The method for manufacturing a high-current, high-voltage diamond diode according to claim 7, characterized in that: In step A, the growth process of the substrate diamond (1) is any one of MPCVD, HFCVD, and HTHP, and the growth crystal orientation includes, but is not limited to, 100, 110, and 111. The etching of the trenches on the upper surface of the diamond substrate (1) is any one of reactive ion etching, electron cyclotron resonance etching, and laser etching; the terminal processing technology of the type-1 conductive channel (7) is any one of H terminal processing technology and Si terminal processing technology. The terminal treatment of the barrier adjustment layer (6) is any one of surface terminal treatment, asymmetric deposition treatment of high and low barrier metals, or optical modulation of Schottky barrier height treatment.

9. The method for manufacturing a high-current, high-voltage diamond diode according to claim 6, characterized in that: The type-1 doped diamond (2) is p-type doped; the type-1 conductive channel (7) is p-type conductive; the first electrode (4) is a material capable of forming an ohmic contact; the second electrode (5) is a material capable of forming a Schottky contact or a semiconductor heterojunction with the barrier adjustment layer (6); the dielectric layer (3) is an insulating dielectric material capable of forming a passivation effect.

Images