Schottky device and method of making the same

Abstract

The application provides a Schottky device and a manufacturing method thereof. The manufacturing method comprises the following steps: providing a substrate, the substrate comprising a first region and a second region; performing a cleaning treatment on the substrate to remove the oxide on the surface of the substrate; performing a plasma treatment on the surface of the substrate to form a silicon oxynitride barrier layer, the gas used in the plasma treatment comprising dinitrogen monoxide, and the silicon oxynitride barrier layer covering at least the first region; forming a metal layer on the substrate, the metal layer covering the first region; and performing a heat treatment on the substrate, so that the metal in the metal layer reacts with the silicon in the substrate to form a metal silicide. The silicon oxynitride barrier layer formed between the metal layer and the substrate by the plasma treatment can reduce the reverse leakage current of the Schottky device, passivate the interface defects and improve the barrier uniformity.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, and in particular to a Schottky device and a method for fabricating the same. Background Technology

[0002] Schottky devices are semiconductor devices that achieve unidirectional conductivity by utilizing the Schottky barrier formed by the metal-semiconductor contact, providing low forward voltage drop and ultra-fast switching speeds. However, a drawback of Schottky devices is their relatively large reverse leakage current. Therefore, existing Schottky devices and their fabrication methods still require improvement. Summary of the Invention

[0003] One of the purposes of this application is to provide a Schottky device and a method for fabricating the same, which can reduce the reverse leakage current of the Schottky device.

[0004] To achieve the above objectives, this application provides a method for fabricating a Schottky device. The method includes: providing a substrate comprising a first region and a second region; cleaning the substrate to remove oxides from its surface; performing plasma treatment on the substrate surface to form a silicon oxynitride barrier layer, wherein the plasma treatment uses a gas including nitrous oxide, and the silicon oxynitride barrier layer at least covers the first region; forming a metal layer on the substrate, the metal layer covering the first region; and performing heat treatment on the substrate, wherein the metal in the metal layer reacts with silicon in the substrate to form a metal silicide.

[0005] Optionally, the plasma treatment uses a time greater than or equal to 20s and less than or equal to 30s, a frequency greater than or equal to 10MHz and less than or equal to 15MHz, a power greater than or equal to 300W and less than or equal to 600W, and a nitrous oxide flow rate greater than or equal to 20SCCM and less than or equal to 40SCCM.

[0006] Optionally, the thickness of the silicon oxynitride barrier layer is greater than or equal to 0.5 nm and less than or equal to 1.5 nm.

[0007] Optionally, the material of the metal layer includes cobalt.

[0008] Optionally, the step of providing a substrate includes: forming a deep well of a first conductivity type on top of the substrate of a second conductivity type, the deep well covering the first region and the second region; forming an isolation structure in the substrate, the isolation structure being located in the deep well and separating the first region and the second region; and forming a heavily doped region of the first conductivity type on top of the substrate of the second region, the heavily doped region being located on top of the deep well.

[0009] Optionally, the method of forming a metal layer on the substrate includes: depositing a metal material layer on the substrate, the metal material layer covering the first region and the second region; forming a patterned mask layer on the metal material layer, the patterned mask layer covering the first region and exposing the second region; using the patterned mask layer as a mask, etching away the metal material layer of the second region, retaining the metal material layer of the first region as the metal layer.

[0010] Optionally, after forming a metal layer on the substrate and before heat treating the substrate, a protective layer is formed on the metal layer, the protective layer covering the metal layer.

[0011] Optionally, the method of heat-treating the substrate to form a metal silicide includes: performing a first heat treatment on the substrate, wherein a portion of the metal in the metal layer reacts with silicon in the substrate to form a first metal silicide; removing the metal in the metal layer that has not reacted with silicon; and performing a second heat treatment on the substrate, wherein the first metal silicide is transformed into a second metal silicide; wherein the temperature of the first heat treatment is lower than the temperature of the second heat treatment, and the impedance of the first metal silicide is greater than the impedance of the second metal silicide.

[0012] Optionally, the first region is used to form a Schottky junction, and the second region is used to form an ohmic contact.

[0013] This application also provides a Schottky device. The Schottky device is fabricated using the above-described method for fabricating a Schottky device, comprising: a substrate including a first region and a second region; a metal silicide located in the first region and on the substrate; and a silicon oxynitride barrier layer located at least between the metal silicide and the substrate.

[0014] The Schottky device and its fabrication method provided in this application include a substrate comprising a first region and a second region; the substrate is cleaned to remove oxides from its surface; the substrate surface is subjected to plasma treatment to form a silicon oxynitride barrier layer, wherein the plasma treatment uses nitrous oxide as the gas, and the silicon oxynitride barrier layer at least covers the first region; a metal layer is formed on the substrate, the metal layer covering the first region; and the substrate is heat-treated, wherein the metal in the metal layer reacts with the silicon in the substrate to form a metal silicide. In this application, nitrous oxide gas can release oxygen and nitrogen free radicals under ultra-vacuum conditions, which break Si-Si and Si-H bonds to generate an ultrathin silicon oxynitride barrier layer. The silicon oxynitride barrier layer can physically block the rapid diffusion channels of metals such as cobalt atoms in the metal layer, suppress cobalt spikes, force the silicide reaction to proceed uniformly and laterally at the interface, effectively protect the integrity of the shallow junction below the barrier layer, reduce the reverse leakage current of the Schottky device, and improve the consistency of forward conduction; in addition, nitrogen and oxygen free radicals can fill the substrate surface. The dangling bonds form dense and strong Si-N or Si-O bonds, which can effectively reduce interface defects and interface state density (Dit). This can passivate interface defects, improve barrier uniformity, and enhance the degree of freedom in adjusting the barrier. Furthermore, the nitrogen free radicals accumulate on the substrate surface to form a nitrogen-rich silicon oxynitride barrier layer, which can significantly improve the thermal stability of the interface between the metal layer and the substrate during heat treatment processes. This helps to prevent chemical corrosion of the substrate during wet etching to remove metals that have not reacted with silicon, and thus helps to improve the performance of Schottky devices. Attached Figure Description

[0015] Figures 1 to 3 This is a schematic diagram of the fabrication process of a Schottky device.

[0016] Figure 4 A flowchart illustrating a method for fabricating a Schottky device according to an embodiment of this application.

[0017] Figures 5 to 11 This is a step-by-step structural diagram of a method for fabricating a Schottky device according to an embodiment of this application.

[0018] Figure 12 This is an IV curve diagram of a Schottky device in the related technology for which no barrier layer is formed between the metal silicide and the substrate.

[0019] Figure 13 For this application Figure 11 The diagram shows the IV curve of the Schottky device.

[0020] Explanation of reference numerals in the attached figures: 10-substrate; 11-oxide; 12-cobalt metal layer; 13-cobalt silicide; 100-substrate; 100a-first region; 100b-second region; 101-deep well; 102-isolation structure; 103-oxide; 104-heavily doped region; 105-silicon oxynitride barrier layer; 106a-metal material layer; 106-metal layer; 107-metal silicide. Detailed Implementation

[0021] Cobalt silicides (especially cobalt disilicide, CoSi2) are among the most studied and widely used materials in silicon-based Schottky devices. They offer significant advantages in high-frequency and high-speed integrated circuits, and are particularly favored due to their perfect compatibility with CMOS processes.

[0022] Figures 1 to 3 This is a schematic diagram illustrating the fabrication process of a Schottky device. The traditional fabrication process for a Schottky device includes: Figure 1 As shown, the oxide 11 on the substrate 10 is removed; as Figure 2 As shown, a cobalt metal layer 12 is deposited on the substrate 10; as Figure 3 As shown, the substrate 10 is heat-treated, and the cobalt in the cobalt metal layer 12 reacts with the silicon in the substrate 10 to form cobalt silicide 13. However, during the heat treatment process, cobalt atoms can easily penetrate through the shallow junction and enter the substrate 10 to form cobalt spikes, which can introduce traps in the depletion region, leading to a sharp increase in reverse leakage current. In addition, after the cobalt silicide 13 reacts with silicon, there is a "Fermi level pinning" effect at the interface, and the barrier height is almost constant in the range of 300-600°C, which limits the degree of freedom to adjust the barrier through the process.

[0023] Therefore, in the Schottky device and its fabrication method provided in this application, before depositing the metal layer, a plasma treatment is performed on the substrate surface using a reactive gas including nitrous oxide to form a silicon oxynitride barrier layer on the substrate surface. This silicon oxynitride barrier layer can physically block the rapid diffusion channels of metals such as cobalt atoms in the metal layer, suppressing cobalt spikes and forcing the silicide reaction to proceed uniformly and laterally at the interface. This effectively protects the integrity of the shallow junction beneath the barrier layer, reduces the reverse leakage current of the Schottky device, and improves the consistency of forward conduction. Furthermore, the nitrogen and oxygen free radicals released by nitrous oxide... Nitrogen radicals can fill dangling bonds on the substrate surface, forming dense and strong Si-N or Si-O bonds, which can effectively reduce interface defects and interface state density (Dit). This can passivate interface defects, improve barrier uniformity, and enhance the degree of freedom in adjusting the barrier. Furthermore, nitrogen radicals accumulate on the substrate surface and form a nitrogen-rich silicon oxynitride barrier layer, which can significantly improve the thermal stability of the interface between the metal layer and the substrate during heat treatment processes. This helps to prevent chemical corrosion of the substrate during wet etching to remove unreacted metals, thus improving the performance of Schottky devices.

[0024] The present application will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present application will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present application.

[0025] As used herein, the singular forms “a,” “an,” and “the” include plural objects unless otherwise expressly indicated. As used herein, the term “or” is generally used to include “and / or” unless otherwise expressly indicated. As used herein, the term “a number” is generally used to include “at least one” unless otherwise expressly indicated. As used herein, the term “at least two” is generally used to include “two or more” unless otherwise expressly indicated. Furthermore, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as “first,” “second,” or “third” may explicitly or implicitly include one or at least two of that feature, unless otherwise expressly indicated.

[0026] Figure 4 A flowchart illustrating a method for fabricating a Schottky device according to an embodiment of this application. (See reference...) Figure 4 As shown, the method for fabricating a Schottky device provided in this embodiment includes:

[0027] Step S1, providing a substrate, the substrate comprising a first region and a second region;

[0028] Step S2: Clean the substrate to remove oxides from the substrate surface;

[0029] Step S3: Plasma treatment is performed on the surface of the substrate to form a silicon oxynitride barrier layer. The gas used in the plasma treatment includes nitrous oxide. The silicon oxynitride barrier layer at least covers the first region.

[0030] Step S4, forming a metal layer on the substrate, the metal layer covering the first region; and

[0031] Step S5: The substrate is subjected to heat treatment, and the metal in the metal layer reacts with the silicon in the substrate to form metal silicide.

[0032] Figures 5 to 11 This is a step-by-step structural diagram illustrating a method for fabricating a Schottky device according to an embodiment of this application. The following is in conjunction with... Figure 4 , Figures 5 to 11 The method for fabricating the Schottky device of this application is described.

[0033] refer to Figure 5 As shown, in step S1, a substrate 100 is provided, the substrate 100 including a first region 100a and a second region 100b. The first region 100a can be used to form a Schottky junction, and the second region 100b can be used to form an ohmic contact.

[0034] The substrate 100 may be made of silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbide (SiC), silicon germanium carbide (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP), or other III / V compound semiconductors, and may also include multilayer structures composed of these semiconductors, or may be silicon on insulator (SOI), silicon on insulator (SSOI), silicon on insulator (S-SiGeOI), silicon on insulator (SiGeOI), and germanium on insulator (GeOI).

[0035] For example, the step of providing substrate 100 may further include: referring to Figure 5 As shown, a deep well 101 of a first conductivity type is formed on top of the substrate 100 of the second conductivity type, the deep well 101 covering the first region 100a and the second region 100b; an isolation structure 102 is formed in the substrate 100, the isolation structure 102 is located in the deep well 101, and the isolation structure 102 separates the first region 100a and the second region 100b; as Figure 6 As shown, a heavily doped region 104 of a first conductivity type is formed on the top of the substrate in the second region 100b, and the heavily doped region 104 is located on top of the deep well 101.

[0036] In this embodiment, the first conductivity type is N-type, the second conductivity type is P-type, the substrate 100 can be a P-type substrate, the deep well 101 is a deep N-well, and the heavily doped region 104 can be an N+ implantation region, with the doping concentration of the heavily doped region 104 being greater than the doping concentration of the deep well 101. In other embodiments, the first conductivity type can also be P-type, and the second conductivity type can be N-type.

[0037] In this embodiment, both the deep well 101 and the heavily doped region 104 can be formed by ion implantation, for example by implanting dopants such as phosphorus (P), arsenic (As) or antimony (Sb) into the substrate 100.

[0038] In this embodiment, the isolation structure 102 can be a shallow trench isolation (STI) or a localized field oxidation isolation (LOCOS). The isolation structure 102 can improve the isolation effect between the first region 100a and the second region 100b. In other embodiments, the isolation structure 102 may not be provided between the first region 100a and the second region 100b.

[0039] Taking the shallow trench isolation structure 102 as an example, the method for forming the isolation structure 102 may include: forming a patterned mask layer on a substrate 100, the patterned mask layer defining the formation area of ​​the isolation structure 102; using the patterned mask layer as a mask, etching the substrate 100 and stopping in the substrate 100 to form a shallow trench; depositing an isolation material on the substrate 100, the isolation material covering the substrate 100 and filling the shallow trench; grinding to remove the isolation material on the top surface of the substrate while retaining the isolation material in the shallow trench, thus forming the isolation structure 102. The patterned mask layer may be a photoresist layer or a hard mask layer including silicon oxide or silicon nitride.

[0040] refer to Figure 5 and Figure 6 As shown, before depositing a metal layer on the substrate 100, the surface of the substrate 100 has an oxide 103. The oxide 103 can be silicon oxide formed by the natural oxidation of the substrate 100, or it can be other oxide materials.

[0041] refer to Figure 7 As shown, in step S2, the substrate 100 is cleaned to remove the oxide 103 on the surface of the substrate 100.

[0042] In this embodiment, the oxide 103 on the surface of the substrate 100 can be removed by a wet etching process. This method of removing oxide 103 does not easily damage the surface of the substrate 100 and can make the surface of the substrate 100 flat, which helps to reduce the leakage current of the Schottky device, improve the breakdown voltage (BV) characteristics of the Schottky device, and improve the BV uniformity of multiple Schottky devices on the wafer. In addition, impurities on the surface of the substrate 100 can also be removed during the cleaning process.

[0043] refer to Figure 8 As shown, in step S3, the surface of the substrate 100 is subjected to plasma treatment to form a silicon oxynitride barrier layer 105. The gas used in the plasma treatment includes nitrous oxide (N2O).

[0044] In the ultra-vacuum environment of the plasma device (i.e., the plasma device) and under the action of the electrodes, nitrous oxide gas can release oxygen free radicals and nitrogen free radicals, which will break the Si-Si bonds and Si-H bonds on the surface of the substrate 100 and generate an ultra-thin silicon oxynitride barrier layer 105.

[0045] It should be noted that after cleaning the substrate 100, the wafer can be immediately sent into a plasma device for plasma treatment to form a silicon oxynitride barrier layer 105, or it can be cleaned in situ using radio frequency plasma in a plasma device to ensure that the substrate surface is clean and to avoid the influence of residual oxides on the device barrier uniformity, which is beneficial to improving the device barrier uniformity.

[0046] It should be noted that if the thickness of the silicon oxynitride barrier layer 105 is too thin, such as less than 0.5 nm, it will not effectively block the diffusion of metals such as cobalt atoms; if the thickness of the silicon oxynitride barrier layer 105 is too thick, such as greater than 2 nm, it will become a high-resistance tunneling barrier, increasing the series resistance of the device. Therefore, the thickness of the silicon oxynitride barrier layer 105 needs to be precisely controlled within the critical thickness range of "penetration". In this embodiment, the thickness of the silicon oxynitride barrier layer 105 can be greater than or equal to 0.5 nm and less than or equal to 1.5 nm. This thickness of the silicon oxynitride barrier layer 105 can both prevent the diffusion of metals such as cobalt atoms in the metal layer into the substrate in subsequent processes and avoid becoming a high-resistance tunneling barrier, thus not significantly increasing the series resistance of the device.

[0047] For example, the plasma treatment uses a time greater than or equal to 20 seconds and less than or equal to 30 seconds, a frequency greater than or equal to 10 MHz and less than or equal to 15 MHz, a power greater than or equal to 300 W and less than or equal to 600 W, and a nitrous oxide flow rate greater than or equal to 20 SCCM and less than or equal to 40 SCCM. This allows for precise control of the thickness of the silicon oxynitride barrier layer 105, for example, meeting the requirement of a thickness greater than or equal to 0.5 nm and less than or equal to 1.5 nm. In this embodiment, the plasma treatment uses a time of 25 seconds, a frequency of 13.56 MHz, a power of 350 W, and a nitrous oxide flow rate of 30 SCCM. In other embodiments, the plasma treatment parameters can be adjusted as needed.

[0048] refer to Figure 8 As shown, in step S3 of this embodiment, the silicon oxynitride barrier layer 105 covers the exposed top surface of the substrate 100, and can cover the first region 100a and the second region 100b.

[0049] refer to Figure 10 As shown, in step S4, a metal layer 106 is formed on the substrate 100, and the metal layer 106 covers the first region 100a, that is, the metal layer 106 is located in the first region 100a.

[0050] Specifically, the method for forming a metal layer 106 on the substrate 100 may include: referring to Figure 9As shown, a metal material layer 106a is deposited on a substrate 100, the metal material layer 106a covering the first region 100a and the second region 100b; a patterned mask layer is formed on the metal material layer 106a, the patterned mask layer covering the first region 100a and exposing the second region 100b; using the patterned mask layer as a mask, the metal material layer of the second region 100b is etched away, retaining the metal material layer of the first region 100a as the metal layer 106. The metal layer 106 may laterally cover a portion of the top surface of the isolation structure 102, but is not limited to this.

[0051] In this embodiment, the material of the metal layer 106 includes cobalt (Co). Cobalt and silicon in the substrate 100 can react to form cobalt silicide, particularly cobalt disilicide (CoSi2). CoSi2 can form a lower barrier height on the substrate 100, thereby achieving a lower turn-on voltage and a higher forward current, which is beneficial for the application of Schottky devices in low-voltage radio frequency fields. Of course, the material of the metal layer 106 is not limited to cobalt.

[0052] In step S4, removing the metal material in the second region 100b while retaining the metal material in the first region 100a can provide a basis for the subsequent self-aligned generation of metal silicides.

[0053] In this embodiment, after forming the metal material layer 106a and before etching the metal material layer of the second region 100b, a protective layer can be formed on the metal material layer 106a. The protective layer can protect the underlying metal layer 106a during subsequent heat treatment. For example, the material of the protective layer includes, but is not limited to, titanium nitride (TiN).

[0054] In this embodiment, a wet etching process can be used to remove the metal material layer 106a of the second region 100b, but it is not limited to this.

[0055] refer to Figure 11 As shown, in step S5, the substrate 100 is heat-treated, and the metal in the metal layer 106 reacts with the silicon in the substrate 100 to form a metal silicide 107.

[0056] The metal silicide 107 includes, but is not limited to, cobalt silicide. During the heat treatment process, the silicon oxynitride barrier layer 105 physically blocks the rapid diffusion channels of metals such as cobalt atoms in the metal layer 106, suppressing cobalt spikes and forcing the silicide reaction to proceed uniformly and laterally at the interface. This effectively protects the integrity of the shallow junction beneath the silicon oxynitride barrier layer 105, reduces the reverse leakage current of the Schottky device, and improves the consistency of forward conduction. It should be noted that during the heat treatment process, silicon in the substrate 100 can pass through the silicon oxynitride barrier layer 105 and diffuse to the contact interface between the silicon oxynitride barrier layer 105 and the metal layer 106, reacting with the metal in the metal layer 106 to form metal silicides.

[0057] For example, a method for heat-treating the substrate 100 to form a metal silicide 107 may include: performing a first heat treatment on the substrate 100, wherein a portion of the metal in the metal layer 106 reacts with silicon in the substrate 100 to form a first metal silicide; removing the protective layer and the metal in the metal layer 106 that has not reacted with silicon; performing a second heat treatment on the substrate 100, wherein the first metal silicide is transformed into a second metal silicide; wherein the temperature of the first heat treatment is lower than the temperature of the second heat treatment, and the impedance of the first metal silicide is greater than the impedance of the second metal silicide.

[0058] For example, the first metal silicide can be cobalt monosilicide (CoSi), and the second metal silicide can be cobalt disilicide (CoSi2). Compared with cobalt monosilicide, cobalt disilicide has better thermal stability and lower resistivity.

[0059] The temperature of the first heat treatment can be greater than or equal to 500°C and less than or equal to 600°C, and the temperature of the second heat treatment can be greater than or equal to 700°C and less than or equal to 900°C. By combining high-temperature heat treatment and low-temperature heat treatment, metal silicide 107 with better thermal stability and lower resistivity can be obtained. In this embodiment, the temperature of the first heat treatment is 550°C, and the temperature of the second heat treatment is 750°C.

[0060] In this embodiment, a selective wet etching process can be used to remove the metal in the metal layer 106 that has not reacted with silicon. The silicon oxynitride barrier layer 105 can prevent chemical corrosion of the substrate during the wet etching process that removes part of the metal (i.e., the metal that has not reacted with silicon), which helps to improve the performance of the Schottky device.

[0061] In this embodiment, the metal silicide 107 in the first region 100a is an anode metal and forms a Schottky contact with the substrate 100.

[0062] After the metal silicide 107 is formed, the silicon oxynitride barrier layer 105 on the second region 100b can be removed.

[0063] Subsequently, a dielectric layer (not shown) is formed on the substrate 100. The dielectric layer may have a first conductive structure and a second conductive structure. The first conductive structure is located in a first region 100a and is electrically connected to the metal silicide 107. The second conductive structure is located in a second region 100b and is electrically connected to the heavily doped region 104.

[0064] Figure 12 This is an IV curve diagram of a Schottky device in the related technology for which no barrier layer is formed between the metal silicide and the substrate. Figure 13 For this application Figure 11 The diagram shows the IV curve of the Schottky device. The related art provides Schottky devices and this application. Figure 11 The only difference in the provided Schottky devices is that this application Figure 11 A silicon oxynitride barrier layer 105, with a thickness of 1 nm, is disposed between the metal silicide 107 and the substrate 100 in the provided Schottky device. (Comparison) Figure 12 and Figure 13 It is known that the reverse leakage current of the Schottky device fabricated in this application can be reduced by 1 to 2 orders of magnitude under rated voltage, and the effect of improving the reverse leakage current of the Schottky device is obvious; that is, before forming the metal layer 106, this application performs plasma treatment on the surface of the substrate 100 to form a silicon oxynitride barrier layer 105, which can reduce the reverse leakage current of the Schottky device.

[0065] This application also provides a Schottky device, which can be fabricated using the above-described method for fabricating a Schottky device. (Reference) Figure 11 As shown, the Schottky device includes a substrate 100, a metal silicide 107, and a silicon oxynitride barrier layer 105; the substrate 100 includes a first region 100a and a second region 100b; the metal silicide 107 is located in the first region 100a and on the substrate 100; the silicon oxynitride barrier layer 105 is located at least between the metal silicide 107 and the substrate 100.

[0066] The Schottky device and its fabrication method provided in this application include a substrate 100 comprising a first region 100a and a second region 100b; the substrate 100 is cleaned to remove oxides 103 from its surface; the surface of the substrate 100 is subjected to plasma treatment to form a silicon oxynitride barrier layer 105, wherein the gas used in the plasma treatment includes nitrous oxide, and the silicon oxynitride barrier layer 105 at least covers the first region 100a; a metal layer 106 is formed on the substrate 100, the metal layer 106 covering the first region 100a; and the substrate 100 is heat-treated, wherein the metal in the metal layer 106 reacts with the silicon in the substrate to form a metal silicide. In this application, nitrous oxide gas can release oxygen and nitrogen free radicals under ultra-vacuum conditions, breaking Si-Si and Si-H bonds to generate an ultrathin silicon oxynitride barrier layer 105. The silicon oxynitride barrier layer 105 physically blocks the rapid diffusion channels of metals such as cobalt atoms in the metal layer 106, suppressing cobalt spikes and forcing the silicide reaction to proceed uniformly and laterally at the interface. This effectively protects the integrity of the shallow junction beneath the barrier layer, reduces the reverse leakage current of the Schottky device, and improves the consistency of forward conduction. Furthermore, nitrogen and oxygen free radicals can fill the substrate surface... The dangling bonds form dense and strong Si-N or Si-O bonds, which can effectively reduce interface defects and interface state density (Dit). This can passivate interface defects, improve barrier uniformity, and enhance the degree of freedom in adjusting the barrier. Furthermore, the nitrogen free radicals accumulate on the substrate surface to form a nitrogen-rich silicon oxynitride barrier layer 105, which can significantly improve the thermal stability of the interface between the metal layer 106 and the substrate 100 during the heat treatment process. This helps to prevent chemical corrosion of the substrate during wet etching to remove metals that have not reacted with silicon, and helps to improve the performance of Schottky devices.

[0067] It should be noted that this instruction manual uses a progressive approach, with later descriptions focusing on the differences from earlier descriptions. Similarities and similarities between different sections can be found by referring to each other.

[0068] The above description is merely a description of preferred embodiments of this application and is not intended to limit the scope of the claims of this application. Any person skilled in the art can make possible changes and modifications to the technical solutions of this application by utilizing the methods and techniques disclosed above without departing from the spirit and scope of this application. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall fall within the protection scope of the technical solutions of this application.

Claims

1. A method for fabricating a Schottky device, characterized in that, include: A substrate is provided, the substrate comprising a first region and a second region; The substrate is cleaned to remove oxides from its surface; The substrate surface is subjected to plasma treatment to form a silicon oxynitride barrier layer, wherein the gas used in the plasma treatment includes nitrous oxide, and the silicon oxynitride barrier layer at least covers the first region; A metal layer is formed on the substrate, the metal layer covering the first region; and The substrate is subjected to heat treatment, and the metal in the metal layer reacts with the silicon in the substrate to form a metal silicide.

2. The method for fabricating a Schottky device as described in claim 1, characterized in that, The plasma treatment uses a time greater than or equal to 20s and less than or equal to 30s, a frequency greater than or equal to 10MHz and less than or equal to 15MHz, a power greater than or equal to 300W and less than or equal to 600W, and a nitrous oxide flow rate greater than or equal to 20SCCM and less than or equal to 40SCCM.

3. The method for fabricating a Schottky device as described in claim 1, characterized in that, The thickness of the silicon oxynitride barrier layer is greater than or equal to 0.5 nm and less than or equal to 1.5 nm.

4. The method for fabricating a Schottky device as described in claim 1, characterized in that, The material of the metal layer includes cobalt.

5. The method for fabricating a Schottky device as described in claim 1, characterized in that, The steps for providing the substrate include: A deep well of a first conductivity type is formed on top of the substrate of the second conductivity type, the deep well covering the first region and the second region; An isolation structure is formed in the substrate, the isolation structure being located within the deep well, and the isolation structure separating the first region and the second region; and A heavily doped region of a first conductivity type is formed on top of the substrate in the second region, the heavily doped region being located at the top of the deep well.

6. The method for fabricating a Schottky device as described in claim 1, characterized in that, The method of forming a metal layer on the substrate includes: A metal material layer is deposited on the substrate, the metal material layer covering the first region and the second region; A patterned mask layer is formed on the metal material layer, the patterned mask layer covering the first region and exposing the second region; Using the patterned mask layer as a mask, the metal material layer of the second region is etched away, while the metal material layer of the first region is retained as the metal layer.

7. The method for fabricating a Schottky device as described in claim 1, characterized in that, After a metal layer is formed on the substrate and before the substrate is heat-treated, a protective layer is formed on the metal layer, the protective layer covering the metal layer.

8. The method for fabricating a Schottky device as described in claim 1, characterized in that, A method for heat-treating the substrate to form a metal silicide includes: The substrate is subjected to a first heat treatment, during which a portion of the metal layer reacts with the silicon in the substrate to form a first metal silicide; Remove the metal from the metal layer that has not reacted with silicon; The substrate is subjected to a second heat treatment, during which the first metal silicide is transformed into a second metal silicide; Wherein, the temperature of the first heat treatment is lower than the temperature of the second heat treatment, and the impedance of the first metal silicide is greater than the impedance of the second metal silicide.

9. The method for manufacturing a Schottky device as described in any one of claims 1 to 8, characterized in that, The first region is used to form a Schottky junction, and the second region is used to form an ohmic contact.

10. A Schottky device, characterized in that, The device is manufactured using the method for fabricating a Schottky device as described in any one of claims 1 to 9, comprising: A substrate, the substrate comprising a first region and a second region; Metal silicide, the metal silicide being located in the first region and on the substrate; and A silicon oxynitride barrier layer, wherein the silicon oxynitride barrier layer is located at least between the metal silicide and the substrate.

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