Schottky diode, manufacturing method and chip

Abstract

This application belongs to the field of semiconductor technology and provides a Schottky diode, its fabrication method, and a chip. The Schottky diode includes: a semiconductor substrate, a channel layer, a first barrier layer, a second barrier layer, a first P-pillar, a second P-pillar, a cathode electrode unit, and an anode electrode unit. By setting the anode electrode unit to Schottky metal and making it contact with the first P-pillar and the second P-pillar, a Schottky contact is formed between the anode electrode unit and the first P-pillar, and between the anode electrode unit and the second P-pillar. This results in a high Schottky barrier height between the anode electrode unit and the first P-pillar and the second P-pillar, thereby reducing the leakage current of the anode electrode unit, providing a higher forward threshold voltage, and thus improving the breakdown voltage of the Schottky diode.

Description

Technical Field

[0001] This application belongs to the field of semiconductor technology, and in particular relates to a Schottky diode, its fabrication method, and a chip. Background Technology

[0002] As a high-tech industry, the electronics and information industry plays an increasingly important role in expanding social employment, promoting economic transformation and upgrading, enhancing international competitiveness, and safeguarding national security. Power diodes are key components of circuit systems and are now widely used in civilian products such as high-frequency inverters, digital products, generators, and televisions, as well as in military applications such as satellite receivers, missile and aircraft control systems, and instrumentation equipment.

[0003] Commonly used diodes include ordinary rectifier diodes, Schottky diodes, and PN diodes. Among them, Schottky rectifier diodes are widely used due to their advantages such as low on-state voltage drop, large leakage current, and almost zero reverse recovery time.

[0004] Schottky diodes are diodes made using the principle of a metal-semiconductor junction formed by the contact between a metal and a semiconductor. Compared to PN junction diodes, Schottky diodes offer advantages such as lower power consumption, higher current output, and ultra-high speed, making them popular in electronic devices.

[0005] However, existing Schottky diodes suffer from low breakdown voltage. Summary of the Invention

[0006] To address the aforementioned technical problems, this application provides a Schottky diode, its fabrication method, and a chip, aiming to solve the problem of low breakdown voltage in existing Schottky diodes.

[0007] A first aspect of this application provides a Schottky diode, the Schottky diode comprising:

[0008] Semiconductor substrate;

[0009] A channel layer is disposed on the semiconductor substrate;

[0010] A first barrier layer is disposed on the semiconductor substrate and is in contact with the first surface of the channel layer;

[0011] A second barrier layer is disposed on the semiconductor substrate and is in contact with the second surface of the channel layer;

[0012] A first P-pillar is disposed on the semiconductor substrate, and a first barrier layer is disposed between the first P-pillar and the channel layer;

[0013] A second P-pillar is disposed on the semiconductor substrate, and a second barrier layer is disposed between the second P-pillar and the channel layer;

[0014] A cathode electrode unit is disposed on the semiconductor substrate, and the cathode electrode unit is in contact with the first end of the channel layer, the first end of the first barrier layer and the first end of the second barrier layer, respectively.

[0015] An anode electrode unit is L-shaped; wherein, the vertical portion of the anode electrode unit is disposed on the semiconductor substrate, and the vertical portion is in contact with the second end of the channel layer, the second end of the first barrier layer, and the second end of the second barrier layer, respectively; and the horizontal portion of the anode electrode unit is disposed on the first P-pillar, the second P-pillar, the channel layer, the first barrier layer, and the second barrier layer.

[0016] In one embodiment, the anode electrode unit includes:

[0017] A first anode subunit is disposed on the semiconductor substrate and is in contact with the second end of the channel layer, the second end of the first barrier layer, and the second end of the second barrier layer, respectively.

[0018] Metal field plate sub-units are disposed on the first P-pillar, the second P-pillar, the channel layer, the first barrier layer, and the second barrier layer.

[0019] In one embodiment, the anode electrode unit is Schottky metal and the cathode electrode unit is ohmic metal.

[0020] In one embodiment, the height of the cathode electrode unit is equal to the sum of the heights of the first anode subunit and the metal field plate subunit.

[0021] In one embodiment, the first P-pillar and the second P-pillar are arranged opposite to each other.

[0022] In one embodiment, the distance from the first P-pillar to the cathode electrode unit is the same as the distance from the first P-pillar to the first anode sub-unit.

[0023] In one embodiment, the length of the first P-pillar is less than the length of the first barrier layer.

[0024] In one embodiment, the length of the first P-pillar is 1 / 3 of the length of the first barrier layer.

[0025] A second aspect of this application provides a chip including a plurality of Schottky diodes as described in any of the preceding claims, wherein the plurality of Schottky diodes are disposed on the same semiconductor substrate, and the cathode electrode units of the plurality of Schottky diodes are shared, and the anode electrode units of the plurality of Schottky diodes are shared.

[0026] A third aspect of this application provides a method for fabricating a Schottky diode, comprising:

[0027] A first P-pillar, a channel layer, and a second P-pillar are sequentially and spaced apart on a semiconductor substrate.

[0028] A first barrier layer is formed on the semiconductor substrate; wherein the first barrier layer is located between the first P-pillar and the channel layer;

[0029] A second barrier layer is formed on the semiconductor substrate; wherein the second barrier layer is located between the second P-pillar and the channel layer;

[0030] A cathode electrode unit is formed on the semiconductor substrate; wherein the cathode electrode unit is in contact with a first end of the channel layer, a first end of the first barrier layer, and a first end of the second barrier layer, respectively.

[0031] An anode electrode unit is formed; wherein the anode electrode unit is L-shaped; the vertical portion of the anode electrode unit is disposed on the semiconductor substrate, and the vertical portion is in contact with the second end of the channel layer, the second end of the first barrier layer, and the second end of the second barrier layer, respectively; the horizontal portion of the anode electrode unit is disposed on the first P-pillar, the second P-pillar, the channel layer, the first barrier layer, and the second barrier layer.

[0032] The beneficial effects of this application embodiment compared with the prior art are as follows: In this embodiment, by setting the anode electrode unit to Schottky metal and the anode electrode unit in contact with the first P-pillar and the second P-pillar, such that the anode electrode unit is in Schottky contact with the first P-pillar and the anode electrode unit is in Schottky contact with the second P-pillar, a higher Schottky barrier height can be achieved between the anode electrode unit and the first P-pillar and the second P-pillar, thereby reducing the leakage current of the anode electrode unit, providing a higher forward threshold voltage, and thus improving the breakdown voltage of the Schottky diode. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the vertical cross-sectional structure of a Schottky diode along the anode electrode unit according to an embodiment of this application;

[0034] Figure 2 This is a top view schematic diagram of a Schottky diode provided in one embodiment of this application;

[0035] Figure 3 This is a front view schematic diagram of a Schottky diode provided in one embodiment of this application;

[0036] Figure 4 This is a schematic diagram of the structure of a Schottky diode provided in one embodiment of this application;

[0037] Figure 5 This is a schematic diagram of the structure of a chip provided in one embodiment of this application;

[0038] Figure 6 This is a schematic diagram of the fabrication steps of a Schottky diode according to an embodiment of this application;

[0039] Figure 7 This is a schematic diagram of the formation of the first P-pillar, the channel layer, and the second P-pillar according to an embodiment of this application;

[0040] Figure 8 This is a schematic diagram of the formation of the first barrier layer and the second barrier layer provided in one embodiment of this application;

[0041] Figure 9 This is a schematic diagram of a cathode electrode unit formed according to an embodiment of this application;

[0042] Figure 10 This is a schematic diagram of the anode electrode unit after it has been formed, according to one embodiment of this application. Detailed Implementation

[0043] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0044] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0045] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means one or more, unless otherwise explicitly specified.

[0047] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," "in a particular embodiment," and "in a particular application," appearing in various parts of this specification, do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.

[0048] As a high-tech industry, the electronics and information industry plays an increasingly important role in expanding social employment, promoting economic transformation and upgrading, enhancing international competitiveness, and safeguarding national security. Power diodes are key components of circuit systems and are now widely used in civilian products such as high-frequency inverters, digital products, generators, and televisions, as well as in military applications such as satellite receivers, missile and aircraft control systems, and instrumentation equipment.

[0049] Commonly used diodes include ordinary rectifier diodes, Schottky diodes, and PN diodes. Among them, Schottky rectifier diodes are widely used due to their advantages such as low on-state voltage drop, large leakage current, and almost zero reverse recovery time.

[0050] Schottky diodes are diodes made using the principle of a metal-semiconductor junction formed by the contact between a metal and a semiconductor. Compared to PN junction diodes, Schottky diodes offer advantages such as lower power consumption, higher current output, and ultra-high speed, making them popular in electronic devices.

[0051] However, existing Schottky diodes suffer from low breakdown voltage.

[0052] To address the aforementioned technical problems, embodiments of this application provide a Schottky diode, as shown in the reference. Figure 1 , Figure 2 , Figure 3 As shown, Figure 1This is a schematic diagram of the vertical cross-section structure of a Schottky diode from the first P-pillar 50 and the second P-pillar 60. Figure 2 This is a top view of a Schottky diode. Figure 3 This is a front view schematic diagram of a Schottky diode, which includes: a semiconductor substrate 10, a channel layer 20, a first barrier layer 30, a second barrier layer 40, a first P-pillar 50, a second P-pillar 60, an anode electrode unit 70, and a cathode electrode unit 80.

[0053] Specifically, the channel layer 20 is disposed on the semiconductor substrate 10. A first barrier layer 30 is disposed on the semiconductor substrate 10 and is in contact with the first surface of the channel layer 20. A second barrier layer 40 is disposed on the semiconductor substrate 10 and is in contact with the second surface of the channel layer 20. A first P-pillar 50 is disposed on the semiconductor substrate 10, and the first barrier layer 30 is disposed between the first P-pillar 50 and the channel layer 20. A second P-pillar 60 is disposed on the semiconductor substrate 10, and the second barrier layer 40 is disposed between the second P-pillar 60 and the channel layer 20. A cathode electrode unit 80 is disposed on the semiconductor substrate 10, and the cathode electrode unit 80 is in contact with the first end of the channel layer 20, the first end of the first barrier layer 30, and the first end of the second barrier layer 40, respectively. The anode electrode unit 70 is L-shaped; wherein, the vertical portion of the anode electrode unit 70 is disposed on the semiconductor substrate 10, and the vertical portion is in contact with the second end of the channel layer 20, the second end of the first barrier layer 30, and the second end of the second barrier layer 40, respectively, and the horizontal portion of the anode electrode unit 70 is disposed on the first P-pillar 50, the second P-pillar 60, the channel layer 20, the first barrier layer 30, and the second barrier layer 40.

[0054] In this embodiment, the first barrier layer 30 is in contact with the first surface of the channel layer 20; the second barrier layer 40 is in contact with the second surface of the channel layer 20. It is understood that the channel layer 20 is disposed between the first barrier layer 30 and the second barrier layer 40, with the first barrier layer 30 and the second barrier layer 40 disposed on both sides of the channel layer 20, and the first barrier layer 30 and the second barrier layer 40 are arranged opposite to each other. In this embodiment, by disposing the first barrier layer 30 and the second barrier layer 40 on both sides of the channel layer 20, a double-layered two-dimensional electron gas (2DEG) can be formed on both sides of the channel layer 20, realizing communication between the cathode electrode unit 80 and the anode electrode unit 70.

[0055] In this embodiment, the first barrier layer 30 is disposed between the first P-pillar 50 and the channel layer 20. It can be understood that the first P-pillar 50 is in contact with the first barrier layer 30. The second barrier layer 40 is disposed between the second P-pillar 60 and the channel layer 20, with the second P-pillar 60 in contact with the second barrier layer 40. In this embodiment, by setting the first P-pillar 50 and the second P-pillar 60 to contact the first barrier layer 30 and the second barrier layer 40 respectively, the first P-pillar 50 and the second P-pillar 60 can be used to cancel out the two-dimensional electron gas of the double layer, resulting in a smaller two-dimensional electron gas in the Schottky diode when it is turned off, avoiding leakage current. This achieves complete control of the device and provides a higher forward threshold voltage.

[0056] In this embodiment, the cathode electrode unit 80 is in contact with the first end of the channel layer 20, the first end of the first barrier layer 30, and the first end of the second barrier layer 40, respectively. The anode electrode unit 70 is L-shaped; wherein, the horizontal portion of the anode electrode unit 70 is disposed on the first P-pillar 50, the second P-pillar 60, the channel layer 20, the first barrier layer 30, and the second barrier layer 40. It is understood that the first P-pillar 50 and the second P-pillar 60 are disposed on the semiconductor substrate 10, and the first P-pillar 50 and the second P-pillar 60 are disposed between the vertical portions of the cathode electrode unit 80 and the anode electrode unit 70. The horizontal portion of the anode electrode unit 70 is used to connect the vertical portion of the anode electrode unit 70 and the first P-pillar 50 and the second P-pillar 60. The horizontal portion of the anode electrode unit 70 only contacts the channel layer 20, the first barrier layer 30 and the second barrier layer 40 between the first P-pillar 50, the second P-pillar 60 and the vertical portion of the anode electrode unit 70. In other words, it does not contact the channel layer 20, the first barrier layer 30 and the second barrier layer 40 between the first P-pillar 50, the second P-pillar 60 and the cathode electrode unit 80.

[0057] In this embodiment, the channel layer 20, the first barrier layer 30, and the second barrier layer 40 are all vertically disposed on the semiconductor substrate 10. The horizontal portion of the anode electrode unit 70 is disposed on the channel layer 20, the first barrier layer 30, the second barrier layer 40, the first P-pillar 50, and the second P-pillar 60. The horizontal portion of the anode electrode unit 70 is made of Schottky metal, thus forming a metal field plate. This allows for the regulation of the internal electric field of the Schottky diode during operation, making the internal electric field more uniform and thereby increasing the breakdown voltage of the Schottky diode. Compared to conventional semiconductor devices where the channel layer 20 and barrier layers are parallel to each other on the semiconductor substrate 10, this provides a higher Schottky barrier height, resulting in higher conduction current, thereby reducing the leakage current of the anode electrode unit 70 and providing a higher forward threshold voltage.

[0058] In one embodiment, combined Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, Figure 2 and Figure 4 This is a top view of the device. Figure 5 The device is shown in a three-dimensional view. The anode electrode unit 70 includes a first anode subunit 71 and a metal field plate subunit 72.

[0059] Specifically, the first anode sub-unit 71 is disposed on the semiconductor substrate 10, and the first anode sub-unit 71 is in contact with the second end of the channel layer 20, the second end of the first barrier layer 30, and the second end of the second barrier layer 40, respectively. The metal field plate sub-unit 72 is disposed on the first P-pillar 50, the second P-pillar 60, the channel layer 20, the first barrier layer 30, and the second barrier layer 40.

[0060] In this embodiment, the metal field plate subunit 72 is used to connect the first anode subunit 71, the first P-pillar 50, and the second P-pillar 60. The metal field plate subunit 72 only contacts the channel layer 20, the first barrier layer 30, and the second barrier layer 40 between the first P-pillar 50, the second P-pillar 60, and the vertical portion of the anode electrode unit 70. In other words, the metal field plate subunit 72 does not contact the channel layer 20, the first barrier layer 30, and the second barrier layer 40 between the first P-pillar 50, the second P-pillar 60, and the cathode electrode unit 80. Because the metal field plate subunit 72 is made of Schottky metal, this metal field plate can regulate the internal electric field of the Schottky diode during operation, making the internal electric field more uniform and thus increasing the breakdown voltage of the Schottky diode.

[0061] In one embodiment, the channel layer 20 is GaN.

[0062] In this embodiment, the channel layer 20 can be made of gallium nitride material, for example, by depositing gallium nitride material on the semiconductor substrate 10 or by epitaxially growing gallium nitride material.

[0063] In one embodiment, both the first barrier layer 30 and the second barrier layer 40 are AlGaN.

[0064] In this embodiment, the first barrier layer 30 and the second barrier layer 40 can both be made of aluminum gallium nitride material, for example, by depositing aluminum gallium nitride material on the semiconductor substrate 10 or by epitaxially growing aluminum gallium nitride material to form the first barrier layer 30 and the second barrier layer 40.

[0065] In one embodiment, the first P-pillar 50 and the second P-pillar 60 are P-GaN.

[0066] In this embodiment, P-GaN is formed by doping GaN with a p-type dopant, wherein the p-type dopant can be boron, gallium, aluminum, etc.

[0067] In one embodiment, the semiconductor substrate 10 is a sapphire substrate.

[0068] In one embodiment, the anode electrode unit 70 is Schottky metal and the cathode electrode unit 80 is ohmic metal.

[0069] Specifically, Schottky metals can be layers of platinum, gold, or silver, or conductive semiconductor layers, etc. Ohmic metals are combinations of Ti, Al, Ti, and Au materials.

[0070] In a specific application, Schottky metal is a combination of Ni and Au materials.

[0071] In one embodiment, the thicknesses of the ohmic metals Ti, Al, Ti, and Au are 15 nm, 250 nm, 50 nm, and 150 nm, respectively, and the thicknesses of the Schottky metals Ni and Au are 70 nm and 30 nm, respectively.

[0072] In this embodiment, by setting the anode electrode unit 70 to Schottky metal, the anode is a Schottky contact, which can provide a higher Schottky barrier height. By setting the thickness of Ni and Au of the Schottky metal to 70nm and 30nm respectively, the leakage current of the anode electrode unit 70 is reduced, a higher forward threshold voltage is provided, and the overall performance of the Schottky diode is improved.

[0073] In one embodiment, reference Figure 3 As shown, the height of the cathode electrode unit 80 is equal to the sum of the heights of the first anode sub-unit 71 and the metal field plate sub-unit 72. Specifically, by setting the height of the cathode electrode unit 80 to be equal to the sum of the heights of the first anode sub-unit 71 and the metal field plate sub-unit 72, the resulting Schottky diodes can be positioned at the same horizontal level, which improves the stability of the power device. This results in more stable performance of the power device during operation, thereby extending the lifespan of the Schottky diode.

[0074] In one embodiment, reference Figure 1 As shown, the first P-pillar 50 and the second P-pillar 60 are positioned opposite each other.

[0075] Specifically, the first P-pillar 50 and the second P-pillar 60 are respectively disposed on both sides of the first barrier layer 30 and the second barrier layer 40. This can better cancel the two-dimensional electron gas on both sides of the channel layer 20. Furthermore, by setting the first P-pillar 50 and the second P-pillar 60 to be opposite each other, the areas where the two-dimensional electron gas on both sides of the channel layer 20 is canceled are the same, which can improve the stability of the power device. If the first P-pillar 50 and the second P-pillar 60 are not opposite each other, for example, if they are staggered, the areas where the two-dimensional electron gas on both sides of the channel layer 20 is canceled will be different, which will lead to unstable performance of the power device during operation and shorten the service life of the Schottky diode.

[0076] In one embodiment, reference Figure 4 As shown, for ease of observation, Figure 4 This is a schematic diagram of a Schottky diode with the horizontal portion of the anode electrode unit 70 removed. The distance L2 from the first P-pillar 50 to the cathode electrode unit 80 is the same as the distance L1 from the first P-pillar 50 to the first anode sub-unit 71 (or the vertical portion of the anode electrode unit 70). The distance from the second P-pillar 60 to the cathode electrode unit 80 is the same as the distance from the second P-pillar 60 to the first anode sub-unit 71. Specifically, both the first P-pillar 50 and the second P-pillar 60 are located at the midpoint between the cathode electrode unit 80 and the first anode sub-unit 71. This ensures that the areas where the two-dimensional electron gas is canceled on both sides of the channel layer 20 are the same, thus improving the stability of the power device.

[0077] In one embodiment, because the anode electrode unit 70 is made of Schottky metal and is in contact with the second P-pillar 60, the contact between the anode electrode unit 70 and the second P-pillar 60 is a Schottky contact. This allows for a higher Schottky barrier height between the anode electrode unit 70 and the second P-pillar 60, thereby reducing the leakage current of the anode electrode unit 70, providing a higher forward threshold voltage, and thus improving the performance of the Schottky diode and expanding its application range.

[0078] In one embodiment, reference Figure 4 As shown, the first P-pillar 50 and the second P-pillar 60 have the same length, both denoted by L3. The length of the channel layer 20 is the same as the length of the first barrier layer 30 and the second barrier layer 40, both denoted by L4. Specifically, the length of the channel layer 20 is equal to the length of the first barrier layer 30 and the length of the second barrier layer 40. By setting the lengths of the first P-pillar 50 and the second P-pillar 60 to be the same, the areas where the two-dimensional electron gas on both sides of the channel layer 20 is canceled out are the same, which can improve the stability of the power device, make the Schottky diode work more stably, and expand the application range of the Schottky diode.

[0079] In one embodiment, reference Figure 4As shown, the length L3 of the first P-pillar 50 is less than the length L4 of the first barrier layer 30. Specifically, the length L3 of the first P-pillar 50 is less than the length L4 of the first barrier layer 30 because both the first P-pillar 50 and the second P-pillar 60 are used to cancel the two-dimensional electron gas. The two-dimensional electron gas is used to realize communication between the cathode electrode unit 80 and the anode electrode unit 70. By setting the length of the first P-pillar 50 to be less than the length of the first barrier layer 30 and the length of the second P-pillar 60 to be less than the length of the second barrier layer 40, the two-dimensional electron gas will not be completely canceled. This not only enables the function of a Schottky diode but also allows for complete control of the device and provides a higher forward threshold voltage.

[0080] In one embodiment, the length of the first P-pillar 50 is one-third the length of the first barrier layer 30. Specifically, the length of the second P-pillar 60 is one-third the length of the second barrier layer 40. Since both the first P-pillar 50 and the second P-pillar 60 are used to cancel the two-dimensional electron gas, which is used to enable communication between the cathode electrode unit 80 and the anode electrode unit 70, by setting the length of the first P-pillar 50 to one-third the length of the first barrier layer 30 and the length of the second P-pillar 60 to one-third the length of the second barrier layer 40, the two-dimensional electron gas is not completely canceled out. This not only enables the function of a Schottky diode but also allows for complete control of the device and provides a higher forward threshold voltage.

[0081] In one embodiment, the heights of the first P-pillar 50, the second P-pillar 60, the channel layer 20, the first barrier layer 30, and the second barrier layer 40 are all the same. In this embodiment, by setting the heights of the first P-pillar 50, the second P-pillar 60, the channel layer 20, the first barrier layer 30, and the second barrier layer 40 to be the same, the performance of the Schottky diode can be made more stable, its lifespan extended, and its application range expanded.

[0082] In one embodiment, reference Figure 2 As shown, the width W2 of the first P-pillar 50 is greater than the width W1 of the first barrier layer 30, and the width of the second P-pillar 60 is the same as the width of the first P-pillar 50. Because the first P-pillar 50 and the second P-pillar 60 can cancel out the two-dimensional electron gas, by setting the width of the first P-pillar 50 to be greater than the width of the first barrier layer 30, the first P-pillar 50 and the second P-pillar 60 can better cancel out the two-dimensional electron gas of the double layer, resulting in a smaller two-dimensional electron gas in the Schottky diode when it is turned off, avoiding leakage current. This achieves complete control of the device and provides a higher forward threshold voltage.

[0083] In one embodiment, the width of the first P-pillar 50 is the same as the width of the first barrier layer 30. Specifically, the width of the second P-pillar 60 is the same as the width of the first barrier layer 30, and the width of the first barrier layer 30 is the same as the width of the second barrier layer 40. In this embodiment, by setting the width of the first P-pillar 50 to be the same as the width of the first barrier layer 30, the performance of the Schottky diode can be made more stable, and the service life of the Schottky diode can be extended.

[0084] A second aspect of the embodiments of this application provides a chip, with reference to... Figure 5 As shown, the device includes a plurality of Schottky diodes 100 as described above. The plurality of Schottky diodes 100 are disposed on the same semiconductor substrate 10, and the cathode electrode units 80 of the plurality of Schottky diodes 100 are connected in common, and the anode electrode units 70 of the plurality of Schottky diodes 100 are connected in common.

[0085] Specifically, multiple Schottky diodes 100 are connected together via adjacent first P-pillars 50 and second P-pillars 60. For example, the first P-pillar 50 of the first Schottky diode 100 is connected to the second P-pillar 60 of the second Schottky diode 100, the first P-pillar 50 of the second Schottky diode 100 is connected to the second P-pillar 60 of the third Schottky diode 100, and so on, forming a chip. The biggest advantage of the chip is that it can reduce the leakage current of the anode through the high Schottky barrier height between the anode electrode unit 70, the first P-pillar 50, and the second P-pillar 60, thus providing a higher forward threshold voltage. By setting multiple Schottky diodes 100 together on the same semiconductor substrate 10, and connecting the cathode electrode units 80 and anode electrode units 70 of the multiple Schottky diodes 100 together, the multiple Schottky diodes 100 can be used in parallel. The first P-pillar 50 and the second P-pillar 60 can be used as the connection between two adjacent Schottky diodes 100, which can realize the control of multiple devices, effectively avoid the generation of leakage current, and generate higher forward conduction current.

[0086] This application also provides a method for fabricating a Schottky diode, see reference. Figure 6 As shown, it includes steps S10 to S40.

[0087] Step S10: Reference Figure 7 As shown, a first P-pillar 50, a channel layer 20, and a second P-pillar 60 are sequentially and spaced apart on a semiconductor substrate 10.

[0088] In a specific application, selective etching is performed on the semiconductor substrate 10 to etch out the positions of the first P-pillar 50, the channel layer 20, and the second P-pillar 60, respectively. Then, the corresponding semiconductor materials are filled in the corresponding positions of the first P-pillar 50, the channel layer 20, and the second P-pillar 60. For example, P-GaN material is filled in the first P-pillar 50 and the second P-pillar 60 regions, and GaN material is filled in the channel layer 20 region.

[0089] In one specific application, the semiconductor substrate 10 is a sapphire substrate.

[0090] Step S20: Reference Figure 8 As shown, a first barrier layer 30 is formed on a semiconductor substrate 10; wherein the first barrier layer 30 is located between the first P-pillar 50 and the channel layer 20, and a second barrier layer 40 is formed on the semiconductor substrate 10; wherein the second barrier layer 40 is located between the second P-pillar 60 and the channel layer 20.

[0091] In a specific application, selective etching is performed on the semiconductor substrate 10 to etch out the positions of the first barrier layer 30 and the second barrier layer 40, respectively. Then, the corresponding semiconductor materials are filled into the corresponding positions of the first barrier layer 30 and the second barrier layer 40. For example, AlGaN material is filled into the positions of the first barrier layer 30 and the second barrier layer 40.

[0092] In one embodiment, the heights of the first P-pillar 50, the channel layer 20, the second P-pillar 60, the first barrier layer 30, and the second barrier layer 40 can be determined by repeatedly extending the first P-pillar 50, the channel layer 20, the second P-pillar 60, the first barrier layer 30, and the second barrier layer 40.

[0093] Step S30: Reference Figure 9 As shown, a cathode electrode unit 80 is formed on a semiconductor substrate 10; wherein the cathode electrode unit 80 is in contact with the first end of the channel layer 20, the first end of the first barrier layer 30 and the first end of the second barrier layer 40, respectively.

[0094] In one embodiment, a mask is used to determine the shape of the cathode electrode unit 80, and metal is deposited on the mask to form the cathode electrode unit 80.

[0095] Step S40: Reference Figure 10As shown, an anode electrode unit 70 is formed; wherein, the anode electrode unit 70 is L-shaped; the vertical portion of the anode electrode unit 70 is disposed on the semiconductor substrate, and the vertical portion is in contact with the second end of the channel layer 20, the second end of the first barrier layer 30, and the second end of the second barrier layer 40, respectively; the horizontal portion of the anode electrode unit 70 is disposed on the first P-pillar 50, the second P-pillar 60, the channel layer 20, the first barrier layer 30, and the second barrier layer 40; the anode electrode unit 70 is Schottky metal.

[0096] In one embodiment, a mask is used to determine the shape of the anode electrode unit 70, and metal is deposited on the mask to form the anode electrode unit 70. Because the anode electrode unit 70 is Schottky metal, and the anode electrode unit 70 contacts the first P-pillar 50, making the contact between the anode electrode unit 70 and the first P-pillar 50 a Schottky contact, a high Schottky barrier height can be maintained between the anode electrode unit 70 and the first P-pillar 50, thereby reducing the leakage current of the anode electrode unit 70, providing a higher forward threshold voltage, thereby improving the performance of the Schottky diode and expanding the application range of the Schottky diode.

[0097] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0098] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A Schottky diode, characterized in that, The Schottky diode includes: Semiconductor substrate; A channel layer is disposed on the semiconductor substrate; A first barrier layer is disposed on the semiconductor substrate and is in contact with the first surface of the channel layer; A second barrier layer is disposed on the semiconductor substrate and is in contact with the second surface of the channel layer; A first P-pillar is disposed on the semiconductor substrate, and a first barrier layer is disposed between the first P-pillar and the channel layer; A second P-pillar is disposed on the semiconductor substrate, and a second barrier layer is disposed between the second P-pillar and the channel layer; A cathode electrode unit is disposed on the semiconductor substrate, and the cathode electrode unit is in contact with the first end of the channel layer, the first end of the first barrier layer and the first end of the second barrier layer, respectively. An anode electrode unit is provided, wherein the anode electrode unit is L-shaped; wherein the vertical portion of the anode electrode unit is disposed on the semiconductor substrate, and the vertical portion is in contact with the second end of the channel layer, the second end of the first barrier layer, and the second end of the second barrier layer, respectively; the horizontal portion of the anode electrode unit is disposed on the first P-pillar, the second P-pillar, the channel layer, the first barrier layer, and the second barrier layer; the anode electrode unit is made of Schottky metal; the anode electrode unit and the first P-pillar form a Schottky contact; the anode electrode unit and the second P-pillar form a Schottky contact.

2. The Schottky diode as described in claim 1, characterized in that, The anode electrode unit includes: A first anode subunit is disposed on the semiconductor substrate and is in contact with the second end of the channel layer, the second end of the first barrier layer, and the second end of the second barrier layer, respectively. Metal field plate sub-units are disposed on the first P-pillar, the second P-pillar, the channel layer, the first barrier layer, and the second barrier layer.

3. The Schottky diode as described in claim 1, characterized in that, The anode electrode unit is made of Schottky metal, and the cathode electrode unit is made of ohmic metal.

4. The Schottky diode as described in claim 2, characterized in that, The height of the cathode electrode unit is equal to the sum of the heights of the first anode subunit and the metal field plate subunit.

5. The Schottky diode as described in claim 1, characterized in that, The first P-pillar and the second P-pillar are positioned opposite each other.

6. The Schottky diode as described in claim 2, characterized in that, The distance from the first P-pillar to the cathode electrode unit is the same as the distance from the first P-pillar to the first anode sub-unit.

7. The Schottky diode as described in any one of claims 1-6, characterized in that, The length of the first P-pillar is less than the length of the first barrier layer.

8. The Schottky diode as described in claim 6, characterized in that, The length of the first P-pillar is 1 / 3 of the length of the first barrier layer.

9. A chip, characterized in that, It includes a plurality of Schottky diodes as described in any one of claims 1-8, wherein the plurality of Schottky diodes are disposed on the same semiconductor substrate, and the cathode electrode units of the plurality of Schottky diodes are connected in common, and the anode electrode units of the plurality of Schottky diodes are connected in common.

10. A method for fabricating a Schottky diode as described in any one of claims 1-8, characterized in that, include: A first P-pillar, a channel layer, and a second P-pillar are sequentially and spaced apart on a semiconductor substrate. A first barrier layer is formed on the semiconductor substrate; wherein the first barrier layer is located between the first P-pillar and the channel layer; A second barrier layer is formed on the semiconductor substrate; wherein the second barrier layer is located between the second P-pillar and the channel layer; A cathode electrode unit is formed on the semiconductor substrate; wherein the cathode electrode unit is in contact with a first end of the channel layer, a first end of the first barrier layer, and a first end of the second barrier layer, respectively. An anode electrode unit is formed; wherein the anode electrode unit is L-shaped; the vertical portion of the anode electrode unit is disposed on the semiconductor substrate, and the vertical portion is in contact with the second end of the channel layer, the second end of the first barrier layer, and the second end of the second barrier layer, respectively; the horizontal portion of the anode electrode unit is disposed on the first P-pillar, the second P-pillar, the channel layer, the first barrier layer, and the second barrier layer.

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