A Schottky diode with low forward voltage drop and a method for manufacturing the same

Abstract

The present application provides a Schottky diode with low forward voltage drop and a manufacturing method thereof, the method comprising obtaining the power parameters and structural area of ​​the Schottky diode to be designed, determining the barrier metal of the Schottky diode to be designed according to the power parameters; designing the structure of the Schottky diode to be designed according to the structural area by using the rule of increasing the barrier area to obtain a structural diagram; manufacturing the Schottky diode product chip production process according to the structural diagram and the barrier metal to obtain a Schottky diode with low forward voltage drop. The method ensures the optimal forward voltage drop VF characteristics and reverse leakage current IR characteristics of the Schottky diode product and the reliability of the product through the barrier metal selection design; the rule of increasing the barrier area is used to ensure that the Schottky diode chip area remains unchanged during the manufacturing process of the Schottky diode, increase the area of ​​the barrier region of the Schottky diode, reduce the forward voltage drop, and solve the problem of large forward voltage drop of the existing Schottky diode.

Description

Technical Field

[0001] The present application belongs to the field of semiconductor technology, and in particular relates to a Schottky diode with a low forward voltage drop and a manufacturing method thereof. Background Art

[0002] Schottky diode, also known as Schottky barrier diode (SBD for short), is a low-power, ultra-high-speed semiconductor device. The most notable feature of this semiconductor device is that the reverse recovery time is extremely short (can be as small as a few nanoseconds), and the forward conduction voltage drop is only about 0.4V. It is mostly used as a high-frequency, low-voltage, high-current rectifier diode, freewheeling diode, and protection diode. It is also used as a rectifier diode and a small signal detector diode in microwave communication circuits. It is more common in communication power supplies, inverters, etc.

[0003] Schottky diode is a metal-semiconductor device made of precious metal (Ti, Ni, Ni-PtX, platinum, etc.) A as the positive electrode and N-type semiconductor B as the negative electrode, using the potential barrier formed on the contact surface of the two to have the rectifying property. The electrical parameters of Schottky diode include forward voltage drop, leakage current and reverse voltage; the forward voltage drop is proportional to the reverse voltage, and the forward voltage drop is inversely proportional to the leakage current; at the same time, when other conditions remain unchanged, the forward voltage drop is inversely proportional to the Schottky area. Under the same current, increasing the Schottky area can effectively reduce the forward voltage drop, while the leakage current does not increase significantly.

[0004] The forward voltage drop of the existing Schottky diode is large, and reducing the forward voltage drop is a relatively important issue. Summary of the invention

[0005] An embodiment of the present application provides a Schottky diode with a low forward voltage drop and a manufacturing method thereof, so as to solve the problem of large forward voltage drop of the existing Schottky diode.

[0006] In a first aspect, an embodiment of the present application provides a method for manufacturing a Schottky diode with a low forward voltage drop, comprising the following steps:

[0007] Obtaining power parameters and structural area of ​​the Schottky diode to be designed, and determining the barrier metal of the Schottky diode to be designed according to the power parameters; the structure of the Schottky diode to be designed includes a barrier region, a lead hole and a metal layer;

[0008] According to the structural area, the structure of the Schottky diode to be designed is designed by adopting a rule of increasing the potential barrier area to obtain a structural diagram of the Schottky diode to be designed;

[0009] According to the structure diagram and the barrier metal, a Schottky diode product chip production process is adopted to manufacture a Schottky diode with a low forward voltage drop.

[0010] Optionally, an inner ring line is set on the barrier region, the area between the outer ring line of the metal layer and the lead hole is recorded as the outer ring area, the area between the inner ring line and the lead hole is recorded as the inner ring area, and the area between the inner ring line and the outer ring line of the metal layer is recorded as the base ring; the rules for increasing the barrier area include: not changing the structural area, increasing the width of the base ring and reducing the width of the outer ring area to increase the area of ​​the barrier region.

[0011] Optionally, determining the barrier metal of the Schottky diode to be designed according to the power parameter includes: if the power parameter is not greater than the power threshold, the barrier metal of the Schottky diode to be designed is NiPt5; if the power parameter is greater than the power threshold, the barrier metal of the Schottky diode to be designed is NiPt1.

[0012] Optionally, the NiPt5 is a metal made of metal nickel Ni and metal platinum Pt in a ratio of 19:1.

[0013] Optionally, the NiPt1 is a metal made of metal nickel Ni and metal platinum Pt in a ratio of 17:3.

[0014] Optionally, the Schottky diode product chip production process includes:

[0015] Acquire the epitaxial wafer of the Schottky diode to be designed according to the structural area;

[0016] Performing base ring processing on the epitaxial wafer by laser marking according to the structural diagram to obtain a first processed sample;

[0017] After injecting P+ ring ions into the first processed sample, performing lead hole processing by photolithography to obtain a second processed sample;

[0018] The second processed sample is subjected to sputtering, corrosion, evaporation and annealing to obtain a Schottky diode with a low forward voltage drop.

[0019] Optionally, the epitaxial wafer is subjected to base ring processing by laser marking according to the structural diagram to obtain a first processed sample, which includes performing initial oxidation, laser marking, megasonic cleaning, base ring lithography and base ring etching on the epitaxial wafer in sequence according to the structural diagram to obtain the first processed sample.

[0020] Optionally, after injecting P+ ring ions into the first processed sample, lead hole processing is performed by photolithography to obtain the second processed sample, including: after injecting P+ ring ions into the first processed sample, lead hole processing is performed by cleaning, base ring annealing, lead hole photolithography and lead hole etching in sequence to obtain the second processed sample.

[0021] Optionally, the second processed sample is subjected to sputtering, etching, evaporation and annealing to obtain a Schottky diode with a low forward voltage drop, including: cleaning, sputtering, silicide formation, silicide etching, 10:1 cleaning, evaporation of TiNiAg, metal reverse etching, metal reverse etching corrosion, PMA annealing, electrical testing, thinning, stress relief corrosion, PBMC cleaning, back evaporation, testing and inspection, slicing and slicing the second processed sample to obtain a Schottky diode with a low forward voltage drop.

[0022] In a second aspect, an embodiment of the present application provides a Schottky diode with a low forward voltage drop, including an epitaxial wafer, and the epitaxial wafer is produced by the above-mentioned method for manufacturing a Schottky diode with a low forward voltage drop.

[0023] An embodiment of the present application provides a Schottky diode with low forward voltage drop and a manufacturing method thereof. The manufacturing method of the Schottky diode with low forward voltage drop includes obtaining the power parameters and structural area of ​​the Schottky diode to be designed, determining the barrier metal of the Schottky diode to be designed according to the power parameters; the structure of the Schottky diode to be designed includes a barrier region, a lead hole and a metal layer; the structure of the Schottky diode to be designed is designed according to the structural area by using the rule of increasing the barrier area to obtain the structural diagram of the Schottky diode to be designed; the Schottky diode product chip production process is used to manufacture according to the structural diagram and the barrier metal to obtain the Schottky diode with low forward voltage drop. The manufacturing method of the Schottky diode with low forward voltage drop ensures the optimal forward voltage drop VF characteristics and reverse leakage current IR characteristics of the Schottky diode product and the reliability of the product through the barrier metal selection design; the rule of increasing the barrier area is used to ensure that the Schottky diode chip area remains unchanged during the manufacturing process of the Schottky diode, increase the area of ​​the barrier region of the Schottky diode, reduce the forward voltage drop, and solve the problem of large forward voltage drop of the existing Schottky diode.

[0024] The low forward voltage drop Schottky diode achieves the goal of increasing the area of ​​the Schottky diode barrier region and reducing the forward voltage drop while ensuring that the area of ​​the Schottky diode chip remains unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution in an embodiment of the present application, the following is a brief introduction to the drawings required for the description of the embodiment. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0026] In order to more completely understand the present application and its beneficial effects, the following description will be given in conjunction with the accompanying drawings. In the following description, the same reference numerals represent the same parts.

[0027] Figure 1 A flowchart of a method for manufacturing a Schottky diode with a low forward voltage drop is provided for one embodiment of the present application.

[0028] Figure 2 A schematic diagram of the structure of a Schottky diode in a method for manufacturing a Schottky diode with a low forward voltage drop provided in one embodiment of the present application.

[0029] Figure 3 A planar structural diagram of a Schottky diode to be designed in a method for manufacturing a Schottky diode with a low forward voltage drop provided in one embodiment of the present application. DETAILED DESCRIPTION

[0030] The technical scheme in one embodiment of the present application will be clearly and completely described below in conjunction with the drawings in one embodiment of the present application. Obviously, the described embodiment is only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application.

[0031] An embodiment of the present application provides a Schottky diode with a low forward voltage drop and a manufacturing method thereof, so as to solve the problem of large forward voltage drop of the existing Schottky diode.

[0032] Embodiment 1:

[0033] An embodiment of the present application provides a method for manufacturing a Schottky diode with a low forward voltage drop. For example, see Figure 1 , Figure 1 A flowchart of a method for manufacturing a Schottky diode with a low forward voltage drop provided in one embodiment of the present application is provided. Figure 2 A schematic diagram of the structure of a Schottky diode in a method for manufacturing a Schottky diode with a low forward voltage drop provided in one embodiment of the present application.

[0034] like Figure 1 and Figure 2 As shown, the present invention provides a method for manufacturing a Schottky diode with a low forward voltage drop, comprising the following steps:

[0035] S100. Obtaining the power parameters and structural area of ​​the Schottky diode to be designed, and determining the barrier metal of the Schottky diode to be designed according to the power parameters; the structure of the Schottky diode to be designed includes a barrier region, a lead hole and a metal layer;

[0036] S200. Designing the structure of the Schottky diode to be designed by increasing the barrier area rule according to the structural area, and obtaining a structural diagram of the Schottky diode to be designed;

[0037] S300. According to the structure diagram and the barrier metal, a Schottky diode product chip production process is used to manufacture a Schottky diode with a low forward voltage drop.

[0038] It is further explained that in step S100, the power parameters and structural area required for producing a Schottky diode with a low forward voltage drop are obtained to provide data for the subsequent process. In step S200, the structure of the Schottky diode to be designed is designed according to the structural area obtained after step S100 by using the rule of increasing the barrier area, and the structural diagram of the Schottky diode to be designed is obtained to provide data for step S300. In step S300, the Schottky diode with a low forward voltage drop is manufactured using the Schottky diode product chip production process according to the barrier metal and structural diagram obtained in steps S100 and S200, so as to increase the area of ​​the Schottky diode barrier region and reduce the forward voltage drop while ensuring that the area of ​​the Schottky diode chip remains unchanged. It can be understood that the base area of ​​the Schottky diode is increased as a whole, the forward voltage drop of the Schottky diode is greatly reduced, and the forward surge of the Schottky diode product is increased.

[0039] It is further explained that the method for manufacturing a Schottky diode with a low forward voltage drop ensures the optimal forward voltage drop VF characteristic and reverse leakage current IR characteristic of the Schottky diode product and the reliability of the product through the barrier metal selection design in step S100.

[0040] It is further explained that if Figure 2 As shown, the lead hole is arranged between the barrier region and the metal layer.

[0041] An embodiment of the present application provides a method for manufacturing a Schottky diode with a low forward voltage drop, including obtaining the power parameters and structural area of ​​the Schottky diode to be designed, determining the barrier metal of the Schottky diode to be designed according to the power parameters; the structure of the Schottky diode to be designed includes a barrier region, a lead hole and a metal layer; the structure of the Schottky diode to be designed is designed according to the structural area by using the rule of increasing the barrier area to obtain a structural diagram of the Schottky diode to be designed; the Schottky diode product chip production process is used to manufacture according to the structural diagram and the barrier metal to obtain a Schottky diode with a low forward voltage drop. The method for manufacturing a Schottky diode with a low forward voltage drop ensures the optimal forward voltage drop VF characteristics and reverse leakage current IR characteristics of the Schottky diode product and the reliability of the product through the barrier metal selection design; the rule of increasing the barrier area is used to ensure that the Schottky diode chip area remains unchanged during the manufacturing process of the Schottky diode, increase the area of ​​the barrier region of the Schottky diode, reduce the forward voltage drop, and solve the problem of large forward voltage drop of the existing Schottky diode.

[0042] Figure 3A planar structural diagram of a Schottky diode to be designed in a method for manufacturing a Schottky diode with a low forward voltage drop provided in one embodiment of the present application.

[0043] like Figure 3 As shown, in the embodiment of the invention of the application, an inner ring line is arranged on the barrier region, the area between the outer ring line of the metal layer and the lead hole is recorded as the outer ring area, the area between the inner ring line and the lead hole is recorded as the inner ring area, and the area between the inner ring line and the outer ring line of the metal layer is recorded as the base ring; the rules for increasing the barrier area include: not changing the structural area, increasing the width of the base ring and reducing the width of the outer ring area to increase the area of ​​the barrier region.

[0044] It is further explained that, for a Schottky diode with a planar structure, the larger the barrier area, the smaller the forward voltage drop VF, that is, the area is inversely proportional to the forward voltage drop. In order to ensure the low forward voltage requirement of the low forward voltage drop product, the method for manufacturing a Schottky diode with a low forward voltage drop adopts the rule of increasing the barrier area to design the structural diagram of the Schottky diode to be designed. This can be understood as reasonably increasing the barrier area in the layout design of the structural diagram of the Schottky diode to be designed to reduce the forward voltage drop. Increasing the barrier area refers to increasing the width of the base ring while ensuring that the chip size of the Schottky diode to be designed remains unchanged, adjusting the width of the base ring to become wider, and the width of the outer ring area to become narrower, so as to adjust the barrier area to increase to reduce the forward voltage drop and improve the forward surge of the Schottky diode to be designed. Figure 3 As shown, with the area of ​​the Schottky diode unchanged, the base ring is increased from the original 20 microns to 30 microns, and then the lead hole area is expanded, so that the outer ring area of ​​the base ring is reduced from the original 20 microns to 10 microns, and the inner ring area of ​​the base ring is changed from the original 10 microns to 20 microns, thereby increasing the barrier area and reducing the forward voltage drop of the Schottky diode to be designed.

[0045] In the invention embodiment of the application, the choice of barrier metal directly affects the forward turn-on voltage, reverse leakage current and product junction temperature of the Schottky diode product. Therefore, the reasonable selection and design of the barrier metal of the Schottky diode manufacturing method with low forward voltage drop is also the key to the key technical indicators VF, IR and reliability guarantee of the Schottky diode product to be designed. If the nickel Ni barrier is designed to have a large leakage current and a low VF, it is suitable for a small current Schottky diode. The barrier metal selects a platinum Pt metal alloy with a small leakage current, that is, Ni / Pt to solve the barrier problem, and then selects different alloy component ratios according to the power of the product, specifically for the selection of the barrier metal alloy component ratio of the product. Therefore, the Schottky diode manufacturing method with low forward voltage drop determines the barrier metal of the Schottky diode to be designed in the base ring according to the base ring power parameter, and its content includes: if the base ring power parameter is not greater than the power threshold, the barrier metal of the Schottky diode to be designed in the base ring is NiPt5; if the base ring power parameter is greater than the power threshold, the barrier metal of the Schottky diode to be designed is NiPt1.

[0046] It is further explained that NiPt5 is a metal made of nickel Ni and platinum Pt in a ratio of 19:1. NiPt1 is a metal made of nickel Ni and platinum Pt in a ratio of 17:3. In this embodiment, the power threshold can be selected as 1000W. In other embodiments, the power threshold can also be set according to demand, which is not specifically limited here.

[0047] In the invention embodiment of the application, the Schottky diode product chip production process includes:

[0048] Obtaining the epitaxial wafer of the Schottky diode to be designed according to the structural area;

[0049] According to the structure diagram, a base ring process is performed on the epitaxial wafer by laser marking to obtain a first processed sample;

[0050] After injecting P+ ring ions into the first processed sample, a lead hole is processed by photolithography to obtain a second processed sample;

[0051] The second processed sample is subjected to sputtering, corrosion, evaporation and annealing to obtain a Schottky diode with a low forward voltage drop.

[0052] It is further explained that the production process of the Schottky diode product chip of the method for manufacturing the Schottky diode with a low forward voltage drop can adopt the existing mature production process for generating the Schottky diode product chip, and can also be adjusted according to the production requirements of the method for manufacturing the Schottky diode with a low forward voltage drop. In this embodiment, the epitaxial wafer is subjected to base ring processing by laser marking according to the structure diagram, and the first processed sample is obtained, including the initial oxidation, laser marking, megasonic cleaning, base ring lithography and base ring etching processing of the epitaxial wafer in sequence according to the structure diagram to obtain the first processed sample. After the P+ ring ions are injected into the first processed sample, the lead hole processing is performed by photolithography to obtain the second processed sample, including: after the P+ ring ions are injected into the first processed sample, the lead hole processing is performed by cleaning, base ring annealing, lead hole lithography and lead hole etching in sequence to obtain the second processed sample. The second processed sample is subjected to sputtering, etching, evaporation, and annealing to obtain a Schottky diode with a low forward voltage drop, including: cleaning, sputtering, silicide formation, silicide etching, 10:1 cleaning, evaporation of TiNiAg, metal reverse etching, metal reverse etching corrosion, PMA annealing, electrical testing, thinning, stress relief corrosion, PBMC cleaning, back evaporation, testing and inspection, slicing and slicing to obtain a Schottky diode with a low forward voltage drop.

[0053] In the invention embodiment of the application, the method for manufacturing the Schottky diode with low forward voltage drop uses the SL340-70 Schottky diode product with NiPt5 as the barrier metal and the SL3100-70 Schottky diode product with NiPt1 as examples, and the trial production process conditions and parameters shown in Table 1 are manufactured using the Schottky diode product chip production process. As shown in Tables 2 and 3, it is a parameter comparison table of the low forward voltage drop Schottky diode manufactured by the Schottky diode manufacturing method with low forward voltage drop and the same product produced by the existing production. According to Tables 1, 2 and 3, it can be seen that the forward voltage drop of the Schottky diode product produced by the conventional process is about 60mV larger than that of the Schottky diode product produced by the Schottky diode manufacturing method with low forward voltage drop, and the leakage current is about 30uA larger. The forward voltage drop of the Schottky diode product produced by the conventional process is about 50mV larger than that of the Schottky diode product produced by the Schottky diode manufacturing method with low forward voltage drop, and the leakage current is about 10uA larger.

[0054] Table 1 shows the data of the original Schottky diode products.

[0055]

[0056] Table 2 is a comparison table of parameters of SL340-70 Schottky diode products and conventional Schottky diode varieties

[0057]

[0058] Table 3 is a comparison table of parameters of SL3100-70 Schottky diode products and conventional Schottky diode varieties

[0059]

[0060] Embodiment 2:

[0061] The present invention also provides a Schottky diode with a low forward voltage drop, comprising an epitaxial wafer, and the epitaxial wafer is manufactured by using the above-mentioned method for manufacturing the Schottky diode with a low forward voltage drop.

[0062] It is further explained that the content of the manufacturing method of the low forward voltage drop Schottky diode has been described in Example 1. The low forward voltage drop Schottky diode achieves the situation of ensuring that the area of ​​the Schottky diode chip remains unchanged, increasing the area of ​​the Schottky diode barrier region, and reducing the forward voltage drop.

[0063] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0064] The above is a detailed introduction to the method for manufacturing a Schottky diode with a low forward voltage drop provided by an embodiment of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technicians in this field, according to the ideas of the present application, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A method for manufacturing a Schottky diode with a low forward voltage drop, characterized in that: The following steps are involved: Acquire power parameters and structural area of ​​the Schottky diode to be designed, and determine the barrier metal of the Schottky diode to be designed according to the power parameters; The structure of the Schottky diode to be designed includes a barrier region, a lead hole and a metal layer; According to the structural area, the structure of the Schottky diode to be designed is designed by adopting a rule of increasing the potential barrier area to obtain a structural diagram of the Schottky diode to be designed; According to the structure diagram and the barrier metal, a Schottky diode product chip production process is used to manufacture a Schottky diode with a low forward voltage drop; An inner ring line is arranged on the barrier region, the area between the outer ring line of the metal layer and the lead hole is recorded as the outer ring area, the area between the inner ring line and the lead hole is recorded as the inner ring area, and the area between the inner ring line and the outer ring line of the metal layer is recorded as the base ring; The rule for increasing the potential barrier area includes: without changing the structural area, increasing the width of the base ring and reducing the width of the outer ring area to increase the area of ​​the potential barrier area; Determining the barrier metal of the Schottky diode to be designed according to the power parameter includes: if the power parameter is not greater than the power threshold, the barrier metal of the Schottky diode to be designed is NiPt5; if the power parameter is greater than the power threshold, the barrier metal of the Schottky diode to be designed is NiPt1.

2. The method for manufacturing a Schottky diode with a low forward voltage drop according to claim 1, characterized in that: The NiPt5 is a metal made of nickel (Ni) and platinum (Pt) in a ratio of 19:

1.

3. The method for manufacturing a Schottky diode with a low forward voltage drop according to claim 1, characterized in that: The NiPt1 is a metal made of nickel Ni and platinum Pt in a ratio of 17:

3.

4. The method for manufacturing a Schottky diode with a low forward voltage drop according to any one of claims 1 to 3, characterized in that: The Schottky diode product chip production process includes: Acquire the epitaxial wafer of the Schottky diode to be designed according to the structural area; Performing base ring processing on the epitaxial wafer by laser marking according to the structural diagram to obtain a first processed sample; After injecting P+ ring ions into the first processed sample, performing lead hole processing by photolithography to obtain a second processed sample; The second processed sample is subjected to sputtering, corrosion, evaporation and annealing to obtain a Schottky diode with a low forward voltage drop.

5. The method for manufacturing a Schottky diode with a low forward voltage drop according to claim 4, characterized in that: According to the structure diagram, the epitaxial wafer is subjected to base ring processing by laser marking to obtain a first processed sample, including performing initial oxidation, laser marking, megasonic cleaning, base ring lithography and base ring etching processing on the epitaxial wafer in sequence according to the structure diagram to obtain the first processed sample.

6. The method for manufacturing a Schottky diode with a low forward voltage drop according to claim 4, characterized in that: After injecting P+ ring ions into the first processed sample, lead hole processing is performed by photolithography to obtain the second processed sample, which includes: after injecting P+ ring ions into the first processed sample, lead hole processing is performed by cleaning, base ring annealing, lead hole photolithography and lead hole etching in sequence to obtain the second processed sample.

7. The method for manufacturing a Schottky diode with a low forward voltage drop according to claim 4, characterized in that: The second processed sample is subjected to sputtering, etching, evaporation, and annealing to obtain a Schottky diode with a low forward voltage drop, including: cleaning, sputtering, silicide formation, silicide etching, 10:1 cleaning, evaporation of TiNiAg, metal reverse etching, metal reverse etching corrosion, PMA annealing, electrical testing, thinning, stress relief corrosion, PBMC cleaning, back evaporation, testing and inspection, slicing and slicing the second processed sample to obtain a Schottky diode with a low forward voltage drop.

8. A Schottky diode with low forward voltage drop, characterized in that: It comprises an epitaxial wafer, and the epitaxial wafer is produced by the method for manufacturing a Schottky diode with a low forward voltage drop according to any one of claims 1 to 7.

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