Diode processing method and diode
By forming a groove on the epitaxial layer of the diode and injecting boron to form an anode layer, the problem of insufficient turn-off softness of the diode is solved, and electromagnetic compatibility is improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BYD SEMICON CO LTD
- Filing Date
- 2021-12-21
- Publication Date
- 2026-05-29
Smart Images
Figure CN116313784B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of diode technology, specifically to a diode processing method and a diode. Background Technology
[0002] With the development of technology, diodes are being used more and more widely. Typically, during diode manufacturing, boron is implanted into a silicon wafer to form the anode layer. However, during boron implantation, a large amount of boron enters the silicon wafer, increasing the boron content and resulting in a lower turn-off softness in the final diode, thus affecting its electromagnetic compatibility.
[0003] Application content
[0004] This application provides a diode processing method and a diode to solve the problem of low turn-off softness of diodes in related technologies, which affects the electromagnetic compatibility of diodes.
[0005] To solve the above-mentioned technical problems, this application is implemented as follows:
[0006] In a first aspect, embodiments of this application provide a diode fabrication method, the method comprising:
[0007] A substrate layer is obtained, the substrate layer comprising a substrate layer, an epitaxial transition layer and an epitaxial layer stacked together;
[0008] Multiple grooves are formed on the formation surface of the epitaxial layer, and the formation surface of the epitaxial layer is a surface that faces away from the epitaxial transition layer.
[0009] An anode layer is formed on the forming surface;
[0010] A first metal layer is formed on the anode layer, and a second metal layer is formed on the surface of the substrate layer opposite to the epitaxial transition layer.
[0011] Optionally, forming a plurality of grooves on the forming surface of the epitaxial layer includes:
[0012] The grooves are formed by bombarding the forming surface with high-energy particles.
[0013] Optionally, forming a plurality of grooves on the forming surface of the epitaxial layer includes:
[0014] The forming surface is etched to form a plurality of the grooves.
[0015] Optionally, obtaining the base layer includes:
[0016] Obtain the substrate layer;
[0017] An epitaxial transition layer is formed on the first surface of the substrate layer;
[0018] The epitaxial layer is formed on the first surface of the epitaxial transition layer.
[0019] Optionally, the thickness of the anode layer ranges from 2 micrometers to 10 micrometers.
[0020] Optionally, before forming the anode layer on the forming surface, the method further includes:
[0021] The lifespan of the diode is increased by irradiating the epitaxial layer and the substrate layer with electrons.
[0022] Optionally, before forming the anode layer on the forming surface, the method further includes:
[0023] A platinum metal layer is formed on the surface of the epitaxial layer and the substrate layer to increase the lifespan of the diode.
[0024] Optionally, the anode layer has a plurality of recesses, each recess having an opening facing away from the forming surface.
[0025] Optionally, the depth of the groove ranges from 10 nanometers to 100 nanometers.
[0026] Optionally, forming the anode layer on the forming surface includes:
[0027] Boron is implanted onto the formation surface to form the anode layer; wherein the implantation density of the boron is 2*103. 12 -5*10 13 cm -2 Any value in the range.
[0028] Secondly, embodiments of this application provide a diode, which is manufactured by the diode manufacturing method described in any one of the first aspects above.
[0029] In this embodiment, a substrate layer is obtained, comprising a substrate layer, an epitaxial transition layer, and an epitaxial layer stacked together. Multiple grooves are formed on the formation surface of the epitaxial layer, which is a surface facing away from the epitaxial transition layer. An anode layer is formed on the formation surface. A first metal layer is formed on the anode layer, and a second metal layer is formed on the surface of the substrate layer facing away from the epitaxial transition layer. This increases the roughness of the formation surface, resulting in less dielectric material entering the epitaxial layer from the anode layer during anode layer formation. This reduces the attenuation rate of the reverse current in the epitaxial layer, thereby improving the turn-off softness of the final diode and enhancing its electromagnetic compatibility. Attached Figure Description
[0030] Figure 1This is a flowchart illustrating a diode fabrication method provided in an embodiment of this application;
[0031] Figure 2 This is a schematic diagram illustrating a substrate layer provided in an embodiment of this application;
[0032] Figure 3 This diagram illustrates a high-energy particle bombardment of a substrate layer according to an embodiment of this application.
[0033] Figure 4 This is a schematic diagram illustrating a high-energy particle bombardment of a substrate layer forming a groove on its surface, as provided in an embodiment of this application.
[0034] Figure 5 This is a schematic diagram illustrating the formation of an anode layer on a forming surface according to an embodiment of this application.
[0035] Figure 6 This is a schematic diagram illustrating a diode provided in an embodiment of this application.
[0036] Figure label:
[0037] 10: Base layer; 11: Substrate layer; 12: Epitaxial transition layer; 13: Epitaxial layer; 131: Groove; 20: Anode layer; 21: Recess; 30: First metal layer; 40: Second metal layer. Detailed Implementation
[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0039] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.
[0040] Reference Figure 1 The diagram shows a flowchart of a diode fabrication method provided in an embodiment of this application.
[0041] As shown in the figure, the diode fabrication method includes:
[0042] Step 101: Obtain the substrate layer, which includes a substrate layer, an epitaxial transition layer, and an epitaxial layer stacked together.
[0043] A diode typically includes a substrate layer 10. Other layers are deposited on the substrate layer 10 to finally form a diode. Therefore, the substrate layer 10 needs to be obtained first.
[0044] Additionally, refer to Figure 2 This illustration shows a schematic diagram of a base layer provided in an embodiment of this application, such as... Figure 2 As shown, the substrate layer 10 may include a substrate layer 11, an epitaxial transition layer 12, and an epitaxial layer 13 stacked together.
[0045] The thickness of the substrate layer 11 can be any value between 300 micrometers and 500 micrometers. For example, the substrate layer 11 can be 300 micrometers, 350 micrometers, 400 micrometers, 450 micrometers, or 500 micrometers. Furthermore, the substrate layer 11 typically contains ions, and the ion concentration can be 1*103 18 -1*10 19 cm -3 Any value in the range, for example, the concentration of ions can be 1*10. 18 cm -3 It can also be 1*10 19 cm -3 It can also be 2*10 18 cm -3 .
[0046] Furthermore, the thickness of the epitaxial transition layer 12 can be any value between 10 micrometers and 50 micrometers. For example, the thickness of the epitaxial transition layer 12 can be 10 micrometers, 20 micrometers, 30 micrometers, 40 micrometers, or 50 micrometers. Additionally, the epitaxial transition layer 12 typically includes ions, and the ion concentration can be 5*10⁻⁶. 14 -1*10 17 cm -3 For example, the concentration of ions can be 5*10. 14 cm -3 It can also be 6*10 14 cm -3 It can also be 1*10 17 cm -3 .
[0047] Furthermore, the thickness of the epitaxial layer 13 can be any value between 10 micrometers and 150 micrometers. For example, the thickness of the epitaxial layer 13 can be 10 micrometers, 30 micrometers, 50 micrometers, 100 micrometers, 130 micrometers, or 150 micrometers. Additionally, the epitaxial layer 13 typically contains ions, and the ion concentration can be 1*102 13 cm -3 -5*1014 cm -3 For example, the concentration of ions can be 1*10. 13 cm -3 It can also be 2*10 13 cm -3 It can also be 5*10 14 cm -3 .
[0048] In addition, in the embodiments of this application, the substrate layer 11, the epitaxial transition layer 12 and the epitaxial layer 13 may all include silicon, that is, the substrate layer 11, the epitaxial transition layer 12 and the epitaxial layer 13 may all be made of silicon.
[0049] In some implementations, step 101 can be implemented as follows: obtaining a substrate layer 11; forming an epitaxial transition layer 12 on a first surface of the substrate layer 11; and forming an epitaxial layer 13 on a first surface of the epitaxial transition layer 12.
[0050] After obtaining the substrate layer 11, an epitaxial transition layer 12 can be formed on the first surface of the substrate layer 11 using an epitaxial process. Then, an epitaxial layer 13 is formed on the epitaxial transition layer 12 using another epitaxial process. The essence of epitaxy is the growth of silicon on the substrate layer 11, forming the epitaxial transition layer 12 on the substrate layer 11, and then forming the epitaxial layer 13.
[0051] Step 102: Form multiple grooves on the formation surface of the epitaxial layer, wherein the formation surface of the epitaxial layer is the surface opposite to the epitaxial transition layer.
[0052] After multiple grooves 131 are formed on the formation surface of the epitaxial layer 13, the surface roughness of the formation surface increases, which facilitates the formation of other layers on the formation surface of the epitaxial layer 13. That is, by forming multiple grooves 131 on the formation surface of the epitaxial layer 13, it is convenient to form other layers on the epitaxial layer 13.
[0053] Furthermore, step 102 can be implemented in different ways. This application embodiment will illustrate the following implementation methods as examples:
[0054] Implementation method (1): Form a surface by bombarding with high-energy particles to form multiple grooves.
[0055] Among them, such as Figure 3 and Figure 4As shown, high-energy particles can be used to bombard the forming surface. When high-energy particles bombard the forming surface, they collide with it, essentially creating a high-energy particle impact on the forming surface. Upon contact with the forming surface, the high-energy particles are blocked, but they can still use their own energy to impact and form grooves 131. Typically, multiple high-energy particles are used; therefore, by bombarding the forming surface with multiple high-energy particles, multiple grooves 131 can be formed.
[0056] In addition, since high-energy particles are usually emitted through specific equipment and a large number of high-energy particles are emitted, the high-energy particles are distributed more evenly when bombarding the forming surface. Therefore, the high-energy particles are in more even contact with the forming surface, and the multiple grooves 131 formed can be distributed more evenly on the forming surface. This makes it easier to form the anode layer 20 when forming the anode layer 20 on the forming surface.
[0057] Alternatively, high-energy argon particle bombardment can be used to form the surface. Of course, other high-energy particle bombardment can also be used to form the surface, such as high-energy helium particle bombardment. This application does not limit the specific application in this embodiment.
[0058] Implementation method (2): Etching to form a surface to form multiple grooves.
[0059] In this process, a dry etching process can be used to etch the surface, thereby forming multiple grooves 131. Specifically, the dry etching process is a technique for thin film etching using plasma. When the gas exists in the form of plasma, it has two characteristics: First, the chemical reactivity of these gases in plasma is much stronger than under normal conditions. Depending on the material being etched, selecting a suitable gas can allow it to react with the material more quickly, achieving the purpose of etching removal. Second, an electric field can be used to guide and accelerate the plasma, giving it a certain amount of energy. When it bombards the surface of the object being etched, it will eject the atoms of the material being etched, thereby achieving the purpose of etching through physical energy transfer.
[0060] Furthermore, dry etching processes can be divided into three types: physical etching and chemical etching. Physical etching is also known as sputtering etching. Chemical etching utilizes the chemically active atomic groups in plasma to react chemically with the material being etched, thereby achieving the etching purpose.
[0061] Furthermore, in this embodiment, the depth of the groove 131 ranges from 10 nanometers to 100 nanometers. Specifically, the depth of the groove 131 can be any value within the range of 10 nanometers to 100 nanometers. For example, as... Figure 4As shown, the depth of the groove 131 is H, which can be 10 nanometers, 20 nanometers, 40 nanometers, 60 nanometers, 80 nanometers, or 100 nanometers.
[0062] When the depth of the groove 131 is in the range of 10 nanometers to 100 nanometers, the multiple grooves 131 are equivalent to forming a rough layer, that is, a rough layer is formed on the forming surface through the multiple grooves 131, and the thickness of the rough layer is in the range of 10 nanometers to 100 nanometers.
[0063] Step 103: Form an anode layer on the forming surface.
[0064] Step 103 can be implemented as follows: Figure 5 As shown, boron is injected into the formation surface to form an anode layer 20. Specifically, when injecting boron into the formation surface, a high-temperature annealing process can be used to enrich the boron on the formation surface, thereby forming the anode layer 20. The high-temperature annealing process essentially involves placing the substrate layer 10 at a preset temperature and holding it at that temperature for a preset time. In other words, the high-temperature annealing process essentially enriches the boron on the formation surface under preset temperature and preset time conditions to form the anode layer 20.
[0065] In addition, in this embodiment, since multiple grooves 131 are formed on the forming surface, the roughness of the forming surface is increased. After a certain amount of boron is injected on the forming surface, the boron will be enriched on the forming surface, which reduces the amount of boron entering the forming surface. That is, the amount of boron entering the epitaxial layer 13 is reduced, which is equivalent to the amount of boron entering the silicon wafer. As a result, the turn-off softness of the diode can be improved after the diode is formed.
[0066] It should be noted that in the embodiments of this application, the anode layer 20 can be P-type and the base layer 10 can be N-type, that is, the diode can be a PN junction diode.
[0067] Furthermore, in this embodiment of the application, the boron injection density can be 2*102. 12 -5*10 13 cm -2 Any value in the range. For example, the injection density can be 2*10. 12 cm -2 It can also be 3*10 12 cm -2 It can also be 4*10 13 cm -2 It can also be 5*10 13 cm -2 .
[0068] Furthermore, in some implementations, the thickness of the anode layer 20 can range from 2 micrometers to 10 micrometers. Specifically, the thickness of the anode layer 20 can be any value within the range of 2 micrometers to 10 micrometers. For example, as... Figure 5 As shown, the thickness of the anode layer 20 is L, which can be 2 micrometers, 3 micrometers, 6 micrometers, 8 micrometers, or 10 micrometers.
[0069] When the thickness of the anode layer 20 is in the range of 2 micrometers to 10 micrometers, the thickness of the anode layer 20 is not too small, which would affect the use of the diode, and the thickness of the anode layer is not too large, so that when there is reverse current in the epitaxial layer, the thickness of the anode layer 20 formed by boron is smaller, thereby reducing the attenuation rate of the reverse current and improving the turn-off softness of the diode.
[0070] In addition, in some implementations, to improve the lifespan of the diode, further processing can be performed on the diode before step 103. The following two methods will be used as examples:
[0071] Implementation method (a): Increase the lifespan of the diode by electron irradiation of the epitaxial layer and the substrate layer.
[0072] The epitaxial layer 13 and the substrate layer 10 can be irradiated with a high-energy electron beam, thereby extending the lifespan of the epitaxial layer 13 and the substrate layer 10, and consequently extending the lifespan of the diode.
[0073] Implementation method (b): A platinum metal layer is formed on the surface of the epitaxial layer and the substrate layer to increase the lifespan of the diode.
[0074] Platinum metal can be sputtered onto the surfaces of the epitaxial layer 13 and the base layer 10 through a sputtering process. This is equivalent to applying a platinum expansion process to the epitaxial layer 13 and the base layer 10, which extends the lifespan of the epitaxial layer 13 and the base layer 10, thereby extending the lifespan of the diode.
[0075] In some implementations, after multiple grooves 131 are formed on the formation surface by bombardment with high-energy particles, boron can be injected into the formation surface to form an anode layer 20. When boron is injected into the formation surface, it will accumulate there. As boron accumulates on the formation surface, it will also accumulate in the grooves 131. Thus, after the anode layer 20 is formed, the anode layer 20 will have multiple recesses 21 due to the effect of the multiple grooves 131 on the formation surface, and the notch of each recess 21 will face away from the formation surface.
[0076] Step 104: Form a first metal layer on the anode layer and form a second metal layer on the surface of the substrate layer opposite to the epitaxial transition layer.
[0077] Among them, such as Figure 6 As shown, after a first metal layer 30 is formed on the anode layer 20 and a second metal layer 40 is formed on the surface of the substrate layer 11 away from the epitaxial transition layer 12, the substrate layer 10 and the anode layer 20 are both located between the first metal layer 30 and the second metal layer 40. The first metal layer 30 and the second metal layer 40 can achieve the effect of conduction, thereby enabling the diode to carry current.
[0078] Furthermore, the first metal layer 30 can serve as an anode metal layer, and the thickness of the first metal layer 30 can be any value from 1 micrometer to 4 micrometers. For example, the thickness of the first metal layer 30 can be 1 micrometer, 2 micrometers, 3 micrometers, or 4 micrometers.
[0079] In addition, when forming the first metal layer 30 on the anode layer 20, a sputtering process can be used, that is, sputtering metal onto the anode layer 20 to form the first metal layer 30.
[0080] Furthermore, the thickness of the second metal layer 40 can be any value from 1 micrometer to 2 micrometers. For example, the second metal layer 40 can be 1 micrometer, 1.5 micrometers, or 2 micrometers. The material of the second metal layer 40 can be silver, titanium, nickel, or other metals; however, this embodiment does not limit the specific materials used.
[0081] Furthermore, in this embodiment, after the first metal layer 30 is formed on the anode layer 20, since the anode layer 20 is essentially formed by boron implantation on the formation surface, and the formation surface has multiple grooves 131, less boron enters the epitaxial layer 13, while more accumulates on the formation surface. Therefore, the potential barrier height between the anode layer 20 and the first metal layer 30 can be reduced, allowing a better ohmic contact to be formed between the anode layer 20 and the first metal layer 30, thereby reducing the forward voltage drop of the diode. Here, ohmic contact refers to the contact between a semiconductor and a metal.
[0082] In this embodiment, a substrate layer 10 is obtained, comprising a substrate layer 11, an epitaxial transition layer 12, and an epitaxial layer 13 stacked together. Multiple grooves 131 are formed on the formation surface of the epitaxial layer 13, which is the surface facing away from the epitaxial transition layer 12. An anode layer 20 is formed on the formation surface. A first metal layer 30 is formed on the anode layer 20, and a second metal layer 40 is formed on the surface of the substrate layer 11 facing away from the epitaxial transition layer 12. This increases the roughness of the formation surface, resulting in less dielectric material entering the epitaxial layer 13 when the anode layer 20 is formed on the formation surface. This reduces the attenuation rate of the reverse current in the epitaxial layer 13, thereby improving the turn-off softness of the final diode and enhancing its electromagnetic compatibility.
[0083] This application provides a diode manufactured by a diode fabrication method.
[0084] In this embodiment, a substrate layer 10 is obtained, comprising a substrate layer 11, an epitaxial transition layer 12, and an epitaxial layer 13 stacked together. Multiple grooves 131 are formed on the formation surface of the epitaxial layer 13, which is the surface facing away from the epitaxial transition layer 12. An anode layer 20 is formed on the formation surface. A first metal layer 30 is formed on the anode layer 20, and a second metal layer 40 is formed on the surface of the substrate layer 11 facing away from the epitaxial transition layer 12. This increases the roughness of the formation surface, resulting in less dielectric material entering the epitaxial layer 13 when the anode layer 20 is formed on the formation surface. This reduces the attenuation rate of the reverse current in the epitaxial layer 13, thereby improving the turn-off softness of the final diode and enhancing its electromagnetic compatibility.
[0085] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0086] Although optional embodiments of the present application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the optional embodiments as well as all changes and modifications falling within the scope of the embodiments of the present application.
[0087] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used merely to distinguish one entity from another, and do not necessarily require or imply any such actual relationship or order between these entities. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or terminal device that includes that element.
[0088] The technical solutions provided in this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the principles and implementation methods of this application. Therefore, the content of this specification should not be construed as a limitation of this application.
Claims
1. A diode fabrication method, characterized in that, The method includes: A substrate layer is obtained, the substrate layer comprising a substrate layer, an epitaxial transition layer and an epitaxial layer stacked together; Multiple grooves are formed on the formation surface of the epitaxial layer, and the formation surface of the epitaxial layer is the surface facing away from the epitaxial transition layer; the depth of the grooves ranges from 10 nanometers to 100 nanometers. Boron is implanted into the forming surface to form an anode layer on the forming surface; wherein, during the implantation of boron into the forming surface, a high-temperature annealing process is used to enrich the boron on the forming surface. A first metal layer is formed on the anode layer, and a second metal layer is formed on the surface of the substrate layer opposite to the epitaxial transition layer.
2. The diode processing method according to claim 1, characterized in that, The formation of multiple grooves on the forming surface of the epitaxial layer includes: The grooves are formed by bombarding the forming surface with high-energy particles.
3. The diode fabrication method according to claim 1, characterized in that, The formation of multiple grooves on the forming surface of the epitaxial layer includes: The forming surface is etched to form a plurality of the grooves.
4. The diode fabrication method according to claim 1, characterized in that, The acquisition of the base layer includes: Obtain the substrate layer; An epitaxial transition layer is formed on the first surface of the substrate layer; The epitaxial layer is formed on the first surface of the epitaxial transition layer.
5. The diode fabrication method according to claim 1, characterized in that, The thickness of the anode layer ranges from 2 micrometers to 10 micrometers.
6. The diode fabrication method according to claim 1, characterized in that, Before forming the anode layer on the forming surface, the method further includes: The lifespan of the diode is increased by irradiating the epitaxial layer and the substrate layer with electrons.
7. The diode fabrication method according to claim 1, characterized in that, Before forming the anode layer on the forming surface, the method further includes: A platinum metal layer is formed on the surface of the epitaxial layer and the substrate layer to increase the lifespan of the diode.
8. The diode fabrication method according to any one of claims 1-7, characterized in that, The anode layer has multiple recesses, and the notch of each recess is opposite to the forming surface.
9. The diode processing method according to any one of claims 1-7, characterized in that, The boron injection density is 2*10 12 -5*10 13 cm -2 Any value in the range.
10. A diode, characterized in that, The diode is manufactured by the diode manufacturing method according to any one of claims 1-9.