Silicon carbide bipolar junction transistor and preparation method thereof

Abstract

The invention provides a silicon carbide bipolar junction transistor and a preparation method thereof. The silicon carbide bipolar junction transistor comprises a substrate; the epitaxial layer is formed on the substrate; the base region is formed downwards from the upper surface of the epitaxial layer, and a gap is formed between the lower surface of the base region and the lower surface of the epitaxial layer; the emitter region of the first doping type is formed on the base region; an emitter metal formed over the emitter region; wherein the emitter region of the first doping type is in metal connection with the emitter. According to the invention, the technical problem that the preparation technology of a traditional SiC BJT device has high requirements is solved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and specifically, to a silicon carbide bipolar junction transistor and a method for manufacturing the same. Background Art

[0002] Silicon carbide (SiC) material is a third-generation wide bandgap semiconductor. Its bandgap width of 3.2 eV is much larger than that of traditional silicon material of 1.1 eV, and its critical breakdown field strength is one order of magnitude higher than that of silicon material. It has the advantages of high temperature and high pressure resistance. At the same time, its saturated drift velocity is fast, making it suitable for manufacturing high-temperature and high-pressure power semiconductor devices with fast response. For example, silicon carbide (SiC) bipolar junction transistor (BJT, the full English name is Bipolar Junction Transistor, and the Chinese abbreviation is triode), because it has no gate oxide and has a low on-resistance, has a high current gain β. For high-voltage applications, a high-gain BJT can provide lower power loss in the base drive circuit.

[0003] The SiC BJT device of the traditional technical solution is applied as a power device, usually vertical, and the collector is located at the bottom of the chip.

[0004] The current gain β of the SiC BJT device is closely related to the concentration and thickness of the base region. The thinner the thickness, the greater the gain, and the lighter the doping concentration, the greater the gain. However, if it is too light, it is easy to break down. Therefore, the performance of the SiC BJT device is very sensitive to the concentration of the base region, and a thinner base region with a stable concentration is required.

[0005] The electrical connection between the base region and the base metal of the SiC BJT device also has a great impact on the device. When the electrical connection between the base region and the base metal is poor, the base resistance will share more voltage, resulting in a larger turn-on voltage and switching loss of the device.

[0006] If the thickness of the base region is set to be thinner and the doping concentration is lower. In this way, the current gain β is higher, but the electrical connection between the base region and the base metal is not good enough, resulting in a larger turn-on voltage and switching loss of the SiC BJT device.

[0007] If the doping concentration of the base region is set to be higher. In this way, the electrical connection between the base region and the base metal is good, but the current gain β of the SiC BJT device is lower.

[0008] In addition, the emitter region and the base region are formed at least by an implantation method from the upper surface of the self-epitaxial layer downward, that is, the base region is not formed starting from the upper surface of the epitaxial layer, resulting in higher requirements for the manufacturing process of the SiC BJT device.

[0009] Therefore, the preparation process of traditional SiC BJT devices has relatively high requirements, which is a technical problem that needs to be urgently solved by those skilled in the art.

[0010] The above information disclosed in the background art is only used to enhance the understanding of the background of the present application. Therefore, it may contain information on the prior art that is not known to those of ordinary skill in the art. Summary of the Invention

[0011] The present application provides a silicon carbide bipolar junction transistor and a preparation method thereof to solve the technical problem that the preparation process of traditional SiC BJT devices has relatively high requirements.

[0012] The present application provides a silicon carbide bipolar junction transistor, including:

[0013] A substrate of a first doping type;

[0014] An epitaxial layer of a first doping type, formed on the substrate;

[0015] A base region of a second doping type, formed downward from the upper surface of the epitaxial layer, and there is a gap between the lower surface of the base region and the lower surface of the epitaxial layer;

[0016] An emitter region of a first doping type, formed on the base region;

[0017] Emitter metal, formed on the emitter region;

[0018] Wherein, the emitter region of the first doping type is connected to the emitter metal.

[0019] The present application also provides a preparation method of a silicon carbide bipolar junction transistor, including the following steps:

[0020] Form an epitaxial layer of a first doping type on a substrate of a first doping type;

[0021] Form a base region of a second doping type downward from the upper surface of the epitaxial layer by an implantation process; there is a gap between the lower surface of the base region and the lower surface of the epitaxial layer;

[0022] Form an emitter region of a first doping type on the base region by an epitaxial process;

[0023] Form emitter metal, located on the emitter region;

[0024] Wherein, the emitter region of the first doping type is connected to the emitter metal.

[0025] Due to the adoption of the above technical solutions, the present application has the following technical effects:

[0026] The present application breaks through the technical idea of forming the emitter region of the semiconductor within the epitaxial layer, and creates a new technical idea that the emitter region 8, one of the functional regions of the semiconductor, is formed on the base region 5 and is located above the epitaxial layer, so that the preparation process requirements of the base region 5 are relatively low, thereby making the silicon carbide bipolar junction transistor of the present application simple in structure and easy to prepare.

[0027] In the prior art, there are at least an emitter region and a base region from the upper surface of the epitaxial layer downward, that is, the base region is not formed starting from the upper surface of the epitaxial layer. When the base region is formed by injection, a position needs to be reserved for the emitter region. That is, the base region formed by injection starts from a preset position downward from the upper surface of the epitaxial layer, so the process requirements for injecting the base region are also relatively high. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0029] Figure 1 A schematic diagram of an implementation of the silicon carbide bipolar junction transistor of the present application;

[0030] Figure 2 A schematic diagram of another implementation of the silicon carbide bipolar junction transistor of the present application;

[0031] Figure 3 A schematic diagram of completing step 1 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0032] Figure 4 A schematic diagram of completing step 2 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0033] Figure 5 A schematic diagram of completing step 3 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0034] Figure 6 A schematic diagram of completing step 4 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0035] Figure 7 A schematic diagram of completing step 5 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0036] Figure 8 A schematic diagram of completing step 6 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0037] Figure 9 A schematic diagram of completing step 7 of the method for preparing a silicon carbide bipolar junction transistor of the present application;

[0038] Figure 10 Schematic diagram for completing step 8 of the preparation method of the silicon carbide bipolar junction transistor of the present application;

[0039] Figure 11 Schematic diagram for completing step 9 of the preparation method of the silicon carbide bipolar junction transistor of the present application;

[0040] Figure 12 Schematic diagram for completing step 10 of the preparation method of the silicon carbide bipolar junction transistor of the present application;

[0041] Figure 13 Schematic diagram for completing step 11 of the preparation method of the silicon carbide bipolar junction transistor of the present application;

[0042] Figure 14 Schematic diagram of the current simulation results of the base connection regions with different thicknesses of the silicon carbide bipolar junction transistor of the present application.

[0043] Reference numerals:

[0044] Substrate 1, epitaxial layer 2, collector region 3, first isolation region 4, base region 5, base connection region 6,

[0045] Second isolation region 7, first layer of the second isolation region 7-1, second layer of the second isolation region 7-2,

[0046] Emitter region 8, base metal 9, emitter metal 10, collector metal 11. Detailed implementation manners

[0047] In order to make the technical solutions and advantages in the present application clearer and more understandable, the following further details the exemplary embodiments of the present application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0048] Embodiment 1

[0049] As Figure 1 and Figure 2 shown, a silicon carbide bipolar junction transistor of the present application includes:

[0050] A substrate 1 of the first doping type;

[0051] An epitaxial layer 2 of the first doping type, formed on the substrate 1;

[0052] A base region 5 of the second doping type, formed downward from the upper surface of the epitaxial layer 2, and there is a gap between the lower surface of the base region 5 and the lower surface of the epitaxial layer 2;

[0053] An emitter region 8 of a first doping type is formed on the base region 5;

[0054] An emitter metal 10 is formed on the emitter region 8;

[0055] The emitter region 8 of the first doping type and the emitter metal 10 are connected.

[0056] The present application breaks through the technical idea of forming the emitter region of the semiconductor within the epitaxial layer, and creates a new technical idea that the emitter region 8, one of the functional regions of the semiconductor, is formed on the base region 5 and is located above the epitaxial layer, so that the preparation process requirements of the base region 5 are relatively low, thereby making the silicon carbide bipolar junction transistor of the present application simple in structure and easy to prepare.

[0057] In the prior art, there are at least an emitter region and a base region from the upper surface of the epitaxial layer downward, that is, the base region is not formed starting from the upper surface of the epitaxial layer. When the base region is formed by injection, a position needs to be reserved for the emitter region. That is, the base region formed by injection starts from a preset position downward from the upper surface of the epitaxial layer, so the process requirements for injecting the base region are also relatively high.

[0058] Specifically, the base region 5 is first formed downward from the upper surface of the epitaxial layer, and then the emitter region is formed on the base region 5 through an epitaxial process. This also brings the advantage of a simpler preparation process for the base region 5. The base region 5 is directly formed from the upper surface of the epitaxial layer, and the preparation process is simpler.

[0059] The present application breaks through the technical idea of forming the functional area of the semiconductor through the injection process, and creates a new technical idea of forming the emitter area 8, one of the functional areas of the semiconductor, through the epitaxial process, so that the doping concentration of the emitter area 8 formed by the epitaxial process can be very high, and the contact between the emitter area 8 and the emitter metal 10 is ohmic contact.

[0060] In the implementation, the doping concentration of the emitter region is in the range of greater than or equal to 1×10 20 cm -3 Less than or equal to 1×10 22 cm -3 , so that there is an ohmic contact between the emitter region 8 and the emitter metal 10;

[0061] The base region 5 is first formed, and then the emitter region 8 is formed on the base region 5 by an epitaxial process. The emitter region 8 is formed by the epitaxial process so that the doping concentration of the emitter region 8 has a value range greater than or equal to 1×10 20 cm -3 Less than or equal to 1×10 22 cm -3 .

[0062] In implementation, as Figure 1 and Figure 2 shown, the silicon carbide bipolar junction transistor further includes:

[0063] A base connection region 6 of a second doping type, formed on the base region 5, and the doping concentration of the base connection region 6 is greater than the doping concentration of the base region 5;

[0064] A base metal 9, formed on the base connection region 6;

[0065] Wherein, the base region 5 of the second doping type, the base connection region 6 of the second doping type, and the base metal 9 are connected, and the doping concentration of the base connection region 6 ranges from greater than or equal to 1×10 20 cm -3 less than or equal to 1×10 22 cm -3 , so that an ohmic contact is formed between the base connection region 6 and the base metal 9.

[0066] The requirement for the base region 5 of the second doping type is that the doping concentration is low and the thickness of the base region 5 is thin, so that a higher current gain β can be achieved. In this application, a base connection region 6 of the second doping type with a high doping concentration is provided. In this way, the base region 5 of the second doping type and the base connection region 6 of the second doping type have the same doping type, so that the electrical connection between the base region 5 and the base connection region is good. A doping concentration greater than or equal to 1×1020 cm-3 is a very high doping concentration. The relatively high base connection region 6 is connected to the base metal 9 of the metal material, so that the contact between the base connection region 6 and the base metal 9 is an ohmic contact, reducing the contact resistance at the base metal 9. Thus, a good electrical connection is achieved among the base region 5 of the second doping type, the base connection region 6 of the second doping type, and the base metal 6. For the silicon carbide bipolar junction transistor of this application, by introducing the base connection region 6 of the second doping type with a relatively high doping concentration, on the one hand, the doping concentration of the base region 5 of the second doping type can be kept low to achieve a relatively high current gain β; on the other hand, through the good electrical connection between the base region 5 of the second doping type and the base connection region 6 of the second doping type, and the good electrical connection between the highly doped base connection region 6 and the base metal 9, the high electrical connection of the base region 5 can be led out, and thus the turn-on voltage and switching loss of the silicon carbide bipolar junction transistor are both small. The structure of the silicon carbide bipolar junction transistor of this application achieves a relatively high current gain β and a small switching loss.

[0067] It should be noted that in traditional SiC BJT devices, only the epitaxial layer is formed by the epitaxial process. The process of forming the functional area in the epitaxial layer is formed by an implantation process or a process of trenching first and then deposition. For example, in traditional SiC BJT devices, the base region is formed by an implantation process, and the base metal is formed by a process of trenching first and then deposition. At present, the doping concentration of the implanted region by the implantation process is limited by the implantation process, so that the doping concentration of the implanted region is limited to less than 1×10 19 cm -3 The process of trenching first and then deposition is generally applicable to the preparation of metal structures and oxide layers.

[0068] In the present application, the base connection region 6 is not formed by an implantation process, but by an epitaxial process. Thus, the doping concentration of the base connection region 6 has a value range greater than or equal to 1×10 20 cm -3 Less than or equal to 1×10 22 cm -3 , breaking through the fact that the injection doping concentration can only be less than 1×10 19 cm -3 restrictions.

[0069] The present application breaks through the technical idea of forming the functional area of the semiconductor through the injection process, and creates a new technical idea of forming the base connection area 6, one of the functional areas of the semiconductor, through the epitaxial process, so that the doping concentration of the base connection area 6 formed by the epitaxial process can be very high, and the contact between the base connection area 6 and the base metal 9 is ohmic contact.

[0070] In implementation, as an optional method, such as Figure 1 As shown, the cross section of the emitting area 8 is a T-shaped structure.

[0071] The emitter region 8 formed by the epitaxial process can realize a T-shaped cross-section structure. In this way, the upper surface area of the emitter region 8 is large, which facilitates the subsequent formation of the emitter metal 10 on the emitter region 8.

[0072] In implementation, as another optional method, such as Figure 2 As shown, the cross section of the emission area 8 is an I-type structure.

[0073] In this way, the preparation of the emission region 8 is simpler.

[0074] In practice, the doping concentration of the base region 5 is in the range of greater than or equal to 1×10 16 cm -3 Less than 1×10 19 cm -3 .

[0075] The base region 5 is formed by an implantation process, and the doping concentration ranges from greater than or equal to 1×10 16 cm -3 to less than 1×10 19 cm -3 . For a relatively high current gain β, the doping concentration of the base region 5 is relatively low. Therefore, the implantation process can meet the requirements for its doping concentration.

[0076] In implementation, the base region connection region 6 is a base region connection region 6 made of single-crystal or polycrystalline silicon carbide material;

[0077] The emitter region 8 is an emitter region 8 made of single-crystal or polycrystalline silicon carbide material.

[0078] Polycrystalline silicon carbide is grown by an epitaxial process. The doping concentration of polycrystalline silicon carbide is uniform and easier to control. Therefore, it is more convenient to form the base region connection region 6 made of polycrystalline silicon carbide material and the emitter region 8 made of polycrystalline silicon carbide material by the epitaxial process, and the preparation cost is also relatively low.

[0079] The doping concentration of the single-crystal silicon carbide grown by the epitaxial process can also meet the requirements for the doping concentration. The preparation cost of the single-crystal silicon carbide grown epitaxially is slightly higher.

[0080] In implementation, the thickness of the base region connection region 6 ranges from greater than or equal to 0.1 μm to less than or equal to 1 μm;

[0081] The thickness of the emitter region 8 ranges from greater than or equal to 0.1 μm to less than or equal to 1 μm.

[0082] In implementation, as shown in Figure 1 and Figure 2 , the silicon carbide bipolar junction transistor further includes:

[0083] A collector region 3 of a first doping type, formed between the lower surfaces of the base region 5, and the lower surface of the base region 5 is connected to the lower surface of the epitaxial layer 2;

[0084] A collector metal 11, formed on the back side of the substrate 1;

[0085] Among them, the collector region 3 of the first doping type, the substrate 1 of the first doping type, and the collector metal 11 are connected.

[0086] The connection of the collector region 3 of the first doping type, the substrate 1 of the first doping type, and the collector metal 11 realizes taking out the collector region 3.

[0087] Specifically, as shown in Figure 1 and Figure 2As shown, the silicon carbide bipolar junction transistor further includes a first isolation region 4 formed at both ends of the base region 5; correspondingly, the base region connection region 6 is located above the first isolation region 4 and the base region 5.

[0088] The first isolation region realizes the isolation function. The first isolation region uses an oxide material.

[0089] Specifically, the collector region 3 of the first doping type and the base region 5 of the second doping type are each formed by an implantation process.

[0090] Specifically, the substrate 1 is a silicon carbide substrate; the epitaxial layer 2 is a silicon carbide epitaxial layer;

[0091] Specifically, the thickness of the substrate of the first doping type of silicon carbide material ranges from greater than or equal to 80 μm to less than or equal to 500 μm, and the doping concentration ranges from greater than or equal to 1×10 18 cm -3 less than or equal to 1×10 22 cm -3 . The substrate 1 of the first doping type is used to connect the collector metal 11 and the collector region 3.

[0092] Specifically, the epitaxial layer 2 of the first doping type of silicon carbide material has a thickness ranging from greater than or equal to 1 μm to less than or equal to 10 μm, and the doping concentration ranges from greater than or equal to 1×10 14 cm -3 less than or equal to 1×10 17 cm -3 . The epitaxial layer serves as the collector.

[0093] Specifically, the collector region 3 of the first doping type of silicon carbide has a thickness ranging from greater than or equal to 0.5 μm to less than or equal to 10 μm, and the doping concentration ranges from greater than or equal to 1×10 16 cm -3 less than or equal to 1×10 19 cm -3 . The collector region 3 serves as the collector.

[0094] Specifically, the thickness of the base region 5 of the second doping type ranges from greater than or equal to 0.01 μm to less than or equal to 0.5 μm, and the doping concentration ranges from greater than or equal to 1×10 16 cm -3 less than or equal to 1×10 19 cm -3 . The base region 5 serves as the base. The shallower the implantation depth of the base region 5, the larger the ratio β of the collector current to the base current, and the better the performance of the device.

[0095] Specifically, the base connection region 6 of polycrystalline silicon carbide (Poly SiC) of the second doping type has a thickness ranging from greater than or equal to 0.1 μm to less than or equal to 1 μm, and a doping concentration ranging from greater than or equal to 1×10 20 cm -3 less than or equal to 1×10 22 cm -3 . The base connection region 6 is doped during growth with an extremely high doping concentration, which can be used to provide good ohmic contact and conduction effect.

[0096] Specifically, the emitter region 8 of polycrystalline silicon carbide (Poly SiC) of the first doping type has a thickness ranging from greater than or equal to 0.1 μm to less than or equal to 1 μm, and a doping concentration ranging from greater than or equal to 1×10 20 cm -3 less than or equal to 1×10 22 cm -3 . The emitter region 8 is doped during growth with an extremely high doping concentration. As the device emitter, it can also provide good ohmic contact.

[0097] The base connection region 6 of the silicon carbide bipolar junction transistor of the present application uses a base connection region 6 of polycrystalline silicon carbide material with high doping (>1×10 20 cm -3 ), which reduces the ohmic contact resistance between the base connection region 6 and the base metal 9 of the metal by one order of magnitude, and thus affects the performance of the device.

[0098] The simulation results of the silicon carbide bipolar junction transistor of the present application and the silicon carbide bipolar junction transistor in the background technology are shown in the following table.

[0099]

[0100]

[0101] As can be seen from the above table, the Pout@maxP (maximum output power at the power point) and β (current gain) of the device of the present application are both larger.

[0102] For the silicon carbide bipolar junction transistor of the present application, the current simulation results of the base connection region 6 with different thicknesses are as Figure 14 shown:

[0103] Below is the I B -V B curve, and above is the I C -V B curve. I C / I B=β, it is obtained that for the silicon carbide bipolar junction transistor of the present application with the same structure, when the thickness of the base region 5 is 0.09μm, 0.08μm, and 0.07μm, β is 227, 375, and 953, respectively. The reduction of the thickness of the base region 5 has a significant increase in β.

[0104] Embodiment 2

[0105] The method for preparing the silicon carbide bipolar junction transistor of the embodiment of the present application comprises the following steps:

[0106] forming an epitaxial layer 2 of a first doping type on a substrate 1 of a first doping type;

[0107] A base region 5 of a second doping type is formed downward from the upper surface of the epitaxial layer 2 by an implantation process; a gap is provided between the lower surface of the base region 5 and the lower surface of the epitaxial layer 2;

[0108] forming an emitter region 8 of a first doping type on the base region 5 by an epitaxial process;

[0109] forming an emitter metal 10 located on the emitter region 8;

[0110] The emitter region 8 of the first doping type and the emitter metal 10 are connected.

[0111] The present application breaks through the technical idea of forming the emitter region of the semiconductor within the epitaxial layer, and creates a new technical idea that the emitter region 8, one of the functional regions of the semiconductor, is formed on the base region 5 and is located above the epitaxial layer, so that the preparation process requirements of the base region 5 are relatively low, thereby making the silicon carbide bipolar junction transistor of the present application simple in structure and easy to prepare.

[0112] The method of first forming the base region 5 from the upper surface of the epitaxial layer downwards, and then forming the emitter region on the base region 5 through the epitaxial process also brings the advantage of a simpler preparation process for the base region 5. The base region 5 is directly formed from the upper surface of the epitaxial layer, and the preparation process is simpler.

[0113] In the prior art, there are at least an emitter region and a base region from the upper surface of the epitaxial layer downward, that is, the base region is not formed starting from the upper surface of the epitaxial layer. Therefore, when the base region is formed by injection, a position needs to be reserved for the emitter region. That is, the base region formed by injection starts at a position downward from the upper surface of the epitaxial layer, so the process requirements for injecting the base region are also relatively high.

[0114] In the implementation, the doping concentration of the emitter region is in the range of greater than or equal to 1×10 20 cm -3 Less than or equal to 1×10 22 cm -3 , so that there is ohmic contact between the emitter region 8 and the emitter metal 10.

[0115] The present application breaks through the technical idea of forming the functional area of the semiconductor through the injection process, and creates a new technical idea of forming the emitter area 8, one of the functional areas of the semiconductor, through the epitaxial process, so that the doping concentration of the emitter area 8 formed by the epitaxial process can be very high, and the contact between the emitter area 8 and the emitter metal 10 is ohmic contact.

[0116] In practice, the method for preparing a silicon carbide bipolar junction transistor further includes the following steps:

[0117] forming a base region connection region 6 of a second doping type on the base region 5 by an epitaxial process, wherein the doping concentration of the base region connection region 6 is greater than the doping concentration of the base region 5;

[0118] forming a base metal 9, wherein the base metal 9 is located on the base region connection region 6;

[0119] The base region 5 of the second doping type, the base region connection region 6 of the second doping type, and the base metal 9 are connected, and the doping concentration of the base region connection region 6 is in the range of greater than or equal to 1×10 20 cm -3 Less than or equal to 1×10 22 cm -3 , so that there is ohmic contact between the base connection region 6 and the base metal 9.

[0120] In the present application, the base connection region 6 is not formed by an implantation process, but by an epitaxial process. Thus, the doping concentration of the base connection region 6 has a value range greater than or equal to 1×10 20 cm -3 Less than or equal to 1×10 22 cm -3 , breaking through the fact that the injection doping concentration can only be less than 1×10 19 cm -3 restrictions.

[0121] The present application breaks through the technical idea of forming the functional area of the semiconductor through the injection process, and creates a new technical idea of forming the base connection area 6, one of the functional areas of the semiconductor, through the epitaxial process, so that the doping concentration of the base connection area 6 formed by the epitaxial process can be very high, and the contact between the base connection area 6 and the base metal 9 is ohmic contact.

[0122] The following is a description of the preparation method of the silicon carbide bipolar junction transistor in chronological order:

[0123] like Figure 3 As shown, step 1, selecting a substrate 1 of a first doping type;

[0124] like Figure 4As shown, in step 2, an epitaxial layer 2 of silicon carbide of the first doping type is epitaxially grown on the substrate 1;

[0125] As Figure 5 shown, in step 3, a collector region 3 of silicon carbide of the first doping type is obtained by implantation process in the epitaxial layer 2 of silicon carbide of the first doping type;

[0126] As Figure 6 shown, in step 4, after etching deep grooves on both sides of the epitaxial layer 2 of silicon carbide of the first doping type, a first isolation region 4 of silicon dioxide material is deposited in the deep grooves;

[0127] As Figure 7 shown, in step 5, a base region 5 of silicon carbide of the second doping type is obtained by implantation on the surface of the epitaxial layer 2 of silicon carbide of the first doping type;

[0128] As Figure 8 shown, in step 6, a base region connection region material layer of polycrystalline silicon carbide (Poly SiC) of the second doping type is deposited and formed above the base region 5 of silicon carbide of the second doping type;

[0129] As Figure 9 shown, in step 7, the base region connection region material layer is etched to form a base region connection region 6;

[0130] As Figure 10 shown, in step 8, a first layer 7-1 of the second isolation region is deposited above the base region connection region 6 of polycrystalline silicon carbide (Poly SiC) of the second doping type;

[0131] As Figure 11 shown, in step 9, an emitter region 8 of polycrystalline silicon carbide (Poly SiC) of the first doping type is formed by epitaxial process above the base region 5;

[0132] As Figure 12 shown, in step 10, a second layer 7-2 of the second isolation region is deposited;

[0133] As Figure 13 shown, in step 11, by etching the second layer 7-2 of the second isolation region, and depositing base metal and emitter metal to form silicide, and then by depositing metal, base metal 9 and emitter metal 10 are formed; a collector metal 11 is deposited on the back of the first doping type substrate 1. The first layer 7-1 of the second isolation region and the second layer 7-2 of the second isolation region form the second isolation region 7;

[0134] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0135] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0136] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0137] These computer program instructions can also be loaded onto a computer or other programmable data processing device, such that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or blocks.

[0138] Although the preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic creative concepts. Therefore, the appended claims are intended to be construed to include the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0139] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application is also intended to include these modifications and variations.

Claims

1. A silicon carbide bipolar junction transistor, characterized in that, Comprising: A substrate (1) of a first doping type; An epitaxial layer (2) of a first doping type, formed on top of the substrate (1); A base region (5) of a second doping type, formed downward from the upper surface of the epitaxial layer (2), and having a gap between the lower surface of the base region (5) and the lower surface of the epitaxial layer (2); An emitter region (8) of a first doping type, formed on top of the base region (5); Emitter metal (10), formed on top of the emitter region (8); Wherein, the emitter region (8) of the first doping type and the emitter metal (10) are connected.

2. The silicon carbide bipolar junction transistor according to claim 1, wherein Further comprising: A base region connection region (6) of a second doping type, formed on top of the base region (5), and the doping concentration of the base region connection region (6) is greater than the doping concentration of the base region (5); Base metal (9), formed on top of the base region connection region (6); Among them, a base region (5) of a second doping type, a base region connection region (6) of a second doping type, and a base metal (9) are connected. The doping concentration of the base region connection region (6) ranges from greater than or equal to 1×10 20 cm -3 to less than or equal to 1×10 22 cm -3 , so that an ohmic contact is formed between the base region connection region (6) and the base metal (9).

3. The silicon carbide bipolar junction transistor according to claim 1, characterized in that The doping concentration of the base region (5) ranges from greater than or equal to 1×10 16 cm -3 to less than 1×10 20 cm -3 ; The doping concentration of the emitter region ranges from greater than or equal to 1×10 20 cm-3 to less than or equal to 1×10 22 cm -3 , so that an ohmic contact is formed between the emitter region (8) and the emitter metal (10).

4. The silicon carbide bipolar junction transistor according to claim 2, characterized in that, The base region connection region (6) is formed by an epitaxial process such that the doping concentration of the base region connection region (6) has a value range greater than or equal to 1×10 20 cm -3 and less than or equal to 1×10 22 cm -3 .

5. The silicon carbide bipolar junction transistor according to claim 1, characterized in that, The cross-section of the emitter region (8) is a T-shaped structure.

6. The silicon carbide bipolar junction transistor according to claim 2, characterized in that, The base region connection region (6) is a base region connection region (6) of single-crystal or polycrystalline silicon carbide material; The emitter region (8) is an emitter region (8) of single-crystal or polycrystalline silicon carbide material.

7. The silicon carbide bipolar junction transistor according to claim 2, wherein The thickness of the base region connection region (6) ranges from greater than or equal to 0.1 μm to less than or equal to 1 μm; The thickness of the emitter region (8) ranges from greater than or equal to 0.1 μm to less than or equal to 1 μm.

8. The silicon carbide bipolar junction transistor according to claim 2, characterized in that, Further comprising: A collector region (3) of a first doping type, formed between the lower surfaces of the base region (5), and the lower surface of the base region (5) is connected to the lower surface of the epitaxial layer (2); Collector metal (11), formed on the back side of the substrate (1); Wherein, the collector region (3) of the first doping type, the substrate (1) of the first doping type, and the collector metal (11) are connected.

9. A method for fabricating a silicon carbide bipolar junction transistor, characterized in that, Including the following steps: Forming an epitaxial layer (2) of a first doping type on top of a substrate (1) of a first doping type; Forming a base region (5) of a second doping type downward from the upper surface of the epitaxial layer (2) by an implantation process; there is a gap between the lower surface of the base region (5) and the lower surface of the epitaxial layer (2); Forming an emitter region (8) of a first doping type on top of the base region (5) by an epitaxial process; Forming emitter metal (10), located on top of the emitter region (8); Wherein, the emitter region (8) of the first doping type and the emitter metal (10) are connected.

10. The manufacturing method of the silicon carbide bipolar junction transistor according to claim 9, characterized in that, The doping concentration of the emitter region ranges from greater than or equal to 1×10 20 cm -3 to less than or equal to 1×10 22 cm -3 , so that an ohmic contact is formed between the emitter region (8) and the emitter metal (10).

11. The manufacturing method of the silicon carbide bipolar junction transistor according to claim 10, characterized in that, Further including the following steps: Forming a base region connection region (6) of a second doping type on top of the base region (5) by an epitaxial process, and the doping concentration of the base region connection region (6) is greater than the doping concentration of the base region (5); Forming base metal (9), and the base metal (9) is located on top of the base region connection region (6); Among them, a base region (5) of a second doping type, a base region connection region (6) of a second doping type, and a base metal (9) are connected. The doping concentration of the base region connection region (6) ranges from greater than or equal to 1×10 20 cm -3 to less than or equal to 1×10 22 cm -3 , so that an ohmic contact is formed between the base region connection region (6) and the base metal (9).

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