A bipolar SIC power device

Abstract

The present application provides a bipolar SIC power device, comprising: a collector, formed by alternating multiple collector first doping type regions and multiple collector second doping type regions; a substrate, formed by alternating multiple substrate second doping type regions and multiple substrate first doping type regions; wherein the substrate is located above the collector; an epitaxial layer of the second doping type is formed above the substrate; wherein the collector second doping type region is connected to the substrate second doping type region, the collector first doping type region is connected to the substrate second doping type region, and the collector second doping type region is connected to the substrate first doping type region. The present application solves the technical problem that the conventional SiC IGBT device has large conduction loss under low current conditions.

Description

Technical Field

[0001] The present application relates to the technical field of power amplifiers, and in particular to a control circuit and a power amplifier chip suitable for a power amplifier chip. Background Art

[0002] Thanks to the excellent physical properties of silicon carbide (SiC) materials, SiC power devices have become high-voltage, high-speed switching devices with great potential. Compared with Si-based devices, power devices represented by SiC MOSFET have lower on-resistance and smaller chip size. The above advantages make the devices competent for high-voltage, high-current, and high-frequency applications. In addition, SiC materials have the advantage of high-temperature operation. The corresponding devices can operate under high-temperature conditions above 175°C, and their on-state voltage drop increases significantly with increasing temperature.

[0003] In order to further improve the high-temperature current-carrying capacity of SiC devices, trench bipolar SiC IGBT devices have gradually become a research hotspot. Figure 1 It is a traditional trench bipolar SiC IGBT device. For example, the device structure of a SiC IGBT chip above 10kV is as follows Figure 1 As shown. Among them, 1-1 is the emitter metal, 1-2 is the emitter N+ region, 1-3 is the P-type body region, 1-4 is the gate oxide layer, 1-5 is the gate Ploy, 1-6 is the N-drift region, 1-7 is the collector P-type region (as a substrate), and 1-8 is the collector metal. Figure 1 In the figure, the dashed line with an arrow is the electron path, and the line with an arrow is the hole path.

[0004] Traditional SiC IGBT devices have the following problems:

[0005] Question 1: Figure 1 The back structure of the IGBT device is the collector P-type region 1-7 and the N-drift region 1-6. There is a process for the on-current to increase. Figure 1 The trench bipolar SiC IGBT device conducts electrons and holes. The flow paths of electrons and holes are as follows: Figure 1 shown.

[0006] Generally, the on-state voltage of the PN junction formed by the collector P-type region 1-7 and the N-drift region 1-6 is above 3 V. Thus, even under low current conditions, the on-state voltage drop is above 3 V, resulting in large conduction loss.

[0007] The specific process is as follows:

[0008] When the voltage drop between the collector and emitter of the device is less than 3V, the PN junction voltage drop between the collector P-type region 1-7 and the N-drift region 1-6 does not reach the forward conduction voltage drop of the SIC PN junction (i.e., the PN junction formed by the collector P-type region 1-7 and the N-drift region 1-6); at this time, the device is not turned on and there is no conduction current.

[0009] When the voltage drop between the collector and emitter of the device is greater than or equal to 3V, the PN junction voltage drop of the collector P-type region 1-7 and the N-drift region 1-6 reaches the forward conduction voltage drop of the SIC PN junction; at this time, the device starts to conduct.

[0010] Question 2: Figure 1 The IGBT device, as the substrate, has the collector P-type region 1-7 made of silicon carbide SiC material. Since the substrate is made of SiC material, the device has a 1-micron thickness and can withstand a voltage of about 150V. The effective thickness of the low-voltage IGBT device (breakdown voltage BV≤1200V) is only 10 microns, and the thinning process is difficult to prepare, and there are no mature products. Therefore, most of the existing SiCIGBT devices have a breakdown voltage of more than 10 kV.

[0011] Therefore, the traditional SiC IGBT device has large conduction losses under low current conditions, which is a technical problem that technical personnel in this field urgently need to solve.

[0012] The above information disclosed in the background section is only for enhancing understanding of the background of the present application and therefore it may contain information that does not form the prior art known to a person of ordinary skill in the art. Summary of the invention

[0013] The present application provides a bipolar SIC power device to solve the technical problem that a traditional SiC IGBT device has large conduction loss under low current conditions.

[0014] The present application provides a bipolar SIC power device, comprising:

[0015] A collector, formed by alternately arranging a plurality of collector first doping type regions and a plurality of collector second doping type regions;

[0016] A substrate, formed by alternating a plurality of substrate second doping type regions and a plurality of substrate first doping type regions; wherein the substrate is located on the collector;

[0017] An epitaxial layer of a second doping type is formed on the substrate;

[0018] The collector second doping type region is connected to the substrate second doping type region, the collector first doping type region is connected to the substrate second doping type region, and the collector second doping type region is connected to the substrate first doping type region.

[0019] In implementation, the collector first doping type region is in the shape of a strip, and the collector second doping type region is in the shape of a strip;

[0020] The second doping type region of the substrate is in a strip shape, and the first doping type region of the substrate is in a strip shape;

[0021] The length direction of the collector first doping type region intersects with the length direction of the substrate first doping type region; the length direction of the strip is the extension direction of the longer side of the strip.

[0022] Due to the adoption of the above technical solution, this application has the following technical effects:

[0023] When the bipolar SIC power device of the present application is forward-conducted and the forward-conducting current is small, the collector-emitter voltage V CE The voltage of the PN junction formed by the collector first doping type region and the substrate second doping type region is too low to reach the conduction voltage. Therefore, the PN junction from the collector first doping type region to the substrate second doping type region is not conductive. At this time, the collector first doping type region does not work, the bipolar SIC power device is unipolar, and only electrons participate in conduction.

[0024] The electron path is as follows:

[0025] The second doping type epitaxial layer → the second doping type region of the substrate → the second doping type region of the collector is part of the electron path. Since the epitaxial layer, the second doping type region of the substrate, and the second doping type region of the collector are all of the second doping type, their function is similar to that of a conductor. To illustrate, for example, when the on-state voltage of the PN junction formed by the first doping type region of the collector and the second doping type region of the substrate is 3V, the collector-emitter voltage V generated by the on-state current is CE When the voltage drop is less than 3V, the bipolar SIC power device of the present application can be turned on by relying solely on electronic conduction, and the on-state voltage drop is small, so that the conduction loss is small.

[0026] Therefore, when the forward conduction current of the bipolar SIC power device of the present application is small, the conduction voltage drop is small, thereby making the conduction loss small. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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:

[0028] Figure 1 It is a traditional trench bipolar SiC IGBT device;

[0029] Figure 2 A schematic diagram of forming a collector electrode on the back side of a substrate of a bipolar SIC power device of the present application;

[0030] Figure 3 The bipolar SIC power device of this application is Figure 2 A cross-sectional view of the AA position;

[0031] Figure 4 The bipolar SIC power device of this application is Figure 2 Cross-sectional view of the BB position;

[0032] Figure 5 The bipolar SIC power device of this application is Figure 2 A partial cross-sectional enlarged view of the CC position;

[0033] Figure 6 A schematic diagram showing the completion of step S3 of the method for preparing a bipolar SIC power device of the present application;

[0034] Figure 7 A schematic diagram showing the step S4 of the method for preparing a bipolar SIC power device of the present application;

[0035] Figure 8 A schematic diagram showing the step S9 of the method for preparing a bipolar SIC power device of the present application;

[0036] Fig. 9 and Fig.10 A schematic diagram of the method for preparing a bipolar SIC power device of the present application after executing step S10;

[0037] Fig.11 It is a comparison diagram of the output characteristics of the bipolar SIC power device of the present application and the device of the prior art.

[0038] Reference numerals:

[0039] In the background technology:

[0040] Emitter metal 1-1, emitter N+ region 1-2, P-type body region 1-3, gate oxide layer 1-4,

[0041] Gate Ploy1-5, N-drift region 1-6, collector P-type region 1-7, collector metal 1-8.

[0042] In this application:

[0043] Emitter metal 1, emitter 2, body region 3, gate oxide layer 4, gate 5, collector metal 8,

[0044] Epitaxial layer 9, substrate 10, substrate second doping type region 10-1, substrate first doping type region 10-2,

[0045] A collector first doping type region 11 , a collector second doping type region 12 , and a SiC wafer 13 . DETAILED DESCRIPTION

[0046] In order to make the technical solutions and advantages of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict. Embodiment 1

[0047] like Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the bipolar SIC power device of the present application includes:

[0048] The collector is formed by alternately arranging a plurality of strip-shaped collector first doping type regions 11 and a plurality of strip-shaped collector second doping type regions 12;

[0049] The substrate 10 is formed by alternately arranging a plurality of strip-shaped substrate second doping type regions 10-1 and a plurality of strip-shaped substrate first doping type regions 10-2; wherein the substrate 10 is located on the collector, and the length direction of the collector first doping type region 11 intersects with the length direction of the substrate first doping type region 10-2;

[0050] An epitaxial layer 9 of a second doping type is formed on the substrate 10;

[0051] like Figure 3 , Figure 4 As shown, the bipolar SIC power device of the present application also includes:

[0052] A collector metal 8 formed on the back side of the collector;

[0053] A groove is formed downward from the upper surface of the epitaxial layer;

[0054] A gate oxide layer 4 is formed on the bottom and sidewalls of the trench;

[0055] A gate 5 is filled in the space surrounded by the gate oxide layer 4;

[0056] A body region 3 of a first doping type, formed on both sides of the gate 5;

[0057] An emitter 2 of a second doping type is formed on both sides of the trench;

[0058] The emitter metal 1 is connected to the emitter 2 .

[0059] The following uses the bipolar SIC power device of the present application in which the first doping type is P-type and the second doping type is N-type as an example to explain the conduction mechanism of the bipolar SIC power device of the present application:

[0060] When the bipolar SIC power device of the present application is forward-conducted and the forward-conducting current is small, the collector-emitter voltage V CE The voltage is too low to reach the conduction voltage of the PN junction formed by the collector first doping type region 11 and the substrate second doping type region 10-1. Therefore, the PN junction from the collector first doping type region 11 to the substrate second doping type region 10-1 is not conductive. At this time, the collector first doping type region 11 does not work, the bipolar SIC power device is unipolar, and only electrons participate in conduction.

[0061] The electron path Figure 5 Indicated by a dotted line with an arrow:

[0062] The electron path is the second doping type emitter 2 → the second doping type channel (formed in the body region 3 near the gate oxide layer 4) → the second doping type epitaxial layer 9 → the substrate second doping type region 10-1 → the collector second doping type region 12.

[0063] Since the emitter 2, the channel, the epitaxial layer 9, the substrate second doping type region 10-1, and the collector second doping type region 12 are all of the second doping type, that is, they act similarly as conductors. To illustrate, for example, when the on-voltage of the PN junction formed by the collector first doping type region 11 and the substrate second doping type region 10-1 is 3V, the collector-emitter voltage V generated by the on-current is CE When the voltage drop is less than 3V, the bipolar SIC power device of the present application can be turned on by relying solely on electronic conduction, and the on-state voltage drop is small, so that the conduction loss is small.

[0064] Therefore, when the forward conduction current of the bipolar SIC power device of the present application is small, the conduction voltage drop is small, thereby making the conduction loss small.

[0065] exist Figure 2 In the figure, the blue rectangular frame is the edge of the unpackaged bipolar SIC power device. The part outside the blue rectangular frame is used to show the positional relationship between the collector first doping type region 11 and the collector second doping type region 12, and the substrate second doping type region 10-1 and the substrate first doping type region 10-2. It can be understood that the part of the blue rectangular frame is removed.

[0066] It should be noted that in the first embodiment and its drawings, the collector first doping type region 11 and the collector second doping type region 12 are in the shape of strips, and the substrate second doping type region 10 - 1 and the substrate first doping type region 10 - 2 are in the shape of strips.

[0067] In fact, the shapes of the collector first doping type region 11, the collector second doping type region 12, the substrate second doping type region 10-1, and the substrate first doping type region 10-2 may be other shapes, such as curves, broken lines, and the like.

[0068] As long as the collector second doping type region 12 and the substrate second doping type region 10-1 are connected, the collector first doping type region 11 and the substrate second doping type region 10-1 are connected, and the collector second doping type region 12 and the substrate first doping type region 10-2 are connected, it is feasible.

[0069] When the bipolar SIC power device of the present invention is forward-conducted and the forward-conducting current is large, the collector-emitter voltage V generated by the conduction current is CE The voltage drop reaches the conduction voltage of the PN junction formed by the collector first doping type region 11 and the substrate second doping type region 10-1. At this time, the collector first doping type region 11 works, and the collector first doping type region 11 injects holes into the substrate second doping type region 10-1. At this time, the conductivity type is bipolar, and electrons and holes participate in conduction at the same time.

[0070] The electron path Figure 5 The dotted line with an arrow in the figure is the same as the electron path under small current.

[0071] There are two hole paths. Figure 5 Indicated by a solid line with an arrow:

[0072] One hole path is collector first doping type region 11 → substrate second doping type region 10 - 1 → substrate first doping type region 10 - 2 → epitaxial layer 9 → second doping type channel (formed in the body region 3 near the gate oxide layer 4);

[0073] Another hole path is collector first doping type region 11 → substrate second doping type region 10 - 1 → second doping type epitaxial layer 9 → second doping type channel (formed in the body region 3 near the gate oxide layer 4 ).

[0074] Since the substrate adopts the method of alternating the substrate second doping type region 10-1 and the strip-shaped substrate first doping type region 10-2, the P-type structure in the substrate second doping type region 10-1 and the strip-shaped substrate first doping type region 10-2 provides a low-resistance flow channel for holes, further reducing the on-resistance of the device. When the bipolar SIC power device of the present application is forward-conducted and the forward conduction current is large, the on-resistance is small, thereby reducing the conduction loss.

[0075] The collector formed by the alternating collector first doping type region 11 and the collector second doping type region 12, the substrate 10 formed by the alternating substrate second doping type region 10-1 and the substrate first doping type region 10-2, and the connection between the two (the substrate 10 is located above the collector, and the length direction of the collector first doping type region 11 intersects the length direction of the substrate first doping type region 10-2), realizes four structural types of the collector and the substrate:

[0076] The collector first doping type region 11 and the substrate second doping type region 10-1 are used to inject holes into the substrate second doping type region 10-1 when the forward conduction current is large;

[0077] The collector second doping type region 12 and the substrate second doping type region 10-1 function to provide a flow channel for electrons when the forward conduction current is small.

[0078] The collector first doping type region 11 and the substrate first doping type region 10 - 2 ;

[0079] The collector second doping type region 12 and the substrate first doping type region 10 - 2 function to provide a low-resistance flow channel for holes when the forward conduction current is large.

[0080] The bipolar SIC power device of the present application, the collector formed by the alternating collector first doping type region 11 and the collector second doping type region 12, the substrate 10 formed by the alternating substrate second doping type region 10-1 and the substrate first doping type region 10-2, and the connection method between the two, realizes that when the on-current is a small current, there are two electron paths, and when the on-current is a large current, there are two electron paths and two hole paths, so that the bipolar SIC power device of the present application has a low on-state voltage drop under the condition that the on-state current is a small current, thereby making the on-state voltage drop low.

[0081] Due to the structure of the collector first doping type region 11 and the substrate second doping type region 10-1, and the structure of the collector second doping type region 12 and the substrate second doping type region 10-1, the on-state voltage drop of the bipolar SIC power device of the present application can be better, ensuring the performance of the bipolar SIC power device of the present application under low voltage conditions.

[0082] In implementation, such as Figure 2 and Figure 5 As shown, the same collector first doping type region 11:

[0083] Intersecting and connecting with a plurality of substrate first doping type regions 10 - 2 ;

[0084] and intersects and connects with a plurality of substrate second doping type regions 10 - 1;

[0085] The same collector second doping type region 12:

[0086] Intersecting and connected with a plurality of substrate second doping type regions 10 - 1 ;

[0087] And it intersects and connects with a plurality of substrate first doping type regions 10 - 2 .

[0088] In implementation, such as Figure 2 and Figure 5 As shown, the first doping type is P type, and the second doping type is N type;

[0089] The epitaxial layer 9 of the second doping type, the substrate second doping type region 10 - 1 , and the collector second doping type region 12 serve as a part of the electron path;

[0090] The collector first doping type region 11, the substrate second doping type region 10-1, the substrate first doping type region 10-2, and the second doping type epitaxial layer 9 serve as a part of the hole path.

[0091] In implementation, such as Figure 2 As shown, the area of ​​a parallelogram formed by the intersection of the collector first doping type region 11 and the substrate first doping type region 10-2 is represented by S2;

[0092] The area of ​​the parallelogram formed by the intersection of the collector first doping type region 11 and the substrate second doping type region 10-1 is represented by S1;

[0093] S1 and S2 satisfy the following relationship:

[0094] S1: S2 = the width of the substrate second doping type region 10 - 1: the width of the substrate first doping type region 10 - 2.

[0095] In implementation, such as Figure 2 As shown, the area of ​​the parallelogram formed by the intersection of one of the collector second doping type regions 12 and one of the substrate first doping type regions 10-2 is represented by S4;

[0096] The area of ​​the parallelogram formed by the intersection of one of the collector second doping type regions 12 and one of the substrate second doping type regions 10 - 1 is represented by S3;

[0097] S3 and S4 satisfy the following relationship:

[0098] S3: S4 = the width of the substrate second doping type region 10 - 1: the width of the substrate first doping type region 10 - 2.

[0099] In implementation, such as Figure 2 As shown, the value range of the angle α at which the length direction of the collector first doping type region 11 intersects the length direction of the substrate first doping type region 10 - 2 is greater than or equal to 20 degrees and less than or equal to 90 degrees.

[0100] In implementation, such as Figure 2 As shown, the ratio of the width of the collector first doping type region 11 to the width of the collector second doping type region 12 is in the range of greater than or equal to 1:1 and less than or equal to 10:1.

[0101] In order to ensure a large injection effect when the device is bipolarly turned on, the collector first doping type region 11 needs to be the main part, and then the minimum proportion of the collector second doping type region 12 is comprehensively considered, and the above value range is selected.

[0102] In implementation, such as Figure 2 As shown, the ratio of the width of the substrate second doping type region 10 - 1 to the width of the substrate first doping type region 10 - 2 is in the range of greater than or equal to 1:8 and less than or equal to 8:1.

[0103] The ratio of the width of the second doping type region 10 - 1 of the substrate to the width of the first doping type region 10 - 2 of the substrate is related to the resistance of hole injection and electron and hole channels when the device is turned on.

[0104] If the proportion of the N-type substrate second doping type region 10 - 1 is too large, and the proportion of the P-type substrate first doping type region 10 - 2 is too small, the hole conduction channel resistance is too large, which is not conducive to reducing the on-state voltage drop;

[0105] If the proportion of the P-type substrate first doping type region 10-2 is too large and the proportion of the N-type substrate second doping type region 10-1 is too small, the back PN junction area is very small, the hole injection is too small, and the on-state voltage drop will be very high.

[0106] Finally, the width ratio range is selected by compromising SiC carrier mobility and the electron and hole current densities during conduction.

[0107] In implementation, such as Figure 2 As shown, the first doping type is P type, and the second doping type is N type;

[0108] The width of the collector first doping type region 11 is in the range of greater than or equal to 3 μm and less than or equal to 50 μm, and the doping concentration of the collector first doping type region 11 is in the range of greater than or equal to 1×10 18 cm -3 Less than or equal to 1×10 20 cm -3 ;

[0109] The width of the collector second doping type region 12 is in the range of 3 μm or more and 20 μm or less, and the doping concentration of the collector second doping type region 12 is in the range of 1×10 18 cm -3 Less than or equal to 1×10 20 cm -3 .

[0110] In implementation, such as Figure 2 As shown, the width of the second doping type region 10-1 of the substrate ranges from 5 μm to 40 μm, and the doping concentration of the second doping type region 10-1 of the substrate ranges from 1×10 17 cm -3 Less than or equal to 1×10 19 cm -3 ;

[0111] The width of the first doping type region 10-2 of the substrate is in the range of 5 μm or more and 40 μm or less, and the doping concentration of the first doping type region 10-2 of the substrate is in the range of 1×10 17 cm -3 Less than or equal to 1×10 19 cm -3 .

[0112] In implementation, such as Figure 2 As shown, the collector first doping type region 11 and the collector second doping type region 12 have the same thickness, and the collector thickness ranges from greater than or equal to 0.1 μm to less than or equal to 1.0 μm;

[0113] The thickness of the substrate ranges from greater than or equal to 50 μm to less than or equal to 200 μm.

[0114] In implementation, the substrate first doping type region 10 - 2 is formed by forming a plurality of substrate long strip holes at intervals on the basis of the second doping type substrate, and filling the first doping type material in the substrate long strip holes;

[0115] The portion of the substrate base located between adjacent substrate first doping type regions serves as a substrate second doping type region 10 - 1 .

[0116] In implementation, such as Figure 2 As shown, one of the substrate first doping type region 10 - 2 and the substrate second doping type region 10 - 1 is made of P-type silicon carbide SiC, and the other is made of N-type silicon carbide SiC.

[0117] The prior art uses an N-type substrate. The substrate of the bipolar SIC power device of the present application is a substrate formed by alternately arranging the second doping type region 10-1 of the substrate and the strip-shaped first doping type region 10-2 of the substrate, which can be regarded as introducing a P-type column into an N-type substrate, solving the limitation of the substrate of the low-voltage bipolar SIC power device on the device performance, and the existing thinning process can realize the thinning of the substrate, so that the preparation process of the low-voltage bipolar SIC power device of the present application can be realized.

[0118] By controlling the proportion of silicon carbide SiC in the substrate 10 , the thickness of the bipolar SIC power device of the application can be controlled.

[0119] The substrate 10 is formed by the substrate second doping type region 10 - 1 and the substrate first doping type region 10 - 2 , and the collector is formed by the collector first doping type region 11 and the collector second doping type region 12 .

[0120] The device achieves efficient interconnection of the back collector of the bipolar SIC power device, so that the medium and low voltage (breakdown voltage BV≤ 1200V) SIC power devices can achieve a lower conduction voltage drop under the existing thinning technology.

[0121] Specifically, the epitaxial layer 9 is an N-type SiC epitaxial layer 9 .

[0122] like Fig.11 As shown, a comparison diagram of the output characteristics of the bipolar SIC power device of the present application and the device of the prior art.

[0123] Among them, the 1200V SIC SJ substrate IGBT device is the bipolar SIC power device of the present application; the 1200V SIC IGBT device is the SIC IGBT device of the prior art, and the 1200V MOSFET device is the MOSFET device of the prior art. The horizontal axis is the voltage V between the collector and the emitter of the IGBT device. CE, in V, the horizontal axis is the voltage V between the drain and source of the MOSFET device DS ; The vertical axis is the collector current I of the IGBT device C , in A, the vertical axis is still the drain current I of the MOSFET device DS .

[0124] The comparison between the bipolar SIC power device of the present application, the SIC IGBT device of the prior art, and the MOSFET device of the prior art is as follows:

[0125] When in region (I), the SIC IGBT device of the prior art is turned on and the voltage drop is low. The forward conduction of the SiC IGBT device requires the back P-type collector region and the N-buffer (i.e., N-buffer layer) to be forward-conducted, so there is no conduction current when the voltage drop is low. Fig.11 In the prior art, when the SIC IGBT device is less than or equal to 3.0V, the collector current I C is zero.

[0126] The bipolar SIC power device of the present application can conduct electricity only through electrons at low voltage drop due to the presence of the N-type collector second doping type region 12, and has low voltage current conduction capability. Fig.11 In the present application, the bipolar SIC power device has a collector current I when the voltage is less than or equal to 3.0V. C .

[0127] When in region (ii), as the on-state voltage drop increases, under the same voltage condition, the back side of the SIC IGBT device in the prior art only has a P-type collector region.

[0128] The bipolar SIC power device of the present application has both a P-type collector first doping type region 11 and an N-type collector second doping type region 12. When working under high current conditions, the large injection effect of the device plays a leading role, so its current conduction capability is slightly lower than that of the SIC IGBT device in the prior art.

[0129] When in region (iii), the MOSFET device of the prior art is a unipolar device, and only electron current participates in conduction during forward conduction.

[0130] The bipolar SIC power device of the present application is a bipolar device, and electrons and holes participate in the conduction together when forward conducting. Therefore, under the same conduction voltage drop, the bipolar SIC power device of the present application has a stronger current carrying capacity.

[0131] The preparation method of the bipolar SIC power device of the present application is as follows: Figures 6 to 10 As shown, the following steps are included:

[0132] Preparation of substrate 10;

[0133] Step S1: preparing an N-type SiC wafer 13, and cleaning the SiC wafer using an RCA cleaning method to remove surface contamination;

[0134] Step S2: etching substrate long strip holes on the SiC wafer 13;

[0135] Step S3: Fill the long strip holes of the substrate with P-type SiC material, and then CMP back-etch and flatten to form a SiC substrate 10 of alternating P-type silicon carbide SiC and N-type silicon carbide SiC (substrate first doping type region 10-2 and substrate second doping type region 10-1); Figure 6 As shown;

[0136] Preparation of epitaxial layer 9;

[0137] Step S4: epitaxially grow a 10 micron N-type SiC epitaxial layer 9 on the surface of the SiC substrate 10; Figure 7 As shown;

[0138] Front side preparation process of device structure:

[0139] Step S5: forming a body region foundation of a first doping type (P type);

[0140] Step S6: forming an emitter base of a second doping type (N type) in the body region base by ion implantation;

[0141] Step S7: etching a groove, growing a sacrificial oxide layer, etching away the sacrificial oxide layer, and growing a gate oxide layer 4; at the same time, forming a body region 3 of a first doping type (P type) and an emitter 2 of a second doping type (N type);

[0142] Step S8: depositing a gate 5, which may be a polysilicon gate, and etching it back into the trench;

[0143] Step S9: forming an emitter metal 1; Figure 8 As shown;

[0144] Backside preparation process of device structure:

[0145] Step S10: turning over and performing back thinning to the position of substrate 10;

[0146] Step S11: backside N+ and P+ implantation to form;

[0147] Step S12: depositing back metal to form a P-type collector first doping type region 11 and an N-type collector second doping type region 12; Fig. 9 and Fig.10 shown.

[0148] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt 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.) containing computer-usable program codes.

[0149] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0150] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0151] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0152] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0153] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A bipolar SIC power device, characterized in that: include: A collector, formed by alternately arranging a plurality of collector first doping type regions (11) and a plurality of collector second doping type regions (12); A substrate (10) formed by alternately arranging a plurality of substrate second doping type regions (10-1) and a plurality of substrate first doping type regions (10-2); wherein the substrate (10) is located on the collector; An epitaxial layer (9) of a second doping type is formed on the substrate (10); The collector second doping type region (12) is connected to the substrate second doping type region (10-1), the collector first doping type region (11) is connected to the substrate second doping type region (10-1), and the collector second doping type region (12) is connected to the substrate first doping type region (10-2).

2. The bipolar SIC power device according to claim 1, characterized in that: The collector first doping type region (11) is in the shape of a strip, and the collector second doping type region (12) is in the shape of a strip; The second doping type region (10-1) of the substrate is in a strip shape, and the first doping type region (10-2) of the substrate is in a strip shape; The length direction of the collector first doping type region (11) intersects with the length direction of the substrate first doping type region (10-2); the length direction of the strip is the extension direction of the longer side of the strip.

3. The bipolar SIC power device according to claim 2, characterized in that: The collector first doping type region (11) has: Intersecting and connecting with a plurality of substrate first doping type regions (10-2); and intersects and connects with a plurality of substrate second doping type regions (10-1); The same collector second doping type region (12): Intersecting and connecting with a plurality of substrate second doping type regions (10-1); And it intersects and connects with a plurality of substrate first doping type regions (10-2).

4. The bipolar SIC power device according to claim 3, characterized in that: The first doping type is P type, and the second doping type is N type; The epitaxial layer (9) of the second doping type, the substrate second doping type region (10-1), and the collector second doping type region (12) serve as a part of the electron path; The collector first doping type region (11), the substrate second doping type region (10-1), the substrate first doping type region (10-2), and the second doping type epitaxial layer (9) serve as a part of the hole path.

5. The bipolar SIC power device according to any one of claims 2 to 4, characterized in that: The value range of the ratio of the width of the second doping type region (10-1) of the substrate to the width of the first doping type region (10-2) of the substrate is greater than or equal to 1:8 and less than or equal to 8:

1.

6. The bipolar SIC power device according to any one of claims 2 to 4, characterized in that: The value range of the ratio of the width of the collector first doping type region (11) to the width of the collector second doping type region (12) is greater than or equal to 1:1 and less than or equal to 10:

1.

7. The bipolar SIC power device according to any one of claims 2 to 4, characterized in that: The value range of the angle α at which the length direction of the collector first doping type region (11) intersects the length direction of the substrate first doping type region (10-2) is greater than or equal to 20 degrees and less than or equal to 90 degrees.

8. The bipolar SIC power device according to claim 7, characterized in that: The first doping type is P type, and the second doping type is N type; The width of the collector first doping type region (11) is in the range of greater than or equal to 3 μm and less than or equal to 50 μm, and the doping concentration of the collector first doping type region (11) is in the range of greater than or equal to 1×10 18 cm -3 Less than or equal to 1×10 20 cm -3 ; The width of the collector second doping type region (12) is in the range of greater than or equal to 3 μm and less than or equal to 20 μm, and the doping concentration of the collector second doping type region (12) is in the range of greater than or equal to 1×10 18 cm -3 Less than or equal to 1×10 20 cm -3 .

9. The bipolar SIC power device according to claim 8, characterized in that: The width of the second doping type region (10-1) of the substrate is in the range of greater than or equal to 5 μm and less than or equal to 40 μm, and the doping concentration of the second doping type region (10-1) of the substrate is in the range of greater than or equal to 1×10 17 cm -3 Less than or equal to 1×10 19 cm -3 ; The width of the first doping type region (10-2) of the substrate is in the range of greater than or equal to 5 μm and less than or equal to 40 μm, and the doping concentration of the first doping type region (10-2) of the substrate is in the range of greater than or equal to 1×10 17 cm -3 Less than or equal to 1×10 19 cm -3 .

10. The bipolar SIC power device according to claim 8, characterized in that: The collector first doping type region (11) and the collector second doping type region (12) have the same thickness, and the collector thickness ranges from greater than or equal to 0.1 μm to less than or equal to 1.0 μm; The thickness of the substrate ranges from greater than or equal to 50 μm to less than or equal to 200 μm.

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