Reverse conducting insulated gate bipolar transistor and preparation method thereof

Abstract

The invention relates to a reverse conducting insulated gate bipolar transistor and a preparation method thereof. The reverse conducting insulated gate bipolar transistor comprises an insulated gate bipolar transistor region, a fast recovery diode region and a terminal region; the fast recovery diode region is located between the insulated gate bipolar transistor region and the terminal region; the reverse conducting insulated gate bipolar transistor further comprises a drift region structure which penetrates through the insulated gate bipolar transistor region, the fast recovery diode region and the terminal region; the first emitter structure is positioned on the front surface of the drift region structure in the insulated gate bipolar transistor region; and the second collector structure is positioned on the back surface of the drift region structure in the fast recovery diode region and the back surface of the drift region structure in the terminal region. According to the reverse conducting insulated gate bipolar transistor, the application reliability of the reverse conducting insulated gate bipolar transistor can be effectively improved, and the turn-off loss is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and particularly to a reverse-conducting insulated gate bipolar transistor and a manufacturing method thereof. Background Art

[0002] A reverse-conducting insulated gate bipolar transistor (RC-IGBT) is a semiconductor device that can integrate an insulated gate bipolar transistor (IGBT) and a fast recovery diode (FRD) on a single chip. When the IGBT is turned off, the FRD can play a freewheeling role. The RC-IGBT has characteristics such as high voltage, high current, low on-state voltage drop, and high switching speed, and is widely used in fields such as power electronics, industrial automation, and transportation.

[0003] However, when a traditional RC-IGBT is turned off, the current flowing through the IGBT is provided by the hole current formed by holes injected from the collector into the drift region. At this time, for the terminal region of the RC-IGBT, a large number of holes are injected from the collector of the device into the drift region. However, the injected holes are likely to concentrate in some parts of the terminal region, resulting in a longer hole recombination time, a slower turn-off speed, and an increased turn-off loss; in addition, it is also easy to generate a local accumulation effect of the hole current, leading to local high voltage and large current, causing the device temperature to rise sharply, resulting in dynamic avalanche breakdown and thermal breakdown of the device, and causing the device to burn out and fail. Summary of the Invention

[0004] Based on this, the present application provides a reverse-conducting insulated gate bipolar transistor and a manufacturing method thereof, which can effectively improve the application reliability of the reverse-conducting insulated gate bipolar transistor and reduce the turn-off loss.

[0005] According to some embodiments, on the one hand, the present application provides a reverse-conducting insulated gate bipolar transistor, including an insulated gate bipolar transistor region, a fast recovery diode region, and a terminal region; the fast recovery diode region is located between the insulated gate bipolar transistor region and the terminal region; the reverse-conducting insulated gate bipolar transistor further includes:

[0006] A drift region structure that penetrates the insulated gate bipolar transistor region, the fast recovery diode region, and the terminal region;

[0007] A first emitter structure located on the front of the drift region structure in the insulated gate bipolar transistor region;

[0008] A second collector structure located on the back of the drift region structure in the fast recovery diode region and the back of the drift region structure in the terminal region.

[0009] In some embodiments, the reverse-conducting insulated gate bipolar transistor further includes:

[0010] A back conductive layer covering at least the back surface of the second collector structure;

[0011] The second collector structure includes a metal electrode layer; the metal electrode layer is integrally connected to the back conductive layer.

[0012] In some embodiments, the second collector structure includes a collector doping layer.

[0013] In some embodiments, the collector doping layer includes a first conductivity type doping layer and a second conductivity type doping layer that are alternately distributed in the horizontal direction.

[0014] In some embodiments, the second collector structure includes a first conductivity type collector doping layer located in the fast recovery diode region and an oxide conductive layer located in the terminal region.

[0015] In some embodiments, the second collector structure includes a first conductivity type collector doping layer located in the fast recovery diode region and a second conductivity type collector doping layer located in the terminal region.

[0016] In some embodiments, the reverse conducting insulated gate bipolar transistor further includes a buffer layer; the buffer layer is located between the drift region structure and the second collector structure.

[0017] In some embodiments, a plurality of island regions are arranged at intervals inside the buffer layer; the conductivity type of the island regions is opposite to that of the buffer layer.

[0018] In some embodiments, a plurality of first conductivity type island regions and a plurality of second conductivity type island regions are alternately arranged on one side of the buffer layer close to the drift region structure.

[0019] According to some embodiments, another aspect of the present application provides a method for manufacturing a reverse conducting insulated gate bipolar transistor for manufacturing the reverse conducting insulated gate bipolar transistor provided in the foregoing embodiments.

[0020] The reverse conducting insulated gate bipolar transistor and the method for manufacturing the same provided by the present application may / at least have the following advantages:

[0021] In the embodiments of the present application, by disposing the second collector structure on the back of the drift region structure in the fast recovery diode region and the back of the drift region structure in the terminal region, when the insulated gate bipolar transistor is turned off, the second collector structure can be combined with the first emitter structure disposed on the front of the drift region structure in the insulated gate bipolar transistor region to jointly form a fast recovery diode, which plays a freewheeling role. In this way, when the function of the insulated gate bipolar transistor takes effect, no holes are emitted in the terminal region; when the insulated gate bipolar transistor is turned off, the holes in the drift region structure are greatly reduced, which is beneficial to improving the local accumulation effect of the hole current and avoiding the local generation of high voltage and large current in the device, resulting in a sharp increase in temperature, thereby reducing the risk of the device suffering from dynamic avalanche breakdown or thermal breakdown, and effectively improving the application reliability of the reverse-conducting insulated gate bipolar transistor. Moreover, since no hole accumulation occurs in the terminal region when the insulated gate bipolar transistor is turned off, the turn-off speed is not slowed down due to the lengthening of the hole recombination time, thus reducing the turn-off loss. In addition, by disposing the second collector structure on the back of the drift region structure in the fast recovery diode region and the back of the drift region structure in the terminal region, the occupied area of the device can also be reduced, which is beneficial to the miniaturization design of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0023] Figure 1 FIG. is a schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some embodiments of the present application;

[0024] Figure 2 FIG. is a schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0025] Figure 3 FIG. is a schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0026] Figure 4 FIG. is a schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0027] Figure 5 FIG. is a schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some embodiments of the present application;

[0028] Figure 6Schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0029] Figure 7 Schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0030] Figure 8 Schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0031] Figure 9 Schematic cross-sectional structure diagram of a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0032] Figure 10 Schematic flow diagram of a method for manufacturing a reverse-conducting insulated gate bipolar transistor provided in some embodiments of the present application;

[0033] Figure 11 Schematic flow diagram of forming a second collector structure in a method for manufacturing a reverse-conducting insulated gate bipolar transistor provided in some embodiments of the present application;

[0034] Figure 12 Schematic flow diagram of forming a second collector structure in a method for manufacturing a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application;

[0035] Figure 13 Schematic flow diagram of forming a second collector structure in a method for manufacturing a reverse-conducting insulated gate bipolar transistor provided in some other embodiments of the present application.

[0036] Description of reference numerals:

[0037] 100, drift region structure; 110, well region; 120, source region; 130, cutoff ring region; 140, JTE region; 140', heavily doped JTE region; 200, front conductive layer; 210, first emitter structure; 220, first collector structure; 230, anode electrode; 311, metal electrode layer; 312, collector doping layer; 312a, first conductivity type doping layer; 312b, second conductivity type doping layer; 313, collector doping layer; 314, oxide conductive layer; 315, first conductivity type collector doping layer; 316, second conductivity type collector doping layer; 400, back conductive layer; 500, buffer layer; 510, island region; 510a, first conductivity type island region; 510b, second conductivity type island region; 600, gate structure; 610, gate insulating layer; 620, gate conductive layer; 700, interlayer dielectric layer. Detailed Description

[0038] To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are shown in the drawings. However, the present application may be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete.

[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terms used herein in the specification of this application are for the purpose of describing particular embodiments only and are not intended to limit the present application.

[0040] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers, collector structures and / or parts, these elements, components, regions, layers, collector structures and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, collector structure or part from another. Thus, a first element, component, region, layer, collector structure or part discussed below may be denoted as a second element, component, region, layer or part without departing from the teachings of this application. For example, a first collector structure may be referred to as a second collector structure, and similarly, a second collector structure may be referred to as a first collector structure; the first collector structure and the second collector structure are different collector structures. It should be understood that, in addition to the orientation shown in the figures, spatial relationship terms also include different orientations of the device during use and operation. For example, if the device in the figures is flipped, an element or feature described as "under" or "beneath" or "below" another element or feature will be oriented "above" the other element or feature. Thus, the exemplary terms "under" and "below" can include both an upper and a lower orientation. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are accordingly interpreted.

[0041] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that when the terms "comprising" and / or "including" are used in this specification, the presence of the stated features, integers, steps, operations, elements and / or components can be determined, but one or more other features, integers, steps, operations, elements, components and / or groups may not be excluded. Also, as used herein, the term "and / or" includes any and all combinations of the associated listed items.

[0042] The reverse-conducting insulated gate bipolar transistor (RC-IGBT) is a semiconductor device that can integrate an insulated gate bipolar transistor (IGBT) and a fast recovery diode (FRD) on a single chip. Among them, the IGBT combines the characteristics of voltage control of a metal-oxide-semiconductor field-effect transistor (MOS for short) and current conduction modulation of a bipolar junction transistor (BJT for short), and has the characteristics of high input impedance, low switching loss, fast speed, and low voltage drive power. Therefore, it is widely used in many fields such as new energy vehicles, photovoltaic inverters, mobile energy storage, frequency converters, power transmission and transformation, high-speed train traction, industrial drives, and clean energy. In the RC-IGBT, the IGBT and the FRD are packaged together. When the IGBT is turned off, the FRD can play a freewheeling role. The RC-IGBT has the characteristics of high voltage, high current, low on-state voltage drop, and high switching speed, and is widely used in fields such as power electronics, industrial automation, and transportation.

[0043] When the traditional RC-IGBT is turned off, the current flowing through the IGBT is provided by the hole current formed by the holes injected from the collector into the drift region. At this time, for the terminal region of the RC-IGBT, a large number of holes are injected from the collector of the device into the drift region. However, the injected holes are likely to concentrate in some parts of the terminal region, resulting in a longer hole recombination time, a slower turn-off speed, and an increased turn-off loss; in addition, it is also easy to generate a local accumulation effect of the hole current, resulting in local high voltage and large current, which causes the device temperature to rise rapidly, leading to dynamic avalanche breakdown and thermal breakdown of the device, and causing the device to burn out and fail.

[0044] Based on this, the present application provides a reverse-conducting insulated gate bipolar transistor and a preparation method thereof, which can effectively improve the application reliability of the reverse-conducting insulated gate bipolar transistor and reduce the turn-off loss. The detailed content will be elaborated in the subsequent embodiments.

[0045] It should be noted that in the embodiments of the present application, the first conduction type is P-type and the second conduction type is N-type; or, the first conduction type is N-type and the second conduction type is P-type. Hereinafter, an example will be given with the first conduction type being N-type and the second conduction type being P-type.

[0046] According to some embodiments of the present application, a reverse-conducting insulated gate bipolar transistor (hereinafter also referred to as RC-IGBT) is provided. As Figure 1 shown, the RC-IGBT may include an insulated gate bipolar transistor region I, a fast recovery diode region II, and a terminal region III. Among them, the fast recovery diode region II is located between the insulated gate bipolar transistor region I and the terminal region III.

[0047] Exemplarily, as Figure 1As shown, the RC-IGBT may further include a transition region IV, which is located between the fast recovery diode region II and the terminal region III.

[0048] Please continue to refer to Figure 1 , in some embodiments, the RC-IGBT may specifically include a drift region structure 100, a first emitter structure 210, and a second collector structure.

[0049] The drift region structure 100 penetrates through the insulated gate bipolar transistor region I, the fast recovery diode region II, and the terminal region III. The first emitter structure 210 is located on the front surface of the drift region structure 100 in the insulated gate bipolar transistor region I; the second collector structure is located on the back surface of the drift region structure 100 in the fast recovery diode region II and the back surface of the drift region structure 100 in the terminal region III.

[0050] In the RC-IGBT provided in the above embodiments, by disposing the second collector structure on the back surface of the drift region structure 100 in the fast recovery diode region II and the back surface of the drift region structure 100 in the terminal region III, when the insulated gate bipolar transistor (also referred to as IGBT) is turned off, the second collector structure can be combined with the first emitter structure 210 disposed on the front surface of the drift region structure 100 in the insulated gate bipolar transistor region I to jointly form a fast recovery diode (also referred to as FRD), which plays a freewheeling role. At this time, the entire fast recovery diode region II and the terminal region III jointly act as a fast recovery diode functional region, forming a current path from the front surface of the device to the back surface of the device, thereby reducing the reverse conduction voltage drop of the device. When the IGBT function is in effect, the terminal region III does not emit holes; when the IGBT is turned off, the holes in the drift region structure 100 are greatly reduced, which is beneficial to improving the local accumulation effect of the hole current and avoiding the local generation of high voltage and large current in the RC-IGBT (hereinafter also referred to as "device") resulting in a sharp increase in temperature, thereby reducing the risk of the device suffering from dynamic avalanche breakdown or thermal breakdown and effectively improving the application reliability of the RC-IGBT. Moreover, since there is no hole accumulation phenomenon in the terminal region III when the IGBT is turned off, the turn-off speed is not slowed down due to the lengthening of the hole recombination time, thereby also reducing the turn-off loss. In addition, by disposing the second collector structure on the back surface of the drift region structure 100 in the fast recovery diode region II and the back surface of the drift region structure 100 in the terminal region III, the occupied area of the device can also be reduced, which is beneficial to the miniaturization design of the device.

[0051] Moreover, the manufacturing process of the above RC-IGBT can be well compatible with the manufacturing processes of backside metal deposition and lithography, and the steps are simple and easy to implement without adding additional processes or using additional layouts, so no additional manufacturing cost is brought.

[0052] Please continue to refer to Figure 1 , in some embodiments, the RC-IGBT may further include a first collector structure 220. The first collector structure 220 is located on the back surface of the drift region structure 100 in the insulated gate bipolar transistor region I, and is disposed on the same layer as the second collector structure.

[0053] Please continue to refer to Figure 1 , in some embodiments, the RC-IGBT may further include a backside conductive layer 400. The backside conductive layer 400 covers at least the back surface of the second collector structure.

[0054] As an example, as Figure 1 shown, the RC-IGBT may further include a front-side conductive layer 200. The front-side conductive layer 200 is located on the front surface of the drift region structure 100, and the first emitter structure 210 may be a part of the front-side conductive layer 200.

[0055] Please continue to refer to Figure 1 , in some embodiments, the second collector structure may include a metal electrode layer 311.

[0056] As an example, as Figure 1 shown, the metal electrode layer 311 may be integrally connected to the backside conductive layer 400.

[0057] Please refer to Figure 2 , in some embodiments, the second collector structure may include a collector doping layer 312.

[0058] The collector doping layer 312 may be, for example, a heavily doped (e.g., N+) collector doping layer of a first conductivity type.

[0059] As an example, the RC-IGBT may include a first collector structure 220 of a second conductivity type.

[0060] In the above RC-IGBT, the collector doping layer 312 may be, for example, a collector doping layer of a first conductivity type. The collector doping layer 312 may be, for example, an N+ collector doping layer, and the first collector structure 220 may be, for example, a P+ first collector structure.

[0061] Please refer to Figure 3 , in some embodiments, the collector doping layer 312 may include a first conductivity type doping layer 312a and a second conductivity type doping layer 312b that are alternately distributed in the horizontal direction.

[0062] As an example, the collector doping layer 312 may include an N+ doping layer and a P+ doping layer that are alternately distributed in the horizontal direction.

[0063] Please refer to Figure 4, in some embodiments, the second collector structure may include a collector doping layer 313 of a first conductivity type located in the fast recovery diode region II, and an oxide conductive layer 314 located in the terminal region III.

[0064] As an example, the collector doping layer 313 of the first conductivity type may include an N+ collector doping layer.

[0065] Please refer to Figure 5 , in some embodiments, the second collector structure may include a collector doping layer 315 of a first conductivity type located in the fast recovery diode region II, and a collector doping layer 316 of a second conductivity type located in the terminal region III.

[0066] In the above-mentioned RC-IGBT, the first collector structure 220 may be, for example, a P+ first collector structure; as an example, the doping concentration of the collector doping layer 316 of the second conductivity type located in the terminal region III may be less than the doping concentration of the first collector structure 220, and it may be, for example, a P collector doping layer.

[0067] Please continue to refer to Figure 1 , in some embodiments, the RC-IGBT may further include a buffer layer 500. The buffer layer 500 may be located between the drift region structure 100 and the second collector structure.

[0068] Please refer to Figure 6 , in some embodiments, a plurality of island regions 510 arranged at intervals are provided inside the buffer layer 500.

[0069] It should be noted that the island region 510 being located inside the buffer layer 500 means that there is a distance between the island region 510 and both the top surface and the bottom surface of the buffer layer 500.

[0070] In the RC-IGBT provided in the above embodiment, the island regions 510 in the buffer layer 500 can inject holes during the turn-off period of the RC-IGBT, thereby resisting the premature or overly sudden interruption of the reverse recovery current, and thus improving the use reliability of the RC-IGBT.

[0071] As an example, the buffer layer 500 may be, for example, a buffer layer of a first conductivity type. The island region 510 may be, for example, an island region of a second conductivity type.

[0072] Please refer to Figure 7 , in some other embodiments, a plurality of first conductivity type island regions 510a and a plurality of second conductivity type island regions 510b arranged alternately are provided on the side of the buffer layer 500 close to the drift region structure 100.

[0073] In the RC-IGBT provided in the above embodiment, a plurality of first-conductivity-type island regions 510a and a plurality of second-conductivity-type island regions 510b arranged alternately can inject holes during the turn-off of the RC-IGBT, thereby resisting premature or overly sudden interruption of the reverse recovery current, and thus improving the reliability of use of the RC-IGBT.

[0074] In the embodiment of the present application, the insulated gate bipolar transistor region I and the fast recovery diode region II can jointly form the cell region of the RC-IGBT.

[0075] As an example, as Figure 1 shown, the RC-IGBT may further include a plurality of gate structures 600, a well region 110, and a source region 120 located in the cell region.

[0076] The plurality of gate structures 600 are disposed at intervals on the surface of the drift region structure 100, and include a gate trench ( Figure 1 not labeled in the figure), a gate insulating layer 610, and a gate conductive layer 620. Among them, the gate insulating layer 610 covers the side walls and the bottom of the gate trench, and isolates the gate conductive layer 620 filled in the gate trench from the well region 110, the source region 120, and the drift region structure 100.

[0077] The well region 110 is located on the surface of the drift region structure 100 and between two adjacent gate structures 600. The upper surface of the well region 110 may be flush with the upper surface of the drift region structure 100, and the depth of the well region 110 may be less than the depth of the gate structure 600.

[0078] Exemplarily, the well region 110 may include a first-conductivity-type (e.g., N-type) doped region, a second-conductivity-type (e.g., P-type) doped region, and a second-conductivity-type heavily doped region (e.g., P+ region) distributed in sequence from bottom to top.

[0079] The source region 120 is located on the surface of the well region 110 in the insulated gate bipolar transistor region I and on both sides of the gate structure 600. The upper surface of the source region 120 may be flush with the upper surface of the drift region structure 100, and one side of the source region 120 is in contact with the gate insulating layer 610 of the gate structure 600.

[0080] Exemplarily, the source region 120 may be a first-conductivity-type heavily doped (e.g., N+) source region.

[0081] Exemplarily, when the IGBT of the above RC-IGBT is turned off, the entire fast recovery diode region II and the terminal region III jointly act as a fast recovery diode functional region. As Figure 1 shown, a current channel is formed from the front P junction to the back N+, thereby reducing the reverse conduction voltage drop of the device.

[0082] As an example, as Figure 1 shown, the RC-IGBT may further include an interlayer dielectric layer 700. The interlayer dielectric layer 700 is disposed on the front surface of the drift region structure 100, and contact holes are formed therein ( Figure 1 not labeled in the figure).

[0083] In the above example, the first emitter structure 210 at least fills the contact holes located in the insulated gate bipolar transistor region I, thereby penetrating the interlayer dielectric layer 700 and contacting the front surface of the drift region structure 100.

[0084] As an example, as Figure 1 shown, the RC-IGBT may further include a cutoff ring region 130 and a JTE region 140 located in the terminal region III.

[0085] The cutoff ring region 130 is disposed within the surface of the drift region structure 100 and is located at the outermost periphery of the RC-IGBT, with a relatively high ion doping concentration. The function of the cutoff ring region 130 is to terminate the electric field within the cutoff ring region 130 and prevent it from extending further outwards.

[0086] Exemplarily, the cutoff ring region 130 may include a cutoff ring region of a first conductivity type with heavy doping (e.g., N+).

[0087] The JTE region 140 is disposed within the surface of the drift layer 202 and is located between the cutoff ring region 130 and the cell region of the RC-IGBT.

[0088] Exemplarily, the JTE region 140 may include a JTE region of a second conductivity type (e.g., P-type).

[0089] Please refer to Figure 8 , in some embodiments, a heavily doped JTE region 140' may be provided within the JTE region 140. The heavily doped JTE region 140' is located on one side at the top within the JTE region 140 and has a relatively high doping concentration.

[0090] As an example, as Figure 1 shown, the RC-IGBT may further include an anode electrode 230.

[0091] The anode electrode 230 at least fills the contact holes located in the terminal region III, thereby penetrating the interlayer dielectric layer 700 and contacting the front surfaces of the cutoff ring region 130 and the JTE region 140.

[0092] Please refer to Figure 9 , in some embodiments, the cutoff ring region 130 is disposed within the surface of the drift region structure 100 and extends along the surface of the drift region structure 100 to the bottom.

[0093] In the above-mentioned RC-IGBT, the back conductive layer 400 also covers the periphery of the cutoff ring region 130.

[0094] According to some embodiments, on the other hand, the present application provides a method for manufacturing a reverse-conducting insulated gate bipolar transistor for manufacturing the aforementioned reverse-conducting insulated gate bipolar transistor.

[0095] Please combine Figures 1 to 9 to understand that in some embodiments, the manufacturing method of the RC-IGBT may specifically include the following steps as Figure 10 shown:

[0096] S100: Provide a substrate; the substrate includes an insulated gate bipolar transistor region I, a fast recovery diode region II, and a terminal region III; the fast recovery diode region II is located between the insulated gate bipolar transistor region I and the terminal region III.

[0097] S200: Form a drift region structure 100 in the substrate; the drift region structure 100 penetrates through the insulated gate bipolar transistor region I, the fast recovery diode region II, and the terminal region III.

[0098] S300: Form a first emitter structure 210 on the front surface of the drift region structure 100 in the insulated gate bipolar transistor region I.

[0099] S400: Form a second collector structure on the back surface of the drift region structure 100 in the fast recovery diode region II and the terminal region III.

[0100] In the method for manufacturing the RC-IGBT provided in the above embodiment, by forming the second collector structure on the back of the drift region structure 100 in the fast recovery diode region II and the back of the drift region structure 100 in the terminal region III, when the insulated gate bipolar transistor (also referred to as IGBT) is turned off, the second collector structure can be combined with the first emitter structure 210 formed on the front of the drift region structure 100 in the insulated gate bipolar transistor region I to jointly form a fast recovery diode (also referred to as FRD), which plays a freewheeling role. In this way, when the IGBT function is in effect, no holes are emitted in the terminal region III; when the IGBT is turned off, the holes in the drift region structure 100 are greatly reduced, which is beneficial to improving the local accumulation effect of the hole current, avoiding the local generation of high voltage and large current in the RC-IGBT (hereinafter also referred to as "device") resulting in a sharp increase in temperature, thereby reducing the risk of the device undergoing dynamic avalanche breakdown or thermal breakdown, and effectively improving the application reliability of the RC-IGBT. Moreover, since no hole aggregation occurs in the terminal region III when the IGBT is turned off, the turn-off speed is not slowed down due to the lengthening of the hole recombination time, thereby also reducing the turn-off loss. In addition, by forming the second collector structure on the back of the drift region structure 100 in the fast recovery diode region II and the back of the drift region structure 100 in the terminal region III, the occupied area of the device can also be reduced, which is beneficial to the miniaturization design of the device.

[0101] As an example, during the execution of step S400, the second collector structure can be formed by performing backside metal deposition and lithography on the drift region structure 100 in the fast recovery diode region II and the terminal region III. The method for manufacturing the RC-IGBT can be well compatible with the manufacturing processes of backside metal deposition and lithography, and the steps are simple and easy to implement, without the need to add additional processes or use additional layout, so no additional manufacturing cost is incurred.

[0102] In some embodiments, the second collector structure includes a metal electrode layer 311. The specific steps for step S400 to form the second collector structure can be as follows:

[0103] Deposit the metal electrode layer 311 on the backs of the fast recovery diode region II and the terminal region III.

[0104] Please refer to Figure 11 , in some embodiments, the second collector structure includes a collector doping layer 312. The specific steps for step S400 to form the second collector structure can be as follows:

[0105] S411: Form a collector material layer on the backs of the fast recovery diode region II and the terminal region III.

[0106] S412: Perform ion implantation of the first conduction type on the collector material layer to form the collector doping layer 312.

[0107] Please refer to Figure 12 , in some embodiments, the collector doping layer 312 includes a first conduction type doping layer 312a and a second conduction type doping layer 312b that are alternately distributed in the horizontal direction. The step S400 of forming the second collector structure may specifically be represented by the following steps:

[0108] S421: Form a collector material layer on the back surfaces of the fast recovery diode region II and the terminal region III.

[0109] S422: Perform ion implantation of the first conduction type on the collector material layer to form a first conduction type collector material layer.

[0110] S423: Perform ion implantation of the second conduction type on a partial region of the first conduction type collector material layer to form a first conduction type doping layer 312a and a second conduction type doping layer 312b that are alternately distributed in the horizontal direction.

[0111] Please refer to Figure 13 , in some embodiments, the second collector structure includes a first conduction type collector doping layer 313 located in the fast recovery diode region II and an oxide conduction layer 314 located in the terminal region III. The step S400 of forming the second collector structure may specifically be represented by the following steps:

[0112] S431: Form a collector material layer on the back surfaces of the fast recovery diode region II and the terminal region III.

[0113] S432: Remove a partial collector material layer on the back surface of the drift region structure 100 in the terminal region III, and form an oxide conduction layer 314 on the back surface of the drift region structure 100 in the terminal region III.

[0114] It should be understood that although Figures 10 to 13 the steps in the flowchart of Figures 10 to 13 are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated in this article, there is no strict order limit for the execution of these steps, and these steps may be executed in other orders. Moreover,

[0115] It should be noted that the preparation methods of the reverse-conducting insulated gate bipolar transistors in the embodiments of the present application can all be used to prepare the corresponding reverse-conducting insulated gate bipolar transistors. Therefore, the technical features between the method embodiments and the structure embodiments can be replaced and supplemented with each other on the premise of not generating conflicts, so that those skilled in the art can learn about the technical content of the present application.

[0116] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features of the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0117] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An inverse-conductance insulated gate bipolar transistor, characterized in that, It includes an insulated gate bipolar transistor region, a fast recovery diode region, and a terminal region; the fast recovery diode region is located between the insulated gate bipolar transistor region and the terminal region; The reverse conducting insulated gate bipolar transistor further includes: A drift region structure that penetrates the insulated gate bipolar transistor region, the fast recovery diode region, and the terminal region; A first emitter structure located on the front of the drift region structure in the insulated gate bipolar transistor region; A second collector structure located on the back of the drift region structure in the fast recovery diode region and the back of the drift region structure in the terminal region.

2. The reverse-conducting insulated gate bipolar transistor according to claim 1, wherein It further includes: A back conductive layer that covers at least the back of the second collector structure; The second collector structure includes a metal electrode layer; The metal electrode layer is integrally connected to the back conductive layer.

3. The reverse-conducting insulated gate bipolar transistor according to claim 1, characterized in that, The second collector structure includes a collector doping layer.

4. The reverse-conducting insulated gate bipolar transistor according to claim 3, characterized in that The collector doping layer includes a first conductivity type doping layer and a second conductivity type doping layer that are alternately distributed in the horizontal direction.

5. The reverse-conducting insulated gate bipolar transistor according to claim 1, wherein The second collector structure includes a first conductivity type collector doping layer in the fast recovery diode region and an oxide conductive layer in the terminal region.

6. The reverse-conducting insulated gate bipolar transistor according to claim 1, wherein The second collector structure includes a first conductivity type collector doping layer in the fast recovery diode region and a second conductivity type collector doping layer in the terminal region.

7. The reverse-conducting insulated gate bipolar transistor according to any one of claims 1 to 6, characterized in that, It further includes a buffer layer; the buffer layer is located between the drift region structure and the second collector structure.

8. The reverse-conducting insulated gate bipolar transistor according to claim 7, wherein A plurality of island regions arranged at intervals are provided inside the buffer layer; the conductivity type of the island region is opposite to that of the buffer layer.

9. The reverse-conducting insulated gate bipolar transistor according to claim 8, characterized in that, On the side of the buffer layer close to the drift region structure, a plurality of first conductivity type island regions and a plurality of second conductivity type island regions are alternately arranged.

10. A preparation method of an inverse-conducting insulated gate bipolar transistor, characterized in that The manufacturing method of the reverse conducting insulated gate bipolar transistor is used to manufacture the reverse conducting insulated gate bipolar transistor according to any one of claims 1 to 9.

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