Reverse conducting insulated gate bipolar transistor IGBT

Abstract

According to an embodiment, the RC-IGBT (1000) includes a semiconductor body, a collector layer, and a collector electrode. The semiconductor body has an emitter side and a collector side (as shown in FIG. 4). The collector layer is located on the collector side and has at least one pilot region (10) and at least one mixed region (11). The collector electrode is on the collector side and is electrically contacted with the collector layer. The pilot region (10) has a first conductivity type. The mixed region (11) includes a first sub-region (111) having a first conductivity type and a second sub-region (112) having a second conductivity type. The doping concentration in the first sub-region is different from the doping concentration in the pilot region. The collector region further includes an edge region (12) surrounding the pilot region (10) and the mixed region (11). The edge region may primarily have the first conductivity type or have the second conductivity type, and the first and second sub-regions (111, 112) may partially extend into the edge region (12).

Description

Technical Field

[0001] This disclosure relates to a reverse-conducting insulated-gate bipolar transistor, also referred to below as an RC-IGBT. Furthermore, this disclosure relates to a method for manufacturing a reverse-conducting insulated-gate bipolar transistor. Background Technology

[0002] Document WO 2015 / 097157 A1 relates to a reverse-conducting semiconductor device. Document US2015 / 236143 A1 relates to a semiconductor device and an RC-IGBT having a region directly adjacent to the rear electrode. Document US2005 / 017290 A1 relates to an insulated-gate bipolar transistor with a built-in freewheeling diode. Document US2018 / 226397 A1 relates to a semiconductor device and an electrical apparatus.

[0003] Improved RC-IGBTs are needed, for example, those with a trade-off between improved robustness (such as safe operating area (SOA) capability) and static losses. Furthermore, improved methods for manufacturing such RC-IGBTs are required. Summary of the Invention

[0004] Embodiments of this disclosure relate to an RC-IGBT with an improved trade-off between SOA capability and static losses. SOA is an abbreviation for safe operating area. Further embodiments relate to methods for manufacturing RC-IGBTs.

[0005] First, the RC-IGBT will be described in detail.

[0006] According to an embodiment, an RC-IGBT includes a semiconductor body, a collector layer, and a collector electrode. The semiconductor body has an emitter side and a collector side. The collector layer is located on the collector side and has at least one leader region and at least one hybrid region. The collector electrode is on the collector side and is in electrical contact with the collector layer. The leader region has a first conductivity type. The hybrid region has a first sub-region of the first conductivity type and a second sub-region of the second conductivity type. The doping concentration in the first sub-region is different from the doping concentration in the leader region.

[0007] By using different doping concentrations for the leader region and the first sub-region, robustness can be improved without increasing static losses. For example, by decreasing the doping concentration in the leader region and / or increasing the doping concentration in the first sub-region, the reverse bias SOA (RBSOA) can be increased while maintaining or reducing static losses. A more uniform current / plasma distribution can be obtained throughout the active region of the device, especially during high current turn-off (RBSOA).

[0008] The disclosed RC-IGBT combines improved robustness (particularly high RBSOA) without increasing or only slightly increasing conduction losses. This improvement provides an opportunity to expand the range of possibilities for low-on-state loss devices that are not limited by RBSOA. This is particularly advantageous for low-frequency, high-voltage DC (HVDC) systems that primarily utilize RC-IGBTs. Furthermore, the disclosed RC-IGBT does not require significant changes to the fabrication method, but at most requires additional photolithography steps.

[0009] As disclosed herein, RC-IGBTs with a pilot region are also commonly referred to as dual-mode integrated gate transistors, or simply BIGTs. BIGTs constitute a hybrid structure of IGBTs and standard RC-IGBTs. The IGBT is implemented in the pilot region and can therefore also be called a pilot IGBT. The standard RC-IGBT is implemented in the hybrid region. Both the IGBT and the standard RC-IGBT are implemented in a single device or a single chip. For example, the size of the pilot IGBT is designed to reduce the negative resistance effect (snapback) in the forward conduction mode at low temperatures. In the following text, unless otherwise stated, "RC-IGBT" refers to an RC-IGBT with a pilot region, and therefore to a BIGT, not to a standard RC-IGBT that forms part of a BIGT.

[0010] The semiconductor body may include or be made of silicon. The emitter side and collector side are, for example, opposite sides defining the semiconductor body in two opposite directions. The distance between the emitter side and the collector side is the thickness of the semiconductor body.

[0011] The collector layer can be part of the semiconductor body. The collector layer can be made of a semiconductor material, such as silicon. For example, the collector layer forms the collector side.

[0012] Different regions on the collector side, such as the leader region, sub-regions, and edge regions as defined below, can reach the collector side, i.e., each can form a part or a region of the collector side. These different regions can each extend across the entire thickness of the collector layer.

[0013] The collector electrode may be adjacent to the collector side and may be in electrical contact with the collector layer. The collector electrode may include or may be made of metal.

[0014] The leader region has a first conductivity type, for example, only a first conductivity type. The first conductivity type can be hole conduction or electron conduction. Accordingly, the leader region can be p-doped or n-doped. For example, the leader region is uniformly doped over its entire volume and / or its entire lateral extension.

[0015] In this context and below, uniform doping concentration means that it is uniform within manufacturing tolerances, for example, the maximum deviation from the average doping concentration is at most 5%.

[0016] Lateral direction in this paper should be understood as the direction parallel to the collector side or parallel to the main extension plane of the collector layer or semiconductor body, respectively.

[0017] The hybrid region comprises a first sub-region having a first conductivity type (e.g., having only the first conductivity type) and a second sub-region having a second conductivity type (e.g., having only the second conductivity type). The second conductivity type can be either electron conduction or hole conduction, respectively. For example, the first sub-region is p-doped and the second sub-region is n-doped, or vice versa. All first sub-regions can have the same doping concentration and / or can be uniformly doped over their respective entire lateral extension and / or volume. Similarly, all second sub-regions can have the same doping concentration and / or can be uniformly doped over their respective entire lateral extension and / or volume within manufacturing tolerances. For example, the first and second sub-regions are arranged alternately in the hybrid region.

[0018] In this context and below, "the same doping concentration" means the same doping concentration within the limits of manufacturing tolerances, such as a maximum deviation of 5% in the maximum or average doping concentration.

[0019] The area of ​​the leader region may be greater than the area of ​​each of the first sub-region and / or the second sub-region. For example, the area of ​​the leader region may be at least 5 times, at least 10 times, or at least 100 times the area of ​​each of the first sub-region and / or the second sub-region. For example, the area of ​​a region or sub-region should be understood herein as the area of ​​the corresponding region / sub-region on the collector side.

[0020] The leader region and / or mixed region can be a continuous region. For example, the leader region is a simply connected region, that is, a continuous region without interruption.

[0021] The doping concentration of the leader region differs from that of the first sub-region. For example, the doping concentrations may differ from each other by at least 1.1 times, or at least 1.5 times, or at least 2 times, or at least 5 times, or at least 10 times. Here and below, a comparison between the doping concentrations of two regions / sub-regions may be a comparison between the average doping concentration and / or the maximum doping concentration of these regions / sub-regions. This comparison may also focus on the doping concentration of the region / sub-region, for example, at the surface on the collector side. The maximum doping concentration may be at the surface of the region.

[0022] For example, the doping concentration in the pilot region is 1.10 16 cm -3 (including 1.10) 16 cm -3 ) to 5.1019 cm -3 (including 5.10) 19 cm -3 Between 1.10, for example, in 1.10 15 cm -3 (including 1.10) 15 cm -3 ) to 5.10 18 cm -3 (including 5.10) 18 cm -3 )between.

[0023] According to a further embodiment, the doping concentration in the first sub-region is greater than the doping concentration in the pilot region. For example, the doping concentration in each first sub-region is at least 1.1 times, or at least 1.5 times, or at least 2 times, or at least 5 times, or at least 10 times the doping concentration in the pilot region. The dopant in the pilot region and the dopant in the first sub-region can be the same, such as boron.

[0024] Reducing the doping concentration in the leader region improves the RBSOA capability and short-circuit SOA (SCSOA) (thermal) capability, but it may have undesirable effects on static losses and may increase on-state losses in IGBT operating modes. Increasing the doping concentration in the first sub-region of the mixing region reduces on-state losses in IGBT operating modes, compensating for the effect of the reduced doping concentration in the leader region. In this way, a BIGT device with similar on-state losses to known devices can be provided, but with improved RBSOA and SCSOA (thermal) capabilities.

[0025] According to a further embodiment, the collector layer further includes an edge region. The edge region may extend to the collector layer edges that define the collector layer in the lateral direction. For example, the edge region forms all edges of the collector layer.

[0026] In the lateral direction, the edge region may overlap with the termination region of the RC-IGBT. For example, the edge region may completely or partially overlap with the termination region of the RC-IGBT.

[0027] According to a further embodiment, the edge region laterally surrounds the pilot region and / or the blending region. For example, the edge region laterally completely surrounds the pilot region and / or the blending region. The edge region may form a border surrounding the pilot region and / or the blending region. The area of ​​the edge region may be larger than the area of ​​each first sub-region and / or second sub-region. For example, the edge region has a constant width along its extension line surrounding the blending region and / or the pilot region.

[0028] According to a further embodiment, a larger portion (most of) of the edge region has a first conductivity type or a second conductivity type. A larger portion of the edge region herein may refer to the portion of the edge region on the collector side that has a larger area or a larger volume of the edge region. "A larger portion" means, for example, greater than 50% or at least 75%. "A larger portion," "more of the portion," "most of the portion," and "most" are used as synonyms herein.

[0029] For example, the edge region includes a sub-region (also called a third sub-region) that has only a first or second conductivity type. The third sub-region may form a large portion of the edge region. The third sub-region may be a continuous sub-region of the edge region. For example, the third sub-region may laterally completely surround the mixing region and / or the leader region. The third sub-region may be uniformly doped.

[0030] According to a further embodiment, a larger portion of the edge region has the same conductivity type as the first sub-region and the same doping concentration as the first sub-region.

[0031] According to a further embodiment, a larger portion of the edge region has the same conductivity type as the first sub-region, but a different doping concentration. For example, a larger portion of the edge region has a lower doping concentration than the first sub-region. In this way, leakage can be reduced while further improving SCSOA (thermal) capability.

[0032] The doping concentration of the edge region may be at most 0.9 times, at most 0.5 times, or at most 0.1 times the doping concentration of the first sub-region. For example, the doping concentration of the edge region may be the same as the doping concentration in the leader region. Alternatively, the doping concentration of the edge region may be at least 1.1 times, at least 2 times, or at least 10 times the doping concentration of the first sub-region.

[0033] According to a further embodiment, a larger portion of the edge region has the same conductivity type as the leader region and has the same doping concentration as the leader region.

[0034] According to a further embodiment, a larger portion of the edge region has the same conductivity type as the second sub-region. In this case, the larger portion of the edge region may have a different doping concentration than the second sub-region or the same doping concentration. For example, the larger portion of the edge region is n-doped. In this way, since the emitter connection portion of the p-type termination region serves as an additional anode region for the internal diode of the BIGT, the on-state loss in the diode operating mode can be reduced.

[0035] The doping concentration in a larger portion of the edge region can be lower than the doping concentration in the second sub-region of the mixing region, for example, at most 0.9 times, 0.5 times, or 0.1 times the doping concentration of the second sub-region. Additionally or alternatively, the doping concentration in a larger portion of the edge region can be at least 1.1 times, at least 2 times, or at least 10 times the doping concentration in the first sub-region. Adjusting the doping distribution provides an opportunity to improve the plasma distribution below the termination region and maintain or improve the (termination-restricted) diode turn-off SOA.

[0036] According to a further embodiment, the second sub-region extends into the edge region. The edge region may consist of the portion of the second sub-region that extends into the edge region and a larger portion of the edge region described above. The first sub-region may end before the edge region, i.e., it may not extend into the edge region. For example, the first sub-region may be adjacent to the edge region.

[0037] According to a further embodiment, the pilot region is laterally surrounded by the mixing region, for example, it is completely laterally surrounded by the mixing region. For example, the pilot region is separated from the edge region by the mixing region.

[0038] According to a further embodiment, the leader region (i.e., the shape of the leader region) has rotational symmetry about an axis of symmetry. The axis of symmetry may extend obliquely (e.g., vertically) and / or through the collector layer relative to it. Obliquely or vertically relative to the collector layer means obliquely or vertically relative to the main extension plane of the collector layer. The axis of symmetry may extend through the leader region.

[0039] For example, the leader region may have double, triple, or quadruple rotational symmetry or circular symmetry about the axis of symmetry. In a top view on the collector side, the leader region may have a circular, cross, star, or rectangular shape.

[0040] According to a further embodiment, the arrangement of the first and second sub-regions in the mixing region has rotational symmetry about the axis of symmetry. For example, the rotational symmetry is double, triple, or quadruple rotational symmetry, or circular symmetry.

[0041] According to a further embodiment, the pilot region has at least two arms extending radially from the center of the pilot region. For example, the pilot region has at least three or at least four such arms. The center of the pilot region may coincide with the center of the collector side.

[0042] The radial direction should be understood in this paper as the lateral direction that extends through the center of the pilot zone and points towards or away from the center of the pilot zone.

[0043] According to a further embodiment, on the collector side, the first sub-region and the second sub-region extend from the leader region in a direction away from the leader region (e.g., in a direction away from the center of the leader region).

[0044] On the collector side, both the first and second sub-regions can extend parallel to the radial direction. For example, the first and second sub-regions are each formed as strips. The width of the first and / or second sub-regions can each be smaller than the width of the edge region and / or the leader region. For example, the width of each of the first and / or second sub-regions is at most 50%, at most 10%, or at most 1% of the width of the edge region and / or the leader region.

[0045] According to a further embodiment, the pilot area is connected to one or more first sub-areas and / or second sub-areas. This means that the pilot area is directly adjacent to one or more first sub-areas and / or one or more second sub-areas.

[0046] According to a further embodiment, the total area of ​​the pilot area is at least 10% or at least 20% of the total area of ​​the mixing area. Additionally or alternatively, the total area of ​​the pilot area may be at most 60%, at most 45%, or at most 35% of the total area of ​​the mixing area.

[0047] According to a further embodiment, the pilot region is a continuous region, such as a simply connected region.

[0048] According to a further embodiment, the semiconductor body further includes a substrate. The substrate may have a second conductivity type. For example, the substrate is n-doped. The doping concentration in the substrate may be less than the doping concentration in the second sub-region.

[0049] According to a further embodiment, the semiconductor body includes at least one well region. For example, the semiconductor body includes several (e.g., at least ten or at least 100) well regions. All features disclosed in combination with one well region are also disclosed for the other well regions. For example, the well region has a first conductivity type. For example, the well region is p-doped. The doping concentration of the well region may be less than, equal to, or greater than the doping concentration of the leader region and / or the first sub-region.

[0050] The well region can be separated from the collector layer by a base layer. In other words, the base layer can be arranged between the well region and the collector layer. For example, there is no direct connection between the well region and the collector layer.

[0051] According to a further embodiment, the semiconductor body further includes at least one emitter region. The semiconductor body may include multiple emitter regions, for example, at least ten or at least 100 emitter regions. All features disclosed for one emitter region are also disclosed for the other emitter regions.

[0052] The emitter region can have a second conductivity type. For example, each well region is assigned at least one emitter region. The emitter region can be embedded within the well region. The emitter region can be separated from the substrate by the well region, i.e., there is no direct contact between the substrate and the emitter region. The doping concentration in the emitter region can be less than, equal to, or greater than the doping concentration in the second sub-region. For example, the doping concentration in the emitter region is greater than the doping concentration in the substrate.

[0053] The well region and / or emitter region may be adjacent to the emitter side of the semiconductor body.

[0054] According to a further embodiment, at least one emitter electrode is disposed on the emitter side. The emitter electrode may include or be made of metal. The emitter electrode may be in electrical contact with at least one emitter region. The RC-IGBT may include several emitter electrodes. All features disclosed in combination with one emitter electrode are also disclosed for the other emitter electrodes. For example, each emitter region is assigned a separate emitter electrode. The emitter electrode may be adjacent to the assigned emitter region on the emitter side.

[0055] According to a further embodiment, at least one gate electrode is disposed on the emitter side. The gate electrode may be electrically insulated from the at least one well region and / or the at least one emitter region. For example, the gate electrode is disposed above the well region but laterally offset from the emitter region. For example, the gate electrode is electrically insulated from the semiconductor body or any conductive region of the semiconductor body. The RC-IGBT may include several gate electrodes. All features disclosed in combination with one gate electrode are also disclosed for the other gate electrodes. For example, each well region is assigned a separate gate electrode. The gate electrode may include or be composed of at least one of the following: metal, heavily doped polysilicon.

[0056] In the lateral direction, the edge region and / or termination region of the RC-IGBT may not overlap with any gate electrode or any emitter electrode or any well region or any emitter region.

[0057] According to a further embodiment, the width of the pilot zone is at least the same as the thickness of the base layer, or at least two or three times the thickness of the base layer. The width of the first sub-zone and / or the second sub-zone may be less than the thickness of the base layer, or at most twice the thickness of the base layer. The total width of the mixing zone may be at least twice the thickness of the base layer.

[0058] The method for manufacturing RC-IGBTs will now be described in detail. This method is particularly suitable for manufacturing RC-IGBTs according to any of the embodiments described herein. Therefore, all the features described in connection with RC-IGBTs are also disclosed in this method, and vice versa.

[0059] According to an embodiment of the method, a semiconductor body having an emitter side and a collector side is provided. The semiconductor body includes a collector layer comprising at least one leader region having a first conductivity type and a hybrid region comprising a first sub-region having a first conductivity type and a second sub-region having a second conductivity type. The first sub-region and the leader region may have the same doping concentration. Then, the doping concentration in the leader region and / or the first sub-region is changed until the doping concentrations in the leader region and the first sub-region are different.

[0060] To change the doping concentration, the leader region can be masked, and an additional implantation process can be performed to increase the doping concentration in the first sub-region, while the doping concentration in the leader region remains unchanged or changes only slightly due to masking. This results in a lower doping concentration in the leader region compared to the first sub-region of the mixed region, improving RBSOA performance. Alternatively, to change the doping concentration, a local activation process can be performed, in which the first sub-region is annealed while the leader region is not annealed.

[0061] To improve diode (third quadrant) performance, the doping concentration of the leader region can be higher than that of the first sub-region. To increase the doping concentration of the leader region, the first sub-region can be masked, and an additional implantation process can be performed to increase the doping concentration in the leader region while, due to masking, the doping concentration in the first sub-region remains unchanged or changes only slightly. Alternatively, to change the doping concentration, a local activation process can be performed, in which the leader region is annealed while the first sub-region is not annealed.

[0062] In the following, the RC-IGBT and the method for manufacturing the RC-IGBT will be explained in more detail with reference to the accompanying drawings based on exemplary embodiments. The drawings are included to provide further understanding. In the drawings, elements with the same structure and / or function may be represented by the same reference numerals. It should be understood that the embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale. Descriptions of elements or components will not be repeated for subsequent drawings as long as their functions correspond to each other in different drawings. For clarity, elements may not appear with corresponding reference numerals in all figures. Attached Figure Description

[0063] Figure 1 A first exemplary embodiment of the RC-IGBT is shown in a top view from the collector side.

[0064] Figure 2 A second exemplary embodiment of the RC-IGBT is shown in cross-sectional view.

[0065] Figure 3 Showing more details Figure 2 Part of

[0066] Figure 4 A second exemplary embodiment of the RC-IGBT is shown in a top view from the collector side.

[0067] Figure 5 and Figure 6 Further exemplary embodiments of the RC-IGBT are shown in top view from the collector side.

[0068] Figure 7 and Figure 8 The measurement results are shown.

[0069] Figure 9 A flowchart illustrating an exemplary embodiment of a method for manufacturing RC-IGBTs is shown. Detailed Implementation

[0070] Figure 1 A first exemplary embodiment of the RC-IGBT 1000 is shown in a top view of the collector side. The RC-IGBT 1000 includes a semiconductor body having an emitter side and a collector side, and a collector layer on the collector side. The collector layer forming the collector side includes a leader region 10 and a mixed region 11 (separated by dashed lines for illustration). The leader region 10 has a first conductivity type. The mixed region includes a first sub-region 11, which also has a first conductivity type, and a second sub-region 112, which has a second conductivity type. For example, the leader region 10 and the first sub-region 111 are p-doped, while the second sub-region 112 is n-doped.

[0071] As shown by the different structures of these different regions / subregions, the doping concentration in the pilot region 10 is different from the doping concentration in the first subregion 111. For example, the doping concentration in the pilot region 10 is less than the doping concentration in the first subregion 111.

[0072] Figures 2 to 4 A second exemplary embodiment of the RC-IGBT 1000 is shown. Therefore, Figure 2 yes Figure 4 The view on the cross-sectional plane AA'. Figure 4 The RC-IGBT 1000 is shown in a top view of the collector side of the RC-IGBT. Figure 3 Showing more details Figure 2 The part within the box.

[0073] The RC-IGBT 1000 includes a semiconductor body 100 having a substrate 3, a buffer layer 8, and a collector layer 1. The buffer layer 8 and the substrate 3 may have a second conductivity type. In this exemplary embodiment, the first conductivity type is hole conduction, and the second conductivity type is electron conduction. Therefore, both the substrate 3 and the buffer layer 8 are n-doped. However, the substrate and the buffer layer may have different doping concentrations. For example, the doping concentration in the buffer layer 8 may be greater than the doping concentration in the substrate 3. The substrate 3 may be thicker than the buffer layer 8. Furthermore, the substrate 3 and / or the buffer layer 8 may be thicker than the collector layer 1.

[0074] Collector layer 1 includes a pilot region 10 and a hybrid region 11. Hybrid region 11 includes a plurality of first sub-regions 111 and a plurality of second sub-regions 112. Both the first sub-regions 111 and the pilot region 10 have a first conductivity type but different doping concentrations. Therefore, in the present case, both the first sub-regions and the pilot region are p-doped. For example, the doping concentration in the pilot region 10 is less than the doping concentration in the first sub-regions 111, for example, by at least half.

[0075] The second sub-regions 112 have a second conductivity type, and therefore are n-doped in the present case. The collector layer 1 forms the collector side 102 of the semiconductor body 100. The leader region 10 and sub-regions 111, 112 reach the collector side 102, i.e., each forms a portion of the collector side 102. The collector electrode 2 is disposed on top of the collector side 102 and is in electrical contact with the collector side 102. The collector electrode 2 is made of, for example, metal.

[0076] Furthermore, the collector layer 1 includes an edge region 12. The edge region 12 is adjacent to or forms a lateral edge of the collector layer 1. The edge region 12 may partially or completely overlap with the termination region of the RC-IGBT in the lateral direction. For example, the edge region 12 is defined by the termination region.

[0077] The termination region is the RC-IGBT region that laterally surrounds the active region of the RC-IGBT. The active region is the area where the device conducts current during the on-state.

[0078] On the emitter side 101, opposite to the collector side 102, the semiconductor body 100 includes a plurality of well regions 4 (see [link to documentation] for better illustration). Figure 3 The well region 4 has, for example, a first conductivity type, i.e., p-doped. Embedded in the well region 4 are emitter regions 5, which have, for example, a second conductivity type, i.e., n-doped. On the top of the emitter side 101, an emitter electrode 6 is disposed in electrical contact with the emitter region 5. Further, a gate electrode 7 is disposed on the emitter side 101 and is insulated from the semiconductor body 100 by an insulating material 9. The emitter electrode 6 and the gate electrode 7 are, for example, formed of metal. The insulating material 9 may include SiO2 or be composed of it.

[0079] The termination region and / or edge region 12 may be defined by a region on the lateral side of the RC-IGBT that does not overlap with any emitter electrode 6 and / or any gate electrode 7 and / or any emitter region 5 and / or any well region 4 in the lateral direction.

[0080] Looking at it now Figure 4 A second exemplary embodiment of the RC-IGBT 1000 is shown in a top view of the collector side 101, revealing that the pilot region 10 has a cross shape. The center 103 of the pilot region 10 coincides with the center of the collector side 102. The pilot region 10 has four-fold rotational symmetry about an axis of symmetry 20 extending perpendicular to the plane of the drawing and passing through the center 103.

[0081] from Figure 4 It can also be seen that the arrangement of the first sub-region 111 and the second sub-region 112 in the mixing region 11 also follows a fourfold rotational symmetry about the axis of symmetry 20. The mixing region 11 laterally completely surrounds the pilot region 10. The mixing region 11 and the pilot region 10 are further laterally completely surrounded by the edge region 12. The boundaries between the mixing region 11 and the pilot region 10, and between the mixing region 11 and the edge region 12, are each represented by dashed lines.

[0082] exist Figure 4 In an exemplary embodiment, the area of ​​the pilot region 10 is larger than the area of ​​each of the first sub-region 111 and / or the second sub-region 112, for example, at least five times the area of ​​each of the first sub-region 111 and / or the second sub-region 112. The area of ​​the pilot region 10 is, for example, between 10% and 35% of the area of ​​the mixing region. The width of the pilot region 10 may be at least twice the thickness of the base layer 3.

[0083] The first sub-region 111 and the second sub-region 112 are each formed in a strip shape. The width of each of the sub-regions 111 and 112 may be less than the thickness of the base layer 3, for example, at most 50% of the thickness of the base layer 3.

[0084] The area of ​​edge region 12 may also be larger than the area of ​​each of the first sub-region 111 and / or the second sub-region 112, for example, at least 5 times larger.

[0085] exist Figures 2 to 4 In an exemplary embodiment, the second sub-region 112 extends into the edge region 12 and forms a portion of the edge region 12. The remaining portion of the edge region 12 (i.e., the larger portion of the edge region 12) has the same conductivity type as the leader region 10 and the first sub-region 111, i.e., it has the first conductivity type.

[0086] In this exemplary embodiment, the doping concentration of a larger portion of the edge region 12 is the same as the doping concentration in the first sub-region 111. However, the doping concentration in the pilot region 10 is lower than the doping concentration in the first sub-region 111 and a larger portion of the edge region 12.

[0087] The larger portion of the edge region 12 having a first conductivity type forms a continuous sub-region of the edge region, which completely surrounds the mixing region 11 and the pilot region 10.

[0088] Figure 5 A further exemplary embodiment of the RC-IGBT 1000 is shown. The cross-section of this RC-IGBT 1000 can look similar to... Figure 2 The cross-section. However, the top view of the collector side looks different compared to the previous exemplary embodiment. Compared to the previous exemplary embodiment, a larger portion of the edge region 12 does not have the same doping concentration as the first sub-region 111, but instead has the same doping concentration as the guide region 11.

[0089] exist Figure 6 In the exemplary embodiment, only a top view of the collector side is shown again. Here, compared to the previous exemplary embodiment, a larger portion of the edge region 12 is not of the first conductivity type, but of the second conductivity type. The larger portion of the edge region can thus have a different doping concentration than the second sub-region 112 of the mixing region 11.

[0090] A common feature of all the exemplary embodiments shown is that the doping concentrations in the first sub-region and the leader region of the mixing region are different. In the described exemplary embodiments, the first conductivity type is hole conduction, and the second conductivity type is electron conduction. However, this is only one example, and the opposite (i.e., the first conductivity type is electron conduction, and the second conductivity type is hole conduction) is also possible.

[0091] Figure 7(Left side) shows a measurement example of the effect of increasing the implantation dose (20% and 40%, respectively) on the technology curve (see arrows) when both the first sub-region and the leader region always have the same doping concentration. On the y-axis, the turn-off switching loss (i.e., the energy dissipated during the switching event from the on-state to the off-state) is shown. On the x-axis, VCEsat (the voltage between the emitter and collector at saturation) is shown. As expected, increasing the implantation dose (increasing the doping concentration) decreases VCEsat, and also shows a corresponding decrease in RBSOA (from 4x Inom to 1.5x Inom in terms of maximum current turn-off capability). For all three points, the RBSOA failure location is observed above the leader region. This indicates that the leader region is a weak point across all doping ranges. This particularly limits movement to the lower-state loss portion of the technology curve, i.e., the region favorable for (low switching frequency) HVDC applications that primarily use BIGT. By tailoring the doping in the leader region specifically for the improved RBSOA, and tailoring the doping in the hybrid region to the improved on-state and estimated SOA performance, it can be expected that... Figure 7 The improvements are shown on the right.

[0092] Figure 8 The figure shows experimental results for reduced diode on-state with (left) and without (right) BIGT MOS control. The y-axis indicates the conduction loss in diode mode. In both figures, the left data point corresponds to the case where the edge region below the termination region has the same doping concentration and the same conductivity type as the first sub-region (see figure). Figure 4 The reduced on-state at the right data point is due to the use of an edge region, a larger portion of which has a different conductivity type, such as n-doping, than the lead region or the first sub-region. Here, as an example, the n-doping in the edge region is equal to the n-doping in the second sub-region of the mixed region. Similar to the improvement in IGBT on-state, the improvement in diode on-state is again key to achieving better system-level performance in low-frequency HVDC systems. Finally, the improved on-state without MOS control also benefits systems where the BIGT is used as a plug-and-play component in a more general (MOS-free) system topology.

[0093] Figure 9A flowchart illustrating an exemplary embodiment of a method for manufacturing an RC-IGBT is shown. First, in step S1, a semiconductor body having an emitter side and a collector side is provided. The semiconductor body includes a collector layer comprising at least one leader region having a first conductivity type and a hybrid region having a first sub-region of the first conductivity type and a second sub-region of a second conductivity type. The first sub-region and the leader region have the same doping concentration. Then, in step S2, the doping concentration in the leader region and / or the first sub-region is varied until the doping concentrations in the leader region and the first sub-region are different.

[0094] As mentioned above, Figures 1 to 6 and Figure 9 The embodiments shown represent exemplary embodiments of the improved RC-IGBT and method; therefore, these exemplary embodiments do not constitute a complete list of all embodiments according to the improved RC-IGBT and method. For example, actual RC-IGBTs and actual methods may differ in arrangement from the embodiments shown.

[0095] Figure Labels

[0096] 1 Collector layer

[0097] 2 Collector Electrode

[0098] 3. Grassroots

[0099] 4. Tunnel

[0100] 5. Emission polar regions

[0101] 6 Emitter electrode

[0102] 7 Gate electrode

[0103] 8. Buffer layer

[0104] 9. Insulation materials

[0105] 10 Pilot Zones

[0106] 11 Mixed Zone

[0107] 12 Edge Zone

[0108] 20. Axis of symmetry

[0109] 100 Semiconductor Body

[0110] 101 Emitting polar side

[0111] 102 Collector side

[0112] 103 Center

[0113] 111 First Sub-region

[0114] 112 Second Sub-region

[0115] 1000 Reverse-biased Insulated Gate Bipolar Transistor

[0116] S1, S2 Method Steps

Claims

1. A reverse-conducting insulated-gate bipolar transistor (1000), comprising: - Semiconductor body (100), the semiconductor body having an emitter side (101) and a collector side (102). - Collector layer (1), the collector layer is located at the collector side (102) and has at least one pilot region (10) and at least one mixing region (11). - Collector electrode (2), the collector electrode is on the collector side (102) and in electrical contact with the collector layer (1), wherein, -The pilot region (10) has a first conductivity type, - The mixing region (11) includes a first sub-region (111) having the first conductivity type and a second sub-region (112) having the second conductivity type. - The pilot region (10) is a continuous region, and the area of ​​the pilot region (10) on the collector side (102) is greater than the area of ​​each of the first sub-region (111) and / or the second sub-region (112) on the collector side (102). - The doping concentration in the first sub-region (111) is different from the doping concentration in the pilot region (10). -The current collector layer (1) also includes an edge region (12). - The edge region (12) laterally surrounds the pilot region (10) and the mixing region (11). - More than 50% of the edge region (12) has the same conductivity type as the first sub-region (111), or - More than 50% of the edge region (12) has the same conductivity type as the second sub-region (112), but has a different doping concentration than the second sub-region (112). - The second sub-region (112) extends into the edge region (12), and the first sub-region (111) ends before the edge region (12). - The formation of the edge region (12) The sub-regions of the edge region (12) have only one type of conductivity, are formed continuously, and are laterally completely surrounding the hybrid region (11) and the leader region (10).

2. The reverse-conduction insulated-gate bipolar transistor (1000) according to claim 1, wherein, - The doping concentration in the first sub-region (111) is greater than the doping concentration in the pilot region (10).

3. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, - The edge region (12) has the same conductivity type as the leader region (10) and the same doping concentration as the leader region (10).

4. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, - On the collector side (102), the first sub-region (111) and the second sub-region (112) extend from the pilot region (10) in a direction away from the pilot region (10).

5. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, - The pilot region (10) is laterally surrounded by the mixing region (11).

6. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, - The pilot region (10) has rotational symmetry about the axis of symmetry (20), which extends obliquely relative to the collector layer (1) and extends through the collector layer, and - The arrangement of the first sub-region (111) and the second sub-region (112) in the mixing region (11) has rotational symmetry about the axis of symmetry (20).

7. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, - The pilot region (10) has at least two arms that extend radially from the center (103) of the pilot region (10).

8. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, - The pilot area (10) is connected to one or more first sub-areas (111). - The total area of ​​the pilot region (10) is at least 10% of the total area of ​​the mixing region (11). -The pilot region (10) is a continuous region.

9. The reverse-conducting insulated-gate bipolar transistor (1000) according to claim 1 or 2, wherein, -The semiconductor body (100) further includes: - Substrate (3), the substrate having the second conductivity type. - At least one well region (4), the at least one well region having the first conductivity type and being separated from the collector layer (1) by the base layer (3), - At least one emitter region (5), the at least one emitter region having the second conductivity type and being separated from the substrate (3) by the well region (4), - At least one emitter electrode (6), said at least one emitter electrode is disposed on the emitter side (101) and is in electrical contact with at least one emitter region (5), - At least one gate electrode (7), which is disposed on the emitter side (101) and electrically insulated from the well region (4).

10. A method for manufacturing a reverse-conducting insulated-gate bipolar transistor (1000), comprising: - A semiconductor body (100) is provided having an emitter side (101) and a collector side (102), wherein the semiconductor body (100) includes a collector layer (1) having at least one pilot region (10) and a hybrid region (11), the at least one pilot region having a first conductivity type, and the hybrid region including a first sub-region (111) having the first conductivity type and a second sub-region (112) having a second conductivity type, wherein the first sub-region (111) and the pilot region (10) have the same doping concentration. - Change the doping concentration in the pilot region (10) and / or the first sub-region (111) until the doping concentrations in the pilot region (10) and the first sub-region (111) are different, wherein, - The pilot region (10) is a continuous region, and the area of ​​the pilot region (10) on the collector side (102) is greater than the area of ​​each of the first sub-region (111) and / or the second sub-region (112) on the collector side (102). -The current collector layer (1) also includes an edge region (12). - The edge region (12) laterally surrounds the pilot region (10) and the mixing region (11). - More than 50% of the edge region (12) has the same conductivity type as the first sub-region (111), or more than 50% of the edge region (12) has the same conductivity type as the second sub-region (112), but has a different doping concentration than the second sub-region (112). - The second sub-region (112) extends into the edge region (12), and the first sub-region (111) ends before the edge region (12). - The formation of the edge region (12) The sub-regions of the edge region (12) have only one type of conductivity, are formed continuously, and are laterally completely surrounding the hybrid region (11) and the leader region (10).

11. The method according to claim 10, wherein, In order to change the doping concentration - Mask the pilot region (10) or the first sub-region (111) and perform an implantation process, during which the doping concentration in the first sub-region (111) or the pilot region (10) is increased, while the doping concentration in the other of the pilot region (10) and the first sub-region (111) remains unchanged due to the masking, and / or - Perform a local activation process in which the first sub-region (111) or the leader region (10) is annealed without annealing the other of the leader region (10) and the first sub-region (111).

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