RC IGBT and method of operating half-bridge circuit

Abstract

The invention relates to an RC IGBT and a method of operating a half-bridge circuit. The RC IGBT (1) comprises, in a single chip, an active region (1-2) configured to conduct both a forward load current and a reverse load current between a first load terminal (11) of a front side (110) of a semiconductor body (10) of the RC IGBT (1) and a second load terminal (12) of a rear side (120) of the semiconductor body (10), where the active region (1-2) is separated into at least: only IGBT regions (1-21), at least 90% of the first control circuit is configured to conduct only a forward load current based on a first control signal (13-21); and an RC IGBT region (1-22), at least 90% of which is configured to conduct a reverse load current and to conduct a forward load current based on the second control signal (13-22).

Description

Technical Field

[0001] The present description relates to embodiments of an RC IGBT and to embodiments operating a half-bridge circuit. Background Art

[0002] Many functions of modern devices in automotive, consumer and industrial applications, such as converting electrical energy and driving motors or electric machines, rely on power semiconductor devices. For example, insulated gate bipolar transistors (IGBTs), metal oxide semiconductor field effect transistors (MOSFETs), and diodes, to name a few, have been used in a variety of applications including, but not limited to, switches in power supplies and power converters.

[0003] A power semiconductor device typically includes a semiconductor body configured to conduct a forward load current along a load current path between two load terminals of the device. Typically, the load current is conducted by means of an active region of the power semiconductor device. The active region is typically surrounded by an edge termination region that is terminated by the edge of the chip.

[0004] In the case of a controllable power semiconductor device, such as a transistor, the load current path can be controlled by means of an insulated electrode, usually referred to as a gate electrode. For example, upon receiving a corresponding control signal, such as via a control terminal of the device from a driver unit, the control electrode can set the power semiconductor device in one of a forward conducting state and a blocking state.

[0005] In addition, some devices provide reverse load current capability; that is, the active area of ​​the semiconductor body is also configured to conduct a reverse load current along a reverse load current path between the two load terminals of the device. For example, the RC (reverse current) IGBT is a representative of such a device. In an RC IGBT, a single chip combines an IGBT structure and a diode structure, wherein not only the IGBT can be controlled based on the gate signal, but also the characteristics of the diode behavior can be affected. Compared to a separate diode and a separate IGBT connected in anti-parallel to each other, the RC IGBT exhibits some advantages, for example in terms of on-state losses and / or thermal behavior, and may also be more complex to control. Summary of the invention

[0006] The subject matter of the independent claims is presented. Features of exemplary embodiments are defined in the dependent claims.

[0007] According to an embodiment, an RC IGBT includes an active region in a single chip, the active region being configured to conduct both a forward load current and a reverse load current between a first load terminal on a front side of a semiconductor body of the RC IGBT and a second load terminal on a rear side of the semiconductor body. The active region is separated into at least: an IGBT-only region, at least 90% of which is configured to conduct only a forward load current based on a first control signal; and an RC IGBT region, at least 90% of which is configured to conduct a reverse load current and conduct a forward load current based on a second control signal.

[0008] According to another embodiment, a method of operating a half-bridge circuit is presented. The half-bridge circuit includes a first RC IGBT according to the above embodiment and a second RC IGBT according to the above embodiment. The method includes: controlling the first RC IGBT based on a first control signal and a second control signal of the first RC IGBT; and controlling the second RC IGBT based on the first control signal and the second control signal of the second RC IGBT.

[0009] Those skilled in the art will recognize additional features and advantages upon reading the following detailed description, and upon viewing the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The components in the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

[0011] Moreover, in the drawings, like reference numerals designate corresponding parts. In the drawings:

[0012] Figure 1 schematically and exemplarily illustrates a horizontally projected segment of a RC IGBT according to one or more embodiments;

[0013] Figure 2 schematically and exemplarily illustrates a horizontally projected section of an active area of ​​an RC IGBT according to one or more embodiments;

[0014] Figure 3-5 each schematically and exemplarily illustrates a section of a vertical cross section of an RC IGBT according to one or more embodiments; and

[0015] Figure 6 A method of operating a half-bridge circuit according to one or more embodiments is schematically and exemplarily illustrated. DETAILED DESCRIPTION

[0016] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced.

[0017] In this regard, directional terms such as "top", "bottom", "below", "front", "behind", "rear", "first", "last", "above", etc. may be used with reference to the orientation of the drawings being described. Because portions of the embodiments can be placed in many different orientations, the directional terms are used for illustrative purposes and are in no way limiting. It should be understood that other embodiments may be used and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description should not be understood in a limiting sense, and the scope of the present invention is defined by the appended claims.

[0018] Reference will now be made in detail to various embodiments, one or more examples of which are illustrated in the accompanying drawings. Each example is provided as an explanation, and each example is not intended to be a limitation of the present invention. For example, a feature illustrated or described as part of one embodiment can be used on other embodiments or used in conjunction with other embodiments to produce another embodiment. It is intended that the present invention includes such modifications and variations. Examples are described using specific language, which should not be interpreted as limiting the scope of the appended claims. The accompanying drawings are not drawn to scale and are for illustrative purposes only. For clarity, the same elements or manufacturing steps have been designated by the same reference numerals in different drawings if not otherwise indicated.

[0019] As used in this specification, the term "horizontal" is intended to describe an orientation substantially parallel to a horizontal surface of a semiconductor substrate or semiconductor structure. This can be, for example, a surface of a semiconductor wafer or die or chip. For example, both the first lateral direction X and the second lateral direction Y mentioned below can be horizontal directions, wherein the first lateral direction X and the second lateral direction Y can be perpendicular to each other.

[0020] As used in this specification, the term "vertical" is intended to describe an orientation that is substantially arranged perpendicular to a horizontal surface (i.e., parallel to the normal direction of the surface of the semiconductor wafer / chip / die). For example, the extension direction Z mentioned below may be an extension direction perpendicular to both the first lateral direction X and the second lateral direction Y. The extension direction Z is also referred to herein as the "vertical direction Z".

[0021] In this specification, n-doping is referred to as “first conductivity type” and p-doping is referred to as “second conductivity type.” Alternatively, the opposite doping relationship can be adopted, so that the first conductivity type can be p-doped and the second conductivity type can be n-doped.

[0022] In the context of this specification, the terms "in ohmic contact", "in electrical contact", "ohmically connected", and "electrically connected" are intended to describe that there is a low-ohmic electrical connection or a low-ohmic current path between two regions, sections, zones, portions or parts of a semiconductor device or between different terminals of one or more devices or between a terminal or metallization or electrode and a portion or part of a semiconductor device, where "low ohmic" may mean that the characteristics of the respective contact are essentially not affected by ohmic resistance. In addition, in the context of this specification, the term "in contact" is intended to describe that there is a direct physical connection between two elements of the respective semiconductor device; for example, the transition between two elements that are in contact with each other may not include another intermediate element, etc.

[0023] In addition, in the context of this specification, if not otherwise indicated, the term "electrically insulating" is used with the generally valid understanding of the term "electrically insulating", and therefore, the term "electrically insulating" is intended to describe that two or more components are arranged to be separated from each other and there is no ohmic connection connecting those components. However, components that are electrically insulated from each other may still be coupled to each other, for example mechanically coupled and / or capacitively coupled and / or inductively coupled and / or electrostatically coupled (for example, in the case of a junction). As an example, two electrodes of a capacitor may be electrically insulated from each other and, at the same time, mechanically and capacitively coupled to each other, for example, by means of an insulator (for example, a dielectric).

[0024] The specific embodiments described in this specification relate to RC IGBTs, for example, power semiconductor devices that can be used in power converters or power supplies. Therefore, in embodiments, such RC IGBTs can be configured to carry a load current to be fed to a load and / or provided by a power supply. For example, the RC IGBT may include one or more active power semiconductor unit cells, such as a monolithically integrated diode cell, a derivative of a monolithically integrated diode cell, a monolithically integrated transistor cell (e.g., a monolithically integrated IGBT cell), and / or a derivative thereof. Such a diode / transistor cell may be integrated in a power semiconductor module. A plurality of such cells may constitute a cell field, which is arranged in an active region of a power semiconductor device.

[0025] The term "blocking state" of the RC IGBT may refer to a condition when the RC IGBT is in a state configured to block the flow of a load current while an external voltage is applied. More specifically, the RC IGBT may be configured to block a forward load current through the RC IGBT while a forward voltage bias is applied. In contrast, the RC IGBT may be configured to conduct a forward load current in a "conducting state" of the RC IGBT while a forward voltage bias is applied. The transition between the blocking state and the conducting state may be controlled by a control electrode, or more specifically, by the potential of the control electrode. The electrical characteristics may of course only apply within a predetermined operating range of an external voltage and current density within the RC IGBT. The term "forward biased blocking state" may therefore refer to a condition in which the RC IGBT is in a blocking state while a forward voltage bias is applied.

[0026] As used in this specification, the term "RC IGBT" is intended to describe an RC IGBT on a single chip having high voltage blocking and / or high current carrying capabilities. In other words, such an RC IGBT is intended for: high currents, typically in the ampere range, such as up to tens or hundreds of amperes; and / or high voltages, typically 100 V and above, such as at least 400 V or even higher, such as at least 3 kV, or even up to 10 kV or higher, depending on the respective application.

[0027] For example, as used in this specification, the term "RC IGBT" does not refer to a logic semiconductor device used, for example, to store data, calculate data, and / or other types of semiconductor-based data processing.

[0028] For example, the RC IGBT described below may be a single semiconductor chip exhibiting, for example, a stripe cell configuration (or a honeycomb / needle cell configuration) and can be configured for use as a power component in low voltage, medium voltage, and / or high voltage applications.

[0029] Figure 1 Schematically and exemplarily illustrates a horizontally projected section of an RC IGBT 1 according to one or more embodiments. Figures 3 to 5 The vertical section shown in the figure and the Figure 2 A more detailed illustration of an exemplary active region 1-2 of FIG.

[0030] Thus, the RC IGBT 1 comprises a semiconductor body 10 coupled to a first load terminal at a front side (also referred to as the first side) 110 and to a second load terminal 12 at a rear side (also referred to as the back side) 120, which is opposite to the front side 110 with respect to the vertical direction Z. The semiconductor body 10 is part of a single chip comprising an active area 1-2 configured to conduct both a forward load current and a reverse load current between the first load terminal 11 and the second load terminal 12 at the back side 120.

[0031] The RC IGBT 1 may thus exhibit a vertical configuration according to which both the forward load current and the reverse load current flow substantially parallel to the vertical direction Z.

[0032] For example, the first load terminal 11 may be a source (or emitter) terminal, and the second load terminal 12 may be a drain (collector) terminal.

[0033] The active region 1-2 is surrounded by an edge termination region 1-3 which is terminated by a chip edge 1-4. In this document, the terms "active region" (sometimes also referred to as "element field"), "edge termination region" and "chip edge" have the technical meanings that a skilled person usually associates with them in the context of RC IGBTs and are therefore not explained in more detail.

[0034] According to the embodiments disclosed herein, the active region 1-2 of the RC IGBT 1 is separated into at least an IGBT-only region 1-21 and an RC IGBT region 1-22. At least 90% of the IGBT-only region 1-21 is configured to conduct only a forward load current based on a first control signal 13-21. At least 90% of the RC IGBT region 1-22 is configured to conduct a reverse load current and conduct a forward load current based on a second control signal 13-22.

[0035] Additionally, the active region 1-2 may include a diode-only region 1-23, which will be explained in more detail below.

[0036] It should be understood that Figure 2The arrangement of the IGBT-only region 1-21, the RC IGBT region 1-22 and the optional diode-only region 1-23 shown in the figure is only exemplary. For example, the three regions 1-21, 1-22 and 1-23 are not necessarily adjacent regions, but can also be composed of spatially distributed sub-regions. In addition, instead of being arranged in the center, the IGBT-only region 1-21 can be arranged alternatively or additionally in the peripheral part of the active region 1-2. The technician can determine the size of the three regions 1-21, 1-22 and 1-23 within the active region 1-2 according to the specified characteristics of the RC IGBT 1 and arrange the three regions 1-21, 1-22 and 1-23.

[0037] In an embodiment, the second control signal 13-22 is different from the first control signal 13-21. For example, the second control signal 13-22 is determined / generated separately from the first control signal 13-21. Thereby, the control of the IGBT-only region 1-21 can be independent of the control of the RC IGBT region 1-22. That is, in an embodiment, instead of providing only the RC IGBT region in the active region, the active region is separated into at least: a) a different IGBT-only region 1-21, carrying only the forward load current (and not the reverse load current), and being controlled based on the first control signal 13-21; and b) a different RC IGBT region 1-22, carrying both the forward load current and the reverse load current, and being controlled based on the second control signal 13-22, the second control signal 13-22 being independent of the first control signal 13-21.

[0038] In an embodiment, the RC IGBT region 1 - 22 is configured to conduct a reverse load current regardless of the second control signal 13 - 22 .

[0039] The IGBT-only region 1-21 and the RC IGBT-only region 1-22 may occupy a majority of the active region 1-2; for example, the IGBT-only region 1-21 and the RC IGBT-only region 1-22 equal at least 80% of the active region 1-2. The remainder of the active region 1-2 may be occupied, for example, by an optional diode-only region 1-23.

[0040] In an embodiment, the IGBT-only region 1-21 is spatially separated from the RC IGBT region 1-22. For example, there is no spatial overlap between the IGBT-only region 1-21 and the RC IGBT region 1-22.

[0041] In addition, only the IGBT region 1 - 21 can be the first adjacent region, and the RC IGBT region 1 - 22 can be the second adjacent region, which is arranged separately from the first adjacent region, for example.

[0042] For example, at least 90% of the optional diode-only regions 1-23 are configured to conduct only reverse load current (but not, for example, forward load current).In an embodiment, the diode-only regions 1-23 are not affected by the first control signal 13-21 or the second control signal 13-22.

[0043] As indicated above, the skilled person may size and arrange the three zones 1-21, 1-22 and 1-23 within the active area 1-2 according to the specified characteristics of the RC IGBT 1. Furthermore, the expression "at least 90%" used in the context of describing these zones shall mean that the main purpose of these zones is to conduct only forward load current (in the case of the IGBT-only zone 1-21) or only reverse load current (in the case of the optional diode-only zone 1-23) or both forward and reverse load current (in the case of the RC IGBT zone 1-22). Of course, in smaller sub-portions of the zones, for example in the transition zone where the IGBT-only zone 1-21 adjoins the RC IGBT zone 1-22, the characteristics may deviate. Such transitions will be described in more detail below.

[0044] We will now refer to Figure 3 , Figure 3 A section of a vertical cross section of an exemplary embodiment of an active region 1-2 is shown, the active region 1-2 comprising an IGBT-only region 1-21, an RC IGBT region 1-22, and a diode-only region 1-23. It is again emphasized that the diode-only region 1-23 is optional. In other embodiments, the reverse load current is completely carried by the RC IGBT region 1-22, so that the different diode-only region 1-23 can be omitted.

[0045] As shown in the figure, the active region 1-2 exhibits a vertical configuration, the first load terminal 11 is arranged at the semiconductor body front side 110 and the second load terminal 12 is arranged at the semiconductor body back side 120. The first load terminal 11 and the second load terminal 12 may be shared by each of the IGBT-only region 1-21, the RC IGBT region 1-22, and the diode-only region 1-23.

[0046] A drift region 100 of the first conductivity type may form a major central portion of the semiconductor body 10 with respect to the vertical direction Z. Such a drift region 100 may be shared by each of the IGBT-only regions 1-21, the RC IGBT regions 1-22, and by the diode-only regions 1-23 if implemented.

[0047] According to the distribution of the IGBT-only region 1 - 21 , the RC IGBT region 1 - 22 , and the diode-only region 1 - 23 , the active region 1 - 2 may be configured both at the front side 110 and at the back side 120 .

[0048] For example, with respect to the back side 120, a back side emitter 108 coupled to the drift region 100 is arranged, the back side emitter 108 being in electrical connection with the second load terminal 12, wherein the back side emitter 108 is configured according to the active region 1-2 being separated into at least only the IGBT region 1-21 and the RCIGBT region 1-22 and only the diode region 1-23 (if only the diode region 1-23 is implemented).

[0049] In an embodiment, the back side emitter 108 may be configured to have:

[0050] - a first section 108 - 21 of the second conductivity type, located in the portion of the active area 1 - 2 where only the IGBT area 1 - 21 exists;

[0051] - a second section 108-22, located in the portion of the active region 1-2 where the RC IGBT region 1-22 exists, including both a first sub-section 108-221 of the first conductivity type and a second sub-section 108-222 of the second conductivity type;

[0052] - and optionally, if only the diode region 1-23 is implemented, a third section 108-23 of the first conductivity type, said third section 108-23 being located in the portion of the active region 1-2 where only the diode region 1-23 is present.

[0053] For example, the first section 108 - 21 of the back side emitter 108 exhibits, for its total lateral extension along the first lateral direction X and at a certain vertical level, at least 1*10 13 cm -3 Or even at least 1*10 14 cm -3 In addition, the first section 108 - 21 can be shifted relative to the RC IGBT region 1 - 22 by a first distance d1 of at least 20% of the thickness of the drift region 100 along the vertical direction Z.

[0054] In an embodiment, each of the first sub-segments 108-221 of the second segment 108-22 of the back side emitter 108 exhibits, for its respective total lateral extension along the first lateral direction X and at a certain vertical level, at least 1*10 13 cm -3 Or even at least 1*10 14 cm -3 Furthermore, each of the first sub-segments 108 - 221 can be shifted by a second distance d2 of at least 20% of the thickness of the drift region 100 along the vertical direction Z relative to only the diode region 1 - 23 .

[0055] In another embodiment, the RC IGBT 1 further comprises a field stop zone 107 of the first conductivity type, the field stop zone 107 being arranged to contact both the drift region 100 and each of the first section 108-21, the second section 108-22 and the third section 108-23 (if the third section 108-23 is implemented) of the back side emitter 108. The dopant concentration of the field stop zone 107 can be greater than the dopant concentration of the drift region 100.

[0056] As indicated above, the configuration of the active region 1-2 may also reflect the separation of the active region 1-2 into at least only the IGBT region 1-21 and the RC IGBT region 1-22 and only the diode region 1-23 (if only the diode region 1-23 is implemented) at the front side 110. For example, between the first load terminal 11 and the drift region 100, the RC IGBT 1 further comprises a trench-mesa pattern, wherein the trench-mesa pattern is configured according to the separation of the active region 1-2 into at least only the IGBT region 1-21 and the RC IGBT region 1-22 and only the diode region 1-23 (if only the diode region 1-23 is implemented).

[0057] An exemplary configuration of the front side trench mesa pattern is shown in Figure 3 For example, the trench-terrace pattern configuration is:

[0058] - a first control trench 14-21, arranged in the IGBT region 1-21 only, and configured to receive the first control signal 13-21; and configured with

[0059] A second control trench 14 - 22 , arranged in the RC IGBT region 1 - 22 and configured to receive the second control signal 13 - 22 .

[0060] In an embodiment, the RC IGBT region 1-22 does not include any first control trench 14-21. In addition, a case may be provided where only the IGBT region 1-21 does not include any second control trench 14-22.

[0061] In an embodiment, the trench-mesa pattern may also be configured with source trenches 16, which are electrically connected to the first load terminal 11 and are arranged at least in the IGBT-only region 1-21 and optionally also in the diode-only region 1-23 (if the diode-only region 1-23 is implemented). For example, the RC IGBT region 1-22 does not include any source trenches 16.

[0062] In an embodiment, the trench-mesa pattern may also be configured with first-type mesas 17, which are arranged both in the IGBT-only region 1-21 and in the RC IGBT region 1-23, wherein each first-type mesa 17 includes a source region 101 of a first conductivity type and a body region 102 of a second conductivity type. For clear representation, only a few source regions 101 present in the RC IGBT region 1-22 are provided with reference numbers. Each bold small square represents a source region. In addition, each illustrated trench in the RC IGBT region 1-22 represents a second control trench 14-22, wherein the second control trench 14-22 laterally confines the first-type mesas 17 in the RC IGBT region 1-22.

[0063] With regard to both the RC IGBT region 1-22 and the IGBT-only region 1-21, both the source region 101 and the body region 102 are electrically connected to the first load terminal 11. At least the body region 102 isolates the source region 101 from the drift region 100.

[0064] In an example, in the IGBT-only region 1-21, each first type mesa 17 is arranged adjacent to at least one first control trench 14-21 of the first control trenches 14-21. Each first control trench 14-21 is configured to induce a conductive channel in an adjacent first type mesa 17 for conduction of a forward load current in response to receiving a corresponding configuration of the first control signal 13-21. Correspondingly, in the RC IGBT region 1-22, each first type mesa 17 may be arranged adjacent to at least one second control trench 14-22 of the second control trenches 14-22. Each second control trench 14-22 is configured to induce a conductive channel in an adjacent first type mesa 17 for conduction of a forward load current in response to receiving a corresponding configuration of the second control signal 13-22.

[0065] As explained above, the above-described trench-mesa pattern is only one of many possible examples. For example, at least in the IGBT region 1-21 only, the trench-mesa pattern may also include a second type of mesa 18, which is not equipped with a source region 101 and may or may not be electrically connected to the first load terminal 11. In addition, further trench types (such as floating trenches (whose trench electrodes are not electrically connected to a defined potential) or further control trenches) may be provided.

[0066] For example, in the optionally provided diode-only region 1 - 23 , only source trenches 16 are provided, but no control trenches are provided. These source trenches 16 may laterally delimit a diode mesa 19 , wherein the body region 102 is electrically connected to the first load terminal 11 .

[0067] Here, it should be understood that according to the separation of the active region 1-2 into the RC IGBT region 1-22, the IGBT-only region 1-21, and the optional diode-only region 1-23, the configurations of the front side 110 and the back side 120 (i.e., the trench-mesa pattern at the front side 110 and the back side emitter 108 at the back side 120) are aligned with each other. That is, according to an embodiment, the trench-mesa configuration in the diode-only region 1-23 explained above laterally overlaps with the configuration of the back side emitter 108 in the diode-only region 1-23 explained above, and the trench-mesa configuration in the IGBT-only region 1-21 explained above laterally overlaps with the configuration of the back side emitter 108 in the IGBT-only region 1-21 explained above, and the trench-mesa configuration in the RC IGBT region 1-22 explained above laterally overlaps with the configuration of the back side emitter 108 in the RC IGBT region 1-22 explained above.

[0068] In an embodiment, in the RC IGBT regions 1-22, the body regions 102 in the first type mesas 17 exhibit a corresponding lateral dopant profile, according to which the dopant concentration peaks in the lateral central region 171 of the corresponding first type mesas 17. This optional aspect is illustrated in Figure 4 middle, Figure 4 A more detailed configuration of the second control trenches 14-22 is also illustrated exemplarily. Each second control trench 14-22 may exhibit a second control trench electrode 141-22, which is electrically insulated from the semiconductor body 10 by a second control trench insulator 142-22. As explained above, two of such second control trenches 14-22 laterally confine first type mesas 17, which are equipped with one or more of a source region 101 and a body region 102, which may isolate the (one or more) source regions 101 from the drift region 100 (or an optionally implemented barrier region 105, as explained below). For example, based on a contact plug 111, both the (one or more) source regions and the body region 102 are electrically connected to the first load terminal 11, as shown in FIG. Figure 4 In the RC IGBT region 1-22, the dopant concentration of the body region 102 may reach a peak in the lateral center region 171 of the corresponding first type mesa 17, as shown in FIG. Figure 4 A section of the trench-mesa pattern is schematically shown in the graph on the right.

[0069] In contrast, only the dopant concentration of the body region 102 in the IGBT region 1-21 may be constant. This optional aspect is illustrated in FIG. Figure 5 middle, Figure 5A more detailed configuration of the trench-mesa pattern in only the IGBT region 1-21 is also exemplarily illustrated. As the second control trench 14-22, each first control trench 14-21 may exhibit a first control trench electrode 141-21, which is electrically insulated from the semiconductor body 10 by a first control trench insulator 142-21. Similarly, each source trench 16 may exhibit a source trench electrode 161, which is electrically insulated from the semiconductor body 10 by a source trench insulator 162. For example, on each side of the first control trench 14-21, a corresponding first type of mesa 17 is arranged, which is laterally delimited by a corresponding source trench 16 of the source trenches 16 on the other side of the first type of mesa 17. In this example, the first type mesa 17 is provided with only one source region 101, which is arranged adjacent to the trench sidewall of the first control trench 14. No source region 101 is arranged adjacent to the trench sidewall of the source trench 16. In the IGBT region 1-21 only, the dopant concentration of the body region 102 may be substantially constant in the corresponding first type mesa 17 along the first lateral direction X, as shown in FIG. Figure 5 A section of the trench-mesa pattern is schematically shown in the graph on the right.

[0070] In an embodiment, the RC IGBT 1 further includes a barrier region 105 of the first conductivity type, the barrier region 105 coupling the trench-mesa pattern in only the IGBT region 1-21 to the drift region 100, wherein the dopant concentration of the barrier region 105 is greater than the dopant concentration of the drift region 100. Figure 3 , 4 As shown in FIGS. 1 and 5 , for example, the barrier region 105 is provided only in the IGBT-only region 1 - 21 , and is provided neither in the RC IGBT region 1 - 22 nor in the diode-only region 1 - 23 .

[0071] More generally, a first channel width to area ratio can be defined by the total channel width in only the IGBT region 1-21 divided by the total lateral area of ​​only the IGBT region 1-21, and a second channel width to area ratio can be defined by the total channel width in the RC IGBT region 1-22 divided by the total lateral area of ​​the RC IGBT region 1-22. In an embodiment, the second channel width to area ratio is equal to at least 120% of the first channel width to area ratio.

[0072] Based on the above exemplary design, only the IGBT region 1-21 can constitute a low saturation IGBT controlled based on the first control signal 13-21 (Gate 1), and the RC IGBT region 1-22 can constitute an RCDC IGBT region with reverse conductivity (RC) and diode control (DC) characteristics controlled based on the second control signal 13-22 (Gate 2).

[0073] In an embodiment, the RC IGBT region 1-22 occupies a total of 20% to 30% of the active region 1-2, and the IGBT-only region 1-21 occupies a total of 65% to 75% of the active region 1-2, and the diode-only region 1-23 occupies a total of 0% to 15% of the active region 1-2. Alternatively, the RC IGBT region 1-22 occupies a volume that is equal to at least ...% of the volume occupied by the IGBT-only region 1-21.

[0074] Also presented herein is a method of operating a half-bridge circuit 2 comprising a first RC IGBT 1-A according to one of the previous embodiments and a second RC IGBT 1-B according to one of the previous embodiments. Figure 6 Exemplary methods are explained.

[0075] RC IGBTs 1-A and 1-B can be configured similarly.

[0076] Generally, the method includes controlling a first RC IGBT 1-A based on first and second control signals 13-21A and 13-22A of the first RC IGBT 1-A and controlling a second RC IGBT 1-B based on first and second control signals 13-21B and 13-22B of the second RC IGBT 1-B.

[0077] For a better understanding of the exemplary control method, the following table exemplarily summarizes the states and corresponding control signals for the RC IGBT 1-A (and correspondingly for the second RC IGBT 1-B):

[0078] Table 1

[0079]

[0080] Table 2

[0081]

[0082] Table 3

[0083]

[0084] For example, considered in isolation, only IGBT region 1-21 thus behaves like a regular IGBT, RC IGBT region 1-22 behaves like a regular RC IGBT, and only diode region 1-23 behaves like a regular diode. Using the states summarized in Tables 1 to 3, RC IGBT 1 (1-A / 1-B) can be set to the following states.

[0085] Table 4

[0086]

[0087] With these states in mind, it becomes clear that desaturation is possible both in the diode mode of the RC IGBT 1 and in the IGBT mode of the RC IGBT 1, as Figure 6 It is exemplarily shown for the first RC IGBT 1-A.

[0088] In an embodiment, four control signals 13-21A, 13-22A, 13-21B and 13-22B are derived from a PWM signal (PWM 1-A) for a first RC IGBT 1-A and from a PWM signal (PWM 1-B) for a second RC IGBT 1-B. Figure 6 In FIG. 1 , these signals PWM 1-A and PWM 1-B are illustrated for the following two scenarios: (1) The half-bridge load current I L is positive (see Figure 6 and (2) the half-bridge load current I L is negative (see Figure 6 the lower half of the ).

[0089] Figure 6 The upper part (I L >0) illustrates the situation where the first RC IGBT 1-A is in IGBT mode, and Figure 6 The lower part (I L >0) illustrates the situation where the first RC IGBT 1-A is in diode mode.

[0090] An exemplary embodiment will now be explained:

[0091] As soon as the PWM signal PWM 1-A is switched to "high" (or "on"), the control signal 13-21A is set to +15V and the control signal 13-22A is kept at (-15V...0V). This ensures low saturation conduction in IGBT mode as well as in diode mode (see Table 4). When the PWM signal PWM 1-A is switched to "low" (or "off"), the control signal 13-22A is set to +15V. In case of a small overlap, the control signal 13-21A is set to (-15V...0V). This ensures desaturation in IGBT mode as well as in diode mode. After a predefined desaturation time (e.g., 2μs to 200μs), the additional behavior depends on I L In transistor mode, I L >0 (this situation can be detected, for example, by the positive collector-emitter voltage), the IGBT is turned off by setting the control signal 13-22A to (-15V...0V). In the case of diode mode, I L <0 (this can be detected, for example, by a negative collector-emitter voltage), the diode is kept in desaturation mode by keeping the control signal 13-22A at +15 V. In this case, 13-22A is set to (-15 V ... 0 V) ​​just before the opposite IGBT is turned on.

[0092] Above, embodiments and corresponding operation methods of RC IGBTs are explained. For example, these RC IGBTs are based on silicon (Si). Therefore, a single crystal semiconductor region or layer (e.g., a semiconductor body and its regions / zones, such as regions, etc.) can be a single crystal Si region or Si layer. In other embodiments, polycrystalline or amorphous silicon may be used.

[0093] However, it should be understood that the semiconductor body and its regions / zones can be made of any semiconductor material suitable for manufacturing semiconductor devices. Examples of such materials include, but are not limited to: elemental semiconductor materials, such as silicon (Si) or germanium (Ge); Group IV compound semiconductor materials, such as silicon carbide (SiC) or silicon germanium (SiGe); binary, ternary or quaternary III-V semiconductor materials, such as gallium nitride (GaN), gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), indium gallium phosphide (InGaPa), aluminum gallium nitride (AlGaN), aluminum indium nitride (AlInN), indium gallium nitride (InGaN), aluminum gallium indium nitride (AlGaInN) or indium gallium arsenide phosphide (InGaAsP); and binary or ternary II-VI semiconductor materials, such as cadmium telluride (CdTe) and mercury cadmium telluride (HgCdTe) (to name a few examples). The aforementioned semiconductor materials are also referred to as "homojunction semiconductor materials". When two different semiconductor materials are combined, a heterojunction semiconductor material is formed. Examples of heterojunction semiconductor materials include, but are not limited to, aluminum gallium nitride (AlGaN)-aluminum gallium indium nitride (AlGaInN), indium gallium nitride (InGaN)-aluminum gallium indium nitride (AlGaInN), indium gallium nitride (InGaN)-gallium nitride (GaN), aluminum gallium nitride (AlGaN)-gallium nitride (GaN), indium gallium nitride (InGaN)-aluminum gallium nitride (AlGaN), silicon-silicon carbide (SixC1-x) and silicon-SiGe heterojunction semiconductor materials. For power semiconductor switch applications, Si, SiC, GaAs and GaN materials are currently used.

[0094] Spatially relative terms such as "under," "beneath," "lower," "over," "upper," etc. are used for ease of description to explain the positioning of one element relative to a second element. These terms are intended to encompass different orientations of the respective devices in addition to those depicted in the drawings. Additionally, terms such as "first," "second," etc. are also used to describe various elements, regions, sections, etc., and are also not intended to be limiting. Similar terms may refer to similar elements throughout the description.

[0095] As used herein, the terms “having,” “containing,” “including,” “comprising,” “exhibiting,” and the like are open-ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features.

[0096] With the above range of variations and applications in mind, it should be understood that the present invention is not limited by the foregoing description, nor by the accompanying drawings. Instead, the present invention is limited only by the following claims and their legal equivalents.

Claims

1. A RCIGBT (1) comprising an active region (1-2) in a single chip, the active region (1-2) being configured to conduct both a forward load current and a reverse load current between a first load terminal (11) at a front side (110) of a semiconductor body (10) of the RCIGBT (1) and a second load terminal (12) at a rear side (120) of the semiconductor body (10), wherein the active region (1-2) is separated into at least: - only IGBT regions (1-21), at least 90% of which are configured to conduct only the forward load current based on the first control signal (13-21); -RC IGBT regions (1-22), at least 90% of which are configured to conduct othe reverse load current, and o Based on the second control signal (13-22), conduct the forward load current.

2. The RCIGBT (1) of claim 1, wherein the second control signal (13-22) is different from the first control signal (13-21).

3. The RCIGBT (1) according to claim 1 or 2, wherein the IGBT-only area (1-21) and the RCIGBT area (1-22) are equal to at least 80% of the active area (1-2).

4. The RC IGBT (1) according to one or more of the preceding claims, wherein the IGBT-only region (1-21) is spatially separated from the RC IGBT region (1-22), and optionally wherein: - the IGBT-only region (1-21) is the first adjacent region; and / or - The RCIGBT region (1-22) is a second adjacent region.

5. The RCIGBT (1) as claimed in one or more of the preceding claims, further comprising: - diode-only regions (1-23), at least 90% of which are configured to conduct only said reverse load current.

6. The RCIGBT (1) as claimed in one or more of the preceding claims, further comprising: A drift region (100) of a first conductivity type is located in the semiconductor body (10), wherein the drift region (100) is shared by each of the IGBT-only region (1-21), the RCIGBT region (1-22) and by the diode-only region (1-23) if the diode-only region (1-23) is implemented.

7. The RCIGBT (1) according to claim 6, further comprising: A backside emitter (108), coupled to the drift region (100), is in electrical connection with the second load terminal (12), wherein the backside emitter (108) is configured according to the active region (1-2) being separated into at least the IGBT-only region (1-21) and the RC IGBT region (1-22) and the diode-only region (1-23) if the diode-only region (1-23) is implemented.

8. The RCIGBT (1) according to claim 7, wherein the rear side emitter (108) is configured with: - a first segment (108-21) of a second conductivity type located in a portion of the active region (1-2) where the IGBT-only region (1-21) exists; and - a second section (108-22), located in the part of the active area (1-2) where the RCIGBT area (1-22) exists, comprising both a first sub-section (108-221) of the first conductivity type and a second sub-section (108-222) of the second conductivity type; and optionally, if the diode-only area (1-23) is implemented, it is configured with - a third section (108-23) of the first conductivity type, located in the portion of the active region (1-2) where the diode-only region (1-23) exists.

9. The RCIGBT (1) of claim 8, wherein the first section (108-21) of the back-side emitter (108) exhibits, for its total lateral extension along the first lateral direction (X) and at a certain vertical level, a linear relationship of at least 1*10 13 cm -3 and wherein the first section (108-21) is shifted relative to the RCIGBT region (1-22) by a first distance (d1) of at least 20% of the thickness of the drift region (100).

10. The RCIGBT (1) of claim 5 and claim 8 or 9, wherein each of the first sub-segments (108-221) of the second segment (108-22) of the back-side emitter (108) exhibits, for its respective total lateral extension along the first lateral direction (X) and at a certain vertical level, at least 1*10 13 cm -3 an average dopant concentration of, and wherein each of the first sub-segments (108-221) is shifted relative to the diode-only region (1-23) by a second distance (d2) of at least 20% of the thickness of the drift region (100).

11. The RCIGBT (1) as claimed in one or more of the preceding claims 7 to 10, further comprising: The field stop zone (107) of the first conductivity type is arranged to contact both the drift zone (100) and the first segment (108-21), the second segment (108-22) and each of the third segment (108-23) if the third segment (108-23) is implemented, wherein the dopant concentration of the field stop zone (107) is greater than the dopant concentration of the drift zone (100).

12. The RCIGBT (1) as claimed in one or more of the preceding claims 6 to 11, further comprising: A trench-mesa pattern is located between the first load terminal (11) and the drift region (100), wherein the trench-mesa pattern is configured according to the active region (1-2) being separated into at least the IGBT-only region (1-21) and the RCIGBT region (1-22) and the diode-only region (1-23) if the diode-only region (1-23) is implemented.

13. The RCIGBT (1) according to claim 12, wherein the trench-mesa pattern is configured with: - a first control trench (14-21) arranged in the IGBT-only region (1-21) and configured to receive the first control signal (13-21); and - a second control trench (14-22) arranged in the RCIGBT region (1-22) and configured to receive the second control signal (13-22).

14. The RC IGBT (1) according to claim 12 or 13, wherein the trench-mesa pattern is configured with: - a source trench (16) electrically connected to the first load terminal (11) and arranged at least in the IGBT-only area (1-21) and optionally also in the diode-only area (1-23) if the diode-only area (1-23) is implemented.

15. The RCIGBT (1) according to one or more of the preceding claims, wherein the trench-mesa pattern is further provided with: - first type mesas (17) arranged both in the IGBT-only region (1-21) and in the RCIGBT region (1-23), wherein each first type mesa (17) comprises a source region (101) of the first conductivity type and a body region (102) of the second conductivity type, wherein both the source region (101) and the body region (102) are electrically connected to the first load terminal (11), and wherein at least the body region (102) isolates the source region (101) from the drift region (100).

16. The RC IGBT (1) as claimed in claims 13 and 15 and optionally claim 14, wherein - in the IGBT-only region (1-21), each first type mesa (17) is arranged adjacent to at least one of the first control trenches (14-21), and wherein each first control trench (14-21) is configured to induce a conductive channel in an adjacent first type mesa (17) for conduction of the forward load current in response to receiving a corresponding configuration of the first control signal (13-21); and - In the RCIGBT region (1-22), each first type mesa (17) is arranged adjacent to at least one of the second control trenches (14-22), and wherein each second control trench (14-22) is configured to induce a conductive channel in an adjacent first type mesa (17) for conduction of the forward load current in response to receiving a corresponding configuration of the second control signal (13-22).

17. An RCIGBT (1) as claimed in claim 15 or 16, wherein in the RCIGBT region (1-22), the main region (102) in the first type mesa (17) exhibits a corresponding lateral dopant distribution, according to which the dopant concentration reaches a peak in the lateral central region (171) of the corresponding first type mesa (17).

18. The RCIGBT (1) according to one or more of the preceding claims 12 to 17, further comprising: The barrier region (105) of the first conductivity type couples the trench-mesa pattern in the IGBT-only region (1-21) to the drift region (100), wherein the dopant concentration of the barrier region (105) is greater than the dopant concentration of the drift region (100).

19. RCIGBT (1) according to one or more of the preceding claims, wherein - a first channel width to area ratio is defined by dividing the total channel width in the IGBT-only region (1-21) by the total lateral area of ​​the IGBT-only region (1-21); and - a second channel width to area ratio is defined by dividing the total channel width in the RC IGBT region (1-22) by the total lateral area of ​​the RC IGBT region (1-22); and - said second channel width to area ratio is equal to at least 120% of said first channel width to area ratio.

20. A method of operating a half-bridge circuit (2), the half-bridge circuit (2) comprising a first RC IGBT (1-A) according to one of the preceding claims and a second RC IGBT (1-B) according to one of the preceding claims, the method comprising: - controlling the first RC IGBT (1-A) based on a first control signal (13-21A) and a second control signal (13-22A) of the first RC IGBT (1-A); and - controlling the second RC IGBT (1-B) based on a first control signal (13-21B) and a second control signal (13-22B) of the second RC IGBT (1-B).

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