Power semiconductor device and method for processing a power semiconductor device

Abstract

A power semiconductor device includes a semiconductor body and presents an active area and an edge termination area, wherein, within the active area, the semiconductor body includes a drift area of ​​a first conductivity type, and wherein the edge termination area includes: a protection area of ​​a second conductivity type, which is included in the semiconductor body at the front side of the semiconductor body and surrounds the active area; and a field plate trench structure, which vertically extends from the front side into the semiconductor body and is at least partially filled with a conductive material, the conductive material is electrically connected to the protection area and is insulated from the semiconductor body outside the protection area by a field plate insulating structure, wherein a first portion of the field plate trench structure at least partially extends into the protection area and is at least partially arranged under a metal layer arranged at the front side; and a second portion of the field plate trench structure extends to the outside of the protection area and surrounds the active area, wherein the metal layer does not extend above the second portion of the field plate trench structure.

Description

Technical Field

[0001] The present specification relates to embodiments of power semiconductor devices and embodiments of methods of manufacturing such power semiconductor devices. Specifically, the present specification relates to embodiments of power semiconductor devices having edge termination structures including guard zones and field plate structures, and embodiments of methods of manufacturing such power semiconductor devices. Background Art

[0002] Modern devices rely on power semiconductor devices for many functions in automotive, consumer and industrial applications, such as converting electrical energy and driving electric motors or motors. 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, such as in traction applications.

[0003] A power semiconductor device typically comprises a semiconductor body configured to conduct a load current along a load current path between two load terminals of the device. Furthermore, in case the power semiconductor device has a transistor configuration, the load current path may be controlled by an insulated electrode, typically referred to as a gate electrode. For example, upon receiving a corresponding control signal from, for example, a driver unit, the control electrode may set the power semiconductor device in one of a conducting state and a blocking state.

[0004] Furthermore, in order to conduct the load current, the power semiconductor device may include one or more power cells, which may be arranged in a so-called active area of ​​the power semiconductor device. The power semiconductor device may be laterally limited by edges. Between the lateral edges and the active area including the one or more power cells, an edge termination region may be arranged, which may include an edge termination structure. Such an edge termination structure may be used for the purpose of influencing the course of the electric field within the semiconductor body, for example in order to ensure a reliable blocking capability of the power semiconductor device. The edge termination structure may include one or more components arranged within the semiconductor body, and also one or more components arranged above the surface of the semiconductor body.

[0005] A common example of such an edge termination concept is a combination of a p-doped field ring (also called a guard ring or protection zone) and a field plate, wherein the field plate can be configured to provide effective shielding against external charges. For example, the field plate can include a metal, such as aluminum. Alternatively, such a field plate can be formed of polysilicon. For example, in an edge termination structure combining a p-doped field ring with an n-doped polysilicon field plate, a metal layer can still be present to provide electrical contact between the field plate and the field ring, thereby reducing the effect of the electric field on the outer edge of the metal layer.

[0006] It would be desirable to provide further edge termination concepts which are reliable (such as robust against damage due to corrosion) and which can be easily integrated into existing process flows of power semiconductor devices. Summary of the invention

[0007] According to one embodiment, a power semiconductor device includes a semiconductor body and presents an active area and an edge termination area, wherein, inside the active area, the semiconductor body includes a drift area of ​​a first conductivity type, and wherein the edge termination area includes: a protection area of ​​a second conductivity type, the protection area being included in the semiconductor body at the front side of the semiconductor body and surrounding the active area; and a field plate trench structure, which extends vertically into the semiconductor body from the front side and is at least partially filled with a conductive material, the conductive material being electrically connected to the protection area and being insulated from the semiconductor body outside the protection area by a field plate insulating structure. A first portion of the field plate trench structure at least partially extends into the protection area and is at least partially arranged under a metal layer arranged at the front side. A second portion of the field plate trench structure extends outside the protection area and completely surrounds the active area, wherein the metal layer does not extend over the second portion of the field plate trench structure.

[0008] According to another embodiment, a method for forming a power semiconductor device is provided. The method includes: providing a semiconductor body; forming an active region and an edge termination region, wherein, within the active region, the semiconductor body includes a drift region of a first conductivity type, and wherein forming the edge termination region includes: forming a protection region of a second conductivity type, the protection region being included in the semiconductor body at the front side of the semiconductor body and surrounding the active region; forming a field plate trench structure, the field plate trench structure extending vertically from the front side into the semiconductor body and at least partially filled with a conductive material, the conductive material being electrically connected to the protection region and being insulated from the semiconductor body outside the protection region by a field plate insulating structure, wherein a first portion of the field plate trench structure at least partially extends into the protection region and is at least partially arranged below a metal layer arranged at the front side; and a second portion of the field plate trench structure extending outside the protection region and completely surrounding the active region, wherein the metal layer does not extend above the second portion of the field plate trench structure.

[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 parts in the drawings are not necessarily to scale, instead the emphasis is on illustrating the principles of the present invention. In addition, in the drawings, the same reference numerals represent corresponding parts. In the drawings:

[0011] Figure 1A-C each schematically and exemplarily shows a top view of a power semiconductor device according to one or more embodiments;

[0012] Figure 2 schematically and exemplarily shows a portion of a horizontal cross section of a power semiconductor device according to one or more embodiments;

[0013] Figure 3 schematically and exemplarily shows a portion of a horizontal cross section of a power semiconductor device according to one or more embodiments;

[0014] Figure 4 schematically and exemplarily shows a portion of a horizontal cross section of a power semiconductor device according to one or more embodiments;

[0015] Figure 5A schematically and exemplarily illustrates a portion of a vertical cross section of a power semiconductor device according to one or more embodiments;

[0016] Figure 5B schematically and exemplarily illustrates a portion of a vertical cross section of a power semiconductor device according to one or more embodiments;

[0017] Figure 6 schematically and exemplarily shows a portion of a horizontal cross section of a power semiconductor device according to one or more embodiments;

[0018] Figure 7 schematically and exemplarily illustrates a portion of a horizontal cross section of a power semiconductor device according to one or more embodiments; and

[0019] Figure 8 A portion of a horizontal cross section of a power semiconductor device according to one or more embodiments is schematically and exemplarily shown. DETAILED DESCRIPTION

[0020] 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.

[0021] In this regard, directional terms such as "top", "bottom", "below", "front", "rear", "back", "front", "tail", "above", etc. can be used with reference to the orientation of the accompanying drawings described. Because the parts of the embodiments can be positioned in many different orientations, the directional terms are used for illustrative purposes without limitation. It should be understood that other embodiments may also be utilized 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 construed as restrictive, and the scope of the present invention is defined by the appended claims.

[0022] Reference will now be made in detail to various embodiments, one or more examples of which are shown in the accompanying drawings. Each example is provided by way of illustration and is not meant to be a limitation of the present invention. For example, a feature shown or described as part of one embodiment may be used on other embodiments or used in combination with other embodiments to produce yet another embodiment. The present invention is intended to include such modifications and variations. The 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 are represented by the same reference numerals in different drawings unless otherwise specified.

[0023] The term "horizontal" as used in this specification is intended to describe an orientation substantially parallel to a horizontal surface of a semiconductor substrate or semiconductor structure. This may be, for example, a surface of a semiconductor wafer or die or chip. For example, the first lateral direction X and the second lateral direction Y mentioned below may both be horizontal directions, wherein the first lateral direction X and the second lateral direction Y may be perpendicular to each other.

[0024] The term "vertical" as used in this specification is intended to describe an orientation that is arranged substantially 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".

[0025] In this specification, n-doping is referred to as the "first conductivity type" and p-doping is referred to as the "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.

[0026] In the context of this specification, the terms "ohmic contact", "electrical contact", "ohmic connection" and "electrical connection" are intended to describe the presence of a low-ohmic electrical connection or a low-ohmic current path between two regions, sections, zones, parts or portions 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 portion of a semiconductor device. In addition, in the context of this specification, the term "contact" is intended to describe the presence of a direct physical connection between two elements of a respective semiconductor device. For example, a transition between two elements that are in contact with each other may not include additional intermediate elements, etc.

[0027] Furthermore, in the context of this specification, if not otherwise specified, the term "electrically insulated" is used in the context of its general effective understanding, and is therefore intended to describe that two or more components are located separately from each other and there is no ohmic connection connecting these components. However, components that are electrically insulated from each other can still be coupled to each other, such as mechanically coupled and / or capacitively coupled and / or inductively coupled. To give an example, two electrodes of a capacitor can be electrically insulated from each other and at the same time mechanically and capacitively coupled to each other, such as through an insulator (e.g., a dielectric).

[0028] The specific embodiments described in this specification relate to, but are not limited to, power semiconductor devices that present a strip unit or honeycomb unit configuration, for example, a power semiconductor device that can be used in a power converter or power supply. Therefore, in one embodiment, such a device can be configured to carry a load current to be fed to a load and / or provided by a power source. For example, a power semiconductor device may include one or more active power semiconductor units, such as a monolithic integrated diode unit (e.g., a monolithic integrated unit of two anti-series connected diodes), a monolithic integrated transistor unit (e.g., a monolithic integrated IGBT unit) and / or its derivatives. Such a diode / transistor unit can be integrated in a power semiconductor module. A plurality of such units can constitute a unit field in which an active region of a power semiconductor device is arranged.

[0029] The term "power semiconductor device" as used in this specification is intended to describe a semiconductor device on a single chip having high voltage blocking and / or high current carrying capabilities. In other words, such a power semiconductor device is intended for high currents (typically in the ampere range, such as up to tens or hundreds of amperes) and / or high voltages (typically above 15V, more typically 100V and above, such as up to at least 500V or even higher, such as up to at least 6 kV or higher).

[0030] For example, the power semiconductor device described below may be a semiconductor device exhibiting a stripe cell configuration or a honeycomb (column / needle) cell configuration, and may be configured to be used as a power component in low, medium, and / or high voltage applications.

[0031] For example, the term “power semiconductor device” as used in this specification is not directed to a logic semiconductor device used for, for example, storing data, computing data, and / or other types of semiconductor-based data processing.

[0032] Figures 1A to 1CEach schematically and exemplarily shows a top view of a power semiconductor device 1 according to some embodiments. The vertical projections shown are in each case parallel to a plane defined by a first lateral direction X and a second lateral direction Y and orthogonal to a vertical direction Z. The power semiconductor device 1 comprises a semiconductor body 10 having a lateral chip edge 109. The chip edge 109 may be obtained, for example, by wafer dicing.

[0033] Furthermore, the power semiconductor device 1 presents an active region 16 configured to conduct a load current (e.g. substantially along a vertical direction Z) and an edge termination region 17 arranged laterally between the chip edge 109 and the active region 16. For example, as is known in the art, the active region may include a drift region of a first conductivity type (e.g. n-type) configured to conduct a load current. Figures 1A to 1C As schematically shown in each of the Figures 1 and 2 , the active region 16 may be laterally surrounded by an edge termination region 17 .

[0034] For example, the active area 16 includes one or more power cells 14, each of which extends at least partially into the semiconductor body 10. The present description is not limited to a particular kind of configuration of the one or more power cells 14. Instead, the power cells 14 may present any configuration common to power semiconductor devices, such as at least one of a diode configuration, a thyristor configuration, a MOS gate-controlled diode (MGD) configuration, a transistor configuration (such as an IGBT configuration, an RC (reverse conduction) IGBT configuration), a MOSFET configuration, and any configuration derived therefrom. Those skilled in the art are familiar with these types of configurations. Therefore, in Figure 1A -C, the power unit 14 is shown only schematically, since the exact configuration is not the main subject of the present description.

[0035] For example, Figure 1A The configuration shown in may correspond to a power diode configuration including a single power cell 14. In contrast, Figure 1B and 1C The configuration shown in the figure may represent, for example, a semiconductor switch configuration (such as, for example, a MOSFET and / or an IGBT configuration), wherein the power unit 14 may be configured to control the load current by switching the power semiconductor device 1 to one of a conducting state and a blocking state. Such a power unit 14 may, for example, include a control structure such as a MOS control structure. Figure 1B As exemplarily shown in FIG. 1 , the power unit 14 may be in a strip-shaped configuration, which may extend, for example, along the second lateral direction Y throughout the entire active area 16. In another embodiment, as Figure 1C As shown, the power cell 14 may present a honeycomb configuration, for example, having a horizontal cross-section presenting one of a square, a rectangle, a rectangle with rounded corners, a circle, and an ellipse.

[0036] One or more power cells 14 that may be included in the active area 16 of the power semiconductor device 1 may be configured to selectively conduct a load current and block a blocking voltage, for example depending on a switching state of the power semiconductor device 1 and / or depending on a direction in which a current and / or voltage is fed or applied to the power semiconductor device 1 .

[0037] For example, the power semiconductor device 1 may be configured to support a blocking voltage of at least 300 V, at least 500 V, at least 600 V, at least 1000 V, at least 1500 V, or at least 3000 V, or even greater than 6000 V via at least one power cell 14. Furthermore, at least one power cell 14 may present a compensation structure, which is also referred to as a "super junction" structure.

[0038] For example, in order to control one or more power cells 14, a control terminal (not shown) may be provided, which may be configured to forward a control signal to a control electrode structure of one or more power cells 14. For example, the control terminal may be a gate terminal. Thus, the power semiconductor device 1 may be set to one of an on state and a blocking state. In one embodiment, the control terminal and the first load terminal ( Figure 1A -C) to provide such a control signal.

[0039] Turning now to the edge termination region 17, as is known in the art, the edge termination region 17 may include an edge termination structure that is not configured to conduct load current but is configured to ensure a reliable blocking capability of the power semiconductor device 1 ( Figure 1A -C). Such an edge termination structure may be configured to laterally terminate an electric field present in the semiconductor body 10 in the blocking state of the power semiconductor device 1. For example, to this end, the edge termination structure may include at least one of a junction termination extension (JTE) structure, a field ring / field plate termination structure, a lateral doping variation (VLD) structure, and a combined VLD-DLC edge termination structure. As such, those skilled in the art are familiar with these kinds of edge termination structures.

[0040] In the following, reference will be made to Figure 2-8107 and the like. The combination of a field plate trench structure 172 and at least one protection zone 107, each of which is arranged inside the edge termination region 17, is described. For example, the combination of the field plate trench structure 172 and one or more protection zones (such as guard rings) 107 may constitute an edge termination structure or form at least a portion of an edge termination structure. In other words, the combination of the field plate trench structure 172 and one or more protection zones 107 proposed by the present invention may be used as a special kind of field ring / field plate termination structure. For example, in one embodiment, the field ring / field plate termination structure may be completely formed by such a combination of the field plate trench structure 172 and one or more protection zones 107.

[0041] Figure 2 Schematically and exemplarily, a portion of a horizontal cross section of a power semiconductor device 1 according to one or more embodiments of the present invention is shown. More precisely, Figure 2 FIG. 1 shows a portion of a horizontal cross section (parallel to the XY plane) of the edge termination region 17 , wherein the horizontal cross section is close to the front side 10 - 1 of the semiconductor body 10 (see FIG. 1 ). Figure 5A -B) extension. For example, a portion of the edge termination region 17 may be located Figure 1A - near the left chip edge 109 or near the right chip edge 109 of one of the power semiconductor devices 1 depicted in -C.

[0042] The illustrated portion of the edge termination region 17 includes a semiconductor protection zone 107 of the second conductivity type (e.g., p-type). In all figures, one or more protection zones 107 present in different embodiments are shown as shaded areas. The protection zone 107 is included in the semiconductor body 10 at the front side 10-1 of the semiconductor body 10. Furthermore, the protection zone 107 completely surrounds the active zone 16, which is Figure 2 1722 of the field plate trench structure 172 can be seen in the figure because it only depicts a portion of the edge termination region 17. However, it should be understood by those skilled in the art that the second portion 1722 of the field plate trench structure 172 can completely surround the active region 16, for example in the manner of a p-ring of a conventional field ring / field plate termination structure. Correspondingly, the protection zone 107 can also be referred to as a protection ring or a field ring. In the case where the second conductivity type is p-type, the protection zone 107 can also be referred to as a p-ring. For example, in this way, the protection zone 107 can be similar to or the same as a field ring conventionally used as part of a field ring / field plate termination structure.

[0043] Figure 2 The portion of the protection zone 107 depicted has an elongated shape extending in a substantially rectilinear manner along the main lateral extension direction Y. In other words, in the embodiment shown in FIG. Figure 2 In the top view shown, the portion of the protection zone 107 is substantially in the shape of an elongated rectangle. In the exemplary embodiment, the main lateral extension direction coincides with the second lateral direction Y. Figure 2Other parts outside the cross section shown may present different main lateral extension directions. For example, the protection zone 107 is located at the upper and lower chip edges 109 (see Figure 1A -C) may have a main lateral extension direction coinciding with the first lateral direction X. Furthermore, the protection zone 107 surrounding the active zone 16 may present non-linear portions, such as angled or rounded portions, for example near chip corners.

[0044] Furthermore, the edge termination region 17 comprises a field plate trench structure 172 extending vertically (ie, along the vertical direction Z) from the front side 10 - 1 into the semiconductor body 10 . The vertical extension of the field plate trench structure 17 is Figure 2 In this regard, reference will be made to the following description of Figure 5A -Vertical section of B.

[0045] The field plate trench structure 172 includes several trench portions filled with a conductive material 173, wherein the conductive material 173 may, for example, consist of or include polysilicon. The conductive material 173 is insulated from the semiconductor body 10 outside the protection zone 107 (such as from an n-doped semiconductor region of the semiconductor body 10) by a field plate insulating structure 1725 (such as, for example, an oxide forming the corresponding trench sidewalls and trench bottom of the trench portions).

[0046] The first portion 1721 of the field plate trench structure 172 extends vertically and laterally into the protection zone 107 (for vertical dimensions, see also Figure 5A -B). The first portion 1721 is at least partially arranged below the metal layer 174 at the front side 10-1. It should be noted that in all figures, the extension of the metal layer(s) 174 is indicated by dashed lines, even if for example the first portion 1721 of the field plate trench structure 172 (depicted with solid lines) extends below the metal layer 174.

[0047] The second portion 1722 of the field plate trench structure 172 (laterally) extends to the outside of the protection area 107 and completely surrounds the active area 16. The second portion surrounding the active area 16 is Figure 2 Not shown, Figure 2 Only a portion of the edge termination 17 is depicted. However, those skilled in the art will appreciate that the second portion 1722 of the field plate trench structure 172 may completely surround the active region 16, such as in the manner of a P-ring of a conventional field ring / field plate termination structure. The metal layer 174 does not extend over the second portion 1722 of the field plate trench structure 172.

[0048] The first portion 1721 of the field plate trench structure 172 includes a first portion 1731 of the conductive material 173 electrically connected to the guard area 107. For example, the first portion of the conductive material 173 may be electrically connected to the guard area 107 through the metal layer 174. Details of the electrical contact between the guard ring 107 and the conductive material 107 will be further described below with respect to exemplary embodiments.

[0049] Second portion 1722 of field plate trench structure 172 includes second portion 1732 of conductive material 173, wherein second portion 1732 of conductive material 173 is electrically connected to protection zone 107 through first portion 1731 of conductive material 173. For example, second portion of conductive material 173 may be electrically connected to protection zone 107 only via first portion of conductive material 173.

[0050] Figure 2 The second portion 1722 of the field plate trench structure 172 shown in FIG. 1 extends parallel to the main lateral extension direction Y of the protection zone 107. In contrast, Figure 2 The first portion 1721 of the field plate trench structure 172 shown in FIG extends transversely, ie substantially orthogonally, to a main lateral extension direction Y of the protection zone 107 . Therefore, the first portion 1721 extends transversely, ie substantially orthogonally, to the second portion 1722 .

[0051] Figure 3 Another exemplary embodiment is shown, wherein Figure 3 The portion of the edge termination region 107 depicted in FIG. 1 comprises two protection zones 107, each having an associated trench field plate structure 172. The trench field plate structure 172 comprises in each case a first portion 1721 extending orthogonally to the main lateral extension direction Y of the protection zones, and two second portions 1722 which are arranged on each side of the respective protection zone 107 and extend parallel to the main lateral extension direction Y of the protection zones 107. Figure 2 As in the embodiment, Figure 3 The trench field plate structure 172 of the illustrated embodiment includes a conductive material having a first portion and a second portion (see Figure 2 173, 1731, 1732), however, it is not Figure 3 clearly described in.

[0052] In addition, according to Figure 3 In an embodiment of the present invention, an intermediate region 106 of the first conductivity type may be included in the semiconductor body 10 at least partially between the two protection regions, wherein the second portion 1722 of the field plate trench structure 172 extends at least partially in the intermediate region 106. Furthermore, in an embodiment, the second portion of the conductive material arranged inside the second portion 1722 of the field plate trench structure is not electrically connected to the intermediate region 106.

[0053] The metal 174 is arranged in each case above the respective first portion 1721 of the field plate trench structure 172. For example, an insulating layer may be arranged between each metal layer 174 and the associated protection zone 107. Furthermore, the metal layer 174 is connected to the protection zone 107 and the first portion 1731 ( Figure 3 Not depicted, see Figure 5A -B) is established via a respective contact trench 175 provided in the insulating layer 108. The contact trenches extend substantially in a first lateral direction X, ie orthogonal to a main lateral extension direction Y of the protection zone 107.

[0054] For example, the contact groove 175 may be filled with a conductive material and / or the metal layer 174 may extend through the contact groove 175 so as to establish electrical contact with each of the corresponding protection zone 107 and the corresponding first portion 1731 of the conductive material 173. Figure 3 In FIG. 1 , the conductive material 173 and the first and second portions 1731 , 1732 thereof and the field plate insulating structure 1725 are not depicted separately because the focus is on the spatial arrangement of the protection region 107 , the trench field plate structure 172 and the contact groove 175 .

[0055] Figure 4 Shown with Figure 3 Another variant embodiment similar to the embodiment of Figure 3 In contrast to the embodiment of FIG. 1 , in this embodiment, each field plate trench structure 172 has a first portion 1721 including two trench portions, which extend in parallel along the main lateral extension direction Y of the protection zone 107. Figure 3 Also in Figure 4 and Figure 6-8 As described in the above, the conductive material 173 and the first and second parts 1731 and 1732 thereof and the field plate insulating structure 1725 are not separately depicted (reference is made to Figure 2 ). A contact groove 175 extending along the main lateral extension direction Y is provided for establishing electrical contact between the first portion 1731 of the conductive material 173 and the metal layer 174 and between the protection zone 107 and the metal layer 174. At least one contact groove 175 contacting the protection zone 107 and the metal layer 174 is provided between two grooves of the first portion 1721 of the field plate groove structure 172. Another contact groove 175 contacts the first portion 1731 of the conductive material 173 and the metal layer 174. In another embodiment (not shown), a single contact groove 175 may be provided for establishing electrical contact between the first portion 1731 of the conductive material 173 and the metal layer 174 and between the protection zone 107 and the metal layer 174 (not shown). Figure 4 As shown in Figure 6 and7 ).

[0056] Figure 5A FIG. 1 shows a portion of a vertical cross section of a power semiconductor device 1 according to one or more embodiments. For example, Figure 5A It further illustrates how to establish electrical contact between the first portion 1731 and the protection zone 107 through the metal layer 174. The basic arrangement of the protection zone 107 and the field plate trench structure 172 is similar to Figure 4 Therefore, according to Figure 4 In the embodiment, a contact trench 175 is provided in the insulating layer 108 , wherein the contact trench 175 for contacting the protection zone 107 is provided between two trenches of the first portion of the field plate trench structure 172 .

[0057] like Figure 5A As can be further seen in the figure, the first portion 1721 of the field plate trench structure 172 is completely (i.e., including the trench bottom) embedded in the protection zone 107, at least where it is arranged below the metal layer 174. In other words, the protection zone 107 isolates the first portion 1721 of the field plate trench structure 172 at least in the area arranged below the metal layer 174 from the surrounding area of ​​the semiconductor body 10.

[0058] The protection zone 107 may in turn be embedded in the semiconductor zone 102 of the first conductivity type. The intermediate zone 106 may form a part of the semiconductor zone 102 of the first conductivity type. Figure 5A In the exemplary embodiment shown, the protection zone 107 is separated from the trench portion forming the second portion 1722 of the field plate trench structure 172 by the semiconductor region 102. Figure 5B In the illustrated embodiment, the protection zone 107 contacts the sidewalls of the trench that is part of the second portion 1722 of the field plate trench structure 172 (see Figure 5B In addition, a shallow region 107-1 of the second conductivity type is provided near the surface of the semiconductor body 10, extending between the protection area 107 and the right trench and the left trench of the second portion 1722 of the field plate trench structure 172. For example, such a shallow region 107-1 of the second conductivity type may be generated as a byproduct of some processing steps (for example, when forming one or more body regions in the active area 16 of the power semiconductor device 1).

[0059] Figure 6-8Further exemplary embodiments of a spatial arrangement of one or more protection zones 107 and a field plate trench structure 172 in an edge termination region 17 of a power semiconductor device 1 are shown. In these embodiments, the field plate trench structure 172 is at least partially formed as a grid comprising a plurality of trenches or trench portions extending transversely to a main lateral extension direction Y of the protection zone(s) 107 and a plurality of trenches or trench portions extending parallel to the main lateral extension direction Y.

[0060] For example, in Figure 6 and 7 In each of the embodiments, the second portion 1722 of the field plate trench structure 172 is in each case arranged further away from a lateral chip edge 109 of the semiconductor body 10 than the protection zone 107. In other words, the second portion 1722 of the field plate trench structure 172 is located between the protection zone 107 and the active zone 16. In other embodiments (not depicted), the opposite relationship may apply, so that the second portion 1722 of the field plate trench structure 172 is arranged closer to a lateral chip edge 109 of the semiconductor body 10 than the protection zone 107 or, in other words, the protection zone 107 is located between the second portion 1722 and the active zone 16.

[0061] Figure 7 Examples and Figure 6 The embodiment of FIG. 1 is different in that the second portion 1722 of the field plate trench structure 172 includes a greater number of trenches. For example, the functional characteristics of the edge termination structure can be adjusted by providing an appropriate number of trenches.

[0062] exist Figure 6 and 7 In the illustrated embodiment, a larger contact slot / hole 175 can be used to directly establish electrical contact between the first portion 1721 of the field plate trench structure 172 and the protection zone 107, rather than setting a larger contact slot / hole 175 as shown in FIG. Figure 3-5B The separate contact portion 175 shown in the embodiment of FIG. 1 . The contact slot / hole 175 can be part of the metal layer 174. In another embodiment (not shown), the metal layer 174 does not extend over the large contact slot / hole 175.

[0063] Figure 8 175. For example, another variation of the arrangement of the contact grooves 175 is shown. For example, the electrical contact between the conductive material 173 and the protection zone 107 via the metal layer 174 can be established by staggered arrangement of a plurality of contact grooves 175, such as Figure 8 As shown exemplarily in FIG.

[0064] A method for processing a power semiconductor device 1, comprising:

[0065] - providing a semiconductor body 10;

[0066] - forming an active area 16 and an edge termination area 17, wherein within the active area 16 the semiconductor body 10 comprises a drift region of the first conductivity type, and wherein forming the edge termination area 17 comprises:

[0067] - forming a protection zone 107 of the second conductivity type, said protection zone 107 being included in said semiconductor body 10 at said front side 10 - 1 of said semiconductor body 10 and surrounding said active zone 16 ;

[0068] - forming a field plate trench structure 172 extending vertically from the front side 10 - 1 into the semiconductor body 10 and at least partially filled with a conductive material 173 , the conductive material 173 being electrically connected to the protection zone 107 and being insulated from the semiconductor body 10 outside the protection zone 107 by a field plate insulating structure 1725 ,

[0069] in

[0070] - a first portion 1721 of the field plate trench structure 172 at least partially extends into the protection zone 107 and is at least partially arranged below the metal layer 174 arranged at the front side 10 - 1 , and the conductive material 173 of the field plate trench structure 172 is electrically connected to the protection zone 107 ; and

[0071] The second portion 1722 of the field plate trench structure 172 extends to the outside of the protection area 107 and surrounds the active area 16 , wherein the metal layer 174 does not extend over the second portion 1722 of the field plate trench structure 172 .

[0072] The above-described embodiments of the method of forming a power semiconductor device correspond to the above-described embodiments of the power semiconductor, and vice versa. Thus, for example, features of the above-described embodiments of the power semiconductor device may be implemented by performing corresponding processing method steps.

[0073] In the above, embodiments of power semiconductor switches and corresponding processing methods are described. For example, these semiconductor devices are based on silicon (Si). Therefore, a single crystal semiconductor region or layer (such as semiconductor body 10 and its regions / regions, such as region 107, etc.) can be a single crystal Si region or Si layer. In other embodiments, polycrystalline silicon or amorphous silicon can also be used.

[0074] However, it should be understood that the semiconductor body 10 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, basic semiconductor materials (such as silicon (Si) or germanium (Ge)), 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 arsenic phosphide (InGaAsP)), and binary or ternary II-VI semiconductor materials (such as cadmium telluride (CdTe) and mercury cadmium telluride (HgCdTe)), just to name a few. The above semiconductor materials are also called "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.

[0075] For ease of description, spatially relative terms such as "under", "below", "lower", "above", "upper", etc. are used to illustrate the positioning of one element relative to a second element. These terms are intended to cover different orientations of the corresponding devices other than those depicted in the figures. In addition, terms such as "first", "second", etc. are also used to describe various elements, regions, parts, etc., and are not intended to be limiting. Throughout the specification, the same terms refer to the same elements.

[0076] As used herein, the terms “having,” “containing,” “including,” “comprising,” “presenting,” and the like are open-ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features.

[0077] 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 appended claims and their legal equivalents.

Claims

1. A power semiconductor device (1), comprising a semiconductor body (10) and presenting an active region (16) and an edge termination region (17), wherein: The semiconductor body (10) comprises, within the active region (16), a drift region of a first conductivity type, and wherein the edge termination region (17) comprises: - a protection zone (107) of a second conductivity type, said protection zone (107) being included in said semiconductor body (10) at a front side (10-1) of said semiconductor body (10) and surrounding said active zone (16); and a field plate trench structure (172) extending vertically from the front side (10-1) into the semiconductor body (10) and at least partially filled with a conductive material (173), the conductive material (173) being electrically connected to the protection zone (107) and being insulated from the semiconductor body (10) outside the protection zone (107) by a field plate insulating structure (1725), in - a first portion (1721) of the field plate trench structure (172) at least partially extends into the protection zone (107) and is at least partially arranged below a metal layer (174) arranged at the front side (10-1); and - a second portion (1722) of the field plate trench structure (172) extends outside the protection region (107) and surrounds the active region (16), wherein the metal layer (174) does not extend over the second portion (1722) of the field plate trench structure (172).

2. The power semiconductor device (1) according to claim 1, wherein the first portion (1721) of the field plate groove structure (172) includes a first portion (1731) of the conductive material (173), the first portion (1731) of the conductive material (173) being electrically connected to the protection zone (107), and the second portion (1722) of the field plate groove structure (172) includes a second portion (1732) of the conductive material (173), the second portion (1732) of the conductive material (173) being electrically connected to the protection zone (107) via the first portion (1731) of the conductive material (173).

3. The power semiconductor device (1) according to claim 2, wherein the conductive material (173) is electrically connected to the protection region (107) through the metal layer (174).

4. A power semiconductor device (1) according to claim 2 or 3, wherein the electrical connection between the metal layer (174) and each of the protection area (107) and the first portion (1731) of the conductive material (173) is established via corresponding contact holes or contact grooves (175) arranged in an insulating layer (108) between the metal layer (174) and the protection area (107).

5. The power semiconductor device (1) according to claim 2 or 3, wherein: The conductive material is or includes polysilicon.

6. The power semiconductor device (1) according to claim 2 or 3, wherein the second portion (1722) of the field plate trench structure (172) is arranged closer to a lateral chip edge (109) of the semiconductor body (10) than the protection area (107).

7. The power semiconductor device (1) according to claim 2 or 3, wherein the second portion (1722) of the field plate trench structure (172) is arranged further away from a lateral chip edge (109) of the semiconductor body (10) than the protection area (107).

8. The power semiconductor device (1) according to claim 2 or 3, wherein the first portion (1721) of the field plate trench structure (172) is completely embedded in the protection zone (107) at least where it is arranged below the metal layer (174).

9. The power semiconductor device (1) according to claim 2 or 3, wherein at least a portion of the protection zone (107) has an elongated shape extending in a substantially rectilinear manner along a main lateral extension direction (Y).

10. The power semiconductor device (1) according to claim 9, wherein the field plate trench structure (172) comprises one or more trenches or trench portions extending parallel to the main lateral extension direction (Y).

11. The power semiconductor device (1) according to claim 10, wherein the first portion (1721) of the field plate trench structure (172) comprises one or more trenches or trench portions extending parallel to the main lateral extension direction (Y).

12. The power semiconductor device (1) according to claim 10 or 11, wherein the second portion (1722) of the field plate trench structure (172) comprises one or more trenches or trench portions extending parallel to the main lateral extension direction (Y).

13. The power semiconductor device (1) according to claim 9, wherein the field plate trench structure (172) comprises one or more trenches or trench portions extending transversely to the main lateral extension direction (Y).

14. The power semiconductor device (1) according to claim 13, wherein the first portion (1721) of the field plate trench structure (172) comprises one or more trenches or trench portions extending transversely to the main lateral extension direction (Y).

15. The power semiconductor device (1) according to claim 13 or 14, wherein the second portion (1722) of the field plate trench structure (172) comprises one or more trenches or trench portions extending transversely to the main lateral extension direction (Y).

16. A power semiconductor device (1) according to claim 9, wherein the field plate groove structure (172) is at least partially formed as a grid, and the grid includes a plurality of grooves or groove portions extending transversely to the main lateral extension direction (Y), and a plurality of grooves or groove portions extending parallel to the main lateral extension direction (Y).

17. The power semiconductor device (1) according to claim 2 or 3, wherein: The edge termination region (17) comprises: - at least one further protection zone (107) of a second conductivity type, said at least one further protection zone (107) being included in said semiconductor body (10) at a front side (10-1) of said semiconductor body (10) and surrounding said active zone (16); and - an intermediate region (106) of a first conductivity type, at least partially comprised in the semiconductor body (10) between at least two protection regions (107); Wherein, the second portion (1722) of the field plate trench structure (172) at least partially extends in the middle region (106).

18. The power semiconductor device (1) according to claim 17, wherein the second portion (1732) of the electrically conductive material (173) is not electrically connected to the intermediate region (106).

19. The power semiconductor device (1) according to claim 2 or 3, wherein: The power semiconductor device (1) is at least one of an IGBT, a MOSFET and a diode or includes at least one of an IGBT, a MOSFET and a diode.

20. A method for processing a power semiconductor device (1), comprising: - providing a semiconductor body (10); - forming an active region (16) and an edge termination region (17), wherein within the active region (16), the semiconductor body (10) comprises a drift region of a first conductivity type, and wherein forming the edge termination region (17) comprises: - forming a protection zone (107) of the second conductivity type, said protection zone (107) being included in said semiconductor body (10) at a front side (10-1) of said semiconductor body (10) and surrounding said active zone (16); - forming a field plate trench structure (172) extending vertically from the front side (10-1) into the semiconductor body (10) and at least partially filled with a conductive material (173), the conductive material (173) being electrically connected to the protection zone (107) and being insulated from the semiconductor body (10) outside the protection zone (107) by a field plate insulating structure (1725), wherein - a first portion (1721) of the field plate trench structure (172) at least partially extends into the protection zone (107) and is at least partially arranged below a metal layer (174) arranged at the front side (10-1); and - a second portion (1722) of the field plate trench structure (172) extends outside the protection region (107) and surrounds the active region (16), wherein the metal layer (174) does not extend over the second portion (1722) of the field plate trench structure (172).

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