Semiconductor transistor device and method for manufacturing a semiconductor transistor device

Abstract

A semiconductor transistor device and a method for manufacturing a semiconductor transistor device are disclosed. The application relates to a semiconductor transistor device (1), comprising: a source region (2); a body region (3) comprising a channel region (3.1) extending in a vertical direction (10); a drain region (4); a gate region (6) arranged next to the channel region (3.1) in a lateral direction (11); and a body contact region (7) made of a conductive material (9), wherein the body contact region (7) forms a body contact area (8), the body contact region (7) is electrically contacted with the body region (3) via the body contact area (8), and wherein the body contact area (8) is inclined relative to the vertical direction (10) and the lateral direction (11).

Description

Technical Field

[0001] The present disclosure relates to semiconductor transistor devices having a vertical channel formed in a body region. Background Art

[0002] In a vertical field-effect transistor, a vertical channel is formed in the body region. A gate region is arranged aside in the lateral direction and includes a gate interlayer dielectric and a gate electrode. A channel electrically connecting the source region and the drain region is formed or can be formed in the body region, and the channel can be controlled by applying a voltage to the gate electrode. In order to avoid a floating body region, the floating body region can be electrically contacted by a body contact region made of a conductive material. For example, the body region can be short-circuited to the source region to eliminate intrinsic parasitic NPN transistors, especially in power devices. Summary of the Invention

[0003] An object of the present application is to provide a vertical transistor device with improved characteristics and a method of manufacturing such a device.

[0004] This object is achieved by the device of claim 1 and furthermore by the method of claim 13. A body contact region of the device made of a conductive material forms a body contact area that is in electrical contact with the body region. The body contact area is tilted relative to the vertical and lateral directions. The tilted body contact area can allow device optimization, depending on, for example, the reduction of R On or reduce drain-induced barrier lowering (DIBL) or Q GD Which parameter is optimized may depend, for example, on the orientation of the inclined body contact area, see details below.

[0005] Further embodiments and features are provided in the present description and in the dependent claims. Wherein individual features will be disclosed independently of a particular claim class, the present disclosure relates to aspects of apparatus and devices, but also to aspects of methods and uses. For example, if a device manufactured in a particular way is described, this is also a disclosure of the corresponding manufacturing process, and vice versa. In general, the present application provides a semiconductor switching device, in particular a field effect transistor device, having a body region or base region contacted via an inclined contact area of ​​a contact region, the contact region being made of a conductive material.

[0006] The inclined contact area is neither perpendicular nor parallel to the vertical direction, and therefore it is neither perpendicular nor parallel to the lateral direction. In general, the "vertical" direction is, for example, perpendicular to the surface of the device, for example the surface of a layer of the device, for example the surface of a (silicon) substrate and / or the surface of an epitaxial layer (deposited on the substrate). The vertical direction points from the source region to the drain region. The "lateral" direction is perpendicular to the vertical direction, the device or chip area being, for example, taken in the lateral direction. In the case of a device constructed from a plurality of identical transistor cells, these cells can be arranged translationally symmetrically in the lateral direction. The inclination of the body contact area with respect to the vertical and lateral directions can be seen in particular in a vertical cross-section. In general, when referring to a "vertical cross-section", the cross-sectional plane is parallel to the horizontal and lateral directions.

[0007] The body contact region is made of an electrically conductive material, in particular of a metallic material, such as, for example, tungsten. In order to produce such a device and form an inclined body contact region, for example a body contact groove with inclined side walls can be etched into the semiconductor body, for example into the epitaxial layer in which the body region is formed. The orientation of the tilt can be adjusted, for example, by the etching sequence applied, see details below. Subsequently, an electrically conductive material can be deposited to form the body contact region. In general, the inclined contact region is not necessarily the only contact region between the body region and the body contact region, and the body contact region can, for example, form an additional contact region aligned parallel to the lateral direction or parallel to the vertical direction (see for illustration). Figure 3 Alternatively, the inclined contact region may be the only contact region formed between the body region and the body contact region (see for illustration). Figure 1 ).

[0008] The source region and the drain region of the device are of a first conductivity type, and the body region is of a second conductivity type opposite to the first conductivity type. As a power device, the transistor may include a drift region vertically between the body region and the drain region, wherein the drift region has the same first conductivity type as the drain region, but has a lower doping than the drain region. In the illustrated embodiment, the first conductivity type is n-type and the second conductivity type is p-type. The source region and the body region and possibly the drift region can be formed in an epitaxial layer on a substrate, such as a silicon substrate (the epitaxial layer and the substrate forming the semiconductor body).

[0009] The gate region may include a gate electrode and a gate dielectric, in particular a gate oxide, such as silicon oxide. The gate electrode is a conductive portion of the gate region, which is capacitively coupled to the channel region via the gate dielectric. The gate electrode may be made, for example, of metal or polycrystalline silicon (polysilicon). The gate region may be arranged in a gate trench etched into the semiconductor body (the gate dielectric may be formed at the sidewalls of the trench, and the gate electrode may be deposited into the trench, at least partially filling the trench). Optionally, a field plate may be provided in the gate trench below the gate electrode (split gate), isolated from it by an interlayer dielectric.

[0010] In addition to such a split gate or in particular as an alternative to such a split gate, the device may include a field electrode region extending vertically into the semiconductor body, in particular into the drift region. The field electrode region is formed in a field electrode trench separated from one or more gate trenches. Viewed in a vertical cross-section, the field electrode trenches and the gate trenches may alternate in the lateral direction. A field electrode made of a conductive material (e.g., polysilicon) may be arranged in the field electrode trench. In addition, an insulating material filler may be arranged in the trench to isolate the field electrode from the semiconductor body, for example, from the drift region.

[0011] The gate trench may be a longitudinal trench. Generally speaking, the field electrode trench may also be a longitudinal trench extending parallel to the gate trench. In this case, the device may be constructed of longitudinal units, with the lateral direction (direction of translational symmetry) being perpendicular to the longitudinal extension (and perpendicular to the vertical direction). Alternatively, in particular, the field electrode trench may be a needle-shaped trench, with the field electrode region having a needle-shaped or columnar shape. In this case, viewed in top view, the gate trench may, for example, form a grid, which defines each unit, such as a rectangular or square unit. Each unit may be translationally symmetric in the lateral direction, and, for example, translationally symmetric in a further lateral direction perpendicular to the lateral direction and perpendicular to the vertical direction.

[0012] In an embodiment, an inclined body contact region extends from a sidewall of the field electrode trench. Seen in a vertical cross-section, it may extend from the sidewall of the trench in the direction of the gate region (and additionally upward or downward). In the following description, the end of the body contact region arranged at the field electrode trench is referred to as the "proximal end," while the other end of the inclined body contact region is referred to as the "distal end." The distal end is spaced apart from the field electrode trench and may, for example, be arranged laterally between the field electrode trench and the gate region, in particular as seen in a vertical cross-section.

[0013] In an embodiment, the proximal end is located deeper relative to the vertical direction than the distal end. The proximal end is arranged at a lower vertical height, i.e., at a greater depth in the vertical direction pointing downward from the source to the drain. Orienting the body contact region in this way can, for example, reduce the underlying electric field so that depletion does not extend too far into the underlying semiconductor body, in particular into the drift region. Viewed in a vertical cross-section, the body contact region can extend both upward and laterally from the sidewalls of the field electrode trench, i.e., towards the source region and towards the gate region.

[0014] In another embodiment, the proximal end of the body contact region is located higher than the distal end. It is arranged at a greater vertical height, i.e., at a smaller depth in the downwardly directed vertical direction. Seen in a vertical cross-section, the contact region can extend from the sidewalls of the field electrode trench both downwardly and laterally toward the lower end of the body region and toward the gate region. This orientation of the body contact region can, for example, reduce the DIBL or possibly Q GD The reduction aspect is beneficial.

[0015] Generally, the field electrode contact region can be formed of a conductive material in addition to the body contact region. The field electrode region has a field electrode contact area that is in electrical contact with the field electrode. Thus, both the field electrode and the body region can be in contact via the conductive material. The field electrode and the field electrode contact region can be formed of different materials, the former being formed of polysilicon and the latter being formed of a metal (e.g., tungsten).

[0016] An insulating material filling arranged in the field electrode trench in addition to the field electrode can separate the field electrode from the semiconductor body, for example from the drift region. Viewed in a vertical cross-section, it can be arranged to be laterally between the field electrode and the drift region. In an embodiment, the field electrode protrudes vertically above the insulating material filling, and the upper end of the insulating material filling is at a deeper depth than the upper end of the field electrode. With reference to, for example, a field electrode trench in which the electrode and the insulating material filling initially have the same vertical height (in an intermediate step during manufacturing), when etching the body contact groove, the upper part of the insulating material can, for example, be etched back. In other words, in this example, the body contact groove can intersect the sidewalls of the field electrode trench at a vertical height below the upper end of the field electrode.

[0017] In an embodiment, at least a portion of the field electrode contact region formed between the field electrode contact region and the field electrode is arranged at a sidewall of the field electrode. Viewed in a vertical cross-section, the conductive material may laterally cover an upper portion of the field electrode toward the gate region. In particular, it may upwardly cover an upper end of the field electrode and laterally cover the upper portion, which may, for example, allow for a large contact area and reliable contact.

[0018] Generally, the conductive material can cover the upper surface of the insulating material filling, and the proximal end of the body contact region can be arranged at the same vertical height. As an alternative to covering the upper surface, or in combination with covering the upper surface, the conductive material can also cover the sidewalls of the insulating material filling, i.e., the outer sidewalls facing the gate region. When viewed in a vertical cross-section, the conductive material can cover the upper portion of the sidewalls of the insulating material filling.

[0019] In an embodiment, the conductive material covers both the upper surface and the sidewalls of the insulating material filling. Viewed in a vertical cross-section, the conductive material may form a step at this upper corner of the insulating material filling. A corresponding step design will also be disclosed independently of the inclined body contact region (e.g., in combination with a flat body contact region). For example, the conductive material may extend vertically downward from the upper corner along the sidewalls of the insulating material filling and may form a body contact region at a distance above the upper end of the body. The lateral distance between the step and the sidewalls of the field electrode may be as great as the lateral distance between the field electrode and the body region (taken at the lower end of the body region).

[0020] Independently of whether the body contact region is tilted or not, the conductive material can, in particular, completely cover the upper surface of the insulating material filling, for example extending laterally toward the field electrode without further steps (for example, as viewed in a vertical cross-section). In combination with a field electrode protruding vertically above the insulating material filling (see above), the conductive material can, for example, form a first step at an upper corner of the insulating material filling and a second step at an upper corner of the field electrode, the second step being vertically higher than the first step.

[0021] In an embodiment, an insulating material filler is recessed into the field electrode trench, wherein the recess is filled with a conductive material. To manufacture such a structure, after etching and filling the field electrode trench, the upper portion of the insulating material filler can be etched back using a selective etching chemical to form a recess. The upper portion of the sidewall of the field electrode trench is not covered (the sidewall faces the field electrode). Subsequently, the recess can be filled with a conductive material. Therefore, in the manufactured device, the conductive material covers the upper portion of the sidewall of the field electrode trench. In other words, the upper section of the field electrode trench as defined by the sidewall is filled with a conductive material. At the upper end of the sidewall, the conductive material can form a step, and the body contact region extends downward or upward from the step into the body region.

[0022] In an embodiment, the vertical distance between the body contact region and the lower end of the body region is a maximum of 450 nm, with a further upper limit being, for example, a maximum of 375 nm or 300 nm. Possible lower limits may be, for example, 10 nm, 15 nm, or 20 nm. In this embodiment, the minimum vertical distance between the body contact region and the lower end of the body region is considered, for example, the vertical distance between the lower end of the body contact region and the lower end of the body region.

[0023] The minimum vertical distance between the body contact region and the lower end of the body region may be greater than, less than, or equal to the minimum lateral distance between the body contact region and the gate region. The minimum lateral distance between the body contact region and the gate region may be, for example, 350 nm, 275 nm, or 200 nm, with a possible lower limit being, for example, a minimum of 20 nm, 25 nm, or 30 nm (these values ​​will also be disclosed independently of the relationship between the lateral distance and the vertical distance).

[0024] In an embodiment, the inclined body contact area encloses an angle of at least 10° with the transverse direction, with a further lower limit of, for example, at least 20° or 30°. Possible upper limits may be, for example, a maximum of 80°, 70° or 60°. The angle considered is the cutting angle, i.e. the smaller of the two congruent angles (which is an acute angle). The body contact area and the transverse direction may form corresponding angles, in particular in a vertical cross section. In the case where the body contact area has a nonlinear curved shape, for example in a cross-sectional view, the angle enclosed with the transverse direction varies along the curve and an average value of these angles is taken due to the above considerations.

[0025] In an embodiment, the body contact region has a concave shape relative to the body region, as seen in a vertical cross-section. The concave shape means that the recess is visible from the body region. In other words, the body contact region protrudes inwardly into the body contact region. It protrudes or warps away from the body region, and vice versa, for example, in the direction of the insulating layer and / or the front side metallization. However, in general, the body contact region may also have a convex shape relative to the body region (and be seen in a cross-sectional view), i.e., it may protrude outwardly beyond the body contact region. The convex body contact region protrudes or warps into the body region, and vice versa, protrudes away from, for example, the insulating layer and / or the front side metallization. As a further alternative, the body contact region may have a linear shape, i.e., extend as a straight line in a cross-sectional view. The concave shape may be generated, for example, using anisotropic body contact groove etching, while the convex shape may be formed, for example, using isotropic groove etching, in particular corresponding silicon etching.

[0026] The present application also relates to a method for manufacturing a semiconductor transistor device, wherein a body contact region is formed with an inclined body contact area. The inclination can be formed during the deposition of the conductive material, for example during the metal deposition. In particular, a body contact groove can be etched before the conductive material is deposited, wherein the body contact groove has sidewalls that are inclined relative to the vertical direction and the lateral direction (in particular when viewed in a vertical cross-section). The body contact groove is a cavity for the subsequent deposition of the conductive material, wherein the inclined sidewalls define the inclined body contact area. In particular, the conductive material can be deposited to form a direct contact with the semiconductor substrate at the inclined sidewalls. Depending on the details of the process, for example, a (simple) oxide etch can be applied between the groove etching and the conductive material deposition to, for example, remove any native oxide from the semiconductor body.

[0027] In embodiments involving body contact regions extending from the sidewalls of the field electrode trenches, the etching of the body contact recesses comprises different etching steps. For example, in a first etching step, an insulating material filling arranged in the field electrode trench can be etched with a first selective etching chemical (e.g., an oxide etching chemical). After etching back a portion of the insulating material filling, a portion of the semiconductor body next to it can be etched with a second etching chemical in a second etching step. As mentioned above, the etching chemical for the semiconductor body etching can also affect the shape of the resulting inclined sidewalls and, therefore, the shape of the body contact region (e.g., concave or convex). The second etching chemical can be a selective etching chemical for the semiconductor body, or it can also etch the insulating material filling. With this sequence, a body contact region can be formed that rises from the sidewalls of the field electrode trench towards the body region and the source region, for example.

[0028] Alternatively, the sequence can be modified. For example, in a first etching step, the semiconductor body next to the field electrode trench can be etched, in particular using a selective etching chemistry (which etches the semiconductor body but not the insulating material filling). In a subsequent etching step, the insulating material filling can be etched back, for example, using a selective or non-selective etching chemistry (non-selective etching chemistry also etches the semiconductor body). With a corresponding sequence, a body contact region can be formed that descends from the sidewalls of the trench toward the lower end of the body region. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The transistor device and its production are explained in further detail below with reference to exemplary embodiments, wherein the individual features may also be relevant to the present application in different combinations.

[0030] Figure 1 shows a vertical cross-section of a transistor device having a body contact region with an inclined body contact area;

[0031] Figure 2 Show Figure 1 Detailed view of a transistor device;

[0032] Figure 3 A detailed view showing an alternative transistor device having a sloped body contact region;

[0033] Figure 4 showing a detailed view of a further alternative transistor device having a tilted body contact region;

[0034] Figure 5 showing a detailed view of a further alternative transistor device having a tilted body contact region;

[0035] Figure 6 showing a detailed view of a further alternative transistor device having a tilted body contact region;

[0036] Figure 7 shows a top view of a transistor device, illustrating the cell design;

[0037] Figure 8a Illustration for making Figure 1 and Figure 2 A first etching step of the transistor device shown in FIG.

[0038] Figure 8b The picture is Figure 8a a second etching step after the etching step;

[0039] Figure 9 A flow chart outlining the processing steps for fabricating a transistor device is shown. DETAILED DESCRIPTION

[0040] Figure 1 A semiconductor transistor device 1 is shown having a source region 2, a body region 3, and a drain region 4. A channel region 3.1 is arranged in the body region 3, and a gate region 6 is formed adjacent thereto. Gate region 6 includes a gate electrode 6.1 and a gate dielectric 6.2. Channel formation in channel region 3.1 can be controlled by applying a voltage to gate electrode 6.1. In the example shown here, source region 2 and drain region 4 are n-type regions, and body region 3 is p-type.

[0041] The drift region 13 is arranged vertically between the body region 3 and the drain region 4, i.e., in this case, an n-type region having a lower doping concentration than the drain region 4. In addition to the gate region 6 formed in the gate trench 12, the device 1 also includes a field electrode region 15 formed in a field electrode trench 16. A field electrode 15.1 and an insulating material filling 15.2 are arranged in the field electrode trench 16. The trenches 12, 16 extend in a vertical direction 10 into the semiconductor body 17, with a lateral direction 11 additionally shown for illustration purposes.

[0042] The source region 2 and the body region 3 are connected via the same conductive material 9 (i.e., tungsten in this example). The conductive material 9 forms a body contact region 7 having a body contact region 8. An electrical contact is made to the body region 3 via the body contact region 8. The body contact region 8 is tilted relative to the vertical direction 10 and the lateral direction 11 and is neither parallel nor perpendicular to these directions 10, 11.

[0043] Figure 2 A detailed view of the body contact region 7 is shown. The inclined body contact region 8 and the lateral direction 11 enclose an angle 35 of approximately 30° to 60°. The inclined body contact region 8 extends from the sidewall 16.1 of the field electrode trench 16 into the body region 3. The proximal end 8.1 of the body contact region 8 is arranged at the sidewall 16.1 and the distal end 8.2 is arranged at a lateral distance 28 from the sidewall 16.1. Figure 1 / Figure 2 In the embodiment of the present invention, the proximal end 8.1 is located deeper than the distal end 8.2.

[0044] In this example, the minimum vertical distance 25 between the body contact region 8 and the lower end 3.2 of the body region 3 is approximately 50 nm. In this example, the minimum lateral distance 29 between the body contact region 8 and the body region 3 (here taken from the upper end 8.2) is approximately 80 nm. Independent of these details, the inclined body contact region 8 can, for example, reduce the electric field below and allow R On Optimization. As an alternative to the linear shape as shown, the dashed lines illustrate the concave shape 18 that the inclined body contact area 8 may alternatively have.

[0045] In addition to the body contact region 7, the conductive material 9 also forms a field electrode contact region 20. Via the field electrode contact region 21, the field electrode contact region 20 is in electrical contact with the field electrode 15.1. Parts 21.1 of the field electrode contact region 21 are arranged at the sidewalls 15.1.1 of the field electrode 15.1. The body contact region 7 and the field electrode contact region 20 are formed from the same conductive material 9 (which in the example here is tungsten). On top, a front side metallization 26 (on the left) deposited onto the insulating layer 24 is arranged. Figure 2Only partially visible in , see Figure 1 ). The front side metallization 26 may be made of copper or aluminum (eg AlCu), for example.

[0046] exist Figure 3 The transistor device 1 shown in FIG. Figure 1 and Figure 2 The device 1 of FIG. 1 differs in the orientation of the inclined body contact region 8. In this case, the inclined body contact region 8 descends from the sidewall 16.1 towards the lower end 3.2 of the body region 3. As a result, it is located deeper relative to the vertical direction 10 away from the end 8.2 than closer to the end 8.1. Depending on the detailed arrangement, this design can, for example, allow a lower DIBL. Apart from the different orientation of the body contact region 8, this arrangement is similar to FIG. Figure 1 / Figure 2 The same reference numerals identify parts having the same or equivalent functions (this generally applies to the present disclosure).

[0047] Figure 4 A further transistor device 1 is shown having an inclined body contact region 8. Figure 3 As oriented in FIG. 8 , the distal end 8.2 is located deeper than the proximal end 8.1. Figure 4 Examples and Figure 3 The difference is that the conductive material 9 of the body contact region 7 surrounds the insulating material filling 15.2 at the upper end. At the upper corner 15.2.3, it contacts the sidewalls 15.2.1 and the upper surface 15.2.2 of the insulating material filling 15.2. There, the conductive material 9 forms a step 40. To form such a device 1, a selective etching chemical can be applied to etch deeper into the semiconductor body 17 without etching the insulating material filling 15.2 (e.g., after a selective insulating material filling etch).

[0048] Figure 5 A further transistor device 1 is shown, wherein the inclined body contact region 8 is as shown in Figure 1 / Figure 2 As in the embodiment of the present invention, the proximal end 8.1 is located deeper than the distal end 8.2. Figure 1 / Figure 2 The difference is that the conductive material 9 extends into the recess 59 formed in the field electrode trench 16 by etching back the insulating material filling 15.2. To form the recess 59, the insulating material filling 15.2 can be etched back using a selective etching chemical, wherein the upper end 16.1.1 of the sidewall 16.1 of the field electrode trench 16 is uncovered. When the conductive material is subsequently deposited, it covers this upper end 16.1.1 and forms a step 50 there. The body contact region 8 extends from the step 50 into the body region 3.

[0049] Figure 6 A further transistor device 1 is shown having an inclined body contact region 8 which rises from close to the end 8.1 to away from the end 8.2 (as in FIG. Figure 1 、 Figure 2 and Figure 5 ). The difference is that the field electrode contact region 20 and the body contact region 7 are arranged in different grooves 27, 65 that intersect the insulating layer 24 separately. The body contact region 7 is arranged in the body contact groove 27, and the field electrode contact region 20 is arranged in a separate field electrode contact groove 65. Vertically below the upper end 24.1 of the insulating layer 24, the body contact region 7 and the field electrode contact region 20 are not connected to each other. However, in this example, the front side metallization 26 forms an electrical connection vertically above the upper end 24.1 of the insulating layer 24. Here, the insulating material filling 15.2 is not recessed into the field electrode trench 16, and its upper surface 15.2.2 is in the same plane as the upper end 2.1 of the source region 2. As an alternative to the linear shape as shown, the dotted line illustrates the convex shape 19 that the inclined body contact region 8 can alternatively have.

[0050] Figure 7 The transistor device 1 is shown in a top view, i.e., in a vertical viewing direction. The field electrode trenches 16 are formed as needle-shaped trenches 70, and the field electrode regions 15 have a needle-shaped or pillar-shaped shape. The gate trenches 12 are longitudinal trenches 71 that form a grid 72 and define individual cells 73. In this example, the cells 73 have a square shape, with a corresponding needle-shaped trench 70 arranged in the center of each cell 73. This cell-based design has translational symmetry in the lateral direction 11 and in a further lateral direction 111.

[0051] Figure 8a and Figure 8b Graphics used to form Figure 1 / Figure 2 The body of the device 1 is etched into the contact groove 27. Figure 8a In the first etching step 81 shown in FIG, the insulating material filling 15.2 is etched using a first selective etching chemical 82, which does not etch the semiconductor body 17, for example, does not etch the source region 2 and the body region 3. Figure 8bIn a subsequent second etching step 85 shown in FIG, the body contact recess 27 is finally etched using a second etching chemical 86. In the example shown here, the second etching chemical 86 is non-selective, i.e. etches the insulating material filling 15.2 and the semiconductor body 17. Those areas of the semiconductor body 17 that are not to be etched can, for example, be protected by a mask 87. The resulting body contact recess 27 has sidewalls 27.1 that are inclined relative to the vertical direction 10 and the lateral direction 11. When the conductive material 9 is subsequently deposited (at Figure 8a 、 Figure 8b ), the conductive material 9 contacts the inclined side wall 27 . 1 , resulting in an inclined body contact area 8 .

[0052] Figure 9 9. A flow chart illustrates some steps 90 for fabricating a transistor device 1 disclosed herein. After forming 91 the source region 2 and the body region 3, forming 92 the gate region 6, and forming 93 the field electrode region 15 (the order of forming steps 91-93 may vary), the body contact region 7 may be formed 95. In particular, the body contact recess 27 may be etched 96 before depositing 97 the conductive material. As described above, in an example, etching 96 the body contact recess 27 may include etching 96.1 the insulating material filler 15.2 and etching 96.2 the semiconductor body 17. After depositing 97 the conductive material 9 and possibly forming 98 the insulating layer 24, the front side metallization 26 may be deposited 99.

Claims

1. A semiconductor transistor device (1), comprising: source region (2), a body region (3) comprising a channel region (3.1) extending in a vertical direction (10), drain region (4), a gate region (6) arranged beside the channel region (3.1) in a lateral direction (11), and a body contact region (7) made of a conductive material (9), in, The body contact region (7) forms a body contact area (8), and the body contact region (7) is in electrical contact with the body region (3) via the body contact area (8). and wherein the body contact area (8) is inclined relative to the vertical direction (10) and the lateral direction (11), Therein, the body contact area (8) has a concave shape (18) seen in vertical cross-section.

2. The semiconductor transistor device (1) according to claim 1, comprising a field electrode (15.1) arranged in a field electrode trench (16), wherein the inclined body contact region (8) extends from a sidewall (16.1) of the field electrode trench (16).

3. The semiconductor transistor device (1) according to claim 2, wherein The body contact region (8) extends between a proximal end (8.1) arranged at a side wall (16.1) of the field electrode trench (16) and a distal end (8.2) arranged at a certain lateral distance from the side wall (16.1) of the field electrode trench (16), the proximal end (8.1) being deeper relative to the vertical direction (10) than the distal end (8.2).

4. The semiconductor transistor device (1) according to claim 2, wherein The body contact region (8) extends between a proximal end (8.1) arranged at a side wall (16.1) of the field electrode trench (16) and a distal end (8.2) arranged at a certain lateral distance from the side wall (16.1) of the field electrode trench (16), the proximal end (8.1) being located higher relative to the vertical direction (10) than the distal end (8.2).

5. The semiconductor transistor device (1) according to any one of claims 2 to 4, the field electrode contact region (20) being formed of an electrically conductive material (9), wherein the field electrode contact region (20) comprises a field electrode contact area (21), the field electrode contact region (20) being in electrical contact with the field electrode (15.1) via the field electrode contact area (21).

6. The semiconductor transistor device (1) according to claim 2 , wherein an insulating material filling (15.2) is arranged in the field electrode trench (16) in addition to the field electrode (15.1), wherein an upper surface (15.2.2) of the insulating material filling (15.2) is arranged at a lower vertical height than an upper end of the field electrode (15.1).

7. The semiconductor transistor device (1) according to claim 5, wherein a portion (21.1) of the field electrode contact region (21) is arranged at a sidewall (15.1) of the field electrode (15.1).

8. The semiconductor transistor device (1) according to any one of claims 2 to 4, wherein an insulating material filling (15.2) is arranged in the field electrode trench (16) in addition to the field electrode (15.1), wherein the conductive material (9) forms a step (40) at an upper corner (15.2.3) of the insulating material filling (15.2), and the conductive material (9) covers the sidewalls (15.2.1) and the upper surface (15.2.2) of the insulating material filling (15.2) at the upper corner (15.2.3).

9. The semiconductor transistor device (1) according to claim 2 , wherein an insulating material filling (15.2) is arranged in the field electrode trench (16) in addition to the field electrode (15.1), wherein the insulating material filling (15.2) is recessed into the field electrode trench (16), the recess (59) being filled with the conductive material (9) to form a step (50) at the sidewall (16.1) of the field electrode trench (16).

10. The semiconductor transistor device (1) according to any one of claims 1 to 4, wherein The minimum vertical distance (25) between the body contact region (7) and the lower end (3.2) of the body region (3) is a maximum of 450 nm.

11. The semiconductor transistor device (1) according to any one of claims 1 to 4, wherein The angle (35) formed between the inclined body contact area (8) and the transverse direction (11) is at least 10° and at most 80°.

12. A method for manufacturing a semiconductor transistor device (1) according to any one of claims 1 to 11, the method comprising the steps of: - forming (95) a body contact region (7) having an inclined body contact area (8).

13. The method of claim 12, wherein forming (95) the body contact region (7) comprises the following steps: - etching (96) a body contact recess (27) having side walls (27.1) inclined with respect to the vertical direction (10) and the lateral direction (11); - depositing a conductive material (9) into the body contact recess (27) to form a body contact region (7) having an inclined body contact area (8) at the inclined sidewalls of the body contact recess (27).

14. The method according to claim 13, the semiconductor transistor device (1) comprising a field electrode (15.1) and an insulating material filling (15.2), both of which are arranged in a field electrode trench (16) etched into the semiconductor substrate, the body contact region (8) extending from a sidewall (16.1) of the field electrode trench (16), The etching (96) of the body contact groove (27) comprises: - etching (96.1) the insulating material filling (15.2) arranged in the field electrode trench (16) using a first selective etching chemical (82) in a first etching step (81); - In a subsequent second etching step (85), parts of the semiconductor body (17) are etched (96.2) using a second etching chemical (86).

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