Semiconductor power device and manufacturing method thereof
By setting empty slots in the gate electrode and field electrode of semiconductor power devices and filling them with a material with a low coefficient of thermal expansion, the wafer warpage problem caused by polycrystalline silicon materials is solved, thereby improving the manufacturing stability and performance of the devices.
Patent Information
- Application Number
- CN202511283363.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-09
- Publication Date
- 2025-12-12
AI Technical Summary
In the manufacturing process of semiconductor power devices, the large expansion coefficient of polycrystalline silicon material leads to severe wafer warping, which affects device performance.
The electrode design employs a composite sandwich structure, which includes creating slots in the gate electrode and field electrode and filling them with materials with low coefficients of expansion, such as titanium, titanium nitride, tungsten, or silicon dioxide, to alleviate stress.
It effectively alleviates wafer warpage and improves the production stability and performance of devices.
Smart Images
Figure CN121126831A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor technology, and in particular to the structure and manufacturing method of a trench semiconductor power device. Background Technology
[0002] The technological development trend of semiconductor power devices is to reduce device size and improve device performance, thereby reducing device cost. Trench-type semiconductor power devices replace the traditional planar structure with vertical trenching, achieving a shorter current path and a better electric field distribution, effectively reducing the device's on-resistance and increasing the device's current density.
[0003] Shielded gate power devices are a type of trench-type semiconductor power device. In shielded gate power devices, the gate electrode and field electrode are located in a trench, and they are typically made of polycrystalline silicon. However, during device manufacturing, polycrystalline silicon, due to its high coefficient of thermal expansion, leads to significant wafer warping. Summary of the Invention
[0004] This application provides a structure for a semiconductor power device, which alleviates wafer warpage during the manufacturing process by setting the electrode structure in the trench of the semiconductor power device as a composite sandwich structure.
[0005] According to an embodiment of the present invention, a semiconductor power device is provided, comprising: a semiconductor layer having a first surface and a second surface opposite to each other; a trench located in the semiconductor layer and extending from the first surface of the semiconductor layer into the interior of the semiconductor layer; a gate electrode located in the upper half of the trench; and a field electrode located in the lower half of the trench, wherein the field electrode includes a first empty slot.
[0006] In one embodiment, the gate electrode includes a second empty slot.
[0007] In one embodiment, the first empty slot contains a filler whose coefficient of expansion is less than that of the field electrode.
[0008] In one embodiment, the second empty slot has a filler whose coefficient of expansion is less than that of the gate electrode.
[0009] In one embodiment, the first empty slot and the second empty slot are respectively filled with a filling material, the expansion coefficient of the filling material in the first empty slot is less than the expansion coefficient of the field electrode, and the expansion coefficient of the filling material in the second empty slot is less than the expansion coefficient of the gate electrode.
[0010] According to an embodiment of the present invention, a semiconductor power device is provided, comprising: a semiconductor layer having a first surface and a second surface opposite to each other; a trench located in the semiconductor layer and extending from the first surface of the semiconductor layer into the interior of the semiconductor layer; a gate electrode located in the upper half of the trench, wherein the gate electrode includes an empty slot; and a field electrode located in the lower half of the trench.
[0011] In the foregoing embodiments, the empty slot contains a filler, the expansion coefficient of which is less than that of the gate electrode.
[0012] According to an embodiment of the present invention, a semiconductor power device is provided, comprising: a semiconductor layer having a first surface and a second surface opposite to each other; a trench located in the semiconductor layer and extending from the first surface of the semiconductor layer into the interior of the semiconductor layer; a field electrode located in the trench, the field electrode including an empty slot; and a gate electrode including a first gate electrode portion and a second gate electrode portion, the first gate electrode portion and the second gate electrode portion being located in the trench and respectively located on both sides of the field electrode.
[0013] In the foregoing embodiment, the empty slot contains a filler, the expansion coefficient of which is less than that of the field electrode.
[0014] In some embodiments, the aforementioned gate electrode comprises polysilicon.
[0015] In some embodiments, the aforementioned field electrode comprises polycrystalline silicon.
[0016] In some embodiments, the aforementioned filler is any one of titanium, titanium nitride, tungsten, or silicon dioxide. Attached Figure Description
[0017] The above and other objects, features and advantages of this application will become clearer from the following description of embodiments with reference to the accompanying drawings:
[0018] Figure 1 This is a partial cross-sectional structural diagram of an existing semiconductor power device 100;
[0019] Figure 2 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 200 according to an embodiment of this application;
[0020] Figure 3 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 300 according to an embodiment of this application;
[0021] Figure 4 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 400 according to an embodiment of this application;
[0022] Figure 5This is a partial cross-sectional structural schematic diagram of a semiconductor power device 500 according to an embodiment of this application;
[0023] Figure 6 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 600 according to an embodiment of this application;
[0024] Figure 7 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 700 according to an embodiment of this application;
[0025] Figure 8 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 800 according to an embodiment of this application;
[0026] Figure 9 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 900 according to an embodiment of this application. Detailed Implementation
[0027] Specific embodiments of the present invention will now be described in detail. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other instances, well-known circuits, materials, or methods have not been specifically described to avoid obscuring the invention.
[0028] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "in an embodiment," "in an embodiment," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale. The same reference numerals indicate the same elements. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. The drawings are not drawn to scale and are for illustrative purposes only. For clarity, unless otherwise stated, the same elements have been designated by corresponding reference numerals in different drawings.
[0029] The terms “having,” “comprising,” “including,” “include,” etc., are open-ended, and these terms indicate the presence of the said structure, element, or feature, but do not exclude additional elements or features.
[0030] When describing the structure of a device, when referring to a layer or region as being "above" or "on top of" another layer or region, it can mean that it is directly above another layer or region, or that it contains other layers or regions between it and another layer or region. Furthermore, if the device is flipped, the layer or region will be located "below" or "under" another layer or region.
[0031] To describe a situation where it is located directly on another layer or another area, this article will use the expressions "directly on top of" or "on and adjacent to".
[0032] In some of the accompanying figures, relative doping concentrations are indicated by a "-" or "+" sign next to the doping type "n" or "p". For example, "n-" indicates a lower doping concentration than the "n" doped region, while the "n" doped region has a higher doping concentration than the "n-" doped region. Doped regions with the same relative doping concentration do not necessarily have the same absolute doping concentration. For example, two different "n"-type doped regions may have the same or different absolute doping concentrations.
[0033] In this embodiment of the invention, each semiconductor layer or region has a first conductivity type or a second conductivity type. The first conductivity type refers to either n-type or p-type, and the second conductivity type is the other. That is, a semiconductor layer with the first conductivity type can be an n-type semiconductor layer or a p-type semiconductor layer. When the semiconductor layer with the first conductivity type is an n-type semiconductor layer, the semiconductor layer with the second conductivity type is a p-type semiconductor layer. The n-type semiconductor layer is formed by doping the semiconductor layer with n-type impurities. The n-type impurities can be pentavalent elements such as phosphorus and arsenic. The p-type semiconductor layer is formed by doping the semiconductor layer with p-type impurities. The p-type impurities can be trivalent elements such as boron, indium, and gallium.
[0034] Figure 1 This is a partial cross-sectional structural diagram of an existing semiconductor power device 100. (Example) Figure 1 As shown, the semiconductor power device 100 includes a semiconductor layer 101, a trench 102 located in the semiconductor layer 101, a gate electrode 104 located in the upper half of the trench 102, and a field electrode 103 located in the lower half of the trench 102. The gate electrode 104 and the field electrode 103 are typically made of polysilicon. After the gate electrode 104 and the field electrode 103 are fabricated, during subsequent processes, the polysilicon gate electrode 104 and the polysilicon field electrode 103 expand and are squeezed to both sides, such as... Figure 1 As indicated by the arrow, this causes trench expansion and wafer warping.
[0035] Figure 2 This is a partial cross-sectional structural diagram of a semiconductor power device 200 according to an embodiment of this application. Figure 2 As shown, the semiconductor power device 200 includes a semiconductor layer 201, a trench 202 located in the semiconductor layer 201, a gate electrode 204 located in the upper half of the trench 202, and a field electrode 203 located in the lower half of the trench 202. The gate electrode 204 and the field electrode 203 can be made of polycrystalline silicon or other conductive materials. An insulating layer 206 is used for isolation between the gate electrode 204 and the trench 202, between the field electrode 203 and the trench 202, and between the gate electrode 204 and the field electrode 203.
[0036] The field electrode 203 includes a slot 205 (also called a first slot). The slot 205 extends downwards from the top of the field electrode 203 to near its bottom. The slot 205 is used to release stress generated during the expansion of the field electrode 203. The depth h1 of the slot 205 can be adjusted according to the field electrode 203 and its coefficient of expansion. For example, if the coefficient of expansion of the field electrode 203 is large, the depth h1 of the slot 205 can be appropriately increased, and vice versa. In some embodiments, the slot 205 extends through the entire field electrode 203, meaning it passes longitudinally through the entire field electrode 203 from its top to its bottom. In some embodiments, the width w1 of the slot 205 is greater than 0.05 μm and less than half the width w2 of the field electrode 203. In some embodiments, the depth h1 of the empty slot 205 is greater than 1 / 10 of the depth h2 of the field electrode 203, and less than or equal to the depth h2 of the field electrode 203.
[0037] exist Figure 2 In this embodiment, the semiconductor layer 201 includes a substrate layer 2011 and an epitaxial layer 2012 located on the substrate layer 2011. The surface of the epitaxial layer 2012 away from the substrate layer 2011 constitutes a first surface 2015 of the semiconductor layer 201. The surface of the substrate layer 2011 away from the epitaxial layer 2012 constitutes a second surface 2016 of the semiconductor layer 201. The first surface 2015 and the second surface 2016 are opposite to each other. A trench 202 extends from the first surface 2015 of the semiconductor layer 201 into the interior of the semiconductor layer 201, with the bottom of the trench located in the epitaxial layer 2012. A well region 2013 and a source region 2014 are distributed in the epitaxial layer 2012 between the trenches. The well region 2013 is located in the epitaxial layer 2012 below the first surface 2015, and the source region 2014 is distributed in the well region 2013.
[0038] When the semiconductor power device 200 is operating, the epitaxial layer 2012 located below the well region 2013 forms a drift region. A current channel is formed in a portion of the well region 2013 on both sides of the gate electrode 204 near the trench sidewall, providing a current path for the source region 2014 to reach the substrate 2011 through the drift region.
[0039] Figure 3 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 300 according to an embodiment of this application. Figure 2 Compared to the previous embodiment, the empty slot 205 includes a filler 307. To alleviate the stress caused by the expansion of the field electrode 203, the filler 307 comprises a material with a low coefficient of thermal expansion, i.e., the coefficient of thermal expansion of the filler is less than that of the field electrode 203. In some embodiments, the filler material may be any one of titanium, titanium nitride, tungsten, and silicon dioxide. The remaining structure and operating principle of the semiconductor power device 300 are the same as those of the semiconductor power device 200, and will not be described again here.
[0040] Figure 4 This is a partial cross-sectional structural diagram of a semiconductor power device 400 according to an embodiment of this application. Figure 4 As shown, the semiconductor power device 400 includes a semiconductor layer 201, a trench 202 located in the semiconductor layer 201, a gate electrode 404 located in the upper half of the trench 202, and a field electrode 403 located in the lower half of the trench 202. The gate electrode 404 and the field electrode 403 can be made of polycrystalline silicon or other conductive materials. An insulating layer 206 is used to isolate the gate electrode 404 from the trench 202, the field electrode 403 from the trench 202, and the gate electrode 404 from the field electrode 403.
[0041] The gate electrode 404 includes a slot 408 (also called a second slot). The slot 408 extends downwards from the top of the gate electrode 404 to near its bottom. The slot 408 serves to release stress generated during the expansion of the gate electrode 404. The depth h3 of the slot 408 can be adjusted according to the gate electrode 404 and its coefficient of expansion. For example, if the coefficient of expansion of the gate electrode 404 is large, the depth h3 of the slot 408 can be appropriately increased, and vice versa. In some embodiments, the slot 408 extends through the entire gate electrode 404, meaning it passes longitudinally through the entire gate electrode 404 from its top to its bottom. In some embodiments, the width w3 of the slot 404 is greater than 0.05 μm and less than 3 / 4 of the width w4 of the gate electrode 404. In some embodiments, the depth h3 of the slot 408 is greater than 0.1 μm and less than or equal to the depth h4 of the gate electrode 404.
[0042] The remaining structure and working principle of semiconductor power device 400 are the same as those of semiconductor power device 200, and will not be described again here.
[0043] Figure 5 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 500 according to an embodiment of this application. Figure 4Compared to the previous embodiment, the empty slot 408 includes a filler 509. To alleviate the stress caused by the expansion of the gate electrode 404, the filler 509 comprises a material with a low coefficient of thermal expansion, i.e., the coefficient of thermal expansion of the filler is less than that of the gate electrode 404. In some embodiments, the filler material may be any one of titanium, titanium nitride, tungsten, and silicon dioxide. The remaining structure and operating principle of the semiconductor power device 500 are the same as those of the semiconductor power device 200, and will not be described again here.
[0044] Figure 6 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 600 according to an embodiment of this application. Figure 6 As shown, the semiconductor power device 600 includes a semiconductor layer 201, a trench 202 located in the semiconductor layer 201, a gate electrode 404 located in the upper half of the trench 202, and a field electrode 203 located in the lower half of the trench 202. The gate electrode 404 and the field electrode 203 can be made of polycrystalline silicon or other conductive materials. An insulating layer 206 is used to isolate the gate electrode 404 from the trench 202, the field electrode 203 from the trench 202, and the gate electrode 404 from the field electrode 203.
[0045] exist Figure 6 In this embodiment, the field electrode 203 has a slot 205 (also referred to as a first slot). The slot 205 extends downward from the top of the field electrode 203 to near the bottom of the field electrode 203. The slot 205 is used to release the stress generated by the field electrode 203 during expansion. The depth h1 of the slot 205 can be adjusted according to the field electrode 203 and its coefficient of expansion. For example, if the coefficient of expansion of the field electrode 203 is large, the depth h1 of the slot 205 can be appropriately increased, and vice versa. In some embodiments, the slot 205 extends through the entire field electrode 203, that is, the slot 205 passes through the entire field electrode 203 longitudinally, from the top to the bottom of the field electrode 203.
[0046] exist Figure 6 In this embodiment, the gate electrode 404 has a slot 408 (also referred to as a second slot). The slot 408 extends downward from the top of the gate electrode 404 to near the bottom of the gate electrode 404. The slot 408 is used to release the stress generated by the gate electrode 404 during expansion. The depth h3 of the slot 408 can be adjusted according to the gate electrode 404 and its coefficient of expansion. For example, if the coefficient of expansion of the gate electrode 404 is large, the depth h3 of the slot 408 can be appropriately increased, and vice versa. In some embodiments, the slot 408 extends through the entire gate electrode 404, that is, the slot 408 passes through the entire gate electrode 404 longitudinally, from the top of the gate electrode 404 to the bottom of the gate electrode 404.
[0047] The remaining structure and working principle of semiconductor power device 600 are the same as those of semiconductor power device 200, and will not be described again here.
[0048] Figure 7 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 700 according to an embodiment of this application. Figure 6 Compared to the previous embodiment, the empty slot 205 includes filler 307, and the empty slot 408 includes filler 509. To alleviate the stress caused by the expansion of the field electrode 203 and the gate electrode 404, fillers 307 and 509 are made of materials with a low coefficient of thermal expansion, i.e., the coefficient of thermal expansion of the filler is less than that of the field electrode 203 and the gate electrode 404. In some embodiments, the filler material can be any one of titanium, titanium nitride, tungsten, and silicon dioxide. Fillers 307 and 509 can be the same material or different materials. The remaining structure and operating principle of the semiconductor power device 700 are the same as those of the semiconductor power device 200, and will not be described again here.
[0049] Figure 6 The device structure including empty slots in the gate electrode 404 and field electrode 203 is shown. Figure 7 The diagram shows a structure where the empty slots of the gate electrode 404 and the field electrode 203 are filled with material. In other embodiments, both the gate electrode 404 and the field electrode 203 may have empty slots, but only the empty slot of the gate electrode 404 may have filling material, or only the empty slot of the field electrode 203 may have filling material.
[0050] Figure 8 This is a partial cross-sectional structural diagram of a semiconductor power device 800 according to an embodiment of this application. Figure 8 As shown, the semiconductor power device 800 includes a semiconductor layer 201, a trench 202 located in the semiconductor layer 201, a first gate electrode 804-1, a second gate electrode 804-2, and a field electrode 803 located in the trench 202. The field electrode 803 is located in the middle of the trench 202 and extends downward from the top of the trench 202. The first gate electrode 804-1 and the second gate electrode 804-2 are located on both sides of the upper part of the field electrode 803, respectively. The first gate electrode 804-1, the second gate electrode 804-2, and the field electrode 803 can be made of polycrystalline silicon or other conductive materials. An insulating layer 206 is used for isolation between the first gate electrode 804-1 and the second gate electrode 804-2 and the trench 202, between the field electrode 803 and the trench 202, and between the first gate electrode 804-1, the second gate electrode 804-2, and the field electrode 803.
[0051] The field electrode 803 includes a slot 805. The slot 805 extends downwards from the top of the field electrode 803 to near its bottom. The slot 805 is used to release stress generated during the expansion of the field electrode 803. The depth h5 of the slot 805 can be adjusted according to the field electrode 803 and its coefficient of expansion. For example, if the coefficient of expansion of the field electrode 803 is large, the depth h5 of the slot 805 can be appropriately increased, and vice versa. In some embodiments, the slot 805 extends through the entire field electrode 803, meaning it passes longitudinally through the entire field electrode 803 from its top to its bottom. In some embodiments, the width w5 of the slot 805 is greater than 0.05 μm and less than half the width w6 of the field electrode 803. In some embodiments, the depth h5 of the empty slot 805 is greater than half of the depth h6 of the first gate electrode 804-1 and the second gate electrode 804-2, and less than or equal to the depth h7 of the field electrode 803.
[0052] Working principle of semiconductor power device 800 Figure 2 The semiconductor power device 200 in the embodiment is similar and will not be described in detail here.
[0053] Figure 9 This is a partial cross-sectional structural schematic diagram of a semiconductor power device 900 according to an embodiment of this application. Figure 8 Compared to the previous embodiment, the empty slot 805 includes a filler 907. To alleviate the stress caused by the expansion of the field electrode 803, the filler 907 comprises a material with a low coefficient of thermal expansion, i.e., the coefficient of thermal expansion of the filler is less than that of the field electrode 803. In some embodiments, the filler material may be any one of titanium, titanium nitride, tungsten, and silicon dioxide. The remaining structure and operating principle of the semiconductor power device 900 are the same as those of the semiconductor power device 800, and will not be described again here.
[0054] In the embodiments of this application, the respective faces of the field electrode and the gate electrode are drawn as straight lines in the horizontal and vertical directions. It should be understood that the respective faces of the field electrode and the gate electrode may have inclined or curved shapes, for example, at the intersection of the two faces in the horizontal and vertical directions, they may have rounded edges.
[0055] It should be understood that the embodiments of this application only show the device structure related to the technical solution of the present invention. At the same time, the structure in the embodiments of this application is only a partial structural illustration of the semiconductor power device. In order to more clearly and concisely illustrate the technical solution of the present invention, other parts of the device are not shown in the figure. For example, the metal layer covering the device, and the interlayer dielectric layer between the upper surface of the epitaxial layer and the metal layer to prevent short circuit between the metal layer and a part of the upper surface of the epitaxial layer are not shown in the figure. For example, the well contact area is also not shown in the figure.
[0056] It should be understood that the semiconductor layer 201 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); group IV compound semiconductor materials such as silicon carbide (SiC) or silicon germanide (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 (InGaP), aluminum gallium nitride (AlGaN), aluminum indium nitride (AlInN), indium gallium nitride (InGaN), gallium indium aluminum nitride (AlGaInN), or gallium indium arsenide phosphide (InGaAsP); and binary or ternary II-VI semiconductor materials such as cadmium telluride (CdTe) and mercury cadmium telluride (HgCdTe) (to name just a few). The semiconductor materials mentioned above are also known as "homogeneous junction 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)-gallium indium aluminum nitride (AlGaInN), indium gallium nitride (InGaN)-gallium indium aluminum 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 device applications, Si, SiC, GaAs, and GaN materials are currently the primary materials used.
[0057] As described above, these embodiments of the present application do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the present application, thereby enabling those skilled in the art to make good use of the present application and modifications based on it. The present application is limited only by the claims and their full scope and equivalents.
Claims
1. A semiconductor power device, comprising: A semiconductor layer having a first surface and a second surface facing away from each other; A trench, located in the semiconductor layer, extends from the first surface of the semiconductor layer into the interior of the semiconductor layer; The gate electrode is located in the upper half of the trench; as well as A field electrode is located in the lower half of the trench, wherein the field electrode includes a first empty slot.
2. The semiconductor power device as claimed in claim 1, wherein: The first empty slot contains a filler, the expansion coefficient of which is less than that of the field electrode.
3. The semiconductor power device of claim 1, wherein the gate electrode includes a second empty slot.
4. The semiconductor power device as described in claim 3, wherein: The second empty slot contains a filler material whose expansion coefficient is less than that of the gate electrode.
5. The semiconductor power device as described in claim 3, wherein: The first empty slot and the second empty slot are respectively filled with a filling material. The expansion coefficient of the filling material in the first empty slot is less than the expansion coefficient of the field electrode, and the expansion coefficient of the filling material in the second empty slot is less than the expansion coefficient of the gate electrode.
6. The semiconductor power device as claimed in claim 3, wherein: The first empty slot contains a filler, the expansion coefficient of which is less than that of the field electrode.
7. A semiconductor power device, comprising: A semiconductor layer having a first surface and a second surface facing away from each other; A trench, located in the semiconductor layer, extends from the first surface of the semiconductor layer into the interior of the semiconductor layer; A gate electrode, located in the upper half of the trench, wherein the gate electrode includes an empty slot; and The field electrode is located in the lower half of the trench.
8. The semiconductor power device as claimed in claim 7, wherein: The empty slot contains a filler material whose expansion coefficient is less than that of the gate electrode.
9. A semiconductor power device, comprising: A semiconductor layer having a first surface and a second surface facing away from each other; A trench, located in the semiconductor layer, extends from the first surface of the semiconductor layer into the interior of the semiconductor layer; A field electrode, located in a trench, the field electrode including an empty slot; and The gate electrode includes a first gate electrode portion and a second gate electrode portion, which are located in a trench and on opposite sides of the field electrode, respectively.
10. The semiconductor power device of claim 9, wherein: The empty slot contains a filler material whose expansion coefficient is less than that of the field electrode.
11. The semiconductor power device according to any one of claims 1-10, wherein the gate electrode comprises polysilicon.
12. The semiconductor power device according to any one of claims 1-10, wherein the field electrode comprises polycrystalline silicon.
13. The semiconductor power device according to any one of claims 2, 4-6, 8, and 10, wherein, The filler is any one of titanium, titanium nitride, tungsten, or silicon dioxide.