Semiconductor structure

Abstract

The present invention discloses a semiconductor structure, including a substrate, a semiconductor layer, a floating body field ring structure, and an embedded doping region. The semiconductor layer is disposed on the substrate. The semiconductor layer has a first conductivity type. The floating body field ring structure is located in the semiconductor layer. The floating body field ring structure includes at least one floating body field ring. The floating body field ring has a second conductivity type. The embedded doping region is located in the semiconductor layer below the floating body field ring structure and is connected to the floating body field ring structure. The embedded doping region has a second conductivity type.

Description

Technical Field

[0001] The present invention relates to a semiconductor structure, and more particularly to a semiconductor structure having a floating field ring (FFR). Background Art

[0002] Some semiconductor devices (such as power devices) are prone to breakdown at the outermost edge of the main junction. The current solution is to improve the breakdown voltage of the semiconductor device through a floating field ring surrounding the semiconductor device region to prevent breakdown. However, how to further improve the breakdown voltage of the semiconductor device is an ongoing goal. Summary of the Invention

[0003] The present invention provides a semiconductor structure that can improve the breakdown voltage of a semiconductor device.

[0004] The present invention provides a semiconductor structure, including a substrate, a semiconductor layer, a floating field ring structure, and an embedded doped region. The semiconductor layer is disposed on the substrate. The semiconductor layer has a first conductivity type. The floating field ring structure is located in the semiconductor layer. The floating field ring structure includes at least one floating field ring. The floating field ring has a second conductivity type. The embedded doped region is located in the semiconductor layer below the floating field ring structure and is connected to the floating field ring structure. The embedded doped region has a second conductivity type.

[0005] According to an embodiment of the present invention, in the above semiconductor structure, the embedded doped region may be located directly below the entire floating field ring structure.

[0006] According to an embodiment of the present invention, in the above semiconductor structure, the embedded doped region may be located directly below a part of the floating field ring structure.

[0007] According to an embodiment of the present invention, in the above semiconductor structure, the embedded doped region may be located only on one side of the entire floating field ring structure.

[0008] According to an embodiment of the present invention, in the above semiconductor structure, the number of the embedded doped regions may be one.

[0009] According to an embodiment of the present invention, in the above semiconductor structure, the number of the embedded doped regions may be multiple.

[0010] According to an embodiment of the present invention, in the above semiconductor structure, the substrate may include a semiconductor element region. A floating body field ring structure may surround the semiconductor element region. The semiconductor structure may further include semiconductor elements. The semiconductor elements may include a first doped region and a second doped region. The first doped region is located in the semiconductor layer of the semiconductor element region. The first doped region may have a second conductivity type. The second doped region is located in the substrate and is adjacent to the semiconductor layer. The second doped region may have a first conductivity type.

[0011] According to an embodiment of the present invention, in the above semiconductor structure, an embedded doped region may further be located directly below the first doped region.

[0012] According to an embodiment of the present invention, in the above semiconductor structure, the semiconductor element may further include a well region. The well region is located in the semiconductor layer of the semiconductor element region. The well region may have a second conductivity type. The first doped region is located in the well region.

[0013] According to an embodiment of the present invention, in the above semiconductor structure, an embedded doped region may further be located directly below the well region.

[0014] According to an embodiment of the present invention, in the above semiconductor structure, the semiconductor element may further include a third doped region. The third doped region is located in the semiconductor layer on the side of the floating body field ring structure away from the semiconductor element region.

[0015] According to an embodiment of the present invention, in the above semiconductor structure, an embedded doped region is also located directly below the third doped region.

[0016] According to an embodiment of the present invention, in the above semiconductor structure, a fourth doped region may further be included. The fourth doped region is located in the semiconductor layer between the floating body field ring structure and the third doped region. The fourth doped region may have a first conductivity type.

[0017] According to an embodiment of the present invention, in the above semiconductor structure, an embedded doped region may further be located directly below the fourth doped region.

[0018] Based on the above, in the semiconductor structure proposed by the present invention, since the embedded doped region is located in the semiconductor layer below the floating body field ring structure and is connected to the floating body field ring structure, the range of the depletion region can be expanded, thereby improving the breakdown voltage of the semiconductor element. On the other hand, since the semiconductor structure proposed by the present invention can improve the breakdown voltage of the semiconductor element, even if the area of the floating body field ring structure is reduced, the same breakdown voltage as the prior art can be maintained, and a smaller element size can be achieved.

[0019] To make the above features and advantages of the present invention more obvious and understandable, specific embodiments are hereinafter given and described in detail in conjunction with the accompanying drawings as follows. Description of the Drawings

[0020] Figure 1 Upper view of a semiconductor structure according to an embodiment of the present invention;

[0021] Figure 2A is a cross-sectional view of the semiconductor structure along the Figure 1 I-I' section line in;

[0022] Figures 2B to 2G For other embodiments of the present invention, along Figure 1 Cross-sectional view of the semiconductor structure along the I-I' section line in.

[0023] Symbol description

[0024] 10: Semiconductor structure

[0025] 100: Substrate

[0026] 102: Semiconductor layer

[0027] 104: Floating body field ring structure

[0028] 104a: Floating body field ring

[0029] 106: Embedded doping region

[0030] 108: Semiconductor element

[0031] 110, 112, 116, 118: Doping regions

[0032] 114: Well region

[0033] R: Semiconductor element region

[0034] W: Width Detailed implementation manners

[0035] Figure 1 Is an upper view of a semiconductor structure according to an embodiment of the present invention. In Figure 1 Some components in are omitted to clearly describe the Figure 2A Configuration relationship between the components in. Figure 1 Is a cross-sectional view of the semiconductor structure along the Figure 2A I-I' section line in. Figure 1 Is a cross-sectional view of the semiconductor structure along the I-I' section line for other embodiments of the present invention. In Figures 2B to 2G For other embodiments of the present invention, along Figure 1 Cross-sectional view of the semiconductor structure along the I-I' section line in. In Figures 2A to 2G The same or similar components are denoted by the same symbols.

[0036] Please refer to Figure 1 And Figure 2A, the semiconductor structure 10 includes a substrate 100, a semiconductor layer 102, a floating body field ring structure 104, and an embedded doping region 106. The substrate 100 can be a semiconductor substrate, such as a silicon substrate. In addition, the substrate 100 can include a semiconductor element region R.

[0037] The semiconductor layer 102 is disposed on the substrate 100. The material of the semiconductor layer 102 is, for example, a semiconductor material such as epitaxial silicon. The semiconductor layer 102 has a first conductivity type (e.g., N-type). In addition, the first conductivity type and the second conductivity type can be different conductivity types. The first conductivity type and the second conductivity type can be one of N-type and P-type and the other, respectively. In this embodiment, the first conductivity type is taken as an example of N-type, and the second conductivity type is taken as an example of P-type, but the present invention is not limited thereto. In other embodiments, the first conductivity type can be P-type, and the second conductivity type can be N-type.

[0038] The floating body field ring structure 104 is located in the semiconductor layer 102. The floating body field ring structure 104 can surround the semiconductor element region R ( Figure 1 ). The floating body field ring structure 104 includes at least one floating body field ring 104a. In this embodiment, the number of the floating body field rings 104a is taken as an example of a plurality, but the present invention is not limited thereto. In other embodiments, the number of the floating body field rings 104a can be one. The floating body field ring 104a has a second conductivity type (e.g., P-type). For example, the floating body field ring 104a can be a doping region of the second conductivity type (e.g., P-type). In addition, the widths W of the plurality of floating body field rings 104a can be the same or different from each other.

[0039] The embedded doping region 106 is located in the semiconductor layer 102 below the floating body field ring structure 104 and is connected to the floating body field ring structure 104. The embedded doping region 106 has a second conductivity type (e.g., P-type). The embedded doping region 106 can be used to expand the range of the depletion region, thereby increasing the breakdown voltage.

[0040] In addition, the semiconductor structure 10 can further include a semiconductor element 108. The semiconductor element 108 can be an active element, such as a power element. In some embodiments, the semiconductor element 108 is, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET), a diode, or an insulated gate bipolar transistor (IGBT), etc.

[0041] The semiconductor element 108 may include a doped region 110 and a doped region 112. The doped region 110 is located in the semiconductor layer 102 of the semiconductor element region R. The doped region 110 may have a second conductivity type (e.g., P-type). The doped region 112 is located in the substrate 100 and is adjacent to the semiconductor layer 102. In some embodiments, the doped regions 112 may be uniformly distributed throughout the substrate 100. The doped region 112 may have a first conductivity type (e.g., N-type).

[0042] In addition, the semiconductor element 108 may further include at least one of a well region 114 and a doped region 116. The well region 114 is located in the semiconductor layer 102 of the semiconductor element region R. The well region 114 may have a second conductivity type (e.g., P-type). The doped region 110 is located in the well region 114. Additionally, the doping concentration of the doped region 110 may be greater than the doping concentrations of the floating body field ring 104a, the embedded doped region 106, and the well region 114. The doped region 116 is located in the semiconductor layer 102 on a side of the floating body field ring structure 104 away from the semiconductor element region R. On the other hand, the semiconductor element 108 may further include other required components according to the element type, and the description thereof is omitted herein.

[0043] In some embodiments, according to the type of the semiconductor element 108, the doped region 116 may be of the first conductivity type (e.g., N-type) or the second conductivity type (e.g., P-type). In some embodiments, when the doped region 116 is of the first conductivity type (e.g., N-type), the doped region 116 may be coupled to the doped region 112, but the present invention is not limited thereto.

[0044] In addition, the semiconductor structure 10 may further include a doped region 118. The doped region 118 is located in the semiconductor layer 102 between the floating body field ring structure 104 and the doped region 116. The doped region 118 may have the first conductivity type (e.g., N-type). The doped region 118 may serve as a channel stop region.

[0045] In the present embodiment, as Figure 2A shown, the embedded doped region 106 may be located directly below the entire floating body field ring structure 104, and may also be located directly below the doped region 110, the well region 114, the doped region 118, and the doped region 116, but the present invention is not limited thereto. In some other embodiments, the embedded doped region 106 may not be located directly below the floating body field ring structure 104, the doped region 110, the well region 114, the doped region 118, and / or the doped region 116. Additionally, the embedded doped region 106 may be connected to the well region 114, the doped region 118, and the doped region 116, but the present invention is not limited thereto. In some other embodiments, the embedded doped region 106 may not be connected to the well region 114, the doped region 118, and / or the doped region 116.

[0046] In some other embodiments, as Figure 2E shown, the embedded doped region 106 may not be directly below the floating body field ring structure 104. In some other embodiments, as Figure 2B , Figure 2D , Figure 2E and Figure 2F shown, the embedded doped region 106 may not be directly below the doped region 110. In some other embodiments, as Figure 2B , Figure 2D , Figure 2E and Figure 2F shown, the embedded doped region 106 may not be directly below the doped region 114. In some other embodiments, as Figures 2B to 2F shown, the embedded doped region 106 may not be directly below the doped region 116. In some other embodiments, as Figures 2C to 2F shown, the embedded doped region 106 may not be directly below the doped region 118.

[0047] In some other embodiments, the embedded doped region 106 may be located only on one side of the entire floating body field ring structure 104. For example, as Figure 2E shown, the embedded doped region 106 may be located only on one side of the entire floating body field ring structure 104 and away from the semiconductor element region R, but the present invention is not limited thereto. In some other embodiments, the embedded doped region 106 may be located only on one side of the entire floating body field ring structure 104 and close to the semiconductor element region R.

[0048] In addition, as Figures 2A to 2D shown, the embedded doped region 106 may be located directly below the entire floating body field ring structure 104, that is, the embedded doped region 106 may be located directly below each floating body field ring 104a, but the present invention is not limited thereto. In some other embodiments, as Figure 2F shown, the embedded doped region 106 may be located directly below a part of the floating body field ring structure 104.

[0049] In addition, as Figures 2A to 2F shown, the number of the embedded doped regions 106 is taken as one for example, but the present invention is not limited thereto. In some other embodiments, as Figure 2G shown, there may be multiple embedded doped regions 106. In Figure 2GIn [the structure], although multiple embedded doping regions 106 are respectively located directly below the floating body field ring structure 104, directly below the doping region 110, directly below the well region 114, directly below the doping region 118, and / or directly below the doping region 116, the present invention is not limited thereto. In some embodiments, the multiple embedded doping regions 106 may not be respectively located directly below the floating body field ring structure 104, directly below the doping region 110, directly below the well region 114, directly below the doping region 118, and / or directly below the doping region 116.

[0050] Based on the above embodiments, in the semiconductor structure 10, since the embedded doping region 106 is located in the semiconductor layer 102 below the floating body field ring structure 104 and is connected to the floating body field ring structure 104, the range of the depletion region can be expanded, thereby improving the breakdown voltage of the semiconductor element 108. On the other hand, since the semiconductor structure 10 can improve the breakdown voltage of the semiconductor element 108, even if the area of the floating body field ring structure 104 is reduced, the same breakdown voltage as the prior art can be maintained, and a smaller element size can be achieved. In addition, when the area of the embedded doping region 106 is larger (as shown in, Figure 2A ), the effect of improving the breakdown voltage of the semiconductor element 108 is better.

[0051] In summary, in the semiconductor structure of the above embodiments, the range of the depletion region can be expanded by the embedded doping region located below and connected to the floating body field ring structure, so the breakdown voltage of the semiconductor element can be improved.

[0052] Although the present invention is disclosed in combination with the above embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the relevant technical field can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A semiconductor structure, characterized in that, The semiconductor structure includes: a substrate including a semiconductor device region; a semiconductor layer disposed on the substrate and having a first conductivity type; a floating body field ring structure located in the semiconductor layer and including a plurality of floating body field rings, wherein the floating body field rings have a second conductivity type; and an embedded doping region located in the semiconductor layer below the floating body field ring structure and connected to the floating body field ring structure, wherein the embedded doping region has the second conductivity type, wherein the embedded doping region is only located on one side of the entire floating body field ring structure and away from the semiconductor device region, and only one of the plurality of floating body field rings contacts the embedded doping region.

2. The semiconductor structure according to claim 1, wherein the number of the embedded doping regions is one.

3. The semiconductor structure according to claim 1, wherein the number of the embedded doping regions is plural.

4. The semiconductor structure according to claim 1, wherein the floating body field ring structure surrounds the semiconductor device region, and the semiconductor structure further includes: a semiconductor device including: a first doping region located in the semiconductor layer of the semiconductor device region and having the second conductivity type; and a second doping region located in the substrate and adjacent to the semiconductor layer, wherein the second doping region has the first conductivity type.

5. The semiconductor structure according to claim 4, wherein the semiconductor device further includes: a well region located in the semiconductor layer of the semiconductor device region and having the second conductivity type, wherein the first doping region is located in the well region.

6. The semiconductor structure according to claim 4, wherein the semiconductor device further includes: a third doping region located in the semiconductor layer on a side of the floating body field ring structure away from the semiconductor device region.

7. The semiconductor structure according to claim 6, further including: a fourth doping region located in the semiconductor layer between the floating body field ring structure and the third doping region and having the first conductivity type.

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