A semiconductor device and its fabrication method

Abstract

This invention discloses a semiconductor device and its fabrication method. The semiconductor device includes an active region and a passive region surrounding the active region. The semiconductor device also includes a substrate, an epitaxial structure, a bonding structure, and at least one shielding structure. The shielding structure provides shielding protection for the bonding structure and forms an ohmic contact with the two-dimensional electron gas located in the passive region. By adding a shielding structure and forming an ohmic contact with the two-dimensional electron gas in the passive region, the migration of silver ions from the surface mount silver paste to the bonding structure during the packaging process can be effectively prevented. This ensures the stability of the bonding structure and the electrodes connected to the bonding structure, avoids short circuits between the bonding structure, the electrodes connected to the bonding structure, and the source electrode. Furthermore, the ohmic contact between the shielding structure and the two-dimensional electron gas enhances the shielding effect and ensures the normal operation of the semiconductor device.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor device and a method for fabricating the same. Background Technology

[0002] After the semiconductor chip is fabricated, it needs to be packaged to form a semiconductor device. Generally, a surface mount method is used for packaging semiconductor devices. Because surface mount silver paste is relatively inexpensive, it is commonly used to electrically connect some metal connection electrodes of the semiconductor device to the metal electrodes in the package housing.

[0003] However, because the surface-mount silver paste causes silver ions to undergo electrochemical migration under the influence of an electric field, the silver ions migrate to the front side of the semiconductor chip and come into contact with other electrodes on the front side of the semiconductor chip, causing a short circuit and making the semiconductor device unable to function properly. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a semiconductor device and a method for fabricating the same. By setting a shielding structure, the shielding structure is used to shield and protect the bonding structure, ensuring the stability of the bonding structure performance. Furthermore, by forming an ohmic contact between the shielding structure and the two-dimensional electron gas, the shielding effect can be enhanced, ensuring the normal operation of the semiconductor device.

[0005] In a first aspect, embodiments of the present invention provide a semiconductor device, including an active region and a passive region surrounding the active region;

[0006] The semiconductor device further includes:

[0007] Substrate;

[0008] An epitaxial structure located on one side of the substrate, wherein a two-dimensional electron gas is formed in the epitaxial structure, and a portion of the two-dimensional electron gas is located in the passive region;

[0009] At least one bonding structure located on the side of the epitaxial structure away from the substrate and located in the passive region;

[0010] At least one shielding structure is located on the side of the epitaxial structure away from the substrate, the shielding structure is used to shield and protect the bonding structure, and the shielding structure forms an ohmic contact with the two-dimensional electron gas.

[0011] Optionally, the semiconductor device further includes a source and a drain located in the active region and on the side of the epitaxial structure away from the substrate;

[0012] The two-dimensional electron gas also includes a two-dimensional electron gas located in the active region;

[0013] Both the source and the drain form an ohmic contact with the two-dimensional electron gas located in the active region, and the two-dimensional electron gas located in the active region is interconnected with the two-dimensional electron gas located in the passive region.

[0014] Optionally, along the thickness direction of the semiconductor device, the two-dimensional electron gas located in the passive region is staggered from the bonding structure.

[0015] Optionally, along the thickness direction of the semiconductor device, the two-dimensional electron gas that forms an ohmic contact with the shielding structure and the shielding structure overlap.

[0016] Optionally, the shielding structure includes a first boundary;

[0017] The two-dimensional electron gas that forms an ohmic contact with the shielding structure includes a second boundary, which is disposed corresponding to the first boundary;

[0018] The minimum distance between the first boundary and the edge of the semiconductor device is L1, and the minimum distance between the second boundary and the edge of the semiconductor device is L2, wherein |L2-L1|≤10µm.

[0019] Optionally, the two-dimensional electron gas, which forms an ohmic contact with the shielding structure, covers the shielding structure along the thickness direction of the semiconductor device.

[0020] Optionally, the width d of the shielding structure satisfies 0 <d<10µm。

[0021] Optionally, the semiconductor device further includes a source and a drain located in the active region and on the side of the epitaxial structure away from the substrate, wherein the source and the drain both form an ohmic contact with the two-dimensional electron gas located in the active region;

[0022] The shielding structure includes at least a first shielding layer, which is disposed on the same layer as the source electrode.

[0023] Optionally, the shielding structure further includes a second shielding layer, which is located on the side of the first shielding layer away from the substrate and is electrically connected to the first shielding layer.

[0024] The second shielding layer is disposed in the same layer as the bonding structure.

[0025] Secondly, embodiments of the present invention provide a method for fabricating a semiconductor device, used to fabricate the semiconductor device described in any of the above claims, the fabrication method comprising:

[0026] Provide substrate;

[0027] An epitaxial structure is fabricated on one side of the substrate, and a two-dimensional electron gas is formed in the epitaxial structure, with a portion of the two-dimensional electron gas located in the passive region;

[0028] At least one bonding structure is fabricated on the side of the epitaxial structure away from the substrate, and in the passive region;

[0029] At least one shielding structure is prepared on the side of the epitaxial structure away from the substrate. The shielding structure is used to shield and protect the bonding structure, and the shielding structure forms an ohmic contact with the two-dimensional electron gas located in the passive region.

[0030] Optionally, an epitaxial structure is fabricated on one side of the substrate, wherein a two-dimensional electron gas is formed in the epitaxial structure, and a portion of the two-dimensional electron gas is located in the passive region, including:

[0031] An ion implantation process is used to neutralize a portion of the two-dimensional electron gas located in the passive region, while retaining a portion of the two-dimensional electron gas that makes ohmic contact with the shielding structure.

[0032] The semiconductor device provided in this invention, by adding a shielding structure, effectively shields the migration of silver ions from the surface mount silver paste to the bonding structure during the packaging process, ensuring the stability of the bonding structure and the electrodes connected to the bonding structure, preventing short circuits between the bonding structure, the electrodes connected to the bonding structure, and the source electrode. Furthermore, by forming an ohmic contact between the shielding structure and the two-dimensional electron gas located in the passive region, the resistance of the shielding structure can be reduced, thereby enhancing the shielding effect and ensuring the normal operation of the semiconductor device. Attached Figure Description

[0033] Figure 1 This is a top view schematic diagram of a semiconductor device provided in an embodiment of the present invention;

[0034] Figure 2 A top view schematic diagram of another semiconductor device provided in an embodiment of the present invention;

[0035] Figure 3 A top view schematic diagram of another semiconductor device provided in an embodiment of the present invention;

[0036] Figure 4 for Figure 1 A schematic diagram of the cross-sectional structure of the provided semiconductor device along section line A-A';

[0037] Figure 5 for Figure 1 A schematic diagram of the cross-sectional structure of the provided semiconductor device along section line B-B';

[0038] Figure 6 A top view schematic diagram of another semiconductor device provided in an embodiment of the present invention;

[0039] Figure 7 for Figure 6 A schematic diagram of the cross-sectional structure of the provided semiconductor device along the section line C-C';

[0040] Figure 8 A top view schematic diagram of another semiconductor device provided in an embodiment of the present invention;

[0041] Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure of the provided semiconductor device along the section line E-E';

[0042] Figure 10 A top view schematic diagram of another semiconductor device provided in an embodiment of the present invention;

[0043] Figure 11 This is a schematic flowchart of a semiconductor device fabrication method provided in an embodiment of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0045] Figure 1 This is a top view schematic diagram of a semiconductor device provided in an embodiment of the present invention. Figure 2 This is a top view schematic diagram of another semiconductor device provided in an embodiment of the present invention, as shown below. Figure 1 and Figure 2 As shown, the semiconductor device includes an active region aa and a passive region bb surrounding the active region aa; the semiconductor device also includes: a substrate 21; an epitaxial structure 22 located on one side of the substrate 21, in which a two-dimensional electron gas (2DEG) is formed, and a portion of the two-dimensional electron gas is located in the passive region bb; at least one bonding structure 29 located on the side of the epitaxial structure 22 away from the substrate 21 and located in the passive region bb; at least one shielding structure 31 located on the side of the epitaxial structure 22 away from the substrate 21, the shielding structure 31 being used to shield and protect the bonding structure 29, and the shielding structure 31 forming an ohmic contact with the two-dimensional electron gas located in the passive region bb.

[0046] For details, please refer to [link / reference]. Figure 1 and Figure 2The working region 32 can be understood as the area where the semiconductor device operates. It includes the active region aa and the passive region bb. The active region aa can be understood as the region where a two-dimensional electron gas, electrons, or holes exist. Its operating state and characteristics are affected by external circuits, and it is the active operating region of the semiconductor device. The passive region bb can include the first passive region bb1 and the second passive region bb2. The first passive region bb1 can be understood as the region where the active region aa is involved in the device's operation, but its operating state is not affected by external circuits. The second passive region bb2 can be understood as the dicing region, that is, the region where the semiconductor device is diced to form multiple independent semiconductor devices.

[0047] For example, continue to refer to Figure 1 and Figure 2 The substrate 21 can be formed from one or more of the following materials: silicon, sapphire, silicon carbide, gallium arsenide, gallium nitride, diamond, etc., or it can be other materials suitable for growing gallium nitride.

[0048] For example, continue to refer to Figure 1 and Figure 2 The epitaxial structure 22 is located on one side of the substrate 21. Specifically, the epitaxial structure 22 can be a III-V compound semiconductor material, such as gallium arsenide, aluminum gallium arsenide, gallium nitride, aluminum gallium nitride, or indium gallium nitride.

[0049] For details, please refer to [link / reference]. Figure 1 and Figure 2 The bonding structure 29 can be a gate bonding structure 291 located in the first passive region bb1, and the corresponding shielding structure 31 can be a gate shielding structure 301; and / or, the bonding structure 29 is a drain bonding structure 292, and the corresponding shielding structure 31 is a drain shielding structure 302. This embodiment of the invention does not impose specific limitations. Figure 1 Taking the bonding structure 29 as a gate bonding structure 291 as an example, and the shielding structure 31 as a gate shielding structure 301 as an example, the following explanation will be provided. Figure 2 Taking bonding structure 29 as the drain bonding structure 292 and shielding structure 31 as the drain shielding structure 302 as an example, the following explanation will be given. Figure 3 A top view schematic diagram of another semiconductor device provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the example is a bonding structure 29 including a gate bonding structure 291 and a drain bonding structure 292, and a shielding structure 31 including a gate shielding structure 301 and a drain shielding structure 302.

[0050] Furthermore, a two-dimensional electron gas is formed in the epitaxial structure, wherein a portion of the two-dimensional electron gas is located in the passive region. For example, the epitaxial structure may include a channel layer and a barrier layer located on one side of the substrate. The barrier layer and the channel layer can form a heterojunction structure, forming a two-dimensional electron gas at the heterojunction interface. The shielding structure forms an ohmic contact with the two-dimensional electron gas located in the passive region, which can reduce the resistance of the shielding structure and enhance the shielding effect.

[0051] In summary, the semiconductor device provided by the embodiments of the present invention can effectively shield and protect the bonding structure by adding a shielding structure. This effectively prevents the migration of silver ions from the surface mount silver paste to the bonding structure during the packaging process, ensuring the stability of the bonding structure and the electrodes connected to the bonding structure, preventing short circuits between the bonding structure, the electrodes connected to the bonding structure, and the source electrode. Furthermore, the shielding structure forms an ohmic contact with the two-dimensional electron gas located in the passive region, which enhances the shielding effect and ensures the normal operation of the semiconductor device.

[0052] Optional, Figure 4 for Figure 1 A schematic cross-sectional view of the provided semiconductor device along section line A-A'. (Reference) Figure 1 and Figure 4 The shielding structure 31 includes a shielding portion located in the second passive region bb2; the two-dimensional electron gas includes a two-dimensional electron gas located in the second passive region bb2; the shielding portion located in the second passive region bb2 and the two-dimensional electron gas located in the second passive region bb2 form an ohmic contact.

[0053] Specifically, the two-dimensional electron gas can be located in the second passive region bb2 and form an ohmic contact with the shielding part of the shielding structure 31 located in the second passive region bb2. That is, the shielding structure 31 and the two-dimensional electron gas can form an ohmic contact in the second passive region bb2, which can increase the area of ​​the ohmic contact between the shielding structure 31 and the two-dimensional electron gas, further reduce the resistance of the shielding structure 31, and enhance the shielding effect.

[0054] Optional, continue to refer to Figure 1 and Figure 4 The shielding structure 31 includes a shielding portion located in the first passive region bb1; the two-dimensional electron gas includes a two-dimensional electron gas located in the first passive region bb1; the shielding portion located in the first passive region bb1 and the two-dimensional electron gas located in the first passive region bb1 form an ohmic contact.

[0055] As a feasible implementation method, the two-dimensional electron gas can be located in the first passive region bb1 and form an ohmic contact with the shielding portion of the shielding structure 31 located in the first passive region bb1. That is, the shielding structure 31 and the two-dimensional electron gas can form an ohmic contact in the first passive region bb1, which can increase the area of ​​the ohmic contact between the shielding structure 31 and the two-dimensional electron gas, further reduce the resistance of the shielding structure 31, and enhance the shielding effect.

[0056] As another feasible implementation, the two-dimensional electron gas may include two-dimensional electron gases located in the second passive region bb2 and the first passive region bb1. The shielding structure 31 includes a shielding portion located in the second passive region bb2 and a shielding portion located in the first passive region bb1. That is, the shielding portion in the shielding structure 31 located in the second passive region bb2 and the first passive region bb1 forms an ohmic contact with the two-dimensional electron gas located in the second passive region bb2 and the first passive region bb1. This further increases the area of ​​the ohmic contact between the shielding structure 31 and the two-dimensional electron gas, further reduces the resistance of the shielding structure 31, and enhances the shielding effect.

[0057] Optional, continue to refer to Figure 1 and Figure 4 The semiconductor device also includes a source 24 and a drain 26 located in the active region aa and on the side of the epitaxial structure away from the substrate 21; the two-dimensional electron gas also includes the two-dimensional electron gas located in the active region aa; the source 24 and the drain 26 both form ohmic contacts with the two-dimensional electron gas located in the active region aa, and the two-dimensional electron gas located in the active region aa can also be interconnected with the two-dimensional electron gas located in the passive region.

[0058] Specifically, the semiconductor device also includes a source 24 and a drain 26 located in the active region aa and on the side of the epitaxial structure away from the substrate 21. The source 24 and the drain 26 are in ohmic contact with the two-dimensional electron gas located in the active region aa. In other words, the source 24 and the drain 26 serve as ohmic contact electrodes of the semiconductor device to ensure the normal operation of the semiconductor device.

[0059] Furthermore, the two-dimensional electron gas located in the passive region is interconnected with the two-dimensional electron gas located in the active region aa, and this interconnection can only occur through specific locations. For example, the two-dimensional electron gas located in the passive region is interconnected with the two-dimensional electron gas below the source electrode in the active region. Since the shielding structure 31 is in ohmic contact with the two-dimensional electron gas located in the passive region, the resistance of the shielding structure 31 can be effectively reduced, thereby improving the shielding effect of the shielding structure 31.

[0060] Optionally, along the thickness direction of the semiconductor device, the two-dimensional electron gas located in the passive region is staggered from the bonding structure.

[0061] Specifically, along the thickness direction of the semiconductor device, the two-dimensional electron gas located in the passive region is staggered from the bonding structure. In other words, the two-dimensional electron gas is not placed below the bonding structure. This avoids the two forming an ohmic contact. The two-dimensional electron gas only needs to form an ohmic contact with the shielding part located in the passive region of the shielding structure. On the one hand, this can reduce the resistance of the shielding structure, and on the other hand, it can ensure the normal operation of the semiconductor device.

[0062] Optional, continue to refer to Figure 4 Along the thickness direction of the semiconductor device (Z direction as shown in the figure), the two-dimensional electron gas that forms an ohmic contact with the shielding structure 31 overlaps with the shielding structure 31.

[0063] Specifically, the two-dimensional electron gas that forms an ohmic contact with the shielding structure 31 overlaps with the shielding structure 31. The way the shielding structure 31 forms an ohmic contact with the two-dimensional electron gas is simple, which can achieve the stability of the ohmic contact between the shielding structure 31 and the two-dimensional electron gas. In addition, it can also ensure the compact structure of the semiconductor device.

[0064] Optional, continue to refer to Figure 1 and Figure 4 The shielding structure 31 includes a first boundary; the two-dimensional electron gas forming an ohmic contact with the shielding structure 31 includes a second boundary, and the second boundary is correspondingly disposed to the first boundary; the minimum distance between the first boundary and the edge of the semiconductor device is L1, and the minimum distance between the second boundary and the edge of the semiconductor device is L2, wherein |L2-L1|≤10µm.

[0065] For example, the correspondence between the second boundary and the first boundary can be understood as the same relative positional relationship between the first boundary and the shielding structure and the second boundary and the two-dimensional electron gas, where the two-dimensional electron gas refers to the two-dimensional electron gas in ohmic contact with the shielding structure. For instance, when the first boundary is the left boundary of the shielding structure, the second boundary is the left boundary of the two-dimensional electron gas; or, when the first boundary is the upper boundary of the shielding structure, the second boundary is the upper boundary of the two-dimensional electron gas. The left boundary can be understood as the boundary of the shielding structure and the two-dimensional electron gas near the left edge of the semiconductor device, and the upper boundary can be understood as the boundary of the shielding structure and the two-dimensional electron gas near the upper edge of the semiconductor device. Furthermore, the minimum distance between the first boundary and the edge of the semiconductor device can be understood as the distance between the first boundary and the edge of the nearest semiconductor device, and the minimum distance between the second boundary and the edge of the semiconductor device can be understood as the distance between the second boundary and the edge of the nearest semiconductor device. For example, when the first boundary is the left boundary of the shielding structure, and the second boundary is the left boundary of the two-dimensional electron gas, the minimum distance between the first boundary and the edge of the semiconductor device can be understood as the distance between the first boundary and the left edge of the semiconductor device, and the minimum distance between the second boundary and the edge of the semiconductor device can be understood as the distance between the second boundary and the left edge of the semiconductor device. By setting the minimum distance L1 between the first boundary and the edge of the semiconductor device and the minimum distance L2 between the second boundary and the edge of the semiconductor device to satisfy |L2-L1|≤10µm, on the one hand, it can ensure that the distance between the shielding structure and the two-dimensional electron gas in ohmic contact with it is small, and the way the shielding structure and the two-dimensional electron gas form an ohmic contact is simple. On the other hand, it can reduce the area of ​​the semiconductor device and realize the miniaturization design of the semiconductor device.

[0066] Optional, continue to refer to Figure 4 Along the thickness direction Z of the semiconductor device, a two-dimensional electron gas covers the shielding structure 31, forming an ohmic contact with the shielding structure 31.

[0067] Specifically, the two-dimensional electron gas covering the shielding structure 31, which forms an ohmic contact with the shielding structure 31, enables the shielding structure 31 and the two-dimensional electron gas to form a sufficient ohmic contact. This ensures that the area of ​​the ohmic contact between the shielding structure 31 and the two-dimensional electron gas is large, thereby reducing the resistance of the shielding structure 31 and enhancing the shielding effect.

[0068] Optional, continue to refer to Figure 1 The width d of the shielding structure 31 satisfies 0 <d<10µm。

[0069] Specifically, on the basis that the two-dimensional electron gas forming an ohmic contact with the shielding structure 31 covers the shielding structure 31, that is, on the basis that the two-dimensional electron gas forming an ohmic contact with the shielding structure 31 has a large coverage area, the shielding structure 31 can be set to have a small width. For example, the width d of the shielding structure 31 satisfies 0 < d < 10 µm. On the one hand, it will not increase the resistance of the shielding structure 31, and on the other hand, it can realize the miniaturization of the semiconductor device. Exemplarily, the width d of the shielding structure 31 can satisfy d = 1 - 5 µm, so as to fully reduce the width of the shielding structure and further realize the miniaturized design of the semiconductor device.

[0070] Optionally, continue to refer to Figure 1 and Figure 4 As shown, the semiconductor device further includes a source electrode 24 and a drain electrode 26 located in the active region aa and on the side of the epitaxial structure 22 away from the substrate 21. Both the source electrode 24 and the drain electrode 26 form ohmic contacts with the two-dimensional electron gas located in the active region aa; the shielding structure 31 at least includes a first shielding layer 3011, and the first shielding layer 3011 is disposed on the same layer as the source electrode 24.

[0071] Specifically, the semiconductor device further includes a source electrode 24 and a drain electrode 26 located in the active region aa and on the side of the epitaxial structure away from the substrate 21. The source electrode 24 and the drain electrode 26 are in ohmic contact with the two-dimensional electron gas in the active region aa, that is, the source electrode 24 and the drain electrode 26 serve as the ohmic contact electrodes of the semiconductor device to ensure the normal operation of the semiconductor device.

[0072] Furthermore, the shielding structure 31 at least includes a first shielding layer 3011, and the first shielding layer 3011 is disposed on the same layer as the source electrode, which can ensure good ohmic contact performance between the first shielding layer 3011 and the two-dimensional electron gas. Moreover, setting the first shielding layer 3011 on the same layer as the source electrode, and the first shielding layer 3011 and the source electrode are prepared from the same material in the same process, can also ensure that the preparation process of the shielding structure 31 is simple and the structure of the semiconductor device is simple.

[0073] It can be understood that the source electrode 24 can include multiple layers of source metal layers, and the material composition of the multiple layers of source metal layers can include but is not limited to metals such as Ti, Al, Ni, and Au. The shielding structure 31 can include one or more layers of shielding metal layers. When the shielding structure 31 includes one layer of shielding metal layer, the shielding metal layer can be disposed on the same layer as a certain layer of the multiple layers of source metal layers and have the same material, and is prepared in the same process, ensuring that the preparation process of the shielding structure 31 is simple; when the shielding structure 31 includes multiple layers of shielding metal layers, the multiple layers of shielding metal layers can correspond to the multiple layers of source metal layers one by one, and the corresponding shielding metal layer and the source metal layer are disposed on the same layer and have the same material, and are prepared in the same process, ensuring that the preparation process of the shielding structure 31 is simple.

[0074] Optional, Figure 5 for Figure 1 A schematic diagram of the cross-sectional structure of the provided semiconductor device along section line B-B'. (Reference) Figure 1 and Figure 5 As shown, the shielding structure 31 also includes a second shielding layer 3012, which is located on the side of the first shielding layer 3011 away from the substrate 21 and is electrically connected to the first shielding layer 3011; the second shielding layer 3012 is disposed in the same layer as the bonding structure 29.

[0075] For details, please refer to [link / reference]. Figure 1 and Figure 5 The shielding structure 31 also includes a second shielding layer 3012, and the second shielding layer 3012 and the bonding structure 29 are made of the same material and are prepared by the same process. On the one hand, this can ensure that the preparation process of the shielding structure 31 is simple, and on the other hand, it can realize the thin design of semiconductor devices.

[0076] Optional, continue to refer to 1- Figure 3 As shown, the semiconductor device further includes a gate 25 located in the active region aa and on the side of the epitaxial structure 22 away from the substrate 21; at least one bonding structure 29 includes a gate bonding structure 291 electrically connected to the gate 25; at least one shielding structure 31 includes a gate shielding structure 301 for shielding and protecting the gate bonding structure 291; and / or, the semiconductor device further includes a drain 26 located in the active region aa and on the side of the epitaxial structure 22 away from the substrate 21: at least one bonding structure 29 includes a drain bonding structure 292 electrically connected to the drain 26; at least one shielding structure 31 includes a drain shielding structure 302 for shielding and protecting the drain bonding structure 292.

[0077] For example, the gate bonding structure 291 can be a gate pad. The gate 25 in the active region aa can be connected to the gate pad of the first passive region bb1 through the gate interconnect metal. The gate 25 can receive the gate 25 voltage signal through the gate pad, ensuring the normal operation of the semiconductor device. The drain bonding structure 292 can be a drain pad. The drain 26 in the active region aa can be connected to the drain pad of the first passive region bb1 through the drain interconnect metal. The drain 26 can receive the drain 26 voltage signal through the drain pad, ensuring the normal operation of the semiconductor device.

[0078] Optionally, the active region may also include multiple fixed-potential structures; the shielding structure is electrically connected to the fixed-potential structures.

[0079] Specifically, the active region includes multiple fixed-potential structures. For example, the source can be a fixed-potential structure with a source potential of 0; another example is the drain, which can be a fixed-potential structure with a drain potential greater than 0. Therefore, a shielding structure can be set up to be electrically connected to the fixed-potential structure in the active region. This avoids the need for a separate external power supply and ensures the simplicity of the semiconductor device structure.

[0080] Optional, continue to refer to Figures 1-3 The semiconductor device also includes a source 24 located in the active region and aa located on the side of the epitaxial structure away from the substrate 21: the fixed potential structure includes the source 24, and the shielding structure 31 is electrically connected to the source 24.

[0081] Specifically, since the source electrode 24 has a potential of 0, and the preset potential on the shielding structure 31 is greater than or equal to 0, the source electrode 24 is reused as a fixed potential structure. The shielding structure 31 is directly electrically connected to the source electrode 24, thus ensuring the simplicity of the semiconductor device structure while achieving shielding protection for the bonding structure 29. Figures 1-3 As shown, the shielding structure 31 here may include a gate shielding structure 301 and / or a drain shielding structure 302.

[0082] Optional, Figure 6 This is a top view schematic diagram of another semiconductor device provided in an embodiment of the present invention. Figure 6 As shown, the source 24 includes a first source 241 and an Nth source arranged along a first direction (X direction as shown in the figure), the first direction X being parallel to the plane where the substrate 21 is located; the first source 241 is located at the first end of the active region aa, the Nth source is located at the second end of the active region aa, and the first end and the second end are arranged opposite to each other along the first direction X; the shielding structure 31 is electrically connected to the first source 241 and the Nth source respectively, and the gate bonding structure 291 and / or the drain bonding structure 292 are located within the range defined by the shielding structure 31 and the active region aa.

[0083] For example, Figure 6 Let's take N=2 as an example for explanation, such as... Figure 6 As shown, the first source 241, gate 25, and drain 26 extend along the second direction (the Y direction shown in the figure) in the active region aa, and the length of the extension does not exceed the range of the active region aa; simultaneously, the first source 241, gate 25, and drain 26 are arranged along the first direction (the X direction shown in the figure) in the active region aa, and the length of the arrangement does not exceed the range of the active region aa; the first direction is parallel to the direction from the first source 241 to the drain 26, and the second direction intersects the first direction and is parallel to the plane where the substrate 21 is located. Figure 6As shown, one end of the shielding structure 31 is electrically connected to the first source 241, and the other end is electrically connected to the second source 242. The shielding structure 31 has a semi-ring structure. The gate bonding structure 291 is located within the area defined by the shielding structure 31 and the active region aa. The shielding structure 31 completely surrounds the gate bonding structure 291. In this way, the shielding structure 31 is electrically connected to the source 24 to effectively shield the silver ions in the patch silver paste that migrate to the gate 25 under the action of the electric field. Moreover, there is no need to set up a separate power supply and electrically connect it to the shielding structure 31, which reduces complex wiring and lowers costs.

[0084] Optional, continue to refer to Figure 6 The shielding structure 31 includes a first shielding portion 311, a second shielding portion 312, and a third shielding portion 313. The second shielding portion 312 is connected to the first shielding portion 311 and the third shielding portion 313, respectively. The second shielding portion 312 is located in the second passive region bb2, the first shielding portion 311 is located in the working region 32 and is electrically connected to the first source electrode 241, and the third shielding portion 313 is located in the working region 32 and is electrically connected to the Nth source electrode.

[0085] The semiconductor device also includes a first dielectric layer 41 located on the side of the epitaxial structure 22 away from the substrate 21 and located in the first passive region bb1, and the first shielding portion 311 and the third shielding portion 313 are both located on the side of the first dielectric layer 41 away from the substrate 21.

[0086] Along the thickness direction Z of the semiconductor device, the thickness of the shielding structure 31 is greater than the thickness of the first dielectric layer 41, so that both the first shielding portion 311 and the third shielding portion 313 are electrically connected to the second shielding portion 312.

[0087] Along the thickness direction Z of the semiconductor device, the thickness of the source 24 is greater than the thickness of the first dielectric layer 41, so that both the first shielding portion 311 and the third shielding portion 313 are electrically connected to the source 24.

[0088] The semiconductor device also includes a second dielectric layer 42 located on the side of the shielding structure 31 away from the substrate 21 and on the side of the source electrode 24 away from the substrate 21 and located in the working region 32. Along the thickness direction Z of the semiconductor device, the sum of the thicknesses of the first dielectric layer 41, the shielding structure 31 and the second dielectric layer 42 is greater than the thickness of the source electrode 24.

[0089] Specifically, the second shielding portion 312 is located in the second passive region bb2, meaning that most of the structure of the shielding structure 31 is located in the second passive region bb2. Under the premise of shielding silver ions, the setting of the shielding structure 31 can be guaranteed not to affect the normal operation of the semiconductor device, thus ensuring the stable performance of the semiconductor device.

[0090] Based on the above embodiments, Figure 7 for Figure 6A schematic diagram of the cross-sectional structure of the provided semiconductor device along section line C-C'. (Reference) Figure 6 and Figure 7 The semiconductor device may further include a first dielectric layer 41 located in the first passive region bb1. The first dielectric layer 41 may be, for example, an insulating layer or a waterproof layer, to protect the semiconductor structure located in the first passive region bb1. Furthermore, since the second passive region bb2 requires subsequent dicing, to ensure a simple dicing process, the first dielectric layer 41 is generally not provided in the second passive region bb2. Thus, there is a discontinuity between the surface of the second shielding portion 312 located in the second passive region bb2 and the surfaces of the first shielding portion 311 and the second shielding portion 312. To ensure that the second shielding portion 312 remains connected to the first shielding portion 311 and the third shielding portion 313, the thickness of the shielding structure 31 along the thickness direction Z of the semiconductor device must be greater than the thickness of the first dielectric layer 41. This ensures that the connection between the second shielding portion 312 and the first shielding portion 311 and the third shielding portion 313 will not be broken, guaranteeing the integrity of the shielding structure 31 and achieving shielding protection for the gate bonding structure 291.

[0091] Further reference Figure 7 Since the source electrode 24 needs to form an ohmic contact with the epitaxial structure 22, a first dielectric layer 41 is generally not provided between the source electrode 24 and the epitaxial structure 22. Furthermore, since the first shielding portion 311 and the third shielding portion 313 need to be electrically connected to the source electrode 24 to ensure that a fixed potential is connected to the shielding structure 31, the thickness of the source electrode 24 and the thickness of the first dielectric layer 41 need to be reasonably set to ensure that the first shielding portion 311 and the third shielding portion 313 can be electrically connected to the source electrode 24. Specifically, along the thickness direction Z of the semiconductor device, the thickness of the source 24 can be greater than the thickness of the first dielectric layer 41, so that both the first shielding portion 311 and the third shielding portion 313 are electrically connected to the source 24. Otherwise, the source 24 and the shielding structure 31 cannot form an effective connection, which will also cause the shielding structure 31 to float and fail to achieve the electric field shielding effect. The silver ions in the patch silver paste will be transported to the gate bonding structure 291, causing the gate 25 and the source 24 to have the same potential, and a short circuit will occur between the gate 25 and the source 24.

[0092] Continue to refer to Figure 7For example, the semiconductor device provided in this embodiment of the invention may further include a second dielectric layer 42, which covers the working area 32 and can protect the working area 32. Specifically, the second dielectric layer 42 covers the first shielding portion 311, the third shielding portion 313, and the source electrode 24. Since the upper surfaces of the first shielding portion 311 and the third shielding portion 313 located in the first passive region bb1 may not be flush with the upper surface of the source electrode 24, that is, there is a gap between the first shielding portion 311 and the third shielding portion 313 and the source electrode 24, in order to avoid the second dielectric layer 42 from breaking in the area where the first shielding portion 311 and the third shielding portion 313 are connected to the source electrode 24, it is necessary to reasonably set the relationship between the sum of the thicknesses of the first dielectric layer 41, the first shielding portion 311 or the third shielding portion 313, and the second dielectric layer 42 and the thickness of the source electrode 24. Specifically, the thickness of the first dielectric layer 41, the first shielding portion 311, and the second dielectric layer 42 along the thickness direction Z of the semiconductor device can be set to be greater than the thickness of the source electrode 24. Otherwise, the second dielectric layer 42 located in the first passive region bb1 and the second dielectric layer 42 located in the active region aa will break, causing the second dielectric layer 42 to fail to protect the entire working area 32. This will cause water and oxygen to enter the semiconductor device, causing the metal layer of the source electrode 24 to oxidize or fail, resulting in a risk of reliability failure and directly affecting the performance of the semiconductor device.

[0093] The material of the first dielectric layer 41 and the material of the second dielectric layer 42 can be dielectric materials such as SiN and SiO.

[0094] Optional, Figure 8 This is a top view schematic diagram of another semiconductor device provided in an embodiment of the present invention. Figure 8 As shown, the shielding structure 31 includes a first shielding portion 311, a second shielding portion 312, and a third shielding portion 313. The second shielding portion 312 is connected to the first shielding portion 311 and the third shielding portion 313, respectively. The first shielding portion 311, the second shielding portion 312, and the third shielding portion 313 are all located in the working area 32. The first shielding portion 311 is electrically connected to the first source electrode 241, and the third shielding portion 313 is electrically connected to the Nth source electrode.

[0095] The semiconductor device further includes at least one dielectric layer located on the side of the epitaxial structure 22 away from the substrate 21 and located in the first passive region bb1; the at least one dielectric layer includes a first surface located on the side of the epitaxial structure 22 away from the substrate 21; the shielding structure 31 includes a second surface located on the side of the epitaxial structure 22 away from the substrate 21; along the thickness direction of the semiconductor device, the second surface is located on the side of the first surface away from the substrate 21.

[0096] For example, Figure 8Taking N=2 as an example, the Nth source is the second source 242. For example, the first shielding portion 311, the second shielding portion 312 and the third shielding portion 313 are all located in the working region 32, rather than in the second passive region bb2. This ensures that the semiconductor device, including the shielding structure 31, is compact and has a small size, which is beneficial for miniaturizing the semiconductor device.

[0097] Based on the above embodiments, Figure 9 for Figure 8 A schematic diagram of the cross-sectional structure of the provided semiconductor device along the section line E-E'. (See diagram below.) Figure 9 As shown, at least one dielectric layer may include, for example, a first dielectric layer 41 and a second dielectric layer 42. The first dielectric layer 41 may serve as an insulating or waterproof layer to protect the semiconductor structure located in the first passive region bb1. The second dielectric layer 42 may protect the entire working area 32, preventing water and oxygen from entering the semiconductor device and affecting its performance. When the dielectric layer includes multiple dielectric layers, the first surface can be understood as the surface of the uppermost dielectric layer away from the substrate. Figure 10 For example, the first surface is the surface of the second dielectric layer 42 away from the substrate 21. Furthermore, the shielding structure 31 includes a second surface located on the side of the epitaxial structure 22 away from the substrate 21. Along the thickness direction Z of the semiconductor device, the second surface is located on the side of the first surface away from the substrate 21. That is, the shielding structure 31 is more prominent than the dielectric layer. From the perspective of electric field lines, it can be understood that the electric field line radiation area of ​​the shielding structure 31 is more extensive. Thus, the shielding structure 31 can shield more silver ions, resulting in a better shielding effect.

[0098] Furthermore, such as Figure 9 As shown, when both the shielding structure 31 and the second dielectric layer 42 are located on the side of the first dielectric layer 41 away from the substrate 21, the surface of the shielding structure 31 away from the substrate 21 is further away from the substrate 21 than the surface of the second dielectric layer 42 away from the substrate 21. This can be understood as the thickness of the shielding structure 31 being greater than the thickness of the second dielectric layer 42.

[0099] Furthermore, in order to ensure a large thickness of the shielding structure and fully reduce its resistance, the thickness of the shielding structure can be set to be greater than the source electrode thickness (not shown in the figure), or even greater than the sum of the source electrode thickness and the dielectric layer thickness (not shown in the figure), to ensure that the resistance of the shielding structure can be fully reduced and the shielding effect of the shielding structure can be guaranteed.

[0100] It should be noted that when the source or drain is reused as a fixed potential structure and electrically connected to the shielding structure, the two ends of the shielding structure can be connected to the same source or drain, or they can be connected to different sources or drains. This embodiment of the invention does not limit this.

[0101] It should be understood that the embodiments of the present invention, from the perspective of semiconductor device structure design, can effectively shield the migration of silver ions in the surface mount silver paste to the bonding structure during the packaging process by adding a shielding structure, ensuring the stability of the bonding structure and the electrodes connected to the bonding structure, avoiding short circuits between the bonding structure and the electrodes connected to the bonding structure and the source, and enhancing the shielding effect by forming an ohmic contact with the two-dimensional electron gas located in the passive region through the shielding structure, thus ensuring the normal operation of the semiconductor device. The semiconductor devices include, but are not limited to: high-power gallium nitride high electron mobility transistors (HEMTs) operating under high voltage and high current conditions; silicon-on-insulator (SOI) transistors; gallium arsenide (GaAs)-based transistors; and metal-oxide-semiconductor field-effect transistors (MOSFETs), metal-insulator-semiconductor field-effect transistors (MISFETs), double heterojunction field-effect transistors (DHFETs), junction field-effect transistors (JFETs), metal-semiconductor field-effect transistors (MESFETs), and metal-insulator-semiconductor heterojunction field-effect transistors (MESFETs). MISHFET (or other field-effect transistors) or other field-effect transistors.

[0102] Based on the same inventive concept, embodiments of the present invention also provide a method for fabricating a semiconductor device. Figure 11 This is a schematic flowchart of a semiconductor device fabrication method provided in an embodiment of the present invention, as shown below. Figure 11 As shown, the method for fabricating a semiconductor device provided in this embodiment of the invention may include:

[0103] S101, Provide substrate.

[0104] For example, the substrate material can be Si, SiC, gallium nitride, or sapphire, or other materials suitable for growing gallium nitride.

[0105] S102. An epitaxial structure is prepared on one side of the substrate, and a two-dimensional electron gas is formed in the epitaxial structure, with part of the two-dimensional electron gas located in the passive region.

[0106] For example, the epitaxial structure is located on one side of the substrate, and the epitaxial structure can be a semiconductor material of a III-V compound, in which a two-dimensional electron gas is formed.

[0107] Optionally, an ion implantation process can be used to neutralize a portion of the two-dimensional electron gas located in the passive region, while retaining the portion of the two-dimensional electron gas that makes ohmic contact with the shielding structure.

[0108] Specifically, ion implantation can be understood as introducing dopant ions into a passive region, which can neutralize the dopant ions with a portion of the two-dimensional electron gas located in the passive region, while retaining the portion of the two-dimensional electron gas that makes ohmic contact with the shielding structure. In this way, the shielding structure and the two-dimensional electron gas located in the passive region can form an ohmic contact.

[0109] S103. At least one bonding structure is prepared on the side of the epitaxial structure away from the substrate and in the passive region.

[0110] Specifically, the bonding structure can be a gate bonding structure and / or a drain bonding structure.

[0111] S104. At least one shielding structure is prepared on the side of the epitaxial structure away from the substrate. The shielding structure is used to shield and protect the bonding structure, and the shielding structure forms an ohmic contact with the two-dimensional electron gas located in the passive region.

[0112] By fabricating a shielding structure on the side of the epitaxial structure away from the substrate, the migration of silver ions from the patch silver paste to the bonding structure during the packaging process can be effectively blocked, ensuring the stability of the bonding structure and the electrodes connected to the bonding structure, preventing short circuits between the bonding structure and the source electrode, and ensuring the normal operation of the semiconductor device.

[0113] Furthermore, a two-dimensional electron gas is formed in the epitaxial structure. For example, the epitaxial structure may include a channel layer and a barrier layer located on one side of the substrate. The barrier layer and the channel layer can form a heterojunction structure, forming a two-dimensional electron gas at the heterojunction interface. The shielding structure forms an ohmic contact with the two-dimensional electron gas, which can reduce the resistance of the shielding structure and enhance the shielding effect. In addition to the two-dimensional electron gas in the active region and the two-dimensional electron gas forming an ohmic contact with the shielding structure, the two-dimensional electron gas at other locations can be neutralized by ion implantation, preventing the two-dimensional electron gas at other locations from affecting the normal operation of the semiconductor device.

[0114] The semiconductor device fabrication method provided in this invention involves sequentially fabricating at least one bonding structure and at least one shielding structure on the side of the epitaxial structure away from the substrate. Simultaneously, the shielding structure is electrically connected to a preset potential, which can effectively shield the migration of silver ions from the chip silver paste to the bonding structure during the packaging process. This ensures the stability of the bonding structure and the electrodes connected to the bonding structure, avoids short circuits between the bonding structure and the source electrode, and enhances the shielding effect by forming an ohmic contact with the two-dimensional electron gas through the shielding structure, thus ensuring the normal operation of the semiconductor device.

[0115] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A semiconductor device, characterized in that, Includes the active region and the passive region surrounding the active region; The semiconductor device further includes: Substrate; An epitaxial structure located on one side of the substrate, wherein a two-dimensional electron gas is formed in the epitaxial structure, and a portion of the two-dimensional electron gas is located in the passive region; At least one bonding structure located on the side of the epitaxial structure away from the substrate and located in the passive region; At least one shielding structure is located on the side of the epitaxial structure away from the substrate, the shielding structure is used to shield and protect the bonding structure, and the shielding structure forms an ohmic contact with the two-dimensional electron gas located in the passive region; Wherein, along the thickness direction of the semiconductor device, the two-dimensional electron gas that forms an ohmic contact with the shielding structure and the shielding structure overlap; The shielding structure includes a first boundary; The two-dimensional electron gas that forms an ohmic contact with the shielding structure includes a second boundary, which is disposed corresponding to the first boundary; The minimum distance between the first boundary and the edge of the semiconductor device is L1, and the minimum distance between the second boundary and the edge of the semiconductor device is L2, wherein |L2-L1|≤10µm.

2. The semiconductor device according to claim 1, characterized in that, The semiconductor device further includes a source and a drain located in the active region and on the side of the epitaxial structure away from the substrate; The two-dimensional electron gas also includes a two-dimensional electron gas located in the active region; Both the source and the drain form an ohmic contact with the two-dimensional electron gas located in the active region, and the two-dimensional electron gas located in the active region is interconnected with the two-dimensional electron gas located in the passive region.

3. The semiconductor device according to claim 1, characterized in that, Along the thickness direction of the semiconductor device, the two-dimensional electron gas located in the passive region is offset from the bonding structure.

4. The semiconductor device according to claim 1, characterized in that, Along the thickness direction of the semiconductor device, the two-dimensional electron gas that forms an ohmic contact with the shielding structure covers the shielding structure.

5. The semiconductor device according to claim 4, characterized in that, The width d of the shielding structure satisfies 0. <d<10µm。 6. The semiconductor device according to claim 1, characterized in that, The semiconductor device further includes a source and a drain located in the active region and on the side of the epitaxial structure away from the substrate, wherein the source and the drain both form an ohmic contact with the two-dimensional electron gas located in the active region; The shielding structure includes at least a first shielding layer, which is disposed on the same layer as the source electrode.

7. The semiconductor device according to claim 6, characterized in that, The shielding structure further includes a second shielding layer, which is located on the side of the first shielding layer away from the substrate and is electrically connected to the first shielding layer. The second shielding layer is disposed in the same layer as the bonding structure.

8. A method for fabricating a semiconductor device, used to fabricate the semiconductor device according to any one of claims 1-7, characterized in that, include: Provide substrate; An epitaxial structure is fabricated on one side of the substrate, and a two-dimensional electron gas is formed in the epitaxial structure, with a portion of the two-dimensional electron gas located in the passive region; At least one bonding structure is fabricated on the side of the epitaxial structure away from the substrate, and in the passive region; At least one shielding structure is prepared on the side of the epitaxial structure away from the substrate. The shielding structure is used to shield and protect the bonding structure, and the shielding structure forms an ohmic contact with the two-dimensional electron gas located in the passive region. Wherein, along the thickness direction of the semiconductor device, the two-dimensional electron gas that forms an ohmic contact with the shielding structure and the shielding structure overlap; The shielding structure includes a first boundary; The two-dimensional electron gas that forms an ohmic contact with the shielding structure includes a second boundary, which is disposed corresponding to the first boundary; The minimum distance between the first boundary and the edge of the semiconductor device is L1, and the minimum distance between the second boundary and the edge of the semiconductor device is L2, wherein |L2-L1|≤10µm.

9. The method for fabricating a semiconductor device according to claim 8, characterized in that, An epitaxial structure is fabricated on one side of the substrate, wherein a two-dimensional electron gas is formed in the epitaxial structure, and a portion of the two-dimensional electron gas is located in the passive region, including: An ion implantation process is used to neutralize a portion of the two-dimensional electron gas located in the passive region, while retaining a portion of the two-dimensional electron gas that makes ohmic contact with the shielding structure.

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