A high-voltage power semiconductor device

Abstract

The present invention relates to a junction terminal structure of a high-voltage power semiconductor device, comprising: a cellular structure and a terminal structure; an arc-shaped groove is provided on the upper portion of the cellular structure, and the terminal structure comprises doping strips of multiple different conductivity types; the doping strips of different conductivity types are alternately arranged in the groove on the upper portion of the cellular structure. The present invention effectively solves the problems of small process tolerance, complex process, low terminal withstand voltage and low reliability of traditional junction terminal extension terminal structures.

Description

Technical Field

[0001] The present invention belongs to the technical field of power semiconductors, and in particular relates to a high-voltage power semiconductor device. Background Art

[0002] High-voltage power semiconductor devices need to withstand high voltage when in the blocking state. However, due to the curvature effect at the edge of the device cell area, the electric field is concentrated at the edge, causing the device to break down prematurely, making the actual voltage of the device far less than its theoretical design value. In order to solve the problem caused by the curvature effect and improve the breakdown voltage of the device, the industry has carried out research on junction termination technology, and various junction termination structures have been proposed. Figure 1 The figure shows a traditional two-region junction terminal extended terminal structure. Through two ion implantations, the junction terminal extension region far away from the main junction has a lower doping concentration than the junction terminal extension region close to the main junction. This terminal structure uses the additional charges introduced on the surface to generate an electric field in the opposite direction to the main junction, weakening the electric field strength of the main junction and thus increasing the breakdown voltage of the device. The introduced surface junction terminal extension structure is in a fully depleted withstand voltage state before the device breaks down. Therefore, the terminal efficiency is relatively high.

[0003] However, in order to make the introduced surface junction terminal extension structure fully depleted before the device breaks down, the concentration of the junction terminal extension terminal structure itself is low. Even if a long-term thermal push junction process is adopted, the junction depth is still shallow. The shallow junction depth is not conducive to obtaining a high device terminal breakdown voltage.

[0004] At the same time, due to its low concentration, it is more sensitive to the concentration of surface defects and is greatly affected by the surface state. The farther away from the main junction, the lower the concentration, and the more serious the impact of the surface state. Therefore, the traditional junction terminal extended terminal structure has a small process tolerance, complex process, low terminal withstand voltage, low reliability, and the manufactured terminal structure has poor yield, stability, and consistency, which limits its application in high-voltage devices. Summary of the Invention

[0005] In order to solve the technical problems of small process tolerance, complex process, low terminal withstand voltage and low reliability of the traditional junction terminal extended terminal structure in the prior art, the present invention provides a high-voltage power semiconductor device, comprising: a cellular structure and a terminal structure; an arc-shaped groove is provided on the upper part of the cellular structure;

[0006] The terminal structure includes a plurality of doping strips of different conductive types; the doping strips of different conductive types are alternately arranged in the grooves on the upper portion of the cellular structure.

[0007] Preferably, the cell structure comprises a metallized anode (4) and a second conductive type semiconductor region (1);

[0008] The second conductive type semiconductor region (1) is arranged at the upper edge of the cellular structure, and the metallized anode (4) covers the second conductive type semiconductor region (1);

[0009] The terminal structure further comprises a cut-off ring (8), and the cut-off ring (8) is located at the bottom of the arc-shaped groove of the cellular structure;

[0010] The doping strip is arranged between the second conductive type semiconductor region (1) and the cut-off ring (8) in accordance with the shape of the arc-shaped groove.

[0011] Preferably, the doped strips include first conductive type doped strips (11) and second conductive type doped strips (12);

[0012] The area of ​​the first conductive type doped strip (11) near the metallized anode (4) is larger than the area near the cut-off ring (8); the area of ​​the second conductive type doped strip (12) near the metallized anode (4) is smaller than the area near the cut-off ring (8);

[0013] The first conductive type doping strip (11) and the second conductive type doping strip (12) have the same concentration but different conductive types.

[0014] Preferably, the first conductive type doped strip (11) and the second conductive type doped strip (12) are both strip-shaped structures.

[0015] Preferably, the first conductive type doped strip (11) is a strip-shaped structure;

[0016] The second conductive type doping strip (12) comprises a strip structure consisting of a plurality of regions, each region having a different doping concentration.

[0017] Preferably, the first conductive type doped strip (11) is a strip structure, and the second conductive type doped strip (12) is a block structure; there are multiple block structures with equal areas;

[0018] The second conductive type doping strips (12) are embedded in the first conductive type doping strips (11) in the form of multiple rows and columns, and the number of the second conductive type doping strips gradually increases along the direction from the second conductive type semiconductor region (1) to the cut-off ring (8).

[0019] Preferably, the cell structure further comprises a metallized cathode (5), a first conductive type semiconductor region (3) and a semiconductor drift region (2);

[0020] The metallized cathode (5) is located on the back side of the first conductive type semiconductor region (3); and the semiconductor drift region (2) is located on the front side of the first conductive type semiconductor region (3).

[0021] Preferably, the semiconductor device includes silicon, silicon germanium, gallium arsenide, silicon carbide, gallium nitride, gallium oxide or diamond.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention provides a high-voltage power semiconductor device, comprising: a cellular structure and a terminal structure; an arc-shaped groove is provided on the upper part of the cellular structure, and the terminal structure comprises a plurality of doping strips of different conductive types; the doping strips of different conductive types are alternately arranged in the groove on the upper part of the cellular structure. The present invention effectively solves the problems of small process tolerance, complex process, low terminal withstand voltage and low reliability of the traditional junction terminal extended terminal structure.

[0024] 2. The present invention provides a high-voltage power semiconductor device, which improves terminal efficiency and increases breakdown voltage.

[0025] 3. The present invention provides a high-voltage power semiconductor device. This structure can achieve a deeper junction depth without a long thermal push junction process, avoiding the long thermal push junction process required by traditional junction terminal structures to achieve deep junctions. In addition, it further avoids chip warping during the manufacturing process, reduces the difficulty and cost of chip manufacturing, and improves yield, stability and consistency.

[0026] 4. The present invention provides a high-voltage power semiconductor device, in which the smooth transition groove in the terminal area makes the junction terminal extension structure have a deeper junction depth, while avoiding the formation of electric field concentration in the transition area between the groove and the main junction. The junction terminal extension structure formed has a junction depth structure that further reduces the electric field concentration phenomenon at the device interface, so that the peak electric field is effectively transferred from the surface to the interior of the lattice, thereby improving the electric field distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a schematic diagram of the terminal structure extension of the traditional two-zone junction terminal;

[0029] Figure 2 This is a schematic diagram of the terminal structure of Example 1 of the present invention;

[0030] Figure 3 This is a schematic diagram of the terminal structure of Example 2 of the present invention;

[0031] Figure 4 This is a schematic diagram of the terminal structure of Example 3 of the present invention;

[0032] In the figure: 1-second conductive type semiconductor region; 2-semiconductor drift region; 3-first conductive type semiconductor region; 4-metallized anode; 5-metallized cathode; 6-first junction terminal extension region; 7-second junction terminal extension region; 8-cut-off ring; 11-first conductive type doped strip; 12-second conductive type doped strip. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Example 1

[0035] like Figure 1 The figure shows the schematic diagram of the traditional two-zone junction terminal extension terminal structure;

[0036] like Figure 2 As shown, the present invention provides a high-voltage power semiconductor device, comprising: a cellular structure and a terminal structure; an arc-shaped groove is provided on the upper portion of the cellular structure;

[0037] The terminal structure includes doped strips of multiple different conductivity types; the doped strips of different conductivity types are alternately arranged in the grooves on the upper part of the cellular structure. The present invention effectively solves the problems of small process tolerance, complex process, low terminal withstand voltage and low reliability of the traditional junction terminal extension terminal structure, thereby improving the terminal efficiency and the breakdown voltage.

[0038] In addition, the structure can achieve a deeper junction depth without a long thermal push junction process, avoiding the long thermal push junction process required by traditional junction terminal structures to achieve deep junctions, avoiding chip warping during the manufacturing process, reducing chip manufacturing difficulty and cost, and improving yield, stability and consistency;

[0039] Moreover, the smooth transition groove in the terminal region not only makes the junction terminal extension structure have a deeper junction depth, but also avoids the formation of electric field concentration in the transition region between the groove and the main junction. The junction terminal extension structure formed further reduces the electric field concentration phenomenon at the device interface, so that the peak electric field is effectively transferred from the surface to the interior of the lattice, improves the electric field distribution, and further reduces the influence of the surface state, increases the process tolerance, thereby further improving the terminal efficiency of the device, increasing the breakdown voltage of the device, and improving the reliability of the device.

[0040] The cell structure includes a metallized anode 4 and a second conductive type semiconductor region 1;

[0041] The second conductive type semiconductor region 1 is provided at the upper edge of the cell structure, and the metallized anode 4 covers the second conductive type semiconductor region 1;

[0042] The terminal structure further includes a cut-off ring 8, which is located at the bottom of the arc-shaped groove of the cellular structure;

[0043] The doping strip is arranged between the second conductive type semiconductor region 1 and the cut-off ring 8 in accordance with the shape of the arc-shaped groove;

[0044] The doped strips include a first conductive type doped strip 11 and a second conductive type doped strip 12;

[0045] The area of ​​the first conductive type doped strip 11 near the metallized anode 4 is larger than the area near the cut-off ring 8; the area of ​​the second conductive type doped strip 12 near the metallized anode 4 is smaller than the area near the cut-off ring 8;

[0046] Performing multiple ion implantations on the second conductive type doped strip 12 to form multiple regions with different doping concentrations;

[0047] The first conductive type doped strips 11 and the second conductive type doped strips 12 are strip-shaped structures and are alternately arranged near the first conductive type doped strips 11 and the second conductive type doped strips 12 perpendicular to the Y direction;

[0048] The length of the first conductive type doped strip 11 in the Y direction gradually decreases from left to right along the X direction, and the length of the second conductive type doped strip 12 in the Y direction gradually increases from left to right along the X direction;

[0049] The first conductive type doped strip 11 is a strip structure;

[0050] The second conductive type doped strip 12 includes a strip structure consisting of a plurality of regions, each region having a different doping concentration;

[0051] The first conductive type doped strips 11 are strip-shaped structures, and the second conductive type doped strips 12 are block-shaped structures;

[0052] There are multiple block structures with equal areas;

[0053] The second conductive type doping strips 12 are embedded in the first conductive type doping strips 11 in the form of multiple rows and columns, and the number thereof gradually increases along the direction from the second conductive type semiconductor region 1 to the cut-off ring 8;

[0054] The cell structure further includes a metallized cathode 5, a first conductive type semiconductor region 3 and a semiconductor drift region 2;

[0055] The metallized cathode 5 is located on the back side of the first conductive type semiconductor region 3; the semiconductor drift region 2 is located on the front side of the first conductive type semiconductor region 3;

[0056] The cell structure includes a diode, a triode, a MOS or an IGBT, and the semiconductor device includes silicon, silicon germanium, gallium arsenide, silicon carbide, gallium nitride, gallium oxide or diamond;

[0057] The doping concentration of the first conductive type doping strip 11 is 1×1017 cm-3 to 1×1019 cm-3, and the thickness is 0.5 to 1 μm;

[0058] The second conductive type doping strip 12 has a doping concentration of 1×1017 cm-3 to 1×1019 cm-3 and a thickness of 0.5 to 1 μm;

[0059] The first conductive type doping strip 11 and the second conductive type doping strip 12 have the same concentration but different conductive types;

[0060] The doping concentration of the cut-off ring 8 is 5×1018cm-3 to 1×1020cm-3, and the depth is 0.2 to 0.5 μm;

[0061] The doping concentration of the second conductive type semiconductor region 1 is 1×1018cm-3 to 1×1020cm-3, and the depth is 0.5 to 3 μm;

[0062] The semiconductor drift region 2 has a doping concentration of 7×1013cm-3 to 2×1014cm-3 and a thickness of 10 to 120 μm;

[0063] The doping concentration of the first conductive type semiconductor region 3 is 1×1018cm-3 to 1×1020cm-3, and the depth is 0.5 to 3 μm;

[0064] Specific principle: The high-voltage power semiconductor device provided by the present invention has a smoothly transitioned groove in the terminal region, and forms a junction terminal extension structure with high-concentration first conductivity type doping strips 11 and second conductivity type doping strips 12 alternating on the groove surface through multiple ion implantations in a direction perpendicular to the cross section, so that the surface of the junction terminal extension structure has a net second conductivity type doping, and the net second conductivity type doping concentration obtained from the main junction to the cut-off ring 8 gradually decreases;

[0065] In addition, through the three-dimensional depletion effect of the alternating first conductivity type doped strips 11 and second conductivity type doped strips 12 and the semiconductor drift region 2, the alternating first conductivity type doped strips 11 and second conductivity type doped strips 12 on the surface are fully depleted before the device.

[0066] Example 2

[0067] Benru Figure 3 As shown, the second high-voltage power semiconductor device provided by the embodiment, based on embodiment 1, the second conductive type doped strip 12 can also be subjected to multiple ion implantation to form multiple regions with different doping concentrations, and the second conductive type doped strip 12 is fully depleted before the device breaks down.

[0068] Optimizing the concentration of the second conductive type doping strips 12 can further improve the surface electric field distribution, reduce the influence of surface charge, increase process tolerance, improve the terminal efficiency of the device, increase the breakdown voltage of the device, and improve the reliability of the device.

[0069] Example 3

[0070] like Figure 4 As shown, the third high-voltage power semiconductor device provided by this embodiment is, based on Example 1, the second conductive type doping strips 12 can also be embedded in the first conductive type doping strips 11, and the number of the second conductive type doping strips 12 gradually increases from left to right along the X direction, and the first conductive type doping strips 11 and the second conductive type doping strips 12 are fully depleted before the device breaks down.

[0071] The second conductive type doping strip 12 embedded in the first conductive type doping strip 11 causes the net doping concentration of the second conductive type on the surface of the terminal region to gradually decrease from left to right along the X direction, thereby reducing the influence of surface charge, increasing process tolerance, improving the terminal efficiency of the device, increasing the breakdown voltage of the device, and improving the reliability of the device.

[0072] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0073] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0074] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0075] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0076] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be encompassed by the scope of the pending claims.

Claims

1. A high-voltage power semiconductor device, characterized in that: It includes a cellular structure and a terminal structure; an arc-shaped groove is provided on the upper part of the cellular structure; The terminal structure includes a plurality of doping strips of different conductivity types; the doping strips of different conductivity types are alternately arranged in the grooves on the upper part of the cellular structure; The cellular structure comprises a metallized anode (4) and a second conductive type semiconductor region (1); The second conductive type semiconductor region (1) is arranged at the upper edge of the cellular structure, and the metallized anode (4) covers the second conductive type semiconductor region (1); The terminal structure further comprises a cut-off ring (8), and the cut-off ring (8) is located at the bottom of the arc-shaped groove of the cellular structure; The doping strip is arranged between the second conductive type semiconductor region (1) and the cut-off ring (8) in accordance with the shape of the arc-shaped groove; The doped strips include a first conductive type doped strip (11) and a second conductive type doped strip (12); The area of ​​the first conductive type doped strip (11) near the metallized anode (4) is larger than the area near the cut-off ring (8); the area of ​​the second conductive type doped strip (12) near the metallized anode (4) is smaller than the area near the cut-off ring (8); The first conductive type doping strip (11) and the second conductive type doping strip (12) have the same concentration but different conductive types.

2. The semiconductor device according to claim 1, wherein The first conductive type doped strip (11) and the second conductive type doped strip (12) are both strip-shaped structures.

3. The semiconductor device according to claim 1, wherein The first conductive type doped strip (11) is a strip-shaped structure; The second conductive type doping strip (12) comprises a strip structure consisting of a plurality of regions, each region having a different doping concentration.

4. The semiconductor device according to claim 1, wherein The first conductive type doped strip (11) is a strip structure, and the second conductive type doped strip (12) is a block structure; there are multiple block structures with equal areas; The second conductive type doping strips (12) are embedded in the first conductive type doping strips (11) in the form of multiple rows and columns, and the number of the second conductive type doping strips gradually increases along the direction from the second conductive type semiconductor region (1) to the cut-off ring (8).

5. The semiconductor device according to claim 1, wherein The cell structure further includes a metallized cathode (5), a first conductive type semiconductor region (3) and a semiconductor drift region (2); The metallized cathode (5) is located on the back side of the first conductive type semiconductor region (3); and the semiconductor drift region (2) is located on the front side of the first conductive type semiconductor region (3). The semiconductor device according to claim 1 , wherein: The semiconductor device includes silicon, silicon germanium, gallium arsenide, silicon carbide, gallium nitride, gallium oxide or diamond.

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