A super junction termination voltage withstanding device

Abstract

The application provides a super-junction terminal voltage withstanding device, which comprises an active region and a drift region, wherein the drift region comprises an angle terminal and an edge terminal; an active region equivalent PN main junction region is arranged between the active region and the drift region; a plurality of impurity charge compensation columns are arranged, all or part of each of the impurity charge compensation columns is inclined or polyline-extended from the active region equivalent PN main junction region to the angle terminal of the drift region, and the impurity charge compensation columns are arranged in parallel and at intervals. By arranging the impurity charge compensation columns inclined to the angle terminal in the drift region, the active region edge equivalent main PN junction boundary curvature effect can be effectively improved, the structure is simple, the process manufacturing is more convenient, and the manufacturing cost can be reduced.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor device manufacturing, and in particular to a super junction terminal withstand voltage device. Background Art

[0002] Since around 1996, the breakdown principle of a new high-voltage device based on PN junction charge balance has been experimentally verified and has become the mainstream industrial technology standard for silicon multi-conductor high-voltage power devices above 350V and has been widely used. This technology is called Super Junction or SJ super junction technology for short.

[0003] The relatively difficult problem with this SJ super junction technology is that it is a terminal technology suitable for the implementation of microelectronics technology characterized by modern planar technology. Since its breakdown principle is based on the sensitivity of PN junction charge balance, a high-efficiency SJ super junction terminal cannot be simply and easily obtained. The main reason is that the curvature radius of the main withstand voltage PN junction of high-voltage power devices is a problem that must be faced by modern microelectronics planar technology. The same problem also exists for SJ super junction technology, and it is more sensitive.

[0004] Although various SJ superjunction technology companies and research institutions have proposed 20 to 50, or even more, SJ superjunction termination structures and technologies achievable using modern planar microelectronics processes, these technologies are relatively complex. Due to the surface structure limitations of current mainstream planar process technologies, the curvature effect of the active region's equivalent main PN junction corners persists, hindering the achievement of a perfect device breakdown. Existing termination structure solutions to address this curvature effect are relatively complex from a design perspective. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the present invention proposes a super junction terminal voltage withstand device, which mainly solves the problems of complex design, difficulty in manufacturing and high cost of the existing super junction structure.

[0006] In order to achieve the above-mentioned and other purposes, the technical solutions adopted by the present invention are as follows.

[0007] The present application provides a super junction terminal voltage withstand device, comprising:

[0008] an active region and a drift region, wherein the drift region includes side terminations and corner terminations;

[0009] An active region equivalent to a PN main junction region is provided between the active region and the drift region;

[0010] Multiple impurity charge compensation columns, each of which extends in whole or in part from the active region equivalent PN main junction region toward the corner terminal of the drift region in an inclined or broken line, and each impurity charge compensation column is parallel to each other and arranged at equal intervals, and the impurity charge compensation column forms an angle of 45 degrees with the normal of any side of the corner terminal.

[0011] In one embodiment of the present application, the drift region further includes a side terminal, which is the side of the drift region away from the corner terminal. A transition region is formed between the side terminal and the corner terminal. The transition region is close to the side terminal, and the transition region includes at least one impurity charge compensation column with a forked structure at one end away from the active equivalent PN main junction region.

[0012] In one embodiment of the present application, the bifurcated structure is Y-shaped or X-shaped, and one of the bifurcated structures is inclined toward the corner terminal.

[0013] In one embodiment of the present application, the surface horizontal length of the impurity charge compensation column of each corner terminal or side terminal is not less than the depth of the impurity charge compensation column perpendicular to the surface in the semiconductor.

[0014] In one embodiment of the present application, the length of the portion of each impurity charge compensation column inclined toward the corner terminal gradually decreases or becomes equal along the direction from the corner terminal to the side terminal.

[0015] In one embodiment of the present application, the impurity charge compensation columns are symmetrically arranged on both sides of the center line of the corner terminal.

[0016] In an embodiment of the present application, a plurality of active area compensation pillars are provided in the active area, and a distance between adjacent active area compensation pillars is equal to a distance between adjacent impurity charge compensation pillars.

[0017] As described above, the super junction terminal withstand voltage device of the present invention has the following beneficial effects.

[0018] The present application can effectively improve the curvature effect of the equivalent main PN junction boundary at the edge of the active area by setting an impurity charge compensation column with an inclined angle terminal in the drift region. The structure is simple, the process is more convenient, and the production cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the cross-sectional structure of a super junction terminal voltage-withstand device in one embodiment of the present application.

[0020] Figure 2 AA' cross-sectional view of a super junction termination voltage-withstand device in one embodiment of the present application.

[0021] Figure 3BB' cross-sectional view of a super junction termination voltage withstand device in one embodiment of the present application.

[0022] Figure 4 Schematic diagram of the cross-sectional structure of a super junction terminal voltage-withstand device in another embodiment of the present application.

[0023] Figure 5 Schematic diagram of the cross-sectional structure of a super junction terminal voltage-withstand device in another embodiment of the present application.

[0024] Explanation of Figure Numbers

[0025] 1—drift region, 2—active region, 3—active region equivalent to main PN junction region, 4—impurity charge compensation column, 5—surface terminal structure, 6—Y-type impurity charge compensation column, 51—semiconductor internal structure, 52—semiconductor surface structure. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0027] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0028] See also Figure 1 The present invention provides a super junction terminal voltage-withstand device, which comprises: an active region 2 and a drift region 1, wherein the drift region 1 comprises an edge terminal and a corner terminal;

[0029] An active region equivalent PN main junction region 3 is provided between the active region 2 and the drift region 1;

[0030] A plurality of impurity charge compensation columns 4 are provided, and all or part of each impurity charge compensation column 4 extends obliquely or in a broken line from the active region equivalent PN main junction region to the corner terminal of the drift region, and the impurity charge compensation columns 4 are parallel to each other and are arranged at equal intervals.

[0031] In one embodiment, each impurity charge compensation column 4 may form a 45-degree angle with the normal of any long side of the corner terminal. The top corner of the corner terminal may also be configured as a cut surface structure, with the impurity charge compensation column 4 facing the cut surface structure being perpendicular to the cut surface.

[0032] In one embodiment, the side terminal is the side of the drift region 1 away from the corner terminal. A transition region is formed between the side terminal and the corner terminal. The transition region is adjacent to the side terminal and includes at least one impurity charge compensation column 6 having a bifurcated structure at one end away from the active equivalent PN main junction region 3. The length of each impurity charge compensation column 4 gradually decreases from the corner terminal to the side terminal. The impurity charge compensation column 4 closest to the side terminal can be arranged parallel to the side of the side terminal. The impurity charge compensation column 4 in the transition region near the side terminal can include a bifurcated structure, which is arranged at the end of the corresponding impurity charge compensation column 4 away from the active region equivalent PN main junction region 3, i.e., a Y-shaped impurity charge compensation column 6. In another embodiment, the length of each impurity charge compensation column 4 can also be set to be equal from the corner terminal to the side terminal. The specific setting can be based on actual application requirements and is not limited here.

[0033] In one embodiment, because not all of the multiple impurity charge compensation columns 4 are tilted toward the corner terminals, some impurity charge compensation columns 4 may be arranged in a zigzag pattern, with a portion of the zigzag-line impurity charge compensation column 4 tilted toward the corner terminals and another portion parallel to the edge of the edge terminals. Specifically, the closer the impurity charge compensation column 4 is to the edge terminal, the longer the portion parallel to the edge terminal. This is merely an example of one arrangement of the impurity charge compensation columns 4; the specific arrangement and arrangement can be adjusted based on actual application requirements and is not a limitation here.

[0034] In one embodiment, the bifurcated structure is Y-shaped or X-shaped, and one of the bifurcated structures is inclined toward the corner terminal. Specifically, the ends of one or more impurity charge compensation columns 4 in the transition region from the corner terminal to the edge terminal can be configured as the aforementioned bifurcated structure. In the bifurcated structure region of the impurity charge compensation column 4 at the corner terminal, the total amount of impurities in the drift region 1 of the super-junction device is slightly different under typical process technologies. This can be addressed by appropriately extending the length of the bifurcated impurity charge compensation column 4 at the bifurcated structure, so that the bifurcated structure is X-shaped or Y-shaped, thereby adjusting the charge balance.

[0035] In one embodiment, the impurity charge compensation columns 4 are symmetrically arranged along the center line of the corner terminal. For example, the length of the impurity charge compensation column 4 at the center line of the corner terminal can be set to be the longest, and the remaining impurity charge compensation columns 4 on both sides of the longest impurity charge compensation column 4 are symmetrically arranged in parallel at equal intervals W1. For details, please refer to Figure 2The symmetry of the lengths of the impurity charge compensation columns 4 at different positions on the corner terminals makes the lengths of the impurity charge compensation columns 4 at the diagonal naturally decrease in a 45° arrangement or be no greater than the previous impurity charge compensation column 4, that is, L2≥L21≥L22≥L1, that is, the horizontal length of the impurity charge compensation columns on the surface of both the side terminals and the corner terminals is greater than their depth L1 in the semiconductor, which is more beneficial for reducing the curvature effect of the corners of the equivalent main PN junction, while not occupying any additional device chip area.

[0036] In one embodiment, the active region 2 is provided with a plurality of active region compensation columns, and the spacing between adjacent active region compensation columns is equal to the spacing between adjacent impurity charge compensation columns 4. For example, the active region compensation columns can be arranged one-to-one with the impurity charge compensation columns 4 in the drift region 1. The specific arrangement can be adjusted according to actual application requirements and is not limited here. Since the arrangement of compensation columns in the active region of a PN superjunction device is a common practice in the art and is well known to those skilled in the art, the illustration of the active region compensation columns is omitted here, without affecting those skilled in the art in realizing the corresponding arrangement relationship based on the above description.

[0037] See also Figure 1 and 3 In one embodiment, the length of the impurity charge compensation column 4 on the corner terminal and the side terminal from the equivalent active area PN main junction region 3 to the corner terminal end is not less than the depth of the impurity charge compensation column 4 in the semiconductor, that is, L2 ≥ L1, and the length of the impurity charge compensation column 4 at the corner terminal from the equivalent PN main junction of the active area to the corner terminal end can be symmetrically longer than the impurity charge compensation column 4 at the side terminal.

[0038] See also Figure 4 In one embodiment, the lengths of the plurality of impurity charge compensation columns closest to the corner terminal are equal and greater than the lengths of the remaining impurity charge compensation columns 4 .

[0039] See also Figure 5 In one embodiment, the corner terminal can also be set to an arc surface, and the impurity charge compensation columns 4 are evenly arranged along the extension line of the arc surface. The specific length can be adjusted according to actual application requirements and is not limited here.

[0040] In one embodiment, the impurity charge compensation column 4 is generally in contact with the active area equivalent main PN junction region 3. However, an inconspicuous non-conductive contact distance between the active area equivalent main PN junction region 3 and the impurity charge compensation column 4 may be allowed to be no greater than 10% of the one-dimensional theoretical maximum depletion layer thickness of the device drift region 1 without significantly reducing the breakdown voltage of the active area equivalent main PN junction 3.

[0041] In one embodiment, a surface terminal structure 5 may be arranged and fabricated in the active region equivalent PN main junction region 3. The surface terminal structure 5 includes a semiconductor internal structure 51 and a semiconductor surface structure 52. Figure 2 and Figure 3 As shown. The internal structure of the semiconductor includes: a voltage-resistant ring, variable doping, RESURF and a combination structure thereof. The semiconductor surface structure 52 includes: a field plate, a resistance field plate and a combination structure thereof. The surface terminal structure 5 can be arranged and manufactured with reference to the existing super junction technology. If the existing super junction technology referred to does not use a similar surface traditional terminal structure, then such a traditional surface terminal structure is added in a compatible process. This is well known to the general technicians in this technical profession and will not be described in detail here. It should be noted that although a higher breakdown voltage relative to the traditional terminal can be obtained without these surface traditional terminal structures, a higher breakdown protection voltage can be obtained with these surface traditional terminal structures, which can further increase the device operating voltage.

[0042] At the corner terminal and side terminal, the length L2 of the impurity charge compensation columns 4 and 6 from the equivalent active area PN main junction to the corner terminal end is not less than the vertical depth L1 of the impurity charge compensation columns 4 and 6 in the semiconductor, and the length L2 of the corner terminal impurity charge compensation column 4 from the equivalent active area PN main junction area 3 to the corner terminal end can be symmetrically longer than the side terminal impurity charge compensation columns L21 and L22. Under this principle, there can be multiple specific implementation plans for the layout of the impurity charge compensation columns 4 at the corner terminal, which are not fully enumerated in this article.

[0043] It should be noted that:

[0044] The auxiliary graphic description in the text of this technical solution is that this structure contains 1 / 4 of all the elements of the corner super junction device; in addition, this technical solution is aimed at high-voltage semiconductor devices with non-annular active areas, and is aimed at the terminal protection structure of the inner peripheral structure shape of the semiconductor surface of the active area of ​​the annular high-voltage semiconductor device. According to the principle of semiconductor breakdown curvature effect, inspired by this solution, it should be relatively easier for general technicians in this field to implement and infer it, so it will not be described in detail here.

[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A super junction terminal withstand voltage device, characterized in that: include: an active region and a drift region, wherein the drift region includes side terminations and corner terminations; An active region equivalent to a PN main junction region is provided between the active region and the drift region; a plurality of impurity charge compensation columns, wherein all or part of each impurity charge compensation column extends obliquely or in a broken line from the active region equivalent PN main junction region toward a corner terminal of the drift region, and the impurity charge compensation columns are parallel to each other and are arranged at equal intervals; The impurity charge compensation column forms an angle of 45 degrees with the normal of any side of the corner terminal; The drift region further includes a side terminal, the side terminal being a side of the drift region away from the corner terminal, a transition region being formed between the side terminal and the corner terminal, the transition region being close to the side terminal, and the transition region including at least one impurity charge compensation column having a bifurcated structure at one end away from the active equivalent PN main junction region; the bifurcated structure is Y-shaped or X-shaped, and one of the bifurcated structures is inclined toward the corner terminal; The length of the impurity charge compensation column at the corner terminal or the side terminal in the horizontal direction of the surface is not less than the depth of the impurity charge compensation column perpendicular to the surface in the semiconductor.

2. The super junction termination voltage withstand device according to claim 1, characterized in that: The length of the portion of each impurity charge compensation column inclined toward the corner terminal gradually decreases or becomes equal along the direction from the corner terminal to the side terminal.

3. The super junction termination voltage withstand device according to claim 1, characterized in that: The impurity charge compensation columns are symmetrically arranged along the center line of the corner terminal.

4. The super junction termination voltage withstand device according to claim 1, characterized in that: The active area is provided with a plurality of active area compensation columns, and the distance between adjacent active area compensation columns is equal to the distance between adjacent impurity charge compensation columns.

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