Semiconductor device and method of manufacturing the same

Abstract

To provide a semiconductor device that can obtain stable characteristics and a method for manufacturing the semiconductor device.SOLUTION: According to an embodiment, a semiconductor device includes first to third electrodes, first and second semiconductor regions, and a first member. The third semiconductor portion of the second semiconductor region includes silicon and the second semiconductor region does not include silicon. Alternatively, the concentration of silicon in the second semiconductor portion is lower than the concentration of silicon in the third semiconductor portion. The first member includes a first region and a second region. The concentration of silicon in the second region is higher than the concentration of silicon in the first region.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a semiconductor device and a method for manufacturing a semiconductor device.

Background Art

[0002] For example, in semiconductor devices such as transistors, stable characteristics are desired.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Embodiments of the present invention provide a semiconductor device capable of obtaining stable characteristics and a method for manufacturing a semiconductor device.

Means for Solving the Problems

[0005] According to an embodiment of the present invention, a semiconductor device includes a first electrode, a second electrode, a third electrode, a first semiconductor region, a second semiconductor region, and a first member. The direction from the first electrode to the second electrode is along a first direction, and the second electrode includes a first electrode region and a second electrode region. The position of the third electrode in the first direction is between the position of the first electrode in the first direction and the position of the second electrode in the first direction. The first semiconductor region is Al x1 Ga 1-x1It includes N(0≦x1<1). The first semiconductor region includes a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region. The direction from the first partial region to the first electrode is along a second direction that intersects the first direction. The direction from the second partial region to the second electrode is along the second direction. The direction from the third partial region to the third electrode is along the second direction. The fourth partial region is between the first partial region and the third partial region in the first direction. The fifth partial region is between the third partial region and the second partial region in the first direction. The second semiconductor region contains Al x2 Ga 1-x2 It includes N(x1<x2≦1). The second semiconductor region includes a first semiconductor portion, a second semiconductor portion, and a third semiconductor portion. The direction from the fourth partial region to the first semiconductor portion is along the second direction. The direction from the fifth partial region to the second semiconductor portion is along the second direction. At least a part of the third semiconductor portion is between the first semiconductor region and the second electrode region in the second direction. The second semiconductor portion is between the first semiconductor portion and the third semiconductor portion in the first direction. The third semiconductor portion contains silicon and the second semiconductor region does not contain silicon. Or, the concentration of silicon in the second semiconductor portion is lower than the concentration of silicon in the third semiconductor portion. The first member includes at least any one selected from the group consisting of nitrogen and oxygen, and silicon. The first member includes a first region and a second region. The second semiconductor portion is between the fifth partial region and the first region in the second direction. At least a part of the second region is between the third semiconductor portion and the second electrode region in the second direction. The concentration of silicon in the second region is higher than the concentration of silicon in the first region.

Brief Description of the Drawings

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[0007] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationships between the thicknesses and widths of the respective parts, the size ratios between the parts, etc. are not necessarily the same as those in reality. Even when representing the same part, the dimensions and ratios may be represented differently in the drawings. In this specification and each figure, the same reference numerals are assigned to elements similar to those described above with respect to the previously presented figures, and detailed descriptions are omitted as appropriate.

[0008] (First Embodiment) FIG. 1 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. As shown in FIG. 1, the semiconductor device 110 according to the embodiment includes a first electrode 51, a second electrode 52, a third electrode 53, a first semiconductor region 10, a second semiconductor region 20, and a first member 41.

[0009] The first direction D1 from the first electrode 51 to the second electrode 52 is defined as the X-axis direction. One direction perpendicular to the X-axis direction is defined as the Z-axis direction. A direction perpendicular to both the X-axis direction and the Z-axis direction is defined as the Y-axis direction.

[0010] The second electrode 52 includes a first electrode region 52a and a second electrode region 52b.

[0011] The position of the third electrode 53 in the first direction D1 is between the position of the first electrode 51 in the first direction D1 and the position of the second electrode 52 in the first direction D1. For example, the third electrode 53 is between the first electrode 51 and the second electrode 52 in the first direction D1.

[0012] The first semiconductor region 10 contains Al x1 Ga 1-x1 N (0 ≦ x1 < 1). In one example, the composition ratio x1 is 0 or more and 0.1 or less. The first semiconductor region 10 is, for example, a GaN layer.

[0013] The first semiconductor region 10 includes a first partial region 11, a second partial region 12, a third partial region 13, a fourth partial region 14, and a fifth partial region 15. The direction from the first partial region 11 to the first electrode 51 is along the second direction D2. The second direction D2 intersects the first direction D1. The second direction D2 is, for example, the Z-axis direction.

[0014] The direction from the second partial region 12 to the second electrode 52 is along the second direction D2. The direction from the second partial region 12 to at least a part of the second electrode 52 is along the second direction D2. The direction from the third partial region 13 to the third electrode 53 is along the second direction D2. The fourth partial region 14 is between the first partial region 11 and the third partial region 13 in the first direction D1. The fifth partial region 15 is between the third partial region 13 and the second partial region 12 in the first direction D1.

[0015] The first partial region 11 is, for example, a region that overlaps with the first electrode 51 in the Z-axis direction. The second partial region 12 is, for example, a region that overlaps with the second electrode 52 in the Z-axis direction. The third partial region 13 is, for example, a region that overlaps with the third electrode 53 in the Z-axis direction. The first to fifth partial regions 11 to 15 are continuous with each other. The boundaries between the first to fifth partial regions 11 to 15 may be unclear.

[0016] The second semiconductor region 20 is Al x2 Ga 1-x2 N (x1 < x2 ≤ 1). In one example, the composition ratio x2 is 0.05 or more and 0.35 or less. The second semiconductor region 20 is, for example, an AlGaN layer.

[0017] The second semiconductor region 20 includes a first semiconductor part 21, a second semiconductor part 22, and a third semiconductor part 23. The direction from the fourth partial region 14 to the first semiconductor part 21 is along the second direction D2. The direction from the fifth partial region 15 to the second semiconductor part 22 is along the second direction D2.

[0018] At least a part of the third semiconductor portion 23 is between the first semiconductor region 10 and the second electrode region 52b in the second direction D2. For example, the second semiconductor portion 22 is between the first semiconductor portion 21 and the third semiconductor portion 23 in the first direction D1.

[0019] For example, the third semiconductor portion 23 contains silicon, and the second semiconductor portion 22 does not contain silicon. Or, the concentration of silicon in the third semiconductor portion 23 is higher than the concentration of silicon in the second semiconductor portion 22. The third semiconductor portion 23 is a portion that locally contains silicon. For example, the first semiconductor portion 21 is substantially free of silicon. Or, the concentration of silicon in the third semiconductor portion 23 is higher than the concentration of silicon in the first semiconductor portion 21.

[0020] For example, the first electrode 51 is electrically connected to the first semiconductor portion 21. The second electrode 52 is electrically connected to the second semiconductor portion 22.

[0021] The first member 41 contains at least any one selected from the group consisting of nitrogen and oxygen, and silicon. The first member 41 contains, for example, silicon nitride, silicon oxide, or silicon oxynitride. The first member 41 includes a first region 41a and a second region 41b. The second semiconductor portion 22 is between the fifth partial region 15 and the first region 41a in the second direction D2. In this example, at least a part of the second region 41b is between at least a part of the first region 41a and the first electrode region 52a in the first direction D1. At least a part of the second region 41b is between the third semiconductor portion 23 and the second electrode region 52b in the second direction D2. The concentration of silicon in the second region 41b is higher than the concentration of silicon in the first region 41a.

[0022] A part of the first member 41 is between the third partial region 13 and the third electrode 53 in the second direction D2.

[0023] The current flowing between the first electrode 51 and the second electrode 52 can be controlled by the potential of the third electrode 53. The potential of the third electrode 53 may be, for example, a potential based on the potential of the first electrode 51. For example, the distance between the first electrode 51 and the third electrode 53 is shorter than the distance between the second electrode 52 and the third electrode 53. The first electrode 51 functions as a source electrode, for example. The second electrode 52 functions as a drain electrode, for example. The third electrode 53 functions as a gate electrode, for example. The semiconductor device 110 is a transistor, for example. The first member 41 between the third partial region 13 and the third electrode 53 functions as a gate insulating film.

[0024] The first semiconductor region 10 and the second semiconductor region 20 are included in the semiconductor member 10M. The first semiconductor region 10 includes a portion facing the second semiconductor region 20. A carrier region 10c is formed in this facing portion. The carrier region 10c is, for example, a two-dimensional electron gas. The semiconductor device 110 is, for example, a HEMT (high electron mobility transistor).

[0025] The first electrode 51, the second electrode 52, and the third electrode 53 extend along the third direction D3. The third direction D3 intersects the plane including the first direction D1 and the second direction D2. The third direction D3 is, for example, the Y-axis direction.

[0026] In this example, a part of the third semiconductor portion 23 is between the second partial region 12 and the first electrode region 52a in the second direction D2. The above-mentioned part of the third semiconductor portion 23 is in contact with the first electrode region 52a. The second electrode region 52b protrudes toward the third electrode 53 with respect to the first electrode region 52a. The second electrode region 52b is a protruding portion or a shielding portion.

[0027] As shown in FIG. 1, the first electrode 51 may include a third electrode region 51c and a fourth electrode region 51d. The third electrode region 51c is in contact with, for example, the first semiconductor portion 21. The fourth electrode region 51d protrudes toward the third electrode 53 with respect to the third electrode region 51c. The fourth electrode region 51d is a protruding portion or a shielding portion. By providing these protruding portions, a stable electrode shape can be easily obtained. For example, the margin in the manufacturing process is expanded, and a practical semiconductor device can be obtained.

[0028] As shown in FIG. 1, the semiconductor device 110 may include a substrate 18s, a buffer layer 18b, and a nitride semiconductor layer 18c. The substrate 18s may include, for example, a silicon substrate, a GaN substrate, or a sapphire substrate. The buffer layer 18b is provided between the substrate 18s and the first semiconductor region 10. The buffer layer 18b contains Al, Ga, and nitrogen. The nitride semiconductor layer 18c is provided between the buffer layer 18b and the first semiconductor region 10. The nitride semiconductor layer 18c contains GaN containing carbon. The concentration of carbon in the nitride semiconductor layer 18c is higher than the concentration of carbon in the first semiconductor region 10.

[0029] The buffer layer 18b is provided on the substrate 18s. The nitride semiconductor layer 18c is provided on the buffer layer 18b. The first semiconductor region 10 is provided on the nitride semiconductor layer 18c. The second semiconductor region 20 is provided on the first semiconductor region 10. For example, the first electrode 51 and the second electrode 52 are provided on the second semiconductor region 20.

[0030] For example, a high voltage is applied to the second electrode 52. Electric field concentration occurs in the vicinity of the second electrode 52. Due to the local concentration of the electric field, the on-resistance may increase. For example, current collapse may occur. The electric field concentration occurs in the vicinity of the second electrode region 52b.

[0031] In the embodiment, in the second region 41b that overlaps with the second electrode region 52b in the second direction D2, the concentration of silicon is higher than that in the first region 41a. Due to the high concentration of silicon, the electrical resistance locally decreases in the second region 41b. Thereby, current collapse is suppressed. An increase in on-resistance can be suppressed. According to the embodiment, a semiconductor device capable of obtaining stable characteristics can be provided.

[0032] In the embodiment, the third semiconductor portion 23 of the second semiconductor region 20 contains silicon. The third semiconductor portion 23 is, for example, of n-type. In the third semiconductor portion 23, the resistance locally becomes low. For example, the contact resistance between the third semiconductor portion 23 and the second electrode 52 is low. A low on-resistance can be obtained.

[0033] In the embodiment, due to the high concentration of silicon in the second region 41b of the first member 41, the number of traps can be reduced in the second region 41b. Or the release of carriers from the traps can be accelerated. Since the third semiconductor portion 23 of the second semiconductor region 20 contains silicon, the number of traps can be reduced in the third semiconductor portion 23. Or the release of carriers from the traps can be accelerated. With fewer traps, the characteristics are likely to be stabilized. More stable characteristics can be obtained.

[0034] In the embodiment, the concentration of silicon in the third semiconductor portion 23 is, for example, 1×10 17 cm -3 or more and 1×10 21 cm -3 or less. The characteristics can be stabilized more effectively.

[0035] In the embodiment, for example, the concentration of silicon in the second region 41b is preferably 1.01 times or more the concentration of silicon in the first region 41a. The characteristics can be stabilized more effectively. For example, the concentration of silicon in the second region 41b is preferably 1.5 times or less the concentration of silicon in the first region 41a. The concentration of silicon in the second region 41b may also be 1.03 times or more the concentration of silicon in the first region 41a.

[0036] As shown in FIG. 1, in this example, a part of the third semiconductor portion 23 is between the second partial region 12 and the first electrode region 52a in the first direction D1.

[0037] In an embodiment, the concentration of silicon in the first semiconductor portion 21 may be lower than the concentration of silicon in the third semiconductor portion 23.

[0038] In an embodiment, a part of the first semiconductor region 10 may contain silicon. For example, a part of the second partial region 12 contains silicon and the fifth partial region 15 does not contain silicon. Or, for example, the concentration of silicon in a part of the second partial region 12 is higher than the concentration of silicon in the fifth partial region 15.

[0039] For example, the concentration of silicon in the fourth partial region 14 may be lower than the concentration of silicon in the second partial region 12. For example, the concentration of silicon in the third partial region 13 may be lower than the concentration of silicon in the second partial region 12.

[0040] As shown in FIG. 1, the first member 41 includes a boundary 41e between the first region 41a and the second region 41b. The second semiconductor region 20 includes a boundary 20e between the second semiconductor portion 22 and the third semiconductor portion 23. The second electrode region 52b includes an end portion 52e on the side of the third electrode 53. For example, the position of the boundary 41e in the first direction D1 may be between the position of the third electrode 53 in the first direction D1 and the position of the end portion 52e in the first direction D1. For example, the position of the boundary 20e in the first direction D1 may be between the position of the third electrode 53 in the first direction D1 and the position of the end portion 52e in the first direction D1. The characteristics can be stabilized more stably.

[0041] FIG. 2 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. As shown in FIG. 2, the semiconductor device 111 according to the embodiment includes a second member 42. The configuration of the semiconductor device 111 excluding this may be the same as the configuration of the semiconductor device 110.

[0042] The second member 42 includes at least one selected from the group consisting of nitrogen and oxygen, and silicon. The second member 42 includes, for example, silicon nitride, silicon oxide, or silicon oxynitride. The second member 42 includes a third region 42c and a fourth region 42d. At least a part of the fourth region 42d is between the third region 42c and the first electrode region 52a in the first direction D1. The first region 41a is between the fifth partial region 15 and the third region 42c in the second direction D2. At least a part of the fourth region 42d is between the second region 41b and the second electrode region 52b in the second direction D2. The second member 42 functions as, for example, an interlayer insulating film.

[0043] In the embodiment, the concentration of silicon in the fourth region 42d is higher than the concentration of silicon in the third region 42c. Thereby, the change in the on-resistance can be suppressed more effectively.

[0044] In the semiconductor device 111, the concentration of silicon in the fourth region 42d is preferably, for example, 1.01 times or more the concentration of silicon in the third region 42c. Thereby, the change in the on-resistance can be suppressed more stably. The concentration of silicon in the fourth region 42d may be, for example, 1.03 times or more the concentration of silicon in the third region 42c. The concentration of silicon in the fourth region 42d may be 1.5 times or less the concentration of silicon in the third region 42c. Thereby, in the semiconductor device, the deterioration of reliability can be suppressed.

[0045] FIG. 3 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. As shown in FIG. 3, the semiconductor device 112 according to the embodiment includes a third member 43. The configuration of the semiconductor device 112 excluding this may be the same as the configuration of the semiconductor device 111.

[0046] The third member 43 includes at least one selected from the group consisting of nitrogen and oxygen, and silicon. The third member 43 includes, for example, silicon nitride, silicon oxide, or silicon oxynitride. The third region 42c is between the first region 41a and a part of the third member 43 in the second direction D2. The fourth region 42d is between the second region 41b and a part of the third member 43 in the second direction D2. The second electrode region 52b is between the fourth region 42d and a part of the third member 43 in the second direction D2. The third member 43 functions as, for example, an interlayer insulating film.

[0047] In this example, the semiconductor device 112 includes a second conductive member 62. The second conductive member 62 is electrically connected to the second electrode 52. A part of the third member 43 is provided between the second electrode region 52b and the second conductive member 62 in the second direction D2. The second conductive member 62 functions as, for example, a field plate. For example, the concentration of the electric field can be suppressed. The characteristics can be made more stable.

[0048] As shown in FIG. 3, the semiconductor device 112 may include a first conductive member 61 and a third conductive member 63. The first conductive member 61 is electrically connected to the first electrode 51. The third conductive member 63 is electrically connected to the third electrode 53. A part of the third member 43 is between the first semiconductor portion 21 and the first conductive member 61, and between the second semiconductor portion 22 and the third conductive member 63 in the second direction D2. The first conductive member 61 and the third conductive member 63 function as field plates.

[0049] The first member 41 may be formed, for example, by LP-CVD (Low-Pressure Chemical Vapor Deposition). At least one of the second member 42 and the third member 43 may be formed by PE-CVD (Plasma-Enhanced Chemical Vapor Deposition).

[0050] FIG. 4 is a schematic cross-sectional view illustrating the semiconductor device according to the first embodiment. As shown in FIG. 4, in the semiconductor device 113 according to the embodiment, a part of the second region 41b is between the second partial region 12 and the first electrode region 52a in the second direction D2. The configuration of the semiconductor device 113 except this may be the same as the configurations of the semiconductor devices 110 to 112 and the like.

[0051] In the second region 41b, as described above, the concentration of silicon is high. The conductivity of the second region 41b is high. The second electrode 52 is electrically connected to the second semiconductor region 20 (the third semiconductor portion 23) via the second region 41b. A good ohmic connection is obtained. For example, a low on-resistance is obtained.

[0052] FIGS. 5 to 8 are schematic cross-sectional views illustrating the semiconductor device according to the first embodiment. In these figures, the region near the second electrode 52 in the embodiment is enlarged and illustrated.

[0053] As shown in FIG. 5, in the semiconductor device 114 according to the embodiment, a first high silicon concentration region 81 is provided. The first high silicon concentration region 81 can be formed, for example, by ion implantation or the like. The third semiconductor portion 23, the second region 41b, and the fourth region 42d are obtained by the first high silicon concentration region 81. In the semiconductor device 114, the position in the second direction D2 of the end of the first high silicon concentration region 81 in the first direction D1 is at a position corresponding to the first member 41.

[0054] As shown in FIG. 6, in the semiconductor device 115 according to the embodiment, a first high silicon concentration region 81 is provided. In the semiconductor device 115, the position in the second direction D2 of the end of the first high silicon concentration region 81 in the first direction D1 is at a position corresponding to the second semiconductor region 20.

[0055] As shown in FIG. 7, in the semiconductor device 116 according to the embodiment, in addition to the first high silicon concentration region 81, a second high silicon concentration region 82 is provided. The second high silicon concentration region 82 can be formed, for example, by ion implantation or the like. The second high silicon concentration region 82 provides the third semiconductor portion 23 and the high silicon concentration portion of the second partial region 12. In this example, the second high silicon concentration region 8 2 The position in the second direction D2 of the end in the first direction D1 of is at a position corresponding to the first semiconductor region 10.

[0056] As shown in FIG. 8, in the semiconductor device 117 according to the embodiment, in addition to the first high silicon concentration region 81, a third high silicon concentration region 83 is provided. The third high silicon concentration region 83 can be formed, for example, by ion implantation or the like. In the semiconductor device 117, the position in the second direction D2 of the end in the first direction D1 of the first high silicon concentration region 81 is at a position corresponding to the first member 41. The position in the second direction D2 of the end in the first direction D1 of the third high silicon concentration region 83 is at a position corresponding to the third member 43.

[0057] As shown in FIG. 8, the third member 43 may include a fifth region 43e and a sixth region 43f. At least a part of the sixth region 43f is between the third region 42c and the first conductive member 61 in the second direction D2. The third region 42c is between the first region 41a and the fifth region 43e in the second direction D2. At least a part of the fourth region 42d is between the second region 41b and the sixth region 43f in the second direction D2. The concentration of silicon in the sixth region 43f is higher than the concentration of silicon in the fifth region 43e. Thereby, the change in the on-resistance can be more effectively suppressed.

[0058] FIG. 9 is a schematic cross-sectional view illustrating the semiconductor device according to the first embodiment. As shown in FIG. 9, in the semiconductor device 120 according to the embodiment, a part of the third electrode 53 (first electrode portion 53p) is provided between two parts of the second semiconductor region 20 in the first direction D1. The configuration of the semiconductor device 120 other than this may be the same as the configurations of the semiconductor devices 110 to 117 and the like.

[0059] In the semiconductor device 120, at least a part of the third electrode 53 (for example, the first electrode portion 53p) is between the first semiconductor portion 21 and the second semiconductor portion 22 in the first direction D1. The third electrode 53 is, for example, a recessed gate electrode. For example, a high threshold voltage can be obtained. For example, normally-off characteristics can be obtained.

[0060] As shown in FIG. 9, a part of the third electrode 53 (for example, the first electrode portion 53p) is between the fourth partial region 14 and the fifth partial region 15 in the first direction D1. A high threshold voltage can be obtained more stably.

[0061] Also in the semiconductor device 120, the first member 41 includes a first region 41a and a second region 41b. The concentration of silicon in the second region 41b is higher than the concentration of silicon in the first region 41 a than the concentration of silicon in the first region 41.

[0062] In the semiconductor device 120, the first member 41 includes a first portion p1, a second portion p2, and a third portion p3. The first portion p1 is between the first semiconductor portion 21 and at least a part of the third electrode 53 (for example, the first electrode portion 53p) in the first direction D1. The second portion p2 is between at least a part of the third electrode 53 (for example, the first electrode portion 53p) and the second semiconductor portion 22 in the first direction D1. The third portion p3 is between the third partial region 13 and at least a part of the third electrode 53 (for example, the first electrode portion 53p) in the second direction D2.

[0063] The first member 41 electrically insulates between the semiconductor member 10M and the third electrode 53. The third portion p3 is continuous with the first region 41a.

[0064] FIG. 10 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. As shown in FIG. 10, the semiconductor device 121 according to the embodiment includes a first compound member 31. The configuration of the semiconductor device 121 excluding this may be the same as the configuration of the semiconductor device 120.

[0065] The first compound member 31 contains Al y1 Ga 1-y1 N (0 < y1 ≦ 1). The first compound member 31 is, for example, AlN or AlGaN. The composition ratio y1 is, for example, higher than the composition ratio x2. The composition ratio y1 is 0.5 or more and 1 or less.

[0066] The first compound member 31 includes a first compound region 31a, a second compound region 31b, and a third compound region 31c. The first compound region 31a is between the first semiconductor portion 21 and the first portion p1 in the first direction D1. The second compound region 31b is between the second portion p2 and the second semiconductor portion 22 in the first direction D1. The third compound region 31c is between the third portion region 13 and the third portion p3 in the second direction D2. By providing the first compound member 31, for example, high carrier mobility can be easily obtained. For example, a low on-resistance can be obtained.

[0067] The first compound member 31 may include a fourth compound region 31d and a fifth compound region 31e. The fourth compound region 31d is between the second semiconductor portion 22 and the first region 41a in the second direction D2. The fifth compound region 31e is between the third semiconductor portion 23 and the second region 41b in the second direction D2. For example, the fifth compound region 31e contains silicon and the fourth compound region 31d does not contain silicon. Or, the concentration of silicon in the fifth compound region 31e is higher than the concentration of silicon in the fourth compound region 31d.

[0068] The fifth compound region 31e overlaps with the second electrode region 52b in the second direction D2. Because the concentration of silicon in the fifth compound region 31e is high, the electrical resistance in the fifth compound region 31e locally decreases. For example, current collapse is suppressed. An increase in on-resistance can be suppressed.

[0069] As shown in FIG. 10, the semiconductor device 121 may include a second compound member 32. The second compound member 32 includes, for example, at least any one selected from the group consisting of nitrogen and oxygen, and silicon. The second compound member 32 includes, for example, silicon nitride, silicon oxide, or silicon oxynitride. The second compound member 32 includes a sixth compound region 32f and a seventh compound region 32g. The sixth compound region 32f is between the second semiconductor portion 22 and the fourth compound region 31 in the second direction D2. d The seventh compound region 32g is between the third semiconductor portion 23 and the fifth compound region 31e in the second direction D2.

[0070] By providing the second compound member 32, for example, the second semiconductor region 20 is protected. In an embodiment, for example, the seventh compound region 32g contains silicon and the sixth compound region 32f does not contain silicon. Or, the concentration of silicon in the seventh compound region 32g is higher than the concentration of silicon in the sixth compound region 32f.

[0071] The seventh compound region 32g overlaps with the second electrode region 52b in the second direction D2. The 7 high concentration of silicon in the seventh compound region 32g locally reduces the electrical resistance in the seventh compound region 32g. For example, current collapse is suppressed. An increase in on-resistance can be suppressed.

[0072] (Second Embodiment) The second embodiment relates to a method of manufacturing a semiconductor device. Hereinafter, some examples of the method of manufacturing a semiconductor device will be described.

[0073] FIGS. 11(a) to 11(d) are schematic cross-sectional views illustrating a method of manufacturing a semiconductor device according to the second embodiment. As shown in FIG. 11(a), a structure SB1 is prepared. The structure SB1 includes a first semiconductor region 10 containing Al x1 Ga 1-x1 N (0 ≦ x1 < 1), and Al x2 Ga1-x2 It includes a second semiconductor region 20 containing N(x1 < x2 ≦ 1) and a first member 41. The second semiconductor region 20 is between the first semiconductor region 10 and the first member 41. The first member 41 includes at least any one selected from the group consisting of nitrogen and oxygen and silicon.

[0074] The first member 41 includes a first region 41a and a second region 41b. A first direction D1 from the first region 41a to the second region 41b intersects a second direction D2 from the first semiconductor region 10 to the second semiconductor region 20.

[0075] The second semiconductor region 20 includes a first semiconductor portion 21, a second semiconductor portion 22, and a third semiconductor portion 23. The second semiconductor portion 22 is between the first semiconductor portion 21 and the third semiconductor portion 23 in the first direction D1. The second semiconductor portion 22 overlaps the first region 41a in the second direction D2. The third semiconductor portion 23 overlaps the second region 41b in the second direction D2.

[0076] As shown in FIG. 11(b), silicon is introduced into the second region 41b and the third semiconductor portion 23. For example, ion implantation is performed. Thereby, a first high silicon concentration region 81 is formed. By this process, the concentration of silicon in the second region 41b is made higher than the concentration of silicon in the first region 41a. The concentration of silicon in the third semiconductor portion 23 is made higher than the concentration of silicon in the second semiconductor portion 22. Thereafter, heat treatment is performed. Thereby, activation is performed.

[0077] As shown in FIG. 11(c), a second member 42 may be formed. Before the formation of the second member 42, at least a part of the electrode may be formed.

[0078] As shown in FIG. 11(d), after removing a part of the structure SB1, a first electrode 51, a second electrode 52, and a third electrode 53 are formed. The first electrode 51 is electrically connected to the first semiconductor portion 21. The second electrode 52 is electrically connected to the third semiconductor portion 23. A part of the first member 41 is between a part of the first semiconductor region 10 and the third electrode 53.

[0079] The second electrode 52 includes a first electrode region 52a and a second electrode region 52b. At least a part of the second region 41b is between the third semiconductor portion 23 and the second electrode region 52b. The position of the third electrode 53 in the first direction D1 is between the position of the first electrode 51 in the first direction D1 and the position of the first electrode region 52 a in the first direction D1. The position of at least a part of the second electrode region 52b in the first direction D1 is between the position of the third electrode 53 in the first direction D1 and the position of the first electrode region 52a in the first direction D1.

[0080] According to the manufacturing method according to the embodiment, a second region 41b and a third semiconductor portion 23 with a high silicon concentration can be formed under the second electrode region 52b. A semiconductor device capable of obtaining stable characteristics can be manufactured.

[0081] Hereinafter, some other examples of the manufacturing method of the semiconductor device according to the embodiment will be described. Hereinafter, the state in the vicinity of the second electrode 52 is illustrated. The state of the portion including the first electrode 51 and the third electrode 53 may be the same as the state described with respect to FIGS. 11(a) to 11(d). In the following, the description of the same portions as those described with respect to FIGS. 11(a) to 11(d) will be omitted.

[0082] FIGS. 12(a) to 12(c) are schematic cross-sectional views illustrating a manufacturing method of a semiconductor device according to a second embodiment. As shown in FIG. 12(a), in this example, the structure SB1 also includes a second member 42. The second member 42 includes a third region 42c and a fourth region 42d.

[0083] As shown in FIG. 12(b), silicon is introduced into the fourth region 42d, the second region 41b, and the third semiconductor portion 23. For example, ion implantation is performed. Thereby, a first high silicon concentration region 81 is formed.

[0084] By forming the first high silicon concentration region 81, the concentration of silicon in the second region 41b becomes higher than the concentration of silicon in the first region 41a. The concentration of silicon in the third semiconductor portion 23 becomes higher than the concentration of silicon in the second semiconductor portion 22. Thereafter, a heat treatment is performed. Thereby, activation is performed.

[0085] As shown in FIG. 12(c), after removing a part of the structure SB1, the first electrode 51, the second electrode 52, and the third electrode 53 are formed.

[0086] FIGS. 13(a) to 13(d) are schematic cross-sectional views illustrating a method of manufacturing a semiconductor device according to the second embodiment. As shown in FIG. 13(a), in this example, the structure SB1 also includes the second member 42.

[0087] As shown in FIG. 13(b), a part of the structure SB1 is removed. Thereby, a part of the second member 42 and a part of the first member 41 are removed. This removal is performed before the introduction of silicon.

[0088] As shown in FIG. 13(c), silicon is introduced. In this example, the first high silicon concentration region 81 and the second high silicon concentration region 82 are formed. These regions are formed by a plurality of ion implantations. That is, silicon is introduced into the fourth region 42d included in the second member 42 remaining due to the removal of a part of the second member 42. Silicon is introduced into the second region 41b included in the first member 41 remaining due to the removal of a part of the first member 41. Due to the second high silicon concentration region 82, the concentration of silicon in the second partial region 12 of the first semiconductor region 10 becomes locally high.

[0089] As shown in FIG. 13(d), electrodes (first to third electrodes 51 to 53) are formed.

[0090] FIGS. 14(a) to 14(c) are schematic cross-sectional views illustrating a method of manufacturing a semiconductor device according to the second embodiment. As shown in FIG. 14(a), in this example, the structure SB1 also includes the second member 42. As shown in FIG. 14(a), silicon is introduced. That is, the first high silicon concentration region 81 is formed. The first high silicon concentration region 81 is formed by ion implantation. After that, activation by heat treatment is performed.

[0091] As shown in FIG. 14(b), the second introduction of silicon is performed. The third high silicon concentration region 83 is formed. The third high silicon concentration region 83 is formed by ion implantation. Activation by heat treatment is performed. As shown in FIG. 14(c), electrodes (first to third electrodes 51 to 53) are formed.

[0092] FIGS. 15(a) to 15(c) are schematic cross-sectional views illustrating a method for manufacturing a semiconductor device according to the second embodiment. As shown in FIG. 15(a), in this example, the structure SB1 also includes the second member 42. As shown in FIG. 15(a), silicon is introduced. That is, the first high silicon concentration region 81 is formed. The first high silicon concentration region 81 is formed by ion implantation. After that, activation by heat treatment is performed.

[0093] As shown in FIG. 15(b), a part of the structure SB1 is removed. By ion implantation, the second high silicon concentration region 82 and the third high silicon concentration region 83 are formed. After that, activation by heat treatment is performed. As shown in FIG. 15(c), electrodes (first to third electrodes 51 to 53) are formed.

[0094] Through the various steps as described above, the semiconductor device according to the embodiment can be manufactured.

[0095] For example, the material of the first electrode 51 may be the same as the material of the second electrode 52. For example, the first electrode 51 may contain at least one first element selected from the group consisting of Ti, Al, Ga, Ni, Nb, Mo, Ta, Hf, V, and Au.

[0096] The third electrode 53 contains, for example, at least one selected from the group consisting of TiN, WN, Ni, Au, Pt, and Ti. The third electrode 53 may contain, for example, conductive silicon, polysilicon, or the like.

[0097] Information regarding the length and thickness can be obtained by electron microscope observation or the like. Information regarding the composition of the material can be obtained by SIMS (Secondary Ion Mass Spectrometry) or EDX (Energy dispersive X-ray spectroscopy) or the like.

[0098] According to an embodiment, a semiconductor device capable of obtaining stable characteristics and a method for manufacturing the semiconductor device can be provided.

[0099] As described above, the embodiments of the present invention have been described with reference to specific examples. However, the present invention is not limited to these specific examples. For example, regarding the specific configurations of each element such as semiconductor members, semiconductor regions, electrodes, members, and insulating members included in the semiconductor device, the present invention can be similarly implemented by appropriately selecting from the range known to those skilled in the art, and as long as the same effects can be obtained, it is included in the scope of the present invention.

[0100] Also, combinations of any two or more elements of each specific example within a technically possible range are included in the scope of the present invention as long as they include the gist of the present invention.

[0101] In addition, based on the semiconductor device described above as an embodiment of the present invention, all semiconductor devices that can be appropriately designed and modified by those skilled in the art also belong to the scope of the present invention as long as they include the gist of the present invention.

[0102] In addition, within the scope of the idea of the present invention, those skilled in the art can conceive of various modification examples and correction examples, and it is understood that those modification examples and correction examples also belong to the scope of the present invention.

[0103] Although some embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0104] 10…First semiconductor region, 10M…Semiconductor member, 10c…Carrier region, 11 - 15…First to fifth partial regions, 18b…Buffer layer, 18c…Nitride semiconductor layer, 18s…Substrate, 20…Second semiconductor region, 20e…Boundary, 21 - 23…First to third semiconductor portions, 31, 32…First and second compound members, 31a - 32e…First to fifth compound regions, 32f, 32g…Sixth and seventh compound regions, 41 - 43…First to third members, 41a, 41b…First and second regions, 41e…Boundary, 42c, 42d…Third and fourth regions, 43e, 43f…Fifth and sixth regions, 51 - 53…First to third electrodes, 51c, 51d…Third and fourth electrode regions, 52a, 52b…First and second electrode regions, 52e…End portion, 53p…First electrode portion, 61 - 63…First to third conductive members, 81 - 83…First to third high silicon concentration regions, 110 - 117, 120, 121…Semiconductor devices, D1 - D3…First to third directions, SB1…Laminate, p1 - p3…First to third portions

Claims

1. a first electrode, a second electrode, wherein the direction from the first electrode to the second electrode is along a first direction, and the second electrode includes a first electrode region and a second electrode region, a third electrode, wherein the position of the third electrode in the first direction is between the position of the first electrode in the first direction and the position of the second electrode in the first direction, and the distance between the first electrode and the third electrode is shorter than the distance between the second electrode and the third electrode, Al ｘ１ Ga １－ｘ１ a first semiconductor region containing AlGaN (0 ≦ x1 < 1), the first semiconductor region including a first partial region, a second partial region, a third partial region, a fourth partial region, and a fifth partial region, wherein the direction from the first partial region to the first electrode is along a second direction intersecting the first direction, the direction from the second partial region to the second electrode is along the second direction, the direction from the third partial region to the third electrode is along the second direction, the fourth partial region is between the first partial region and the third partial region in the first direction, and the fifth partial region is between the third partial region and the second partial region in the first direction, Al ｘ２ Ga １－ｘ２A second semiconductor region including N (x1 < x2 ≤ 1), wherein the second semiconductor region includes a first semiconductor portion, a second semiconductor portion, and a third semiconductor portion, the direction from the fourth partial region to the first semiconductor portion is along the second direction, the direction from the fifth partial region to the second semiconductor portion is along the second direction, at least a part of the third semiconductor portion is between the first semiconductor region and the second electrode region in the second direction, the second semiconductor portion is between the first semiconductor portion and the third semiconductor portion in the first direction, the position of the first semiconductor portion in the first direction is between the position of the first electrode in the first direction and the position of the third electrode in the first direction, the third semiconductor portion contains silicon and the first semiconductor portion and the second semiconductor portion do not contain silicon, or the concentration of silicon in the first semiconductor portion and the second semiconductor portion is lower than the concentration of silicon in the third semiconductor portion, the second semiconductor region, A first member including at least one selected from the group consisting of nitrogen and oxygen and silicon, the first member including a first region and a second region, the second semiconductor portion is between the fifth partial region and the first region in the second direction, at least a part of the second region is between the third semiconductor portion and the second electrode region in the second direction, the concentration of silicon in the second region is higher than the concentration of silicon in the first region, the first member, A semiconductor device comprising.

2. A part of the third semiconductor portion is between the second partial region and the first electrode region in the second direction, the semiconductor device according to claim 1.

3. A part of the second partial region contains silicon and the fifth partial region does not contain silicon, or, The concentration of silicon in the part of the second partial region is higher than the concentration of silicon in the fifth partial region, the semiconductor device according to claim 1 or 2.

4. The concentration of the silicon in the third semiconductor portion is 1×10 １７ cm －３ or more and 1×10 ２１ cm －３ or less. The semiconductor device according to any one of claims 1 to 3.

5. The concentration of the silicon in the second region is 1.01 times or more the concentration of the silicon in the first region. The semiconductor device according to any one of claims 1 to 4.

6. Further comprising a second member including at least any one selected from the group consisting of nitrogen and oxygen and silicon, The second member includes a third region and a fourth region, At least a part of the fourth region is between the third region and the first electrode region in the first direction, The first region is between the fifth partial region and the third region in the second direction, At least a part of the fourth region is between the second region and the second electrode region in the second direction, The concentration of silicon in the fourth region is higher than the concentration of silicon in the third region. The semiconductor device according to any one of claims 1 to 5.

7. The concentration of the silicon in the fourth region is 1.01 times or more the concentration of the silicon in the third region. The semiconductor device according to claim 6.

8. Further comprising a third member including at least any one selected from the group consisting of nitrogen and oxygen and silicon, The third region is between the first region and a part of the third member in the second direction, The fourth region is between the second region and a part of the third member in the second direction, The second electrode region is between the fourth region and a part of the third member in the second direction. The semiconductor device according to claim 6 or 7.

9. further comprising a second conductive member electrically connected to the second electrode, A semiconductor device according to claim 8, wherein a part of the third member is provided between the second electrode region and the second conductive member in the second direction.

10. a first conductive member electrically connected to the first electrode; a third conductive member electrically connected to the third electrode; and further comprising A semiconductor device according to claim 8 or 9, wherein a part of the third member is between the first semiconductor portion and the first conductive member and between the second semiconductor portion and the third conductive member in the second direction.

11. A semiconductor device according to any one of claims 1 to 10, wherein at least a part of the third electrode is between the first semiconductor portion and the second semiconductor portion in the first direction.

12. A semiconductor device according to claim 11, wherein a part of the third electrode is between the fourth partial region and the fifth partial region in the first direction.

13. The first member includes a first portion, a second portion, and a third portion, The first portion is between the first semiconductor portion and at least a part of the third electrode in the first direction, The second portion is between at least a part of the third electrode and the second semiconductor portion in the first direction, A semiconductor device according to claim 11 or 12, wherein the third portion is between the third partial region and at least a part of the third electrode in the second direction.

14. Al ｙ１ Ga １－ｙ１ further comprising a first compound member containing N (0 < y1 ≤ 1), The first compound member includes a first compound region, a second compound region, and a third compound region, The first compound region is located between the first semiconductor portion and the first portion in the first direction, The second compound region is located between the second portion and the second semiconductor portion in the first direction, The semiconductor device according to claim 13, wherein the third compound region is located between the third partial region and the third portion in the second direction.

15. The first compound member includes a fourth compound region and a fifth compound region, The fourth compound region is located between the second semiconductor portion and the first region in the second direction, The fifth compound region is located between the third semiconductor portion and the second region in the second direction, The semiconductor device according to claim 14, wherein the fifth compound region contains silicon and the fourth compound region does not contain silicon, or the concentration of silicon in the fifth compound region is higher than the concentration of silicon in the fourth compound region.

16. A part of the third semiconductor portion is located between the second partial region and the first electrode region in the second direction, The semiconductor device according to any one of claims 1 to 15, wherein the part of the third semiconductor portion is in contact with the first electrode region.

17. The semiconductor device according to any one of claims 1 to 15, wherein a part of the second region is located between the second partial region and the first electrode region in the second direction.

18. Al ｘ１ Ga １－ｘ１ A first semiconductor region containing Al ｘ２ Ga １－ｘ２Prepare a structure including a second semiconductor region containing N (x1 < x2 ≤ 1) and a first member. The second semiconductor region is between the first semiconductor region and the first member. The first member includes at least one selected from the group consisting of nitrogen and oxygen and silicon. The first member includes a first region and a second region. The first direction from the first region to the second region intersects the second direction from the first semiconductor region to the second semiconductor region. The second semiconductor region includes a first semiconductor portion, a second semiconductor portion, and a third semiconductor portion. The second semiconductor portion is between the first semiconductor portion and the third semiconductor portion in the first direction. The second semiconductor portion overlaps the first region in the second direction. The third semiconductor portion overlaps the second region in the second direction. Introduce silicon into the second region and the third semiconductor portion, make the concentration of silicon in the second region higher than the concentration of silicon in the first region, and make the concentration of silicon in the third semiconductor portion higher than the concentrations of silicon in the first semiconductor portion and the second semiconductor portion. Form a first electrode, a second electrode, and a third electrode. The first electrode is electrically connected to the first semiconductor portion. The second electrode is electrically connected to the third semiconductor portion. A part of the first member is between a part of the first semiconductor region and the third electrode. The second electrode includes a first electrode region and a second electrode region. At least a part of the second region is between the third semiconductor portion and the second electrode region. The position of the third electrode in the first direction is between the position of the first electrode in the first direction and the position of the first electrode region in the first direction. The position of the first semiconductor portion in the first direction is between the position of the first electrode in the first direction and the position of the third electrode in the first direction. The position of the second electrode region in the first direction is between the position of the third electrode in the first direction and the position of the first electrode region in the first direction. The distance between the first electrode and the third electrode is shorter than the distance between the second electrode and the third electrode. A method for manufacturing a semiconductor device.

19. Further, before the introduction of the silicon, a part of the first member is removed, The method of manufacturing a semiconductor device according to claim 18, wherein the silicon is introduced into the second region included in the first member remaining after the removal of the part of the first member.

20. The method of manufacturing a semiconductor device according to claim 19, further comprising introducing silicon into a part of the first semiconductor region after the removal of the first member.

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