Semiconductor device and wafer

Abstract

To provide a semiconductor device and a wafer that can improve characteristics.SOLUTION: According to an embodiment, a semiconductor device includes first and second nitride regions and first and second electrodes. The first nitride region includes a first region and a second region. The first region includes Alx1Ga1-x1 N(0<x1≤1). The second region includes Alx2Ga1-x2 N(0≤x2<x1). The second region is between the first region and the second nitride region. x1 reduces along a first direction to the second nitride region from the first region. x2 reduces along the first direction. The rate of change of x1 relative to a change of position along the first direction is higher than the rate of change of x2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] Embodiments of the present invention relate to a semiconductor device and a wafer.

Background Art

[0002] For example, in a semiconductor device such as a transistor, improvement in characteristics is 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 and a wafer capable of improving characteristics.

Means for Solving the Problems

[0005] According to an embodiment of the present invention, a semiconductor device includes a first nitride region, a second nitride region, a first electrode, and a second electrode. The first nitride region includes a first region and a second region. The first region contains Al x1 Ga 1-x1 N (0 < x1 ≦ 1). The second region contains Al x2 Ga 1-x2 N (0 ≦ x2 < x1). The second nitride region contains Al y2 Ga 1-y2It includes N (0 < y2 ≤ 1). The second region is between the first region and the second nitride region. The first electrode is electrically connected to the first region. The second electrode is electrically connected to the second nitride region. The composition ratio x1 decreases along the first direction from the first region to the second nitride region. The composition ratio x2 decreases along the first direction. The first change rate of the composition ratio x1 with respect to the change in the position along the first direction is higher than the second change rate of the composition ratio x2 with respect to the change in the position along the first direction.

Brief Description of the Drawings

[0006] [Figure 1] FIG. 1 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. [Figure 2] FIG. 2 is a graph illustrating a semiconductor device according to the first embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. [Figure 4] FIG. 4 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view illustrating a wafer according to the second embodiment.

Embodiments for Carrying Out the Invention

[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 thickness and width of each part, the ratio of the sizes between 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 the present specification and each figure, the same reference numerals are given to the same elements as those described above with respect to the previously shown figures, and detailed descriptions will be omitted as appropriate.

[0008] (First Embodiment) FIG. 1 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. FIG. 2 is a graph 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 nitride region 10, a second nitride region 20, a first electrode 51, and a second electrode 52.

[0009] The first nitride region 10 includes a first region 11 and a second region 12. The first region 11 contains Al x1 Ga 1-x1 N (0 < x1 ≤ 1). The second region 12 contains Al x2 Ga 1-x2 N (0 ≤ x2 < x1). The first region 11 and the second region 12 may contain crystals.

[0010] The second nitride region 20 contains Al y2 Ga 1-y2 N (0 < y2 ≤ 1). The second region 12 is between the first region 11 and the second nitride region 20. The second nitride region 20 may contain crystals.

[0011] The first electrode 51 is electrically connected to the first region 11. The second electrode 52 is electrically connected to the second nitride region 20.

[0012] The first direction D1 from the first region 11 to the second nitride region 20 is in the Z-axis direction. One direction perpendicular to the Z-axis direction is the X-axis direction. The direction perpendicular to the Z-axis direction and the X-axis direction is the Y-axis direction. The first region 11, the second region 12, and the second nitride region 20 are, for example, along the X-Y plane.

[0013] FIG. 2 schematically illustrates the profile of the Al composition ratio α in the first region 11, the second region 12, and the second nitride region 20. FIG. 2 illustrates the case where these regions contain Al α Ga 1-α N (0 ≤ α ≤ 1). The horizontal axis in FIG. 2 is the position pZ along the first direction D1 (Z-axis direction). The vertical axis is the Al composition ratio α.

[0014] As illustrated in FIG. 1, the Al composition ratio x1 in the first region 11 decreases along the first direction D1 from the first region 11 to the second nitride region 20. The Al composition ratio x2 in the second region 12 decreases along the first direction D1. A first rate of change of the composition ratio x1 with respect to the change in position pZ along the first direction D1 is higher than a second rate of change of the composition ratio x2 with respect to the change in position pZ along the first direction D1. The first rate of change corresponds to the gradient of the change in the composition ratio x1. The second rate of change corresponds to the gradient of the change in the composition ratio x2.

[0015] With this configuration, the first region 11 is, for example, p + The second region 12 functions as a layer. - The second nitride region 20 may function as an n-layer, and the semiconductor device 110 may function as a pin diode, for example.

[0016] For example, holes are generated due to a steep decrease in the Al composition ratio x1 in the first region 11. The concentration of holes in the first region 11 where the first rate of change is high is higher than the concentration of holes in the second region 12 where the second rate of change is low.

[0017] In the embodiment, the second region 12 may be substantially free of Mg. Alternatively, the concentration of Mg in the second region 12 may be less than 1×10 16 / cm 3 or less. With a small amount of impurities, high crystal quality can be easily obtained in the second region 12. For example, a high breakdown voltage can be easily obtained. For example, stable operation can be easily obtained. According to the embodiment, a semiconductor device capable of improving characteristics can be provided. The first region 11 may contain Mg. The concentration of Mg in the first region 11 is, for example, 1×10 15 / cm 3 More than 1×10 20 / cm 3 The following is fine.

[0018] For example, the second region 12 contacts the first region 11 and the second nitride region 20 .

[0019] The second nitride region 20 may include silicon. The concentration of silicon in the second nitride region 20 may be 1×10 18 / cm 3 More than 1×10 20 / cm 3 The second nitride region 20 is n-type, and the first region 11 is p-type. The first nitride region 10 and the second nitride region 20 function as a diode.

[0020] In an embodiment, the ratio of the first rate of change to the second rate of change may be 20 or greater.

[0021] The composition ratio x1 may vary, for example, between 0.1 and 1. The composition ratio x2 may vary, for example, between 0 and less than 0.3. The composition ratio y2 in the second nitride region 20 may be substantially constant. The composition ratio y2 may be, for example, between 0 and 0.35.

[0022] As shown in FIG. 1, the thickness of the first region 11 along the first direction D1 is referred to as the first region thickness t11. The thickness of the second region 12 along the first direction D1 is referred to as the second region thickness t12. The first region thickness t11 is thinner than the second region thickness t12. A thick second region 12 makes it easier to obtain, for example, a high breakdown voltage.

[0023] In one example, the first region thickness t11 may be 200 nm or more and 1000 nm or less, and the second region thickness t12 may be 3000 nm or more and 150000 nm or less.

[0024] The thickness of the second nitride region 20 along the first direction D1 is defined as the second nitride region thickness t20. The second nitride region thickness t20 is thinner than the second region thickness t12. The second nitride region thickness t20 may be, for example, not less than 20 nm and not more than 500 nm. The second nitride region thickness t20 may be thinner than the first region thickness t11.

[0025] In an example of the semiconductor device 110, the first region 11 includes a first partial region 11a and a second partial region 11b. A second direction D2 from the second partial region 11b to the first partial region 11a intersects a first direction D1. The second direction D2 is, for example, the X-axis direction. The second region 12 is between the first partial region 11a and the second nitride region 20. The first electrode 51 overlaps the second partial region 11b in the first direction D1. In this example, the first electrode 51 overlaps the second region 12 in the second direction D2.

[0026] As shown in FIG. 1, the semiconductor device 110 may further include a first electrode intermediate layer 51a. The first electrode intermediate layer 51a is provided between the second partial region 11b and the first electrode 51. The first electrode intermediate layer 51a includes at least one of Ga and Al and nitrogen. The first electrode intermediate layer 51a includes Mg. The first electrode intermediate layer 51a may be a p-type GaN layer, a p-type AlGaN layer, or a p-type AlN layer, etc. A low resistance can be obtained.

[0027] As shown in FIG. 1, the semiconductor device 110 may include a substrate 18s and a third nitride region 30. In this example, the substrate 18s includes silicon. The third nitride region 30 includes Al z2 Ga 1-z3 N (where y2 < z3 ≦ 1). The composition ratio z3 may be, for example, 0.95 or more and 1 or less. The third nitride region 30 may be, for example, an AlN layer. The first nitride region 10 is between the substrate 18s and the second nitride region 20. The third nitride region 30 is between the substrate 18s and the first nitride region 10. By providing the third nitride region 30, a high-quality first nitride region 10 can be obtained.

[0028] By providing the first nitride region 10 with a graded Al composition ratio, for example, stress is relaxed. For example, warping and the like are suppressed.

[0029] FIG. 3 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. As shown in FIG. 3, in the semiconductor device 111 according to the embodiment, the configuration of the first electrode 51 is different from that in the semiconductor device 110. Except for this, the configuration of the semiconductor device 111 may be the same as that of the semiconductor device 110.

[0030] The semiconductor device 111 includes a substrate 18s containing silicon and Al z2 Ga 1-z3 and a third nitride region 30 containing N (y2 < z3 ≦ 1). In the first direction D1, there is a substrate 18s between at least a part of the first electrode 51 and the second electrode 52. There is a third nitride region 30 between the substrate 18s and the second electrode 52. There is a first nitride region 10 between the third nitride region 30 and the second electrode 52. There is a second nitride region 20 between the first nitride region 10 and the second electrode 52. The direction from another part of the first electrode 51 to the substrate 18s intersects the first direction D1.

[0031] FIG. 4 is a schematic cross-sectional view illustrating a semiconductor device according to the first embodiment. As shown in FIG. 4, in the semiconductor device 112 according to the embodiment, the configuration of the first electrode 51 is different from that in the semiconductor device 110. Except for this, the configuration of the semiconductor device 112 may be the same as that of the semiconductor device 110.

[0032] As shown in FIG. 4, the semiconductor device 112 includes a conductive substrate 18s. There is a substrate 18s between the first electrode 51 and the second electrode 52. There is a first nitride region 10 between the substrate 18s and the second electrode 52. There is a second nitride region 20 between the first nitride region 10 and the second electrode 52. The substrate 18s contains, for example, GaN. The third nitride region 30 may be omitted.

[0033] (Second Embodiment) FIG. 5 is a schematic cross-sectional view illustrating a wafer according to the second embodiment. As shown in FIG. 5, the wafer 210 according to the embodiment includes a substrate 18s, a first nitride region 10, and a second nitride region 20. In the wafer 210, the configurations described in the first embodiment with respect to the substrate 18s, the first nitride region 10, and the second nitride region 20 may be applied.

[0034] The first nitride region 10 is between the substrate 18s and the second nitride region 20. The first nitride region 10 includes a first region 11 and a second region 12. The first region 11 contains Al x1 Ga 1-x1 N (0 < x1 ≤ 1). The second region 12 contains Al x2 Ga 1-x2 N (0 ≤ x2 < x1). The second nitride region 20 contains Al y2 Ga 1-y2 N (0 < y2 ≤ 1). The second region 12 is between the first region 11 and the second nitride region 20.

[0035] In the wafer 210, the composition ratio x1 decreases along the first direction D1 from the first region 11 to the second nitride region 20 (see FIG. 2). The composition ratio x2 decreases along the first direction D1 (see FIG. 2). The first change rate of the composition ratio x1 with respect to the change in the position pZ along the first direction D1 is higher than the second change rate of the composition ratio x2 with respect to the change in the position pZ along the first direction D1.

[0036] For example, a p-type first region 11 can be obtained. For example, the second region 12 may not contain Mg. Or, the concentration of Mg in the second region 12 may be 1×10 16 / cm 3 or less. For example, it is easy to obtain a high crystal quality. For example, a wafer applicable to a semiconductor device with a high breakdown voltage can be provided. According to the embodiment, a wafer capable of improving characteristics can be provided.

[0037] In the wafer 210, the second nitride region 20 may contain silicon. n-type characteristics can be stably obtained.

[0038] In an embodiment, information regarding the shape of the nitride region, etc. can be obtained, for example, by electron microscope observation. Information regarding the composition and element concentration in the nitride region can be obtained, for example, by EDX (Energy Dispersive X-ray Spectroscopy), or SIMS (Secondary Ion Mass Spectrometry), etc. Information regarding the composition in the nitride region may be obtained, for example, by reciprocal lattice space mapping, etc.

[0039] The embodiment may include the following technical solutions. (Technical Solution 1) A first nitride region including a first region and a second region, wherein the first region contains Al x1 Ga 1-x1 N (0 < x1 ≤ 1), and the second region contains Al x2 Ga 1-x2 N (0 ≤ x2 < x1), the first nitride region, Al y2 Ga 1-y2 A second nitride region containing N (0 < y2 ≤ 1), wherein the second region is between the first region and the second nitride region, the second nitride region, A first electrode electrically connected to the first region, A second electrode electrically connected to the second nitride region, Comprising, The composition ratio x1 decreases along a first direction from the first region to the second nitride region, The composition ratio x2 decreases along the first direction, A semiconductor device in which a first change rate of the composition ratio x1 with respect to a change in position along the first direction is higher than a second change rate of the composition ratio x2 with respect to the change in the position along the first direction.

[0040] (Technical Solution 2) The ratio of the first change rate to the second change rate is 20 or more, the semiconductor device according to Technical Solution 1.

[0041] (Technical Solution 3) The semiconductor device according to Technical Scheme 1 or 2, wherein the second nitride region contains silicon.

[0042] (Technical proposal 4) The semiconductor device according to Technical Proposal 3, wherein the second region is in contact with the first region and the second nitride region.

[0043] (Technical proposal 5) the second region does not contain Mg, or The concentration of Mg in the second region is 1×10 16 / cm 3 The semiconductor device according to any one of Technical Solutions 1 to 3 below.

[0044] (Technical proposal 6) The semiconductor device according to any one of Technical Solutions 1 to 5, wherein a first region thickness of the first region along the first direction is thinner than a second region thickness of the second region along the first direction.

[0045] (Technical proposal 7) the first region thickness is 200 nm or more and 1000 nm or less, The semiconductor device according to Technical Proposal 6, wherein the second region thickness is 3000 nm or more and 150,000 nm or less.

[0046] (Technical proposal 8) The semiconductor device according to Technical Solution 6 or 7, wherein a second nitride region thickness along the first direction of the second nitride region is thinner than the second region thickness.

[0047] (Technical proposal 9) The semiconductor device according to Technical Solution 8, wherein the second nitride region thickness is 20 nm or more and 500 nm or less.

[0048] (Technical proposal 10) the first region includes a first partial region and a second partial region, a second direction from the second partial region to the first partial region intersects with the first direction; the second region is between the first partial region and the second nitride region; The first electrode overlaps with the second partial region in the first direction, a semiconductor device according to any one of Technical Solutions 1 to 9.

[0049] (Technical Solution 11) Further comprising a first electrode intermediate layer, The first electrode intermediate layer is provided between the second partial region and the first electrode, The first electrode intermediate layer contains at least one of Ga and Al and nitrogen, The first electrode intermediate layer contains Mg, a semiconductor device according to Technical Solution 10.

[0050] (Technical Solution 12) The first electrode overlaps with the second region in the second direction, a semiconductor device according to Technical Solution 10 or 11.

[0051] (Technical Solution 13) A substrate containing silicon, Al z2 Ga 1-z3 A third nitride region containing N(y2 < z3 ≤ 1), Further comprising, The first nitride region is between the substrate and the second nitride region, The third nitride region is between the substrate and the first nitride region, a semiconductor device according to any one of Technical Solutions 1 to 12.

[0052] (Technical Solution 14) A substrate containing silicon, Al z2 Ga 1-z3 A third nitride region containing N(y2 < z3 ≤ 1), Further comprising, The substrate is between at least a part of the first electrode and the second electrode in the first direction, The third nitride region is between the substrate and the second electrode, The first nitride region is between the third nitride region and the second electrode, The second nitride region is between the first nitride region and the second electrode, In the semiconductor device according to any one of Technical Solutions 1 to 9, the direction from another part of the first electrode to the substrate intersects the first direction.

[0053] (Technical Solution 15) Further comprising a conductive substrate, The substrate is between the first electrode and the second electrode, The first nitride region is between the substrate and the second electrode, In the semiconductor device according to any one of Technical Solutions 1 to 9, the second nitride region is between the first nitride region and the second electrode.

[0054] (Technical Solution 16) In the semiconductor device according to Technical Solution 15, the substrate contains GaN.

[0055] (Technical Solution 17) The first region is p-type, The second nitride region is n-type, In the semiconductor device according to any one of Technical Solutions 1 to 16, the first nitride region and the second nitride region function as a diode.

[0056] (Technical Solution 18) A substrate, A first nitride region, A second nitride region, Comprising, The first nitride region is between the substrate and the second nitride region, The first nitride region includes a first region and a second region, The first region contains Al x1 Ga 1-x1 N(0 < x1 ≤ 1), The second region contains Al x2 Ga 1-x2 N(0 ≤ x2 < x1), The second nitride region contains Al y2 Ga 1-y2 N(0 < y2 ≤ 1), The second region is between the first region and the second nitride region, the composition ratio x1 decreases along a first direction from the first region to the second nitride region; The composition ratio x2 decreases along the first direction, A wafer, wherein a first rate of change of the composition ratio x1 with respect to a change in position along the first direction is higher than a second rate of change of the composition ratio x2 with respect to the change in the position along the first direction.

[0057] (Technical proposal 19) The wafer according to Technical Solution 18, wherein the second nitride region contains silicon.

[0058] (Technical proposal 20) the second region does not contain Mg, or The concentration of Mg in the second region is 1×10 16 / cm 3 A wafer according to Technical Scheme 18 or 19, which is as follows:

[0059] According to the embodiments, a semiconductor device and a wafer capable of improving characteristics are provided.

[0060] In this specification, "electrically connected" includes a state in which multiple conductors are physically in contact with each other and a current flows between these multiple conductors. "Electrically connected" also includes a state in which multiple conductors are connected to each other and a current flows between these multiple conductors.

[0061] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configurations of the elements included in the semiconductor device and wafer, such as the electrodes, nitride regions, and substrate, are within the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting them from known ranges.

[0062] Furthermore, any combination of two or more elements of each specific example within the scope of technical feasibility is also included within the scope of the present invention as long as it includes the gist of the present invention.

[0063] In addition, all wafers and wafers that can be implemented by a person skilled in the art by appropriately modifying the design based on the wafers and wafers described above as embodiments of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention.

[0064] In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations, and these modifications and alterations are also considered to fall within the scope of the present invention.

[0065] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0066] 10, 20, 30: first, second, third nitride region, 11, 12: first, second region, 11a, 11b: first, second partial region, 18s: substrate, 51, 52: first, second electrode, 51a: first electrode intermediate layer, 110~112: semiconductor device, 210: wafer, D1, D2: 1st, 2nd direction, pZ: Position, t11, t12: 1st, 2nd region thickness, t20: 2nd nitride region thickness, x1, x2, y2, z3, α: Composition ratio

Claims

1. a first nitride region including a first region and a second region, the first region being Al ｘ１ Ga １－ｘ１ N (0<x1≦1), and the second region contains Al ｘ２ Ga １－ｘ２ the first nitride region including N (0≦x2<x1); Al ｙ２ Ga １－ｙ２ a second nitride region including N (0<y2≦1), the second region being between the first region and the second nitride region; and a first electrode electrically connected to the first region; a second electrode electrically connected to the second nitride region; Equipped with the composition ratio x1 decreases along a first direction from the first region to the second nitride region; The composition ratio x2 decreases along the first direction, a first rate of change of the composition ratio x1 with respect to a change in position along the first direction is higher than a second rate of change of the composition ratio x2 with respect to the change in the position along the first direction.

2. The semiconductor device of claim 1 , wherein the second nitride region comprises silicon.

3. The semiconductor device according to claim 2 , wherein the second region is in contact with the first region and the second nitride region.

4. The second region does not contain Mg, or The concentration of Mg in the second region is 1×10 １６ / cm ３ 2. The semiconductor device according to claim 1, wherein:

5. 5. The semiconductor device according to claim 1, wherein a first region thickness of said first region along said first direction is thinner than a second region thickness of said second region along said first direction.

6. a substrate comprising silicon; Al ｚ２ Ga １－ｚ３ a third nitride region including N (y2<z3≦1); further comprising the first nitride region is between the substrate and the second nitride region; 2. The semiconductor device of claim 1, wherein said third nitride region is between said substrate and said first nitride region.

7. a substrate comprising silicon; Al ｚ２ Ga １－ｚ３ a third nitride region including N (y2<z3≦1); further comprising the substrate is located between at least a portion of the first electrode and the second electrode in the first direction; the third nitride region is between the substrate and the second electrode; the first nitride region is between the third nitride region and the second electrode; the second nitride region is between the first nitride region and the second electrode; The semiconductor device according to claim 1 , wherein a direction from another part of said first electrode to said base intersects with said first direction.

8. Further comprising a conductive substrate, the substrate is located between the first electrode and the second electrode; the first nitride region is between the substrate and the second electrode; The semiconductor device of claim 1 , wherein the second nitride region is between the first nitride region and the second electrode.

9. the first region is p-type; the second nitride region is n-type; The semiconductor device according to claim 1 , wherein the first nitride region and the second nitride region function as a diode.

10. a substrate; a first nitride region; and a second nitride region; and Equipped with the first nitride region is between the substrate and the second nitride region; the first nitride region includes a first region and a second region; The first region is Al ｘ１ Ga １－ｘ１ N (0<x1≦1), The second region is Al ｘ２ Ga １－ｘ２ N (0≦x2<x1), The second nitride region is Al ｙ２ Ga １－ｙ２ N (0<y2≦1), the second region is between the first region and the second nitride region; the composition ratio x1 decreases along a first direction from the first region to the second nitride region; The composition ratio x2 decreases along the first direction, A wafer, wherein a first rate of change of the composition ratio x1 with respect to a change in position along the first direction is higher than a second rate of change of the composition ratio x2 with respect to the change in the position along the first direction.

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