Optical semiconductor elements and integrated semiconductor lasers

Abstract

The optical semiconductor element comprises: a base having a base surface; a table surface protruding from the base surface in a first direction intersecting the base surface and extending along the base surface; an optical waveguide layer arranged in the table surface, or arranged in the base so as to have at least a portion overlapping with the table surface in the first direction; a resistor layer having a first portion arranged on the table surface and a first extension portion extending from the first portion intersecting with the extension direction of the table surface; and a wiring layer electrically connected to the resistor layer and having a second portion partially covering the first portion and a second extension portion at least partially covering the first extension portion and extending from the second portion intersecting with the extension direction of the table surface, wherein a connection portion electrically connected to the wiring is provided at a position of the second extension portion overlapping with the first extension portion.

Description

Technical Field

[0001] The present invention relates to an optical semiconductor element and an integrated semiconductor laser. Background Art

[0002] Conventionally, there is known an optical semiconductor element including a resistance layer functioning as a heater and a wiring layer for supplying power to the resistance layer on a mesa (Patent Document 1).

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-163081 Summary of the invention

[0006] -Problems to be solved by the invention-

[0007] In the structure of Patent Document 1, burrs may be formed at the edge of the resistance layer. In this case, when forming a wiring layer across the edge, the burrs may prevent the wiring layer from being formed into a desired shape at the edge, and the resistance of the wiring layer may increase.

[0008] Therefore, one of the objects of the present invention is to obtain, in an optical semiconductor element including a resistor layer and a wiring layer on a mesa, a wiring layer which is less susceptible to the influence of burrs generated at the edge of the resistor layer.

[0009] -Methods for solving problems-

[0010] The optical semiconductor element of the present invention, for example, comprises: a base having a base surface; a table surface protruding from the base surface in a first direction intersecting the base surface and extending along the base surface; an optical waveguide layer arranged in the table surface, or arranged in the base so as to have at least a portion overlapping with the table surface in the first direction; a resistor layer having a first portion arranged on the table surface and a first extension portion extending from the first portion intersecting with the extension direction of the table surface; and a wiring layer electrically connected to the resistor layer and having a second portion partially covering the first portion and a second extension portion at least partially covering the first extension portion and extending from the second portion intersecting with the extension direction of the table surface, wherein a connection portion electrically connected to the wiring is provided at a position of the second extension portion overlapping with the first extension portion.

[0011] Furthermore, in the optical semiconductor element, for example, a first edge of the first extending portion and a second edge of the second extending portion overlap each other.

[0012] Furthermore, in the optical semiconductor element, for example, the first extending portion at least partially protrudes outward from the second edge of the second extending portion.

[0013] In addition, the optical semiconductor element of the present invention, for example, comprises: a base having a base surface; a table surface protruding from the base surface in a first direction intersecting the base surface and extending along the base surface; an optical waveguide layer arranged in the table surface, or arranged in the base to have at least a portion overlapping with the table surface in the first direction; a resistor layer having a first portion arranged on the table surface and a first extension portion extending from the first portion to intersect with the extension direction of the table surface; and a wiring layer electrically connected to the resistor layer and having a second portion partially covering the first portion, and a second extension portion at least partially covering the first extension portion and extending from the second portion to intersect with the extension direction of the table surface, the second extension portion having: a third portion having a width larger than the first extension portion and overlapping with the first extension portion; and a connection portion electrically connected to the wiring at a position separated from the second portion.

[0014] Furthermore, in the optical semiconductor element, for example, the second extending portion has a protruding portion that protrudes further outward in the width direction of the second extending portion and further outward in the extending direction of the second extending portion than the first edge of the first extending portion.

[0015] Furthermore, in the optical semiconductor element, for example, the resistivity of the resistance layer is higher than the resistivity of the wiring layer.

[0016] Furthermore, in the optical semiconductor element, for example, a trench is provided adjacent to the mesa, and a buried layer for burying the trench is provided.

[0017] Furthermore, in the optical semiconductor element, for example, a high heat-resistant layer having a lower thermal conductivity than a portion adjacent to the optical waveguide layer is provided.

[0018] Furthermore, in the optical semiconductor element, for example, the high heat-resistant layer is a void.

[0019] Furthermore, in the optical semiconductor element, for example, the high heat-resistant layer is made of a semiconductor material.

[0020] Furthermore, an integrated semiconductor laser according to the present invention includes, for example, any of the above-mentioned optical semiconductor elements.

[0021] -Effects of the Invention-

[0022] According to the present invention, for example, in an optical semiconductor element including a resistor layer and a wiring layer on a mesa, the wiring layer can be formed with higher precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an illustrative and schematic perspective view including a partial cross section of the optical semiconductor element according to the first embodiment.

[0024] Figure 2 yes Figure 1 II-II sectional view.

[0025] Figure 3 This is an illustrative and schematic plan view showing a state in which a wiring layer is removed from a part of the optical semiconductor element according to the first embodiment.

[0026] Figure 4 This is an illustrative and schematic plan view of a part of the optical semiconductor element according to the first embodiment.

[0027] Figure 5 The optical semiconductor element of the first modified example of the embodiment Figure 2 Cross-sectional view at the same position.

[0028] Figure 6 The optical semiconductor element of the second modified example of the embodiment Figure 2 Cross-sectional view at the same position.

[0029] Figure 7 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a third modified example of the embodiment.

[0030] Figure 8 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a fourth modified example of the embodiment.

[0031] Fig. 9 yes Figure 8 IX-IX sectional view.

[0032] Fig.10 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a fifth modification of the embodiment.

[0033] Fig.11 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a sixth modification of the embodiment.

[0034] Fig.12 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a seventh modification example of the embodiment.

[0035] Fig.13 A part of an optical semiconductor element of an eighth variation of the embodiment Figure 4 Top view at the same location.

[0036] Fig.14 A part of an optical semiconductor element of a ninth variation of the embodiment Figure 4Top view at the same location.

[0037] Fig.15 A part of an optical semiconductor element according to a tenth variation of the embodiment Figure 4 Top view at the same location.

[0038] Fig.16 It is a perspective view of an integrated semiconductor laser having an optical semiconductor element according to a second embodiment.

[0039] Fig.17 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a second embodiment applied to a DBR.

[0040] Fig.18 This is an illustrative and schematic perspective view including a partial cross section of an optical semiconductor element according to a second embodiment of the present invention applied to a ring resonator. DETAILED DESCRIPTION

[0041] Hereinafter, exemplary embodiments and variations of the present invention are disclosed. The structures of the embodiments and variations shown below, as well as the functions and results (effects) brought about by the structures are examples. The present invention can also be implemented by structures other than the structures disclosed in the following embodiments and variations. In addition, according to the present invention, at least one of the various effects (including derivative effects) obtained by the structure can be obtained.

[0042] The embodiments and modifications shown below have the same structure. Thus, according to the structure of each embodiment and modification, the same action and effect based on the same structure can be obtained. In addition, the same reference numerals are given to the same structures below, and repeated descriptions are sometimes omitted.

[0043] In this specification, ordinal numbers are given for the convenience of distinguishing components, parts, etc., and do not indicate priority or order.

[0044] In each figure, the X direction is indicated by an arrow X, the Y direction is indicated by an arrow Y, and the Z direction is indicated by an arrow Z. The X direction, the Y direction, and the Z direction intersect each other and are orthogonal to each other. In addition, the X direction can also be called a length direction or an extension direction, the Y direction can also be called a short side direction, a width direction, or a thickness direction, and the Z direction can also be called a height direction or a protrusion direction.

[0045] [First embodiment]

[0046] Figure 1 It is a perspective view including a partial cross section of the optical semiconductor element 10A according to the present embodiment. Figure 1, a cross section perpendicular to the X direction and a cross section perpendicular to the Y direction are shown in the figure. Figure 2 yes Figure 1 II-II sectional view.

[0047] like Figure 1 , 2 As shown, the optical semiconductor element 10A includes a substrate 11 , a mesa 12 , an optical waveguide layer 13 , a laminated portion 14 , a resistor layer 15 , and a wiring layer 16 .

[0048] The substrate 11 is a semiconductor substrate. The substrate 11 extends in a direction intersecting the Z direction. In the present embodiment, the substrate 11 extends along the X direction and the Y direction and is orthogonal to the Z direction. In addition, the substrate 11 has a base surface 11a. The base surface 11a has a planar shape and extends in a direction intersecting the Z direction. In the present embodiment, the base surface 11a extends in the X direction and the Y direction and is orthogonal to the Z direction. The substrate 11 is an example of a base. The base surface 11a can also be called a surface.

[0049] The substrate 11 can be made of, for example, n-type indium phosphide (InP).

[0050] The table 12 protrudes from the base surface 11a of the substrate 11 in the Y direction with a substantially constant width in the Z direction. In addition, the table 12 extends along the X direction with a substantially constant height in the Z direction. That is, the table 12 has a shape like a wall protruding from the base surface 11a. In addition, the table 12 may be curved while extending along the base surface 11a. In addition, the width of the table 12 may vary along the Z direction, i.e., the height direction, or along the X direction, i.e., the extension direction. The Z direction is an example of a first direction.

[0051] The table top 12 has a top surface 12 a and two side surfaces 12 b .

[0052] The top surface 12a extends in a manner intersecting the Z direction. In the present embodiment, the top surface 12a extends in the X direction and the Y direction and is orthogonal to the Z direction. The top surface 12a is substantially parallel to the base surface 11a. In addition, the top surface 12a extends in the X direction with a substantially constant width in the Y direction. In addition, the top surface 12a may be curved while extending substantially parallel to the base surface 11a. In addition, the width of the top surface 12a may also vary along the extension direction of the table 12.

[0053] The side surface 12b extends along the Z direction. The side surface 12b extends along the X direction with a substantially constant width in the Z direction. The side surface 12b may extend along the base surface 11a while being curved.

[0054] An optical waveguide layer 13 is provided in the mesa 12. The optical waveguide layer 13 is located between the base of the mesa 12 and the top surface 12a. The optical waveguide layer 13 extends along the X direction with a substantially constant width in the Y direction and a substantially constant height in the Z direction. In addition, the optical waveguide layer 13 may be curved together with the mesa 12 and extend substantially parallel to the base surface 11a.

[0055] In the present embodiment, the width of the optical waveguide layer 13 is smaller than the width of the mesa 12 , and the periphery of the optical waveguide layer 13 is covered by the mesa 12 (cladding 12 c ).

[0056] The laminated portion 14 protrudes in the Z direction on the substrate 11. The laminated portion 14 has a top surface 14a and side surfaces 14b.

[0057] The top surface 14a extends to intersect the Z direction. In the present embodiment, the top surface 14a extends along the X direction and the Y direction and is orthogonal to the Z direction. The top surface 14a is substantially parallel to the base surface 11a.

[0058] The side surface 14b extends along the Z direction. The side surface 14b extends along the X direction with a substantially constant width in the Z direction. The side surface 14b may extend along the base surface 11a while being curved.

[0059] In the optical semiconductor element 10A, a groove 10 a is provided adjacent to the mesa 12 and the laminated portion 14 .

[0060] The mesa 12 including the optical waveguide layer 13 and the laminated portion 14 can be manufactured by a known semiconductor manufacturing process. The portion of the mesa 12 where the optical waveguide layer 13 is removed functions as a cladding 12c relative to the optical waveguide layer 13. The cladding 12c can be manufactured by a material having a lower refractive index than the material of the optical waveguide layer 13. For example, when the wavelength of the light guided by the optical waveguide layer 13 is 1.55 μm, the cladding 12c can be manufactured by InP, and the optical waveguide layer 13 can be manufactured by InGaAsP. In addition, the materials of the cladding 12c and the optical waveguide layer 13 are not limited to this example, and can be appropriately set according to the wavelength of the light guided by the optical waveguide layer 13. In addition, the laminated portion 14 can be manufactured by a semiconductor material.

[0061] The base surface 11a of the substrate 11, the top surface 12a and the side surface 12b of the table 12, and the top surface 14a and the side surface 14b of the stacked portion 14 may also be covered with a dielectric layer (not shown). In this case, the dielectric layer is formed on each surface with a substantially constant thickness. The dielectric layer has insulating properties. The dielectric layer can be made of, for example, silicon nitride (SiNx) or silicon dioxide (SiO2).

[0062] Figure 31 is a plan view showing a state where the wiring layer 16 is removed from a portion of the optical semiconductor element 10A. Figures 1 to 3 As shown, in the present embodiment, the resistance layer 15 is provided from the top surface 12 a of the mesa 12 to the top surface 14 a of the laminated portion 14 across the trench 10 a .

[0063] The resistance layer 15 can be made of a material that generates heat when electricity is applied, such as an alloy mainly composed of nickel (Ni) and chromium (Cr). The resistance layer 15 generates heat using power supplied from two wiring layers 16 that are separated from each other in the extension direction (in the X direction in this embodiment) of the mesa 12. In the resistance layer 15, current flows along the extension direction of the mesa 12. The resistance layer 15 can also be called a heater.

[0064] like Figure 1 , 3 As shown, the resistance layer 15 has a first portion 15 a provided on the mesa 12 and a first extension portion 15 b extending from the first portion 15 a toward the laminated portion 14 .

[0065] The first portion 15a extends on the top surface 12a of the table 12 along the extension direction of the table 12, that is, the X direction in this embodiment. The first portion 15a has a quadrilateral and plate-like shape. In addition, the first portion 15a has a strip-like shape extending along the top surface 12a of the table 12.

[0066] The first extension portion 15b extends from the end of the first portion 15a in the extension direction, intersecting the extension direction of the table 12. In the present embodiment, the top surface 12a of the table 12 and the top surface 14a of the stacked portion 14 are flush with each other, and the first extension portion 15b extends from the first portion 15a along the width direction of the table 12, i.e., the Y direction in the present embodiment.

[0067] like Figure 3As shown, the first extension portion 15b has a narrow portion 15b1 and a wide portion 15b2. The narrow portion 15b1 has a quadrilateral and plate-like shape and extends from the first portion 15a with a substantially constant width. The wide portion 15b2 is located at the end of the narrow portion 15b1 on the opposite side of the first portion 15a and has a width wider than the narrow portion 15b1. The width of the narrow portion 15b1 is W1, and the width of the wide portion 15b2 is W2 (>W1). In this embodiment, the width W1 of the narrow portion 15b1 is substantially constant, so the width of the first extension portion 15b in the boundary portion 15c with the first portion 15a is also W1. That is, the width W2 of the wide portion 15b2 is greater than the width W1 of the boundary portion 15c. The wide portion 15b2 has a quadrilateral and plate-like shape. As an example, in the present embodiment, the narrow width portion 15b1 has a rectangular shape, and the wide width portion 15b2 has a square shape.

[0068] Figure 4 FIG. 1 is a partial top view of the optical semiconductor element 10A. Figure 1 , 2 4, in this embodiment, a wiring layer 16 is provided across the groove 10a from the first portion 15a of the resistor layer 15 to the wide portion 15b2 of the first extension portion 15b. The wiring layer 16 is adjacent to the side opposite to the terrace 12 and the laminated portion 14 with respect to the resistor layer 15. The wiring layer 16 overlaps with the resistor layer 15 in the Z direction and extends along the resistor layer 15.

[0069] The wiring layer 16 can be made of a conductive material such as titanium (Ti), platinum (Pt), or gold (Au). The wiring layer 16 is a path for supplying power to the resistor layer 15. The resistivity of the resistor layer 15 is greater than that of the wiring layer 16.

[0070] like Figure 1 , 4 As shown, the wiring layer 16 has a second portion 16 a provided on the mesa 12 and a second extension portion 16 b extending from the second portion 16 a toward the laminated portion 14 .

[0071] Reference Figure 1 , 2 , and with Figure 3 as well as Figure 4 By comparison, it can be clearly seen that the second portion 16a partially covers the end of the first portion 15a of the resistor layer 15. In addition, the second extension portion 16b has the same shape as the first extension portion 15b of the resistor layer 15 when viewed in the Z direction, and overlaps with the first extension portion 15b in the Z direction.

[0072] The second portion 16 a has a quadrilateral and plate-like shape.

[0073] The second extension portion 16b extends from the second portion 16a to intersect the extension direction of the mesa 12. In the present embodiment, the second extension portion 16b extends from the second portion 16a along the width direction of the mesa 12, that is, the Y direction in the present embodiment.

[0074] like Figure 4 As shown, the second extension portion 16b has a narrow portion 16b1 and a wide portion 16b2. The narrow portion 16b1 has a quadrilateral and plate-like shape and extends from the second portion 16a with a substantially constant width. The wide portion 16b2 is located at the end of the narrow portion 16b1 on the opposite side of the second portion 16a and has a width wider than the narrow portion 16b1. The wide portion 16b2 is separated from the second portion 16a. The width of the narrow portion 16b1 is W1, and the width of the wide portion 16b2 is W2 (>W1). In the present embodiment, the width W1 of the narrow portion 16b1 is substantially constant, so the width of the second extension portion 16b in the boundary portion 16c with the second portion 16a is also W1. That is, the width W2 of the wide portion 16b2 is greater than the width W1 of the boundary portion 16c. The wide portion 16b2 has a quadrilateral and plate-like shape. As an example, in the present embodiment, the narrow width portion 16b1 has a rectangular shape, and the wide width portion 16b2 has a square shape.

[0075] In this embodiment, the wide portion 16b2 overlaps the wide portion 15b2. In addition, the wiring 17 is joined and electrically connected to the wide portion 16b2 on the opposite side of the wide portion 15b2 by soldering, welding, etc. That is, the wide portion 16b2 is an example of a connection portion.

[0076] In addition, in the present embodiment, the edge 15b3 of the first extension portion 15b of the resistor layer 15 overlaps the edge 16b3 of the second extension portion 16b of the wiring layer 16 in the Z direction. Therefore, the wiring layer 16 does not cross the edge of the resistor layer 15 from the second portion 16a partially covering the first portion 15a of the resistor layer 15 to the wide portion 16b2 electrically connected to the wiring 17. The edge 15b3 is an example of a first edge, and the edge 16b3 is an example of a second edge.

[0077] As described above, in this embodiment, the resistor layer 15 has the first portion 15a provided on the terrace 12 and the first extension portion 15b extending from the first portion 15a in a direction intersecting the extension direction of the terrace 12. In addition, the wiring layer 16 is electrically connected to the resistor layer 15 and has the second portion 16a partially covering the first portion 15a and the second extension portion 16b at least partially covering the first extension portion 15b and extending from the second portion 16a in a direction intersecting the extension direction of the terrace 12. Furthermore, the wide portion 16b2 (connection portion) overlapping the wide portion 15b2, that is, the position of the second extension portion 16b overlapping the first extension portion 15b, is electrically connected to the wiring 17.

[0078] In the above structure, the wiring layer 16 does not cross the edge of the resistor layer 15 until it reaches the wide portion 16b2 electrically connected to the wiring 17 from the second portion 16a. Therefore, according to the above structure, for example, it is possible to avoid the increase in resistance of the wiring layer 16 or the disconnection of the wiring layer 16 due to burrs generated at the edge of the resistor layer 15, and further, it is possible to more efficiently supply power to the resistor layer 15 via the wiring 17 and the wiring layer 16.

[0079] Furthermore, in the present embodiment, the edge 15b3 (first edge) of the first extending portion 15b overlaps with the edge 16b3 (second edge) of the second extending portion 16b.

[0080] According to the above-described structure, there is an advantage that, for example, a mask pattern used when manufacturing the first extension portion 15 b and the second extension portion 16 b can be shared.

[0081] [First Modification]

[0082] Figure 5 The optical semiconductor element 10B of this modification example is Figure 2 Sectional view at the same position. Figure 5 As shown, the optical waveguide layer 13 penetrates between the two side surfaces 12b of the mesa 12. The optical semiconductor element 10B has the same structure as the optical semiconductor element 10A of the first embodiment except that the structure and arrangement of the optical waveguide layer 13 are different. Even in the above-mentioned structure, the same effect as the first embodiment can be obtained.

[0083] [Second Modification]

[0084] Figure 6 The optical semiconductor element 10C of this modification example is Figure 2 Sectional view at the same position. Figure 6As shown in FIG. 1 , in this modification, the optical semiconductor element 10C has a so-called low-mesa structure (ridge structure). The optical waveguide layer 13 is provided in the substrate 11 separated from the mesa 12 in the direction opposite to the Z direction. The optical waveguide layer 13 has a portion overlapping with the mesa 12 in the Z direction. Light passes through the mesa 12, is confined in the region of the optical waveguide layer 13 located in the direction opposite to the mesa 12 in the Z direction, and is waveguided. The optical semiconductor element 10C has the same structure as the optical semiconductor element 10A of the first embodiment except that the structure and arrangement of the optical waveguide layer 13 are different. Even in the above-mentioned structure, the same effect as the first embodiment can be obtained.

[0085] [Third Modification]

[0086] Figure 7 FIG. 1 is a perspective view including a partial cross section of an optical semiconductor element 10D according to this modification. Figure 7 In FIG. 1 , a cross section perpendicular to the X direction and a cross section perpendicular to the Y direction are shown together with the three-dimensional shape. Figure 7 As shown, in the optical semiconductor element 10D, the width of the first extension portion 15b of the resistor layer 15 and the width of the second extension portion 16b of the wiring layer 16 gradually increase as they are separated from the terrace 12, the first portion 15a, and the second portion 16a. According to the above-mentioned structure, the cross-sectional area of ​​the second extension portion 16b can be further increased, and the resistance of the wiring layer 16 can be further reduced.

[0087] In this modification, as in the first embodiment, the second extension portion 16b overlaps the first extension portion 15b in the Z direction, and the edge 16b3 of the second extension portion 16b (see Figure 4 ) and the edge 15b3 of the first extension portion 15b (refer to Figure 3 ) overlap in the Z direction. In addition, the wide portion 16b2 (connection portion) overlapping the wide portion 15b2, that is, the position of the second extension portion 16b overlapping the first extension portion 15b, is electrically connected to the wiring 17. Thus, from the second portion 16a to the wide portion 16b2 electrically connected to the wiring 17, the wiring layer 16 does not cross the edge of the resistor layer 15. Even according to this modification, the same effect as the first embodiment can be obtained.

[0088] [Fourth Modification]

[0089] Figure 8 FIG. 1 is a perspective view including a partial cross section of an optical semiconductor element 10E according to this modification. Figure 8 In FIG. 1 , a cross section perpendicular to the X direction and a cross section perpendicular to the Y direction are shown together with the three-dimensional shape. Fig. 9 yes Figure 8IX-IX sectional view.

[0090] like Figure 8 , 9 As shown, in this variation, the first extension portion 15b of the resistor layer 15 and the second extension portion 16b of the wiring layer 16 are not separated from the base surface 11a and span the groove 10a as in the first embodiment, but extend along the side and bottom surfaces of the groove 10a, that is, along the side surfaces 12b of the table 12, the base surface 11a, the side surfaces 14b of the stacked portion 14, and the top surface 14a.

[0091] In this modification, the second extension portion 16b overlaps the first extension portion 15b in a direction perpendicular to each surface along which the first extension portion 15b extends, and an edge 16b3 of the second extension portion 16b (see Figure 4 ) at the edge 15b3 of the first extension portion 15b (refer to Figure 3 ) overlaps with the edge 15b3 of the first extension portion 15b in the direction orthogonal to each surface along the first extension portion 15b. In addition, the wide portion 16b2 (connection portion) overlapping with the wide portion 15b2, that is, the position in the second extension portion 16b that overlaps with the first extension portion 15b is electrically connected to the wiring 17. As a result, the wiring layer 16 does not cross the edge of the resistor layer 15 from the second portion 16a to the wide portion 16b2 that is electrically connected to the wiring 17. Even according to this variation, the same effect as the first embodiment described above can be obtained. In addition, according to this variation, the first extension portion 15b and the second extension portion 16b do not cross the groove 10a but extend along the groove 10a, so the following advantages can be obtained: the mechanical strength of the first extension portion 15b and the second extension portion 16b can be further increased, and the manufacturing process for forming the first extension portion 15b and the second extension portion 16b can be further simplified.

[0092] [Fifth Modification]

[0093] Fig.10 FIG. 1 is a perspective view including a partial cross section of an optical semiconductor element 10F according to this modification. Fig.10 In FIG. 1 , a cross section perpendicular to the X direction and a cross section perpendicular to the Y direction are shown together with the three-dimensional shape.

[0094] like Fig.10 As shown, in this modification, the trench 10a is buried by the buried layer 18. The top surface 18a of the buried layer 18 is flush with the top surface 12a of the mesa 12 and the top surface 14a of the stacked portion 14.

[0095] The embedding layer 18 is made of an insulating material. Specifically, the embedding layer 18 can be made of a synthetic resin material having insulating properties such as polyimide. The embedding layer 18 can also be called an insulating layer or a reinforcement layer.

[0096] The first extending portion 15 b of the resistor layer 15 and the second extending portion 16 b of the wiring layer 16 are provided from the top surface 18 a of the buried layer 18 to the top surface 14 a of the laminated portion 14 .

[0097] In this modification, similarly to the first embodiment, the second extension portion 16b overlaps the first extension portion 15b in the Z direction, and the edge 16b3 of the second extension portion 16b (see Figure 4 ) and the edge 15b3 of the first extension portion 15b (refer to Figure 3 ) overlap in the Z direction. In addition, the wide portion 16b2 (connection portion) overlapping the wide portion 15b2, that is, the position of the second extension portion 16b overlapping the first extension portion 15b, is electrically connected to the wiring 17. Thus, the wiring layer 16 does not cross the edge of the resistor layer 15 from the second portion 16a to the wide portion 16b2 electrically connected to the wiring 17. Even according to this modification, the same effect as the first embodiment can be obtained.

[0098] In addition, in this modification, a buried layer 18 is provided to bury the groove 10a. According to the above-mentioned structure, for example, the protection of the mesa 12 can be further improved, and the rigidity of the optical semiconductor element 10F can be further improved. In addition, the following advantages can be obtained: the first extension portion 15b and the second extension portion 16b can be supported by the buried layer 18, and the deformation and damage of the first extension portion 15b and the second extension portion 16b can be suppressed accordingly.

[0099] [Sixth Modification]

[0100] Fig.11 FIG. 1 is a perspective view including a partial cross section of an optical semiconductor element 10G according to this modification. Fig.11 In FIG. 1 , a cross section perpendicular to the X direction and a cross section perpendicular to the Y direction are shown together with the three-dimensional shape.

[0101] In this modification, a gap 10b is provided between the substrate 11 and the optical waveguide layer 13, for example, at the boundary between the substrate 11 and the mesa 12. The gap 10b is an air layer. The air has a lower thermal conductivity than the cladding layer 12c adjacent to the optical waveguide layer 13. The gap 10b is an example of a high heat-resistant layer.

[0102] The gap 10b can be formed by etching. Specifically, for example, after the terrace 12 and the laminated portion 14 are formed on the substrate 11 with the sacrificial layer 19 interposed therebetween, the sacrificial layer 19 is etched. By etching, the sacrificial layer 19 disappears from the portion exposed in the groove 10a. When the sacrificial layer 19 between the substrate 11 and the terrace 12 disappears and the sacrificial layer 19 between the substrate 11 and the laminated portion 14 remains, the etching is stopped, thereby obtaining Fig.11The sacrificial layer 19 can be made of a semiconductor mixed crystal material such as InGaAs, InGaAsP, AlInAs, etc. The mesa 12 does not float in the air, but a portion of the mesa 12 (not shown) is supported by the substrate 11 via the sacrificial layer 19 .

[0103] In this modification, as in the first embodiment, the second extension portion 16b overlaps the first extension portion 15b in the Z direction, and the edge 16b3 of the second extension portion 16b (see Figure 4 ) and the edge 15b3 of the first extension portion 15b (refer to Figure 3 ) overlap in the Z direction. In addition, the wide portion 16b2 (connection portion) overlapping the wide portion 15b2, that is, the position of the second extension portion 16b overlapping the first extension portion 15b, is electrically connected to the wiring 17. Thus, from the second portion 16a to the wide portion 16b2 electrically connected to the wiring 17, the wiring layer 16 does not cross the edge of the resistor layer 15. Even according to this modification, the same effect as the first embodiment can be obtained.

[0104] Furthermore, in the present modification, the void 10 b is provided as a high heat-resistant layer having a lower thermal conductivity than the cladding 12 c (a portion adjacent to the optical waveguide layer 13 ).

[0105] According to the above-described structure, for example, compared with a case where the gap 10 b does not exist, it is possible to suppress the heat generated in the resistor layer 15 from being transferred from the mesa 12 to the substrate 11 to reduce the heating efficiency of the resistor layer 15 .

[0106] [Seventh Modification]

[0107] Fig.12 FIG. 1 is a perspective view including a partial cross section of an optical semiconductor element 10H according to this modification. Fig.12 In FIG. 1 , a cross section perpendicular to the X direction and a cross section perpendicular to the Y direction are shown together with the three-dimensional shape.

[0108] In this modification, a semiconductor layer 20 is provided between the substrate 11 and the optical waveguide layer 13, for example, at the boundary portion between the substrate 11 and the mesa 12. The semiconductor layer 20 can be made of a material having a lower thermal conductivity than the cladding layer 12c adjacent to the optical waveguide layer 13, for example, a semiconductor mixed crystal material such as InGaAs, InGaAsP, or AlInAs.

[0109] In the present modification, the semiconductor layer 20 is provided as a high heat-resistant layer having a lower thermal conductivity than the cladding layer 12 c (a portion adjacent to the optical waveguide layer 13 ).

[0110] According to the above-described structure, for example, compared with a case where the semiconductor layer 20 does not exist, it is possible to suppress the heat generated in the resistor layer 15 from being transferred from the mesa 12 to the substrate 11 to reduce the heating efficiency of the resistor layer 15 .

[0111] In this modification, as in the first embodiment, the second extension portion 16b overlaps the first extension portion 15b in the Z direction, and the edge 16b3 of the second extension portion 16b (see Figure 4 ) and the edge 15b3 of the first extension portion 15b (refer to Figure 3 ) overlap in the Z direction. In addition, the wide portion 16b2 (connection portion) overlapping the wide portion 15b2, that is, the position of the second extension portion 16b overlapping the first extension portion 15b, is electrically connected to the wiring 17. Thus, from the second portion 16a to the wide portion 16b2 electrically connected to the wiring 17, the wiring layer 16 does not cross the edge of the resistor layer 15. Even according to this modification, the same effect as the first embodiment can be obtained.

[0112] [Eighth Modification]

[0113] Fig.13 The optical semiconductor element 10I of this modification example is partially Figure 4 The top view at the same position. Fig.13 As shown, in this modification, the first extension portion 15 b of the resistor layer 15 as a whole protrudes outward from the edge 16 b 3 of the second extension portion 16 b of the wiring layer 16 .

[0114] As described above, the wiring layer 16 does not extend over the edge of the resistor layer 15 from the second portion 16a to the wide portion 16b2 electrically connected to the wiring 17. Therefore, according to this modification, the same effects as those of the first embodiment can be obtained.

[0115] [Ninth Modification Example]

[0116] Fig.14 The optical semiconductor element 10J of this modification example is partially Figure 4 The top view at the same position. Fig.14 As shown, in this modification, the first extension portion 15b of the resistor layer 15 does not have the wide portion 15b2. The first extension portion 15b has a strip shape, and as an example, has a rectangular (quadrilateral) and plate-like shape.

[0117] On the other hand, the wiring layer 16 has the same shape as that of the third modification example. That is, the width of the narrow width portion 16b1 gradually increases as it moves away from the mesa 12, the first portion 15a, and the second portion 16a.

[0118] The narrow width portion 16b1 overlaps with the first extension portion 15b. The width of the narrow width portion 16b1 is equal to or greater than the width of the first extension portion 15b (the same as or wider). The narrow width portion 16b1 is an example of a third portion.

[0119] In addition, the second extension portion 16b has an extension portion 16b4 that extends outward in the width direction (outward in the X direction) and outward in the extension direction (outward in the Y direction) from the edge 15b3 of the first extension portion 15b. The wide portion 16b2 is a part of the extension portion 16b4. In addition, the wide portion 16b2 (connection portion) electrically connected to the wiring 17 is separated from the second portion 16a.

[0120] According to the above-mentioned structure, the length of the edge 15b3 of the first extension portion 15b covered by the narrow width portion 16b1 (second extension portion 16b) is further extended. In this case, even if burrs are generated on the edge 15b3, the cross-sectional area of ​​the portion covering the burrs in the narrow width portion 16b1 can be further increased, so the resistance of the second extension portion 16b can be reduced, and power can be supplied to the resistance layer 15 more efficiently via the wiring 17 and the wiring layer 16.

[0121] [Tenth Modification]

[0122] Fig.15 The optical semiconductor device 10K of this modification example is partially Figure 4 The top view at the same position. Fig.15 As shown in FIG. 1 , in this modification, the first extension portion 15b of the resistor layer 15 does not have the wide portion 15b2 (see FIG. 1 ) as in the first embodiment. Figure 3 ). The first extension portion 15b has a strip shape, and as an example, has a rectangular (quadrilateral) and plate-like shape.

[0123] On the other hand, the wiring layer 16 has the narrow width portion 16b1 and the wide width portion 16b2 similar to those in the first embodiment.

[0124] Furthermore, the first extension portion 15 b extends to a position overlapping with the wide portion 16 b 2 of the wiring layer 16 .

[0125] Therefore, the wide portion 16b2 overlaps with the first extension portion 15b. In addition, the width W21 of the wide portion 16b2 is larger than the width W11 of the first extension portion 15b. The wide portion 16b2 is an example of a third portion.

[0126] Furthermore, the wide portion 16b2 has a protruding portion 16b4 that protrudes outward in the width direction (outward in the X direction) and outward in the extending direction (outward in the Y direction) from the edge 15b3 of the first extending portion 15b.

[0127] According to the above-mentioned structure, the length of the edge 15b3 of the first extension portion 15b covered by the wide portion 16b2 (second extension portion 16b) is further extended. In this case, even if burrs are generated on the edge 15b3, the cross-sectional area of ​​the portion of the wide portion 16b2 covering the burrs can be further increased, so the resistance of the second extension portion 16b can be reduced, and power can be supplied to the resistance layer 15 more efficiently via the wiring 17 and the wiring layer 16.

[0128] [Second embodiment]

[0129] Fig.16 FIG. 1 is a perspective view of an integrated semiconductor laser 100 according to the second embodiment. Fig.16 As shown in FIG. 1 , the integrated semiconductor laser 100 includes a first optical waveguide 110 and a second optical waveguide 120 formed on a common substrate 11. The integrated semiconductor laser 100 is configured to perform laser oscillation and output laser light L1. The substrate 11 is composed of, for example, n-type InP. In addition, an n-side electrode 130 is formed on the back side of the substrate 11. The n-side electrode 130 is composed of, for example, AuGeNi, and is in ohmic contact with the substrate 11.

[0130] The first optical waveguide section 110 includes an optical waveguide 111, a laminated section 112, a p-side electrode 113, a micro heater 114 composed of Ti, two electrode pads 115, and a tapered conductor wiring 116. The first optical waveguide section 110 has an embedded structure. The optical waveguide 111 is formed to extend along the X direction in the laminated section 112. The laminated section 112 has a function of a covering section with respect to the optical waveguide 111, etc.

[0131] The p-side electrode 113 is arranged on the laminated portion 112 along a given portion (gain portion) of the optical waveguide 111. In addition, a SiN protective film described later is formed on the laminated portion 112, and the p-side electrode 113 is in contact with the laminated portion 112 via an opening formed in the SiN protective film. The micro heater 114 is arranged on the SiN protective film of the laminated portion 112 along a given portion of the optical waveguide 111. Each electrode pad 115 is arranged on the SiN protective film of the laminated portion 112, and is electrically connected to the micro heater 114 via the conductor wiring 116. The micro heater 114 generates heat by being supplied with current from each electrode pad 115 via the conductor wiring 116.

[0132] The second optical waveguide portion 120 includes a double-branch portion 121 , two arm portions 122 , 123 , a ring waveguide (ring resonator) 124 , and a micro heater 125 made of NiCr or the like.

[0133] The double branching portion 121 is composed of a 1×2 type branching waveguide including a 1×2 type multi-mode interference (MMI) waveguide 121a, and two ports are connected to each of the two arm portions 122 and 123, and one port is connected to the first optical waveguide portion 110. Through the double branching portion 121, one end of the two arm portions 122 and 123 is integrated and connected to the diffraction grating layer 21 ( Fig.17 The diffraction grating layer 21 forms a DBR structure.

[0134] The arms 122 and 123 both extend in the X direction and are configured to clamp the ring waveguide 124. The arms 122 and 123 are close to the ring waveguide 124 and are optically coupled to the ring waveguide 124 with the same coupling coefficient κ. The value of κ is, for example, 0.2. The arms 122 and 123 and the ring waveguide 124 constitute a ring resonator filter RF1. In addition, the ring resonator filter RF1 and the double branch portion 121 constitute a reflector M1. The micro heater 125 is ring-shaped and is configured on a SiN protective film formed to cover the ring waveguide 124. The micro heater 125 is supplied with current to generate heat, thereby heating the ring waveguide 124. By changing the amount of current supplied, the temperature of the ring waveguide 124 changes, and its refractive index changes.

[0135] The double-branch portion 121 , the arm portions 122 , 123 , and the ring waveguide 124 all have a high-mesa structure in which the optical waveguide layer 120 a including GaInAsP is sandwiched between a lower cladding layer and an upper cladding layer.

[0136] In addition, a micro heater 126 is arranged on a local SiN protective film of the arm portion 123. The area below the micro heater 126 in the arm portion 123 functions as a phase adjustment portion 127 that changes the phase of light. The micro heater 126 is supplied with current to generate heat, thereby heating the phase adjustment portion 127. By changing the amount of current supplied, the temperature of the phase adjustment portion 127 changes, and its refractive index changes.

[0137] The first optical waveguide portion 110 and the second optical waveguide portion 120 constitute an optical resonator C1 , and the optical resonator C1 is constituted by a pair of wavelength selective elements, namely, a diffraction grating layer 21 and a reflecting mirror M1 , which are optically connected to each other.

[0138] The integrated semiconductor laser 100 has a DBR (distributed bragg reflector) structure and a ring resonator. The DBR structure has a periodic wavelength characteristic and controls the wavelength characteristic by utilizing the heat generated by the heater, thereby operating as a vernier-type wavelength-variable laser. A schematic diagram of a conductor wiring structure for a heater having an optical waveguide layer included therein is shown in Fig.17 and Fig.18 .

[0139] Fig.17 1 is a perspective view showing a structural example in which the optical semiconductor element 10A according to the first embodiment is applied to a DBR structure. Fig.17 As shown, the optical semiconductor element 10LA has a diffraction grating layer 21 on the opposite side of the substrate 11 adjacent to the optical waveguide layer 13 in the mesa 12, and has the same structure as the optical semiconductor element 10A of the first embodiment except for the above-mentioned points. The optical waveguide 111 corresponds to the mesa 12 including the optical waveguide layer 13, the laminated portion 112 corresponds to the laminated portion 14, the micro heater 114 corresponds to the resistor layer 15, the electrode pad 115 corresponds to the wide portion 16b2 (connection portion) of the wiring layer 16, and the conductor wiring 116 corresponds to the second extension portion 16b of the wiring layer 16.

[0140] Fig.18 1 is a perspective view showing a configuration example in which the optical semiconductor element 10B of the first modification example is applied to a ring resonator. Fig.18 As shown, the optical semiconductor element 10LB has a ring waveguide 124 of a ring resonator structure, and the ring waveguide 124 has the same structure as the optical semiconductor element 10B of the first modification example, which has a high mesa structure. The optical semiconductor element 10LB has the same structure as the optical semiconductor element 10B of the first modification example, except that the mesa 12, the first portion 15a of the resistor layer 15, and the second portion 16a of the wiring layer 16 are ring-shaped. The optical waveguide layer 120a is equivalent to the optical waveguide layer 13, the second optical waveguide portion 120 is equivalent to the mesa 12 including the optical waveguide layer 13, and the micro heater 125 is equivalent to the resistor layer 15.

[0141] The integrated semiconductor laser 100 according to the second embodiment has the same structure as the optical semiconductor element 10A of the first embodiment and the optical semiconductor element 10B of the first modification, and thus can obtain the same effects as those obtained by the optical semiconductor elements 10A and 10B.

[0142] Thus, the structure of the present invention can be applied not only to semiconductor optical waveguides, but also to Fig.17 The DBR shown, Fig.18 An integrated semiconductor laser 100 of a ring resonator is shown.

[0143] The above examples illustrate the embodiments and variations of the present invention, which are examples and are not intended to limit the scope of the invention. The above embodiments and variations can be implemented in various other ways, and various omissions, substitutions, combinations, and changes can be made without departing from the scope of the invention. In addition, the specifications (structure, type, direction, type, size, length, width, thickness, height, quantity, configuration, position, material, etc.) of each structure, shape, etc. can be appropriately changed before implementation.

[0144] -Industrial Applicability-

[0145] The present invention can be used in semiconductor devices and integrated semiconductor lasers.

[0146] -Explanation of symbols-

[0147] 10A~10K、10LA、10LB...Optical semiconductor components

[0148] 10a...groove

[0149] 10b...Gap (high heat resistant layer)

[0150] 11...Substrate (base)

[0151] 11a...base surface

[0152] 12... Countertop

[0153] 12a...top surface

[0154] 12b...side

[0155] 12c...cladding

[0156] 13...Optical waveguide layer

[0157] 14...Lamination

[0158] 14a...Top

[0159] 14b...side

[0160] 15...Resistance layer

[0161] 15a...Part 1

[0162] 15b...first extension

[0163] 15b1...Narrow area

[0164] 15b2...Wide area

[0165] 15b3...edge (first edge)

[0166] 15c...Border area

[0167] 16...Wiring layer

[0168] 16a...Second part

[0169] 16b...second extension

[0170] 16b1...Narrow area

[0171] 16b2...Wide area (connection area)

[0172] 16b3...edge (second edge)

[0173] 16b4...extended part

[0174] 16c...Border area

[0175] 17...Wiring

[0176] 18...Buried layer

[0177] 18a...top

[0178] 19...Sacrificial layer

[0179] 20...Semiconductor layer (high heat-resistant layer)

[0180] 21...Diffraction grating layer

[0181] 100...Integrated semiconductor laser

[0182] 110...First optical waveguide portion

[0183] 111...Optical waveguide

[0184] 112...Lamination

[0185] 113...p-side electrode

[0186] 114...Micro heater

[0187] 115...Electrode pad

[0188] 116...Conductor wiring

[0189] 120...Second optical waveguide portion

[0190] 120a...Optical waveguide layer

[0191] 121...Double Branch

[0192] 121a...Multimode Interference Waveguide

[0193] 122, 123...Arm

[0194] 124...Ring waveguide

[0195] 125...Micro heater

[0196] 126...Micro heater

[0197] 127...Phase adjustment unit

[0198] 130...n-side electrode

[0199] C1...Optical resonator

[0200] L1...Laser

[0201] M1...Reflector

[0202] RF1...Ring Resonator Filter

[0203] W1, W2, W11, W21...Width

[0204] X...direction

[0205] Y...direction

[0206] Z...direction (first direction).

Claims

1. An optical semiconductor element comprising: A base having a base surface; a table top protruding from the base surface toward a first direction intersecting the base surface and extending along a second direction along the base surface; an optical waveguide layer, arranged in the table, or arranged in the base to have at least a portion overlapping with the table in the first direction; The resistance layer has a first portion disposed on the table surface and a first extension portion extending from the first portion in a third direction intersecting the first direction and the second direction; a wiring layer electrically connected to the resistance layer and having a second portion partially covering the first portion, and a second extension portion at least partially covering the first extension portion and extending from the second portion in the third direction; a stacked portion, which protrudes on the base toward the first direction and is located at a position separated from the table in the third direction, and the stacked portion is made of a semiconductor material; as well as A groove is provided between the terrace and the laminated portion, The first extension portion and the second extension portion are disposed between the top surface of the mesa and the top surface of the stacked portion in a mutually overlapping state, separated from the bottom of the groove and spanning the groove. A connection portion electrically connected to a wiring is provided on the top surface of the stacked portion at a position where the second extension portion overlaps with the first extension portion. The first edge of the first extending portion overlaps with the second edge of the second extending portion, The base extends along the second direction and the third direction, The first direction, the second direction, and the third direction are orthogonal to each other.

2. An optical semiconductor element comprising: A base having a base surface; a table top protruding from the base surface toward a first direction intersecting the base surface and extending along a second direction along the base surface; an optical waveguide layer, arranged in the table, or arranged in the base to have at least a portion overlapping with the table in the first direction; The resistance layer has a first portion disposed on the table surface and a first extension portion extending from the first portion in a third direction intersecting the first direction and the second direction; a wiring layer electrically connected to the resistance layer and having a second portion partially covering the first portion, and a second extension portion at least partially covering the first extension portion and extending from the second portion in the third direction; a stacked portion, which protrudes on the base toward the first direction and is located at a position separated from the table in the third direction, and the stacked portion is made of a semiconductor material; as well as A groove is provided between the terrace and the laminated portion, The first extension portion and the second extension portion are disposed between the top surface of the mesa and the top surface of the stacked portion in a mutually overlapping state, separated from the bottom of the groove and spanning the groove. A connection portion electrically connected to a wiring is provided on the top surface of the stacked portion at a position where the second extension portion overlaps with the first extension portion. The first extension portion at least partially extends outward further than the second edge of the second extension portion, The second extension portion does not have a portion extending outward from the first edge of the first extension portion. The base extends along the second direction and the third direction, The first direction, the second direction, and the third direction are orthogonal to each other.

3. An optical semiconductor element comprising: A base having a base surface; a table top protruding from the base surface toward a first direction intersecting the base surface and extending along a second direction along the base surface; an optical waveguide layer, arranged in the table, or arranged in the base to have at least a portion overlapping with the table in the first direction; The resistance layer has a first portion disposed on the table surface and a first extension portion extending from the first portion in a third direction intersecting the first direction and the second direction; a wiring layer electrically connected to the resistance layer and having a second portion partially covering the first portion, and a second extension portion at least partially covering the first extension portion and extending from the second portion in the third direction; a stacked portion, which protrudes on the base toward the first direction and is located at a position separated from the table in the third direction, and the stacked portion is made of a semiconductor material; as well as A groove is provided between the terrace and the laminated portion, The first extension portion and the second extension portion are disposed between the top surface of the mesa and the top surface of the stacked portion in a mutually overlapping state, separated from the bottom of the groove and spanning the groove. The second extension portion has: a third portion having a width greater than that of the first extension portion and overlapping the first extension portion; and a connection portion electrically connected to the wiring at a position separated from the second portion and on the top surface of the laminated portion. The base extends along the second direction and the third direction, The first direction, the second direction, and the third direction are orthogonal to each other.

4. The optical semiconductor element according to claim 3, wherein The second extending portion has a protruding portion that protrudes further outward in the width direction of the second extending portion and further outward in the extending direction of the second extending portion than the first edge of the first extending portion.

5. The optical semiconductor element according to any one of claims 1 to 4, wherein The resistivity of the resistance layer is greater than the resistivity of the wiring layer.

6. The optical semiconductor element according to any one of claims 1 to 4, wherein The optical semiconductor element is provided with a high heat-resistant layer having a lower thermal conductivity than a portion adjacent to the optical waveguide layer.

7. The optical semiconductor element according to claim 6, wherein The high heat-resistant layer is void.

8. The optical semiconductor element according to claim 6, wherein The high heat-resistant layer is made of semiconductor material.

9. An integrated semiconductor laser comprising: The optical semiconductor element according to any one of claims 1 to 8.

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