A semiconductor light emitting structure and a method for preparing the same

Abstract

The present application provides a semiconductor light-emitting structure and a preparation method thereof, wherein the semiconductor light-emitting structure comprises: a substrate layer, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer stacked in sequence; wherein the lower confinement layer comprises a plurality of stacked sub-lower confinement layer groups, the sub-lower confinement layer groups comprise a stacked first sub-lower confinement layer and a second sub-lower confinement layer, the first sub-lower confinement layer is in compressive strain relative to the substrate layer, the second sub-lower confinement layer is in tensile strain relative to the substrate layer, and the refractive index of the second sub-lower confinement layer in the sub-lower confinement layer group is less than the refractive index of the first sub-lower confinement layer. The reliability of the semiconductor light-emitting structure is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a semiconductor light-emitting structure and a preparation method thereof. Background Art

[0002] Semiconductor lasers use specific semiconductor materials as working materials, and mainly generate stimulated emission light amplification under the action of electrical excitation, optical waveguide confinement and cleavage cavity surface confinement. Semiconductor lasers are manufactured using standard semiconductor processes and have the advantages of small size, low cost, high efficiency and high integration. Among them, gallium nitride (GaN)-based wide bandgap semiconductor materials have attracted much attention due to their wide applications in semiconductor lasers. After years of development, gallium nitride (GaN)-based semiconductor lasers are gradually being commercialized.

[0003] However, the reliability of semiconductor lasers still needs to be improved. Summary of the invention

[0004] The present application provides a semiconductor light-emitting structure and a method for preparing the same, so as to solve the problem in the prior art that the reliability of the semiconductor light-emitting structure needs to be improved.

[0005] In order to solve the above technical problems, the present invention provides a semiconductor light-emitting structure, comprising: a substrate layer, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer stacked in sequence; wherein the lower confinement layer comprises a plurality of stacked sub-lower confinement layer groups, the sub-lower confinement layer groups comprise a stacked first sub-lower confinement layer and a second sub-lower confinement layer, the first sub-lower confinement layer is under compressive strain relative to the substrate layer, the second sub-lower confinement layer is under tensile strain relative to the substrate layer, and the refractive index of the second sub-lower confinement layer in the sub-lower confinement layer group is less than the refractive index of the first sub-lower confinement layer.

[0006] Optionally, the second sub-lower limiting layer includes a first zone, a second zone and a third zone, the first zone, the second zone and the third zone in the second sub-lower limiting layer are arranged along the direction from the substrate layer to the active layer, the Al component in the first zone increases from the first component to the second component along the direction from the substrate layer to the active layer, the Al component in the third zone decreases from the third component to the fourth component along the direction from the substrate layer to the active layer, the Al component in the second zone is greater than or equal to the second component and greater than or equal to the third component, and the Al component fluctuation in the second zone is much smaller than the Al component fluctuation in the first zone and much smaller than the Al component fluctuation in the third zone.

[0007] Optionally, the Al composition of the second region in the second lower sub-confining layer is constant.

[0008] Optionally, the multiple stacked sub-lower restriction layer groups include the first sub-lower restriction layer group to the Mth sub-lower restriction layer group in the direction along the substrate layer toward the active layer, where M is an integer greater than or equal to 2; the Al component in the second region in the mth sub-lower restriction layer group decreases as m decreases, where m is an integer greater than or equal to 1 and less than or equal to M.

[0009] Optionally, the multiple stacked sub-lower restriction layer groups include the first sub-lower restriction layer group to the Mth sub-lower restriction layer group along the direction from the substrate layer to the active layer; the In composition of the first sub-lower restriction layer in the mth sub-lower restriction layer group is constant; or, the In composition of the first sub-lower restriction layer in the mth sub-lower restriction layer group decreases as m decreases; m is an integer greater than or equal to 1 and less than or equal to M.

[0010] Optionally, the thickness of the second zone is 1 to 15 times the thickness of the first zone; the thickness of the second zone is 1 to 15 times the thickness of the third zone.

[0011] Optionally, the thickness of the second lower sub-limiting layer in the lower sub-limiting layer group is 2 to 15 times the thickness of the first lower sub-limiting layer.

[0012] Optionally, the material of the first lower sub-limiting layer is In x Ga (1-x) N, the material of the second sub-lower limiting layer is Al (1-y) Ga y N.

[0013] Optionally, the upper confinement layer is a superlattice structure.

[0014] The present invention also provides a method for preparing a semiconductor light-emitting structure, comprising: forming a stacked lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer in sequence on one side of a substrate layer; wherein the step of forming the lower confinement layer comprises forming a plurality of stacked sub-lower confinement layer groups, and the step of forming the sub-lower confinement layer groups comprises forming a stacked first sub-lower confinement layer and a second sub-lower confinement layer, wherein the first sub-lower confinement layer is in compressive strain relative to the substrate layer, and the second sub-lower confinement layer is in tensile strain relative to the substrate layer, and the refractive index of the second sub-lower confinement layer in the sub-lower confinement layer group is less than the refractive index of the first sub-lower confinement layer.

[0015] The technical solution of this invention has the following technical effects:

[0016] In the semiconductor light-emitting structure provided by the technical solution of the present invention, the refractive index of the second sub-lower limiting layer in the sub-lower limiting layer group is relatively small, and it is used to limit the light field. The first sub-lower limiting layer is arranged in the sub-lower limiting layer group, and the first sub-lower limiting layer is in compressive strain relative to the substrate layer, so that the first sub-lower limiting layer can compensate the stress of the second sub-lower limiting layer, alleviate the cracking phenomenon between the sub-lower limiting layer group and the substrate layer, and improve the reliability of the semiconductor light-emitting structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic structural diagram of a semiconductor light emitting structure provided by an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the structure of a lower restriction layer provided in one embodiment of the present invention;

[0020] Figure 3 A schematic diagram of component changes in a lower restricting layer provided in one embodiment of the present invention;

[0021] Figure 4 Schematic diagram of component changes in the lower restricting layer of Comparative Example 1;

[0022] Figure 5 is a schematic diagram of the semiconductor light-emitting structure in Example 1 under an optical microscope;

[0023] Figure 6 This is a schematic diagram of the semiconductor light-emitting structure in Comparative Example 1 under an optical microscope. DETAILED DESCRIPTION

[0024] Research has found that for semiconductor light-emitting structures, regulating the light field and suppressing optical losses are important research directions for improving the performance of semiconductor light-emitting structures. The larger the light field confinement factor of the semiconductor light-emitting structure, the higher the gain and the better the performance of the semiconductor light-emitting structure. The light field confinement factor is mainly affected by the waveguide layer and the confinement layer, so improving the confinement layer of the semiconductor light-emitting structure plays an important role in improving the performance of the semiconductor light-emitting structure. The lower confinement layer of the semiconductor light-emitting structure of the related art is a thick AlGaN lower confinement layer. The thickness of the lower confinement layer of the semiconductor light-emitting structure of the related art is relatively thick, and the Al group of the lower confinement layer is relatively high, so as to improve the confinement effect of the lower confinement layer on light. However, if the thickness of the lower confinement layer is too thick and / or the Al group of the lower confinement layer is too high, the stress of the lower confinement layer will increase, which is not conducive to the growth of the active layer, and in severe cases, it will cause the semiconductor light-emitting structure to crack.

[0025] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] An embodiment of the present invention provides a semiconductor light emitting structure, referring to Figure 1 and Figure 3 , including: a substrate layer 100, a lower confinement layer 110, a lower waveguide layer 120, an active layer 130, an upper waveguide layer 150 and an upper confinement layer 160 stacked in sequence.

[0030] refer to Figure 2 The lower restriction layer 110 includes a plurality of stacked sub-lower restriction layer groups 110a, wherein the sub-lower restriction layer group 110a includes a stacked first sub-lower restriction layer 111 and a second sub-lower restriction layer 112, wherein the first sub-lower restriction layer 111 is in compressive strain relative to the substrate layer 100, and the second sub-lower restriction layer 112 is in tensile strain relative to the substrate layer 100, and the refractive index of the second sub-lower restriction layer 112 in the sub-lower restriction layer group 110a is less than the refractive index of the first sub-lower restriction layer 111.

[0031] In the semiconductor light emitting structure of this embodiment, the refractive index of the second sub-lower confinement layer 112 in the sub-lower confinement layer group 110a is relatively small, and is used to confine the light field. The first sub-lower confinement layer 111 is provided in the sub-lower confinement layer group 110a, and the first sub-lower confinement layer 111 is in compressive strain relative to the substrate layer 100, so that the first sub-lower confinement layer 111 can compensate the stress of the second sub-lower confinement layer 112, alleviate the cracking phenomenon between the sub-lower confinement layer group 110a and the substrate layer 100, and improve the reliability of the semiconductor light emitting structure.

[0032] The semiconductor light emitting structure includes an edge emitting semiconductor laser.

[0033] In one embodiment, the material of the first lower sub-limiting layer 111 is In x Ga (1-x) N, the material of the second lower sub-limiting layer 112 is Al (1-y) Ga y N. x is greater than 0, y is greater than 0.

[0034] The lattice constant of the second lower confinement layer 112 is smaller than that of the substrate layer 100, so the second lower confinement layer 112 is in tensile strain relative to the substrate layer 100. The lattice constant of the first lower confinement layer 111 is larger than that of the substrate layer 100, so the first lower confinement layer 111 is in compressive strain relative to the substrate layer 100.

[0035] The first sub-lower confinement layer 111 includes the In element, and as the In component in the first sub-lower confinement layer 111 increases, the lattice constant of the first sub-lower confinement layer 111 increases, and the refractive index of the first sub-lower confinement layer 111 increases. The second sub-lower confinement layer 112 includes the Al element, and as the Al in the second sub-lower confinement layer 112 increases, the refractive index of the second sub-lower confinement layer 112 decreases, the lattice constant of the second sub-lower confinement layer 112 decreases, and the light confinement effect of the second sub-lower confinement layer 112 becomes stronger.

[0036] In one embodiment, the Al component in the second sub-lower confinement layer 112 is greater than 0 and less than or equal to 15%. The In component in the first sub-lower confinement layer 111 is greater than or equal to 2% and less than or equal to 10%. The significance of the data is that the In component in the first sub-lower confinement layer 111 is for stress consideration. If the In component in the first sub-lower confinement layer 111 is too low, the stress relief effect is weakened. If the In component in the first sub-lower confinement layer 111 is too high, the defects in the grown first sub-lower confinement layer 111 will increase. Therefore, the In component in the first sub-lower confinement layer 111 is greater than or equal to 2% and less than or equal to 10%, taking both aspects of performance into consideration. The In component in the first sub-lower confinement layer 111 is relatively low, so that the growth quality of the first sub-lower confinement layer 111 is better. The Al component content of the second region 1122 of the second sub-lower confinement layer 112 is relatively high, and the growth quality of the second sub-lower confinement layer 112 is improved, which enhances the light confinement effect of the second sub-lower confinement layer 112.

[0037] In one embodiment, the substrate layer 100 includes a GaN substrate layer or a SiC substrate layer. In other embodiments, the substrate layer 100 may also be made of other materials.

[0038] In one embodiment, reference Figure 3 The second sub-lower confinement layer 112 includes a first zone 1121, a second zone 1122 and a third zone 1123. The first zone 1121, the second zone 1122 and the third zone 1123 in the second sub-lower confinement layer 112 are arranged along the direction from the substrate layer 100 to the active layer 130. The Al component in the first zone 1121 increases from the first component to the second component along the direction from the substrate layer 100 to the active layer 130. The Al component in the third zone 1123 decreases from the third component to the fourth component along the direction from the substrate layer 100 to the active layer 130. The Al component in the second zone 1122 is greater than or equal to the second component and greater than or equal to the third component. The Al component fluctuation in the second zone 1122 is much smaller than the Al component fluctuation in the first zone 1121 and much smaller than the Al component fluctuation in the third zone 1123.

[0039] The fluctuation of the Al composition in the second region 1122 is much smaller than the fluctuation of the Al composition in the first region 1121 , which means that the fluctuation of the Al composition in the second region 1122 is smaller than 1 / 10 of the fluctuation of the Al composition in the first region 1121 .

[0040] The fluctuation of the Al composition in the second region 1122 is much smaller than the fluctuation of the Al composition in the third region 1123 , which means that the fluctuation of the Al composition in the second region 1122 is smaller than 1 / 10 of the fluctuation of the Al composition in the third region 1123 .

[0041] The Al composition fluctuation in the first region 1121 refers to the difference between the second composition and the first composition.

[0042] The Al composition fluctuation in the second region 1122 refers to the difference between the highest value and the lowest value of the Al composition in the second region 1122 .

[0043] The Al composition fluctuation in the third region 1123 refers to the difference between the third composition and the fourth composition.

[0044] In one embodiment, the Al composition fluctuation of the second region 1122 in the second lower sub-confinement layer 112 is less than or equal to 1%.

[0045] In one embodiment, the Al composition of the second region 1122 in the second lower sub-confinement layer 112 is constant.

[0046] The second sub-lower limiting layer 112 includes a first zone 1121, a second zone 1122 and a third zone 1123. The Al component gradually changes from a side surface of the first zone 1121 facing away from the second zone 1122 to a side surface of the first zone 1121 facing the second zone 1122, and the Al component gradually changes from a side surface of the third zone 1123 facing the second zone 1122 to a side surface of the third zone 1123 facing away from the second zone 1122. Therefore, the stress caused by the sudden change in composition of the second sub-lower limiting layer 112 relative to the first sub-lower limiting layer 111 is reduced.

[0047] In one embodiment, the first component is zero. The Al component in the first region 1121 increases from zero to the second component along the direction from the substrate layer 100 to the active layer 130. The fourth component is zero. The Al component in the third region 1123 decreases from the third component to zero along the direction from the substrate layer 100 to the active layer 130.

[0048] In one embodiment, the second component is 2% to 15%. The third component is 2% to 15%.

[0049] In other embodiments, the Al composition in any one of the second lower sub-confining layers 112 is constant.

[0050] In one embodiment, the plurality of stacked sub-lower confinement layer groups 110a include the first sub-lower confinement layer group to the Mth sub-lower confinement layer group in the direction from the substrate layer 100 to the active layer 130, where M is an integer greater than or equal to 2. The Al component in the second region 1122 in the mth sub-lower confinement layer group decreases as m decreases, where m is an integer greater than or equal to 1 and less than or equal to M. That is, the Al component in the second region 1122 closer to the substrate layer 100 is smaller, which further reduces the tensile strain of the second sub-lower confinement layer 112 relative to the substrate layer 100, and alleviates the cracking phenomenon between the sub-lower confinement layer group 110a and the substrate layer 100. The Al component in the second region 1122 in the mth sub-lower confinement layer group decreases as m decreases, that is, the Al component in the second region 1122 in the mth sub-lower confinement layer group closer to the active layer 130 is greater, and the light confinement effect of the second sub-lower confinement layer 112 in the mth sub-lower confinement layer group closer to the active layer 130 is stronger, which better confines the light in the active layer 130 and improves the light field confinement factor.

[0051] In one embodiment, M is equal to 3, the In composition of the second region 1122 in the first sub-lower confinement layer group is 0.07, the In composition of the second region 1122 in the second sub-lower confinement layer group is 0.08, and the In composition of the second region 1122 in the third sub-lower confinement layer group is 0.09.

[0052] In one embodiment, the plurality of stacked lower sub-confinement layer groups include a first lower sub-confinement layer group to an Mth lower sub-confinement layer group in a direction from the substrate layer to the active layer. The In composition of the first lower sub-confinement layer in the mth lower sub-confinement layer group is constant, and m is an integer greater than or equal to 1 and less than or equal to M.

[0053] In one embodiment, a plurality of stacked sub-lower confinement layer groups include a first sub-lower confinement layer group to an Mth sub-lower confinement layer group in a direction from the substrate layer toward the active layer. The In component of the first sub-lower confinement layer in the mth sub-lower confinement layer group decreases as m decreases, where m is an integer greater than or equal to 1 and less than or equal to M. The advantage is that the less the In component in the first sub-lower confinement layer closer to the substrate layer, the better the crystal quality of the first sub-lower confinement layer closer to the substrate layer, and the first sub-lower confinement layer is prevented from growing without cracking. Since the Al component in the second region 1122 of the second sub-lower confinement layer 112 closer to the active layer 130 is more, the stress of the second sub-lower confinement layer 112 closer to the active layer 130 will increase. Accordingly, it is necessary to set the In component in the first sub-lower confinement layer closer to the active layer 130 to increase to relieve the greater stress.

[0054] In one embodiment, the thickness of the second zone 1122 is 1 to 15 times, for example, 1, 2, 3, 5, 8, 10, 12 or 15 times, the thickness of the first zone 1121; the thickness of the second zone 1122 is 1 to 15 times, for example, 1, 2, 3, 5, 8, 10, 12 or 15 times, the thickness of the third zone 1123.

[0055] In one embodiment, the thickness of the first region 1121 is greater than or equal to 5 nm and less than or equal to 100 nm, for example, 20 nm. The thickness of the second region 1122 is greater than or equal to 50 nm and less than or equal to 1000 nm, for example, 210 nm. The thickness of the third region 1123 is greater than or equal to 5 nm and less than or equal to 100 nm, for example, 20 nm.

[0056] In one embodiment, the thickness of the second lower sub-confining layer 112 in the lower sub-confining layer group is 2 to 15 times, for example, 2, 3, 5, 8, 10, 12 or 15 times, of the thickness of the first lower sub-confining layer 111. The advantage is that under the stress compensation effect of the thin first lower sub-confining layer 111, the second lower sub-confining layer 112 with a relatively thick thickness is grown, which can reduce the defects caused by the over-thick growth of the second lower sub-confining layer 112, and the second lower sub-confining layer 112 has a thicker thickness, which enhances the light confinement effect.

[0057] In one embodiment, the thickness of the first lower sub-confining layer 111 is greater than or equal to 20 nm and less than or equal to 200 nm, for example, 50 nm. The thickness of the second lower sub-confining layer 112 is greater than or equal to 40 nm and less than or equal to 2000 nm, for example, 250 nm.

[0058] The doping type of lower confinement layer 110 is opposite to the doping type of upper confinement layer 160. The doping type of lower waveguide layer 120 is opposite to the doping type of upper waveguide layer 150. The doping type of lower confinement layer 110 is the same as the doping type of lower waveguide layer 120. The doping type of upper waveguide layer 150 is the same as that of upper confinement layer 160.

[0059] In one embodiment, the conductivity type of the lower confinement layer 110 and the conductivity type of the lower waveguide layer 120 are both n-type, and the conductivity type of the upper waveguide layer 150 and the conductivity type of the upper confinement layer 160 are both p-type.

[0060] In one embodiment, the active layer 130 includes quantum well layers and quantum barrier layers that are alternately stacked, and the band gap of the quantum barrier layer is greater than the band gap of the quantum well layer.

[0061] In one embodiment, the material of the quantum well layer includes In x1 Ga 1-x1N, the material of the quantum barrier layer includes GaN. In one embodiment, x1 is 0.01-0.5, for example 0.14.

[0062] In one embodiment, the thickness of the quantum well layer is 1 nm to 10 nm, for example, 3 nm, and the thickness of the quantum barrier layer is 1 nm to 20 nm, for example, 6 nm.

[0063] In this application, there is no restriction on the material of the active layer, and there is no restriction on the thickness of the quantum barrier layer and the quantum well layer.

[0064] In one embodiment, the lower waveguide layer 120 is a single-layer structure, and the material of the lower waveguide layer 120 is n-type In x2 Ga 1-x2 N, illustratively, x2 is 0.02-0.08, such as 0.04. In one embodiment, the lower waveguide layer 120 is not doped with conductive ions to reduce impurity absorption loss. In one embodiment, the lower waveguide layer 120 is doped with conductive ions, and the doping concentration of the lower waveguide layer 120 is less than the doping concentration of the lower confinement layer 110.

[0065] In one embodiment, the lower waveguide layer 120 includes a first lower waveguide layer and a second lower waveguide layer, the second lower waveguide layer is located between the first lower waveguide layer and the active layer 130, and the refractive index of the second lower waveguide layer is greater than the refractive index of the first lower waveguide layer. The provision of the first lower waveguide layer can improve the growth quality of the second lower waveguide layer and reduce the stress of the second lower waveguide layer.

[0066] In one embodiment, the material of the first lower waveguide layer is n-type GaN, and the material of the second lower waveguide layer is n-type In x21 Ga 1-x21 N. In one embodiment, x21 is 0.02-0.08.

[0067] In one embodiment, the thickness of the lower waveguide layer 120 is 100 nm-300 nm.

[0068] In one embodiment, the upper waveguide layer 150 is a single-layer structure. For example, the material of the upper waveguide layer 150 is p-type In x3 Ga 1-x3 In one embodiment, x3 is 0.02-0.08, for example, x3 is 0.05. In one embodiment, the upper waveguide layer 150 is not doped with conductive ions to reduce impurity absorption loss. For example, the material of the upper waveguide layer 150 is non-doped In x3 Ga 1-x3 N. In one embodiment, the upper waveguide layer 150 is doped with conductive ions, and the concentration of the conductive ions in the upper waveguide layer 150 is less than the concentration of the conductive ions in the upper confinement layer 160 .

[0069] In one embodiment, the thickness of the upper waveguide layer 150 is 100 nm to 300 nm.

[0070] In one embodiment, the upper limiting layer 160 is a single-layer structure, and the material of the upper limiting layer 160 is p-type Al x4 Ga 1-x4 N, in one embodiment, x4 is 0.04~0.1.

[0071] In another embodiment, the upper limiting layer 160 is a multi-layer structure.

[0072] Further, the upper confinement layer 160 is a superlattice structure. The upper confinement layer 160 includes a plurality of stacked sub-upper confinement layer groups. The sub-upper confinement layer group includes a first upper confinement layer and a second upper confinement layer. In the sub-upper confinement layer group, the second upper confinement layer is located on a side of the first upper confinement layer away from the active layer 130, and the refractive index of the second upper confinement layer is greater than the refractive index of the first upper confinement layer. Exemplarily, the material of the first upper confinement layer includes p-type GaN, and the material of the second upper confinement layer includes p-type Al x41 Ga 1-x41 N, wherein. In a specific embodiment, x41 is 0.04-0.1. The first upper confinement layer can improve the growth quality of the second upper confinement layer.

[0073] In one embodiment, the thickness of the upper limiting layer 160 is 100 nm to 800 nm, for example, 300 nm.

[0074] In one embodiment, the semiconductor light emitting structure further includes: a contact layer 170 , which is located on a side of the upper confinement layer 160 away from the active layer 130 . The doping concentration of the contact layer 170 is greater than the doping concentration of the upper confinement layer 160 .

[0075] In one embodiment, the thickness of the contact layer 170 is 10 nm to 50 nm.

[0076] In one embodiment, the material of the contact layer 170 includes p-type GaN.

[0077] In one embodiment, the semiconductor light emitting structure further includes: a carrier blocking layer 140 located between the upper waveguide layer 150 and the active layer 130. When the doping type of the upper waveguide layer 150 is p-type, the carrier blocking layer 140 is an electron blocking layer.

[0078] In one embodiment, the material of the carrier blocking layer 140 includes p-type Al x51 Ga 1-x51 N. In one embodiment, x41 is 0.1-0.3.

[0079] In one embodiment, the thickness of the carrier blocking layer 140 is 5 nm to 20 nm.

[0080] In one embodiment, the semiconductor light emitting structure has a front cavity surface and a rear cavity surface that are arranged opposite to each other. The semiconductor light emitting structure further includes: an anti-reflection film located on the front cavity surface, and a reflective film located on the rear cavity surface.

[0081] In one embodiment, the semiconductor light emitting structure is an edge emitting semiconductor laser.

[0082] The lower confinement layer in the semiconductor light emitting structure of Example 1 refers to the lower confinement layer described above.

[0083] Comparative Example 1: The difference between Comparative Example 1 and Example 1 is that the lower confinement layer 110 of Comparative Example 1 is a single-layer structure, the lower confinement layer is Si-doped AlGaN, the thickness of the lower confinement layer is 750nm, and the Al component in the lower confinement layer is 0.08 (reference Figure 4 ).

[0084] refer to Figure 5 , the semiconductor light emitting structure in Example 1 has no cracks. Figure 6 , the semiconductor light-emitting structure of Comparative Example 1 showed obvious cracks.

[0085] The present invention also provides a method for preparing a semiconductor light-emitting structure, comprising: forming a stacked lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer in sequence on one side of a substrate layer; wherein the step of forming the lower confinement layer comprises forming a plurality of stacked sub-lower confinement layer groups, and the step of forming the sub-lower confinement layer groups comprises forming a stacked first sub-lower confinement layer and a second sub-lower confinement layer, wherein the first sub-lower confinement layer is in compressive strain relative to the substrate layer, and the second sub-lower confinement layer is in tensile strain relative to the substrate layer, and the refractive index of the second sub-lower confinement layer in the sub-lower confinement layer group is less than the refractive index of the first sub-lower confinement layer.

[0086] In one embodiment, the step of forming a second sub-lower limiting layer includes forming a first zone, a second zone and a third zone, the first zone, the second zone and the third zone in the second sub-lower limiting layer are arranged along the direction from the substrate layer to the active layer, the Al component in the first zone increases from the first component to the second component along the direction from the substrate layer to the active layer, the Al component in the third zone decreases from the third component to the fourth component along the direction from the substrate layer to the active layer, the Al component in the second zone is greater than or equal to the second component and greater than or equal to the third component, and the Al component fluctuation in the second zone is much smaller than the Al component fluctuation in the first zone and much smaller than the Al component fluctuation in the third zone.

[0087] The description of the first lower sub-confining layer and the second lower sub-confining layer refers to the description of the aforementioned embodiment and will not be described in detail.

[0088] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A semiconductor light emitting structure, comprising an edge emitting semiconductor laser, characterized in that: include: A substrate layer, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer stacked in sequence; Wherein, the lower restriction layer includes a plurality of stacked sub-lower restriction layer groups, the sub-lower restriction layer group includes a stacked first sub-lower restriction layer and a second sub-lower restriction layer, the first sub-lower restriction layer is in compressive strain relative to the substrate layer, the second sub-lower restriction layer is in tensile strain relative to the substrate layer, and the refractive index of the second sub-lower restriction layer in the sub-lower restriction layer group is less than the refractive index of the first sub-lower restriction layer.

2. The semiconductor light emitting structure according to claim 1, characterized in that: The second sub-lower confinement layer includes a first zone, a second zone and a third zone. The first zone, the second zone and the third zone in the second sub-lower confinement layer are arranged along the direction from the substrate layer to the active layer. The Al component in the first zone increases from the first component to the second component along the direction from the substrate layer to the active layer. The Al component in the third zone decreases from the third component to the fourth component along the direction from the substrate layer to the active layer. The Al component in the second zone is greater than or equal to the second component and greater than or equal to the third component. The Al component fluctuation in the second zone is much smaller than the Al component fluctuation in the first zone and much smaller than the Al component fluctuation in the third zone.

3. The semiconductor light emitting structure according to claim 2, characterized in that: The Al composition of the second region in the second lower sub-confinement layer is constant.

4. The semiconductor light emitting structure according to claim 2, characterized in that: The plurality of stacked lower sub-confinement layer groups include a first lower sub-confinement layer group to an Mth lower sub-confinement layer group in a direction from the substrate layer toward the active layer, where M is an integer greater than or equal to 2; The Al composition in the second region in the m-th sub-lower confinement layer group decreases as m decreases, where m is an integer greater than or equal to 1 and less than or equal to M.

5. The semiconductor light emitting structure according to any one of claims 1 to 4, characterized in that: A plurality of stacked lower sub-confinement layer groups include a first lower sub-confinement layer group to an Mth lower sub-confinement layer group in a direction from the substrate layer toward the active layer; The In composition of the first sub-lower confinement layer in the m-th sub-lower confinement layer group is constant; Alternatively, the In component of the first lower sub-confining layer in the mth lower sub-confining layer group decreases as m decreases; m is an integer greater than or equal to 1 and less than or equal to M.

6. The semiconductor light emitting structure according to claim 2, characterized in that: The thickness of the second zone is 1 to 15 times the thickness of the first zone; the thickness of the second zone is 1 to 15 times the thickness of the third zone.

7. The semiconductor light emitting structure according to any one of claims 1 to 4, characterized in that: The thickness of the second lower sub-confining layer in the lower sub-confining layer group is 2 to 15 times the thickness of the first lower sub-confining layer.

8. The semiconductor light emitting structure according to claim 1, characterized in that: The material of the first lower confinement layer is In x Ga (1-x) N, the material of the second sub-lower limiting layer is Al (1-y) Ga y N.

9. The semiconductor light emitting structure according to claim 1, characterized in that: The upper confinement layer is a superlattice structure.

10. A method for preparing a semiconductor light emitting structure according to any one of claims 1 to 9, characterized in that: include: A lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer and an upper confinement layer are sequentially formed on one side of the substrate layer; Among them, the step of forming the lower restriction layer includes forming a plurality of stacked sub-lower restriction layer groups, and the step of forming the sub-lower restriction layer group includes forming a stacked first sub-lower restriction layer and a second sub-lower restriction layer, the first sub-lower restriction layer is in compressive strain relative to the substrate layer, the second sub-lower restriction layer is in tensile strain relative to the substrate layer, and the refractive index of the second sub-lower restriction layer in the sub-lower restriction layer group is smaller than the refractive index of the first sub-lower restriction layer.

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