Semiconductor light emitting structure integrated with grating and method of fabricating the same

Abstract

The application provides an integrated grating semiconductor light-emitting structure and a preparation method thereof. The integrated grating semiconductor light-emitting structure comprises a semiconductor substrate layer, a gain structure and a grating waveguide medium structure, and the junction of the grating waveguide medium structure and the gain structure has an anti-reflection structure. The gain structure is located on one side of the semiconductor substrate layer along a fast axis direction, and the gain structure comprises a first semiconductor confinement layer, a first semiconductor waveguide layer, an active layer, a second semiconductor waveguide layer and a second semiconductor confinement layer arranged in sequence along the fast axis direction. The grating waveguide medium structure is located on one side of the semiconductor substrate layer along the fast axis direction and on one side of the gain structure along a cavity length direction, and the grating waveguide medium structure is integrated with a grating. The wavelength temperature drift coefficient of the integrated grating semiconductor light-emitting structure is reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to a semiconductor light-emitting structure with an integrated grating and its fabrication method. Background Technology

[0002] Semiconductor light-emitting structures include edge-emitting semiconductor light-emitting structures. An edge-emitting semiconductor light-emitting structure comprises a semiconductor substrate layer, a lower confinement layer, a lower waveguide layer, an active layer, an upper waveguide layer, and an upper confinement layer stacked in the fast axis direction. Summary of the Invention

[0003] The technical problem to be solved by the present invention is how to enhance the wavelength locking temperature drift of the integrated grating semiconductor light-emitting structure, thereby providing an integrated grating semiconductor light-emitting structure and its fabrication method.

[0004] This application provides a semiconductor light-emitting structure with an integrated grating, comprising: a semiconductor substrate, a gain structure, and a grating waveguide dielectric structure; the grating waveguide dielectric structure integrates a grating; wherein, an anti-reflection structure is provided at the junction of the grating waveguide dielectric structure and the gain structure; wherein, the gain structure is located on one side of a portion of the semiconductor substrate along the fast axis direction, and the gain structure includes a first semiconductor confinement layer, a first semiconductor waveguide layer, an active layer, a second semiconductor waveguide layer, and a second semiconductor confinement layer arranged sequentially along the fast axis direction, the second semiconductor confinement layer being located on the side of the first semiconductor confinement layer opposite to the semiconductor substrate; the grating waveguide dielectric structure is located on one side of a portion of the semiconductor substrate along the fast axis direction and on one side of the gain structure along the cavity length direction.

[0005] In some embodiments, the gain structure includes a gain main structure and a plurality of first protrusions arranged along the slow axis direction. The first protrusions are located on the side of the gain main structure facing the grating waveguide dielectric structure and are connected to the gain main structure. The grating waveguide dielectric structure includes a main grating waveguide structure and a plurality of second protrusions arranged along the slow axis direction. The second protrusions are located on the side of the main grating waveguide structure facing the gain structure and are connected to the main grating waveguide structure. A grating is integrated in the main grating waveguide structure. The first protrusions are located between adjacent second protrusions, and the second protrusions are located between adjacent first protrusions. The plurality of first protrusions and the plurality of second protrusions constitute the anti-reflection structure.

[0006] In some embodiments, the first protrusion has a triangular cross-sectional shape along the direction perpendicular to the fast axis, and the second protrusion has a triangular cross-sectional shape along the direction perpendicular to the fast axis.

[0007] In some embodiments, the dimensions of the first protrusion in the cavity length direction and the dimensions of the second protrusion in the cavity length direction are K1, respectively; the distance between the centers of adjacent first protrusions in the slow axis direction and the distance between the centers of adjacent second protrusions in the slow axis direction are K2, respectively; wherein, K1 is less than or equal to 1 μm and K2 is less than or equal to 0.2 μm.

[0008] In some embodiments, the antireflection structure is located between the grating waveguide medium structure and the gain structure; wherein the refractive index of the antireflection structure is greater than the equivalent refractive index of the grating waveguide medium structure and less than the equivalent refractive index of the gain structure.

[0009] In some embodiments, the antireflective structure has a strip-shaped cross-section perpendicular to the fast axis.

[0010] In some embodiments, the grating waveguide dielectric structure includes a first dielectric confinement layer, a dielectric waveguide layer, and a second dielectric confinement layer. The dielectric waveguide layer is located on the side of the first dielectric confinement layer opposite to the semiconductor substrate, and the second dielectric confinement layer is located on the side of the dielectric waveguide layer opposite to the first dielectric confinement layer. The equivalent refractive index of the dielectric waveguide layer is greater than the equivalent refractive index of the second dielectric confinement layer and also greater than the equivalent refractive index of the first dielectric confinement layer. A grating is integrated into the grating waveguide dielectric structure.

[0011] In some embodiments, the second dielectric confinement layer has a grating; or, the dielectric waveguide layer has a grating; or, the first dielectric confinement layer has a grating.

[0012] In some embodiments, the second dielectric confinement layer has overlapping projections with the second semiconductor confinement layer and the second semiconductor waveguide layer in the cavity length direction, and the dielectric waveguide layer and the active layer have overlapping projections in the cavity length direction; the first dielectric confinement layer has overlapping projections with the first semiconductor waveguide layer and the first semiconductor confinement layer in the cavity length direction.

[0013] In some embodiments, the equivalent refractive index of the first dielectric confinement layer is located between the equivalent refractive index of the second dielectric confinement layer and the equivalent refractive index of the dielectric waveguide layer.

[0014] In some embodiments, the dielectric waveguide layer includes a first sub-waveguide layer and a second sub-waveguide layer alternately stacked in the fast axis direction; wherein the refractive index of the first sub-waveguide layer is greater than the refractive index of the first dielectric confinement layer and greater than the refractive index of the second dielectric confinement layer; and the refractive index of the second sub-waveguide layer is less than the refractive index of the first sub-waveguide layer.

[0015] In some embodiments, the first dielectric confinement layer includes a first sub-dielectric confinement layer and a second sub-dielectric confinement layer alternately stacked in the fast axis direction; wherein the refractive index of the first sub-dielectric confinement layer is less than the refractive index of the dielectric waveguide layer, and the refractive index of the second sub-dielectric confinement layer is greater than the refractive index of the first sub-dielectric confinement layer.

[0016] In some embodiments, the second dielectric confinement layer includes a third sub-dielectric confinement layer and a fourth sub-dielectric confinement layer alternately stacked in the fast axis direction, wherein the refractive index of the third sub-dielectric confinement layer is less than the refractive index of the dielectric waveguide layer, and the refractive index of the fourth sub-dielectric confinement layer is greater than the refractive index of the third sub-dielectric confinement layer.

[0017] This application also provides a method for fabricating a semiconductor light-emitting structure with an integrated grating, comprising: forming a gain structure on one side of a portion of a semiconductor substrate along the fast axis direction, the gain structure comprising a first semiconductor confinement layer, a first semiconductor waveguide layer, an active layer, a second semiconductor waveguide layer, and a second semiconductor confinement layer arranged sequentially along the fast axis direction, the second semiconductor confinement layer being located on the side of the first semiconductor confinement layer opposite to the semiconductor substrate; forming a grating waveguide dielectric structure on one side of a portion of the semiconductor substrate along the fast axis direction, the grating waveguide dielectric structure being located on one side of the gain structure along the cavity length direction; integrating a grating in the grating waveguide dielectric structure; and forming an anti-reflection structure, wherein the interface between the grating waveguide dielectric structure and the gain structure has an anti-reflection structure.

[0018] In some embodiments, forming the grating waveguide dielectric structure includes forming a first dielectric confinement layer, a dielectric waveguide layer, and a second dielectric confinement layer, wherein the dielectric waveguide layer is located on the side of the first dielectric confinement layer opposite to the semiconductor substrate, and the second dielectric confinement layer is located on the side of the dielectric waveguide layer opposite to the first dielectric confinement layer; wherein the equivalent refractive index of the dielectric waveguide layer is greater than the equivalent refractive index of the second dielectric confinement layer and greater than the equivalent refractive index of the first dielectric confinement layer; and the grating is integrated in the grating waveguide dielectric structure.

[0019] In some embodiments, forming the gain structure includes: sequentially forming a first initial semiconductor confinement layer, a first initial semiconductor waveguide layer, an initial active layer, a second initial semiconductor waveguide layer, and a second initial semiconductor confinement layer on one side of the semiconductor substrate along the fast axis direction; removing a portion of the first initial semiconductor confinement layer, a portion of the first initial semiconductor waveguide layer, a portion of the initial active layer, a portion of the second initial semiconductor waveguide layer, and a portion of the second initial semiconductor confinement layer, with the remaining first initial semiconductor confinement layer forming the first semiconductor confinement layer, the remaining first initial semiconductor waveguide layer forming the first semiconductor waveguide layer, the remaining initial active layer forming the active layer, the remaining second initial semiconductor waveguide layer forming the second semiconductor waveguide layer, and the remaining second initial semiconductor confinement layer forming the second semiconductor confinement layer.

[0020] In some embodiments, forming the grating waveguide dielectric structure includes: forming the grating waveguide dielectric structure on one side of a portion of the semiconductor substrate along the fast axis direction, with a slot between the grating waveguide dielectric structure and the gain structure; wherein forming the anti-reflection structure includes: forming the anti-reflection structure in the slot, the refractive index of the anti-reflection structure being greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure; or, forming the grating waveguide dielectric structure includes: forming a dielectric waveguide structure on one side of a portion of the semiconductor substrate along the fast axis direction, with a slot between the dielectric waveguide structure and the gain structure, forming a grating in the dielectric waveguide structure, such that the dielectric waveguide structure and the grating constitute a grating waveguide dielectric structure; wherein forming the anti-reflection structure includes: forming the anti-reflection structure in the slot, the refractive index of the anti-reflection structure being greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure.

[0021] In some embodiments, forming the gain structure includes forming a gain main structure and a plurality of first protrusions arranged along the slow axis direction, the first protrusions being located on one side of the gain main structure along the cavity length direction and connected to the gain main structure; wherein, forming the grating waveguide dielectric structure includes forming a main grating waveguide structure and a plurality of second protrusions arranged along the slow axis direction, the second protrusions being located on the side of the main grating waveguide structure facing the gain structure and connected to the main grating waveguide structure, the main grating waveguide structure integrating a grating; wherein, the first protrusions are located between adjacent second protrusions, and the second protrusions are located between adjacent first protrusions; the plurality of first protrusions and the plurality of second protrusions constitute the antireflection structure.

[0022] The technical solution of this invention has the following beneficial effects:

[0023] The semiconductor light-emitting structure with integrated grating provided by this invention uses a dielectric material for the grating waveguide dielectric structure and a semiconductor material for the gain structure. The refractive index temperature drift coefficient of the dielectric material is smaller than that of the semiconductor material. The wavelength temperature drift coefficient decreases as the refractive index temperature drift coefficient decreases, thus reducing the wavelength temperature drift coefficient of the semiconductor light-emitting structure. Light emitted from the gain structure is transmitted to the grating waveguide dielectric structure through an anti-reflection structure. The grating filters wavelengths and feeds back light of a specific wavelength to the gain structure. The anti-reflection structure allows more light to be transmitted from the gain structure to the grating waveguide dielectric structure, forming a stable wavelength lock and reducing the wavelength temperature drift coefficient of the semiconductor light-emitting structure. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the semiconductor light-emitting structure of an integrated grating according to an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of a semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0027] Figure 3 This is a schematic diagram of a semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0028] Figure 4 for Figure 1 , Figure 2 and Figure 3 Top view of the medium-gain structure, grating waveguide dielectric structure, and anti-reflection structure;

[0029] Figure 5 This is a schematic diagram of a semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0030] Figure 6 This is a schematic diagram of a semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0031] Figure 7 This is a schematic diagram of a semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0032] Figure 8 for Figure 5 , Figure 6 and Figure 7 Top view of the medium-gain structure and the grating waveguide dielectric structure;

[0033] Figure 9 The optical field distributions of the gain structure and the grating waveguide dielectric structure are shown in the fast axis direction, respectively.

[0034] Figure 10 This is a curve showing the change in grating reflectivity as a function of wavelength.

[0035] Figure 11 The light field distribution and refractive index of the grating waveguide dielectric structure in the semiconductor light-emitting structure of the integrated grating according to an embodiment of this application are shown in the fast axis direction.

[0036] Figure 12 The light field distribution and refractive index of the grating waveguide dielectric structure in the semiconductor light-emitting structure of the integrated grating according to another embodiment of this application are shown in the fast axis direction.

[0037] Figure 13 The light field distribution and refractive index of the grating waveguide dielectric structure in the semiconductor light-emitting structure of the integrated grating according to another embodiment of this application are shown in the fast axis direction.

[0038] Figures 14 to 19 This is a schematic diagram illustrating the fabrication process of the semiconductor light-emitting structure with an integrated grating according to an embodiment of this application;

[0039] Figures 20 to 25 This is a schematic diagram illustrating the fabrication process of the semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0040] Figures 26 to 28 This is a schematic diagram illustrating the fabrication process of the semiconductor light-emitting structure with an integrated grating according to another embodiment of this application;

[0041] Figures 29 to 31 This is a schematic diagram illustrating the fabrication process of the semiconductor light-emitting structure with an integrated grating according to another embodiment of this application. Detailed Implementation

[0042] High-power semiconductor laser chips operate with a half-width at half-maximum (FWHM) of around 3 nm. However, the peak wavelength of these chips varies with operating temperature, exhibiting a wavelength drift coefficient on the order of 0.3 nm / ℃, necessitating strict temperature control. One method to reduce this coefficient is wavelength locking using an external cavity Bragg grating, which can lower the drift coefficient to below 0.01 nm / ℃. However, this method suffers from system complexity, particularly the inclusion of the external cavity Bragg grating. Another approach involves on-chip grating-based wavelength locking, reducing the drift coefficient to approximately 0.07 nm / ℃. However, for pumping applications requiring a wide temperature range, on-chip grating-based wavelength locking still results in excessively high drift.

[0043] Based on this, this application proposes a semiconductor light-emitting structure with integrated grating and its fabrication method, which reduces the temperature drift coefficient when the semiconductor light-emitting structure with integrated grating is wavelength locked.

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0046] Furthermore, 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.

[0047] One embodiment of the present invention provides a semiconductor light-emitting structure with an integrated grating, referenced to... Figures 1 to 6 The integrated grating semiconductor light-emitting structure includes a semiconductor substrate layer 100, a gain structure A, and a grating waveguide dielectric structure B.

[0048] Gain structure A is located on one side of the partial semiconductor substrate 100 along the fast axis direction Z. Gain structure A includes a first semiconductor confinement layer 110, a first semiconductor waveguide layer 120, an active layer 130, a second semiconductor waveguide layer 140, and a second semiconductor confinement layer 150 arranged sequentially along the fast axis direction Z. The second semiconductor confinement layer 150 is located on the side of the first semiconductor confinement layer 110 opposite to the semiconductor substrate 100. Grating waveguide dielectric structure B is located on one side of the partial semiconductor substrate 100 along the fast axis direction Z and on one side of gain structure A along the cavity length direction X. A grating is integrated in grating waveguide dielectric structure A.

[0049] An anti-reflection structure 240 is present at the junction of the grating waveguide dielectric structure B and the gain structure A. The integrated grating semiconductor light-emitting junction includes an integrated grating semiconductor laser.

[0050] In at least one embodiment of this application, the semiconductor light-emitting structure with integrated grating has a grating waveguide dielectric structure B made of dielectric material and a gain structure A made of semiconductor material. The refractive index temperature drift coefficient of the dielectric material is smaller than that of the semiconductor material. The wavelength temperature drift coefficient decreases as the refractive index temperature drift coefficient decreases, thus reducing the wavelength temperature drift coefficient of the semiconductor light-emitting structure.

[0051] In this embodiment, the light emitted from the gain structure A is transmitted to the grating waveguide dielectric structure B through the anti-reflection structure 240. The grating filters the wavelength and feeds back light of a specific wavelength to the gain structure A. The anti-reflection structure 240 enables more light to be transmitted from the gain structure A to the grating waveguide dielectric structure B, forming a stable wavelength lock and reducing the wavelength temperature drift coefficient of the semiconductor light-emitting structure.

[0052] In this embodiment, the semiconductor structure of the integrated grating further includes: an antireflection film (not shown) and a reflective film (not shown).

[0053] In this embodiment, the end face of the grating waveguide dielectric structure B facing away from the gain structure A serves as the rear cavity face. The reflective film is located on the front cavity face of the gain structure A facing away from the grating waveguide dielectric structure B, and the antireflective film is located on the rear cavity face of the grating waveguide dielectric structure B facing away from the gain structure A. A resonant cavity is formed between the reflective film and the grating waveguide dielectric structure B, and the reflectivity of the reflective film is less than that of the grating.

[0054] In other embodiments, the end face of the grating waveguide dielectric structure B facing away from the gain structure A serves as the front cavity face. The reflective film is located on the rear cavity face of the gain structure A facing away from the grating waveguide dielectric structure B, and the antireflective film is located on the front cavity face of the grating waveguide dielectric structure B facing away from the gain structure A. A resonant cavity is formed between the reflective film and the grating waveguide dielectric structure B. The reflectivity of the reflective film is greater than that of the grating, and the reflectivity of the antireflective film is less than that of the reflective film. Furthermore, the reflectivity of the antireflective film can be less than that of the grating.

[0055] In some embodiments, the refractive index of the first semiconductor waveguide layer 120 is greater than the refractive index of the first semiconductor confinement layer 110 and greater than the refractive index of the second semiconductor confinement layer 150, and the refractive index of the second semiconductor waveguide layer 140 is greater than the refractive index of the first semiconductor confinement layer 110 and greater than the refractive index of the second semiconductor confinement layer 150. The first semiconductor confinement layer 110 and the second semiconductor confinement layer 150 confine the light field.

[0056] In some embodiments, the refractive index of the first semiconductor confinement layer 110 is greater than that of the second semiconductor confinement layer 150, so that the peak of the light field is located in the first semiconductor waveguide layer 120.

[0057] In some embodiments, the material of the first semiconductor confinement layer 110 includes Al. x1 Ga 1-x1 As, the material of the first semiconductor waveguide layer 120 includes Al. x2 Ga 1-x2 As, the material of the second semiconductor waveguide layer 140 includes Al. x2 Ga 1-x2 As, the material of the second semiconductor confinement layer 150 includes Al. x3 Ga 1-x1 As. Where x2 is less than x1 and less than x3, and further, x1 is less than x3.

[0058] In one embodiment, the refractive index temperature drift coefficient of the dielectric material used in the grating waveguide dielectric structure B is 0.05 to 0.2 times that of the refractive index temperature drift coefficient of the semiconductor material used in the gain structure A, for example, 0.05 times, 0.1 times, 0.15 times or 0.2 times.

[0059] Table 1

[0060]

[0061] Table 1 shows the specific values ​​of refractive index, refractive index temperature drift coefficient, coefficient of thermal expansion, and Bragg wavelength temperature drift coefficient dλ / dT for some materials with a working wavelength of 980nm. From Table 1, the dielectric materials are, for example, Si3N4, SiO2, Al2O3, or Ta2O5, and the semiconductor materials are, for example, GaAs, InP, or GaN. The refractive index temperature drift coefficient of the dielectric materials is smaller than that of the semiconductor materials.

[0062] In some embodiments, the grating waveguide dielectric structure B includes a first dielectric confinement layer 210, a second dielectric confinement layer 230, and a dielectric waveguide layer 220. The dielectric waveguide layer 220 is located on the side of the first dielectric confinement layer 210 facing away from the semiconductor substrate 100, and the second dielectric confinement layer 230 is located on the side of the dielectric waveguide layer 220 facing away from the first dielectric confinement layer 210. The equivalent refractive index of the dielectric waveguide layer 220 is greater than the equivalent refractive index of the second dielectric confinement layer 230 and greater than the equivalent refractive index of the first dielectric confinement layer 210; a grating is integrated in the grating waveguide dielectric structure B.

[0063] In some embodiments, when the refractive index of the first semiconductor confinement layer 110 is greater than the refractive index of the second semiconductor confinement layer 150, the equivalent refractive index of the first dielectric confinement layer 210 is located between the equivalent refractive index of the second dielectric confinement layer 230 and the equivalent refractive index of the dielectric waveguide layer 220. The optical field distribution along the fast axis Z of the grating waveguide dielectric structure B should be as close as possible to the optical field distribution along the fast axis Z in the gain structure A to improve the coupling coefficient between the grating waveguide dielectric structure B and the gain structure A.

[0064] In some embodiments, the material of the second dielectric confinement layer 230 is SiO2 or Al2O3. The material of the dielectric waveguide layer 220 is Si3N4 or Ta2O5. The refractive index of the first dielectric confinement layer 210 is between the refractive index of the second dielectric confinement layer 230 and the refractive index of the dielectric waveguide layer 220.

[0065] In some embodiments, the second dielectric confinement layer 230 has overlapping projections with the second semiconductor confinement layer 150 and the second semiconductor waveguide layer 140 in the cavity length direction X, and the dielectric waveguide layer 220 and the active layer 130 have overlapping projections in the cavity length direction X; the first dielectric confinement layer 210 has overlapping projections with the first semiconductor waveguide layer 120 and the first semiconductor confinement layer 110 in the cavity length direction X. The advantage is that it makes the optical field distribution in the grating waveguide dielectric structure B and the gain structure A similar, reducing the transmission loss of light at the interface between the grating waveguide dielectric structure B and the gain structure A.

[0066] In some embodiments, a grating is integrated in the second dielectric confinement layer 230, exemplarily, referring to... Figure 1 and Figure 5 The second dielectric confinement layer 230 has grating grooves that extend along the surface of the second dielectric confinement layer 230 away from the dielectric waveguide layer 220 into a portion of the second dielectric confinement layer 230. The second dielectric confinement layers 230 between adjacent grating grooves constitute a grating. In other embodiments, a grating may be integrated into the second dielectric confinement layer, with the grating and the surface of the second dielectric confinement layer away from the dielectric waveguide layer spaced apart, and the grating and the dielectric waveguide layer 220 spaced apart.

[0067] In some implementations, reference Figure 2 , Figure 3 , Figure 6 and Figure 7 A grating is integrated in the dielectric waveguide layer 220. (Reference) Figure 2 and Figure 6 The dielectric waveguide layer 220 has multiple protrusions on its surface facing the first dielectric confinement layer 210. These protrusions are embedded in the first dielectric confinement layer 210, and together they form a grating. (Reference) Figure 3 and Figure 7 The gratings in the dielectric waveguide layer 220 are respectively arranged at intervals in the fast axis direction Z of the second dielectric confinement layer 230 and the first dielectric confinement layer 210. In other embodiments, the dielectric waveguide layer 220 may have a plurality of protrusions on the side surface facing the second dielectric confinement layer 230, the protrusions being embedded in the second dielectric confinement layer 230, and the plurality of protrusions forming a grating.

[0068] In other embodiments, a grating is integrated in the first dielectric confinement layer.

[0069] In some embodiments, the dielectric waveguide layer 220 includes a first sub-waveguide layer and a second sub-waveguide layer alternately stacked in the fast axis direction Z, and the dielectric waveguide layer 220 is a composite structure. The refractive index of the first sub-waveguide layer is greater than the refractive index of the first dielectric confinement layer 210 and greater than the refractive index of the second dielectric confinement layer 230; the refractive index of the second sub-waveguide layer is less than the refractive index of the first sub-waveguide layer. The equivalent refractive index of the dielectric waveguide layer 220 is greater than the refractive index of the second dielectric confinement layer 230 and greater than the refractive index of the first dielectric confinement layer 210. The refractive index of the second sub-waveguide layer can be less than, equal to, or greater than the refractive index of the first dielectric confinement layer 210, but it is necessary to ensure that the equivalent refractive index of the dielectric waveguide layer 220 is greater than the refractive index of the first dielectric confinement layer 210. Further, the refractive index of the second dielectric confinement layer 230 is less than the refractive index of the first dielectric confinement layer 210.

[0070] In some implementations, the total thickness of the first sub-waveguide layer and the second sub-waveguide layer needs to be small enough to prevent significant fluctuations in the optical mode. For example, the total thickness of the first sub-waveguide layer and the second sub-waveguide layer is less than or equal to 120 nm, such as 120 nm, 100 nm, or 50 nm.

[0071] In some implementations... Figure 11 and Figure 13 The area indicated by the dashed line shows the optical field distribution along the fast axis Z and the refractive index distribution along the fast axis Z in the grating waveguide dielectric structure B. Figure 11 and Figure 13 The horizontal axis in the figure represents the position along the fast axis direction Z. Figure 11 and Figure 13 The vertical axis on the left represents the light field intensity. Figure 11 and Figure 13The right-hand vertical axis represents the refractive index. The dielectric waveguide layer 220 includes a first sub-waveguide layer and a second sub-waveguide layer alternately stacked in the fast axis direction Z. The dielectric waveguide layer 220 is a composite structure. The refractive index of the first sub-waveguide layer is greater than the refractive index of the first dielectric confinement layer 210 and greater than the refractive index of the second dielectric confinement layer 230. The refractive index of the second sub-waveguide layer is less than the refractive index of the first sub-waveguide layer. The equivalent refractive index of the dielectric waveguide layer 220 is greater than the refractive index of the second dielectric confinement layer 230 and greater than the refractive index of the first dielectric confinement layer 210. For example, the refractive index of the second sub-waveguide layer is equal to the refractive index of the first dielectric confinement layer 210. For example, the material of the first sub-waveguide layer is Si3N4, the material of the second sub-waveguide layer is Al2O3; the material of the first dielectric confinement layer 210 is Al2O3, and the material of the second dielectric confinement layer 230 is SiO2. By adjusting the thickness ratio of the first sub-waveguide layer and the second sub-waveguide layer, the equivalent refractive index of the dielectric waveguide layer 220 can be adjusted, thereby adjusting the refractive index difference between the dielectric waveguide layer 220 and the second dielectric confinement layer 230, as well as the refractive index difference between the dielectric waveguide layer 220 and the first dielectric confinement layer 210, to achieve optical field matching between the grating waveguide dielectric structure B and the gain structure A.

[0072] Figure 11 The corresponding semiconductor light-emitting structure with an integrated grating can be: an integrated grating in the second dielectric confinement layer 230, for example, refer to Figure 1 and Figure 5 The second dielectric confinement layer 230 has grating grooves that extend along the surface of the second dielectric confinement layer 230 away from the dielectric waveguide layer 220 into a portion of the second dielectric confinement layer 230. The second dielectric confinement layers 230 between adjacent grating grooves constitute a grating. Alternatively, the grating can be integrated in the first dielectric confinement layer 210.

[0073] Figure 13 The corresponding semiconductor light-emitting structure with an integrated grating can be: an integrated grating in the dielectric waveguide layer 220, for example, see reference. Figure 3 and Figure 7 A grating is integrated in the dielectric waveguide layer 220. The refractive index of the first sub-waveguide layer is lower than that of the other first sub-waveguide layers, and the grating is integrated in the first sub-waveguide layer with the lower refractive index.

[0074] In some embodiments, the first dielectric confinement layer 210 includes a first sub-dielectric confinement layer and a second sub-dielectric confinement layer alternately stacked in the fast axis direction. The refractive index of the first sub-dielectric confinement layer is less than the refractive index of the dielectric waveguide layer 220, and the refractive index of the second sub-dielectric confinement layer is greater than the refractive index of the first sub-dielectric confinement layer. The first dielectric confinement layer 210 is a composite structure. The refractive index of the dielectric waveguide layer 220 is greater than the equivalent refractive index of the first dielectric confinement layer 210 and greater than the refractive index of the second dielectric confinement layer 230. Specifically, the refractive index of the second sub-dielectric confinement layer is greater than, equal to, or less than the refractive index of the dielectric waveguide layer 220, but it is required that the refractive index of the dielectric waveguide layer 220 is greater than the equivalent refractive index of the first dielectric confinement layer 210. Further, the refractive index of the second dielectric confinement layer 230 is less than the equivalent refractive index of the first dielectric confinement layer 210. For example, the refractive index of the second sub-dielectric confinement layer is greater than the refractive index of the second dielectric confinement layer 230, and the refractive index of the first sub-dielectric confinement layer is greater than, equal to, or less than the refractive index of the second dielectric confinement layer 230.

[0075] In some implementations, the total thickness of the first sub-dielectric confinement layer and the second sub-dielectric confinement layer needs to be small enough to prevent significant fluctuations in the optical mode. For example, the total thickness of the first sub-dielectric confinement layer and the second sub-dielectric confinement layer is less than or equal to 120 nm, such as 120 nm, 100 nm, or 50 nm.

[0076] In some implementations... Figure 12 The area indicated by the dashed line shows the optical field distribution along the fast axis Z and the refractive index distribution along the fast axis Z in the grating waveguide dielectric structure B. Figure 12 The horizontal axis in the figure represents the position along the fast axis direction Z. Figure 12 The vertical axis on the left represents the light field intensity. Figure 12 The right-hand vertical axis represents the refractive index. The first dielectric confinement layer 210 includes a first sub-dielectric confinement layer and a second sub-dielectric confinement layer alternately stacked in the fast axis direction. The refractive index of the first sub-dielectric confinement layer is less than the refractive index of the dielectric waveguide layer 220, and the refractive index of the second sub-dielectric confinement layer is greater than the refractive index of the first sub-dielectric confinement layer. The first dielectric confinement layer 210 is a composite structure. Taking an example where the refractive index of the second sub-dielectric confinement layer is equal to the refractive index of the dielectric waveguide layer 220, but the refractive index of the dielectric waveguide layer 220 must be greater than the equivalent refractive index of the first dielectric confinement layer 210. Further, the refractive index of the second dielectric confinement layer 230 is less than the equivalent refractive index of the first dielectric confinement layer 210. Taking an example where the refractive indices of the second sub-dielectric confinement layer and the first sub-dielectric confinement layer are both greater than the refractive index of the second dielectric confinement layer 230.

[0077] In some embodiments, the first sub-dielectric confinement layer is made of SiO2, and the second sub-dielectric confinement layer is made of Si3N4; the dielectric waveguide layer 220 is made of Si3N4, and the second dielectric confinement layer 230 is made of SiO2. By adjusting the thickness ratio of the first and second sub-dielectric confinement layers, the equivalent refractive index of the first dielectric confinement layer 210 can be adjusted, thereby adjusting the refractive index difference between the dielectric waveguide layer 220 and the first dielectric confinement layer 210, achieving optical field matching between the grating waveguide dielectric structure B and the gain structure A.

[0078] Figure 12 The corresponding semiconductor light-emitting structure with an integrated grating can be: an integrated grating in the second dielectric confinement layer 230, for example, refer to Figure 1 and Figure 5 The second dielectric confinement layer 230 has grating grooves that extend along the surface of the second dielectric confinement layer 230 away from the dielectric waveguide layer 220 into a portion of the second dielectric confinement layer 230. The second dielectric confinement layers 230 between adjacent grating grooves constitute a grating. Alternatively, the grating can be integrated into the dielectric waveguide layer 220. When the first dielectric confinement layer 210 is a composite structure, the grating can also be integrated into the first dielectric confinement layer 210.

[0079] In some embodiments, the second dielectric confinement layer 230 includes a third sub-dielectric confinement layer and a fourth sub-dielectric confinement layer alternately stacked in the fast axis direction. The refractive index of the third sub-dielectric confinement layer is less than the refractive index of the dielectric waveguide layer 220, and the refractive index of the fourth sub-dielectric confinement layer is greater than the refractive index of the third sub-dielectric confinement layer. The second dielectric confinement layer 230 is a composite structure. The refractive index of the dielectric waveguide layer 220 is greater than the refractive index of the first dielectric confinement layer 210 and greater than the equivalent refractive index of the second dielectric confinement layer 230. Further, the equivalent refractive index of the second dielectric confinement layer 230 is less than the refractive index of the first dielectric confinement layer 210, wherein the refractive index of the third sub-dielectric confinement layer is less than the refractive index of the first dielectric confinement layer 210, and the refractive index of the fourth sub-dielectric confinement layer is greater than, equal to, or less than the refractive index of the first dielectric confinement layer 210.

[0080] In some implementations, the total thickness of the third sub-dielectric confinement layer and the fourth sub-dielectric confinement layer needs to be small enough to prevent significant fluctuations in the optical mode. For example, the total thickness of the third sub-dielectric confinement layer and the fourth sub-dielectric confinement layer is less than or equal to 120 nm, such as 120 nm, 100 nm, or 50 nm.

[0081] When the second dielectric confinement layer 230 is a composite structure, a grating can be integrated into the second dielectric confinement layer 230, or a grating can be integrated into the dielectric waveguide layer 220 and a grating can be integrated into the first dielectric confinement layer 210; when the dielectric waveguide layer 220 is a composite structure, a grating can be integrated into the second dielectric confinement layer 230, or a grating can be integrated into the dielectric waveguide layer 220 and a grating can be integrated into the first dielectric confinement layer 210; when the first dielectric confinement layer 210 is a composite structure, a grating can be integrated into the second dielectric confinement layer 230, or a grating can be integrated into the dielectric waveguide layer 220 and a grating can be integrated into the first dielectric confinement layer 210.

[0082] When the second dielectric confinement layer 230 is a composite structure, the dielectric waveguide layer 220 can be a single-layer structure, and the first dielectric confinement layer 210 can be a single-layer structure. When the first dielectric confinement layer 210 is a composite structure, the dielectric waveguide layer 220 can be a single-layer structure, and the second dielectric confinement layer 230 can be a single-layer structure.

[0083] In some implementations, reference Figures 1 to 4 The anti-reflection structure 240 is located between the grating waveguide dielectric structure B and the gain structure A; wherein the refractive index of the anti-reflection structure 240 is greater than the equivalent refractive index of the grating waveguide dielectric structure B and less than the equivalent refractive index of the gain structure A.

[0084] refer to Figure 4 In some embodiments, the antireflective structure 240 has an elongated cross-sectional shape perpendicular to the fast axis. In other embodiments, the cross-sectional shape of the antireflective structure 240 perpendicular to the fast axis is not limited.

[0085] In some implementations, reference Figures 5 to 8The gain structure A includes a main gain structure A-1 and multiple first protrusions A-2 arranged along the slow axis. The first protrusions A-2 are located on the side of the main gain structure A-1 facing the grating waveguide dielectric structure B and are connected to the main gain structure A-1. The grating waveguide dielectric structure B includes a main grating waveguide structure B-1 and multiple second protrusions B-2 arranged along the slow axis. The second protrusions B-2 are located on the side of the main grating waveguide structure B-1 facing the gain structure A and are connected to the main grating waveguide structure B-1. A grating is integrated into the main grating waveguide structure B-1. No grating is integrated into the second protrusions B-2. The first protrusions A-2 are located between adjacent second protrusions B-2, and the second protrusions B-2 are located between adjacent first protrusions A-2. The multiple first protrusions A-2 and the multiple second protrusions B-2 constitute an anti-reflection structure 240. The equivalent refractive index of the anti-reflection structure 240 is greater than that of the main grating waveguide structure B-1 and less than that of the gain main structure A-1. The anti-reflection structure 240 is constructed using multiple first protrusions A-2 and multiple second protrusions B-2. This has the advantage of forming the anti-reflection structure 240 through a portion of the gain structure A and a portion of the grating dielectric waveguide structure B, eliminating the need for etching grooves at the interface between the gain structure A and the grating dielectric waveguide structure B, and eliminating the need for additional processes to form the anti-reflection structure, thus simplifying the process and reducing costs.

[0086] In some implementations, reference Figure 8 The first protrusion A-2 and the second protrusion B-2 have a triangular cross-sectional shape perpendicular to the fast axis Z. Furthermore, the triangles can be isosceles triangles, with the two sides symmetrical about the cavity length direction X. This has the advantage of allowing the effective refractive index of the antireflection structure 240 to change continuously and linearly along the cavity length direction X, which is beneficial for better antireflection and further improves the coupling coefficient of optical transmission between the gain structure A and the grating waveguide dielectric structure B. Moreover, the shapes of the first protrusion A-2 and the second protrusion B-2 are suitable for etching process control.

[0087] In other embodiments, there are no restrictions on the cross-sectional shape of the first protrusion A-2 along the direction perpendicular to the fast axis Z and the cross-sectional shape of the second protrusion B-2 along the direction perpendicular to the fast axis Z.

[0088] In some implementations, reference Figure 8The dimension of the first protrusion A-2 in the cavity length direction X is K1; the dimension of the second protrusion B-2 in the cavity length direction X is K1; the distance between the centers of adjacent first protrusions A-2 in the slow axis direction is K2, and the distance between the centers of adjacent second protrusions B-2 in the slow axis direction is K2; wherein, K1 is less than or equal to 1 μm, and K2 is less than or equal to 0.2 μm. The advantage is that it prevents multiple periods of reflection of the light field at the interface between the first protrusion A-2 and the second protrusion B-2, and avoids significant intensity fluctuations of the light field in the slow axis direction.

[0089] Figure 9 The middle horizontal axis represents the position of the fast axis in the Z direction. Figure 9 The vertical axis on the left represents the light field intensity. Figure 9 The dashed curve in the figure represents the optical field distribution along the fast axis Z of the grating waveguide dielectric structure B. Figure 9 The solid curve in the figure represents the optical field distribution along the fast axis Z of the gain structure A. The overlap area between the optical field distributions of the grating waveguide dielectric structure B and the gain structure A along the fast axis Z is relatively large, resulting in a high coupling efficiency between the grating waveguide dielectric structure B and the gain structure A, for example, greater than 99.5%. In this embodiment, due to the inclusion of the anti-reflection structure 240 and the use of a dielectric material for the grating waveguide dielectric structure B, the coupling efficiency between the grating waveguide dielectric structure B and the gain structure A can be improved.

[0090] Figure 10 The horizontal axis represents the wavelength. Figure 10 The vertical axis on the left represents the reflectivity of the grating. The grating has a higher reflectivity for specific wavelengths. In other words, the grating has wavelength selectivity.

[0091] In this embodiment, the integrated grating semiconductor light-emitting structure further includes a front electrode and a back electrode. The front electrode is located on the side of the gain structure A away from the semiconductor substrate 100, and the back electrode is located on the side of the semiconductor substrate 100 away from the gain structure A. The front electrode may not extend to the side of the grating waveguide dielectric structure B away from the semiconductor substrate 100. Alternatively, the front electrode may extend to the side of the grating waveguide dielectric structure B away from the semiconductor substrate 100.

[0092] Another embodiment of this application provides a method for fabricating a semiconductor light-emitting structure with an integrated grating, comprising: forming a gain structure on one side of a portion of a semiconductor substrate along the fast axis direction, the gain structure comprising a first semiconductor confinement layer, a first semiconductor waveguide layer, an active layer, a second semiconductor waveguide layer, and a second semiconductor confinement layer arranged sequentially along the fast axis direction, the second semiconductor confinement layer being located on the side of the first semiconductor confinement layer opposite to the semiconductor substrate; forming a grating waveguide dielectric structure on one side of a portion of the semiconductor substrate along the fast axis direction, the grating waveguide dielectric structure being located on one side of the gain structure along the cavity length direction; integrating a grating in the grating waveguide dielectric structure; and forming an anti-reflection structure, wherein the interface between the grating waveguide dielectric structure and the gain structure has an anti-reflection structure.

[0093] In some embodiments, forming the grating waveguide dielectric structure includes: forming the grating waveguide dielectric structure on one side of a portion of the semiconductor substrate along the fast axis direction, wherein a slot is provided between the grating waveguide dielectric structure and the gain structure; wherein forming the anti-reflection structure includes: forming the anti-reflection structure in the slot, wherein the refractive index of the anti-reflection structure is greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure;

[0094] In some embodiments, forming the grating waveguide dielectric structure includes: forming a dielectric waveguide structure on one side of a portion of the semiconductor substrate along the fast axis direction, having a slot between the dielectric waveguide structure and the gain structure, and forming a grating in the dielectric waveguide structure, such that the dielectric waveguide structure and the grating constitute a grating waveguide dielectric structure; wherein forming the anti-reflection structure includes: forming the anti-reflection structure in the slot, wherein the refractive index of the anti-reflection structure is greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure.

[0095] In some embodiments, forming the gain structure includes forming a gain main structure and a plurality of first protrusions arranged along the slow axis direction, the first protrusions being located on the side of the gain main structure facing along the cavity length direction and connected to the gain main structure; wherein, forming the grating waveguide dielectric structure includes forming a main grating waveguide structure and a plurality of second protrusions arranged along the slow axis direction, the second protrusions being located on the side of the main grating waveguide structure facing the gain structure and connected to the main grating waveguide structure, the main grating waveguide structure integrating a grating; wherein, the first protrusions are located between adjacent second protrusions, the second protrusions are located between adjacent first protrusions, and the plurality of first protrusions and the plurality of second protrusions constitute an anti-reflection structure.

[0096] The following is for reference. Figures 14 to 19 This paper introduces a method for fabricating a semiconductor structure with integrated gratings.

[0097] refer to Figures 14 to 15 A gain structure A is formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z. The gain structure A includes a first semiconductor confinement layer 110, a first semiconductor waveguide layer 120, an active layer 130, a second semiconductor waveguide layer 140, and a second semiconductor confinement layer 150 arranged sequentially along the fast axis direction Z. The second semiconductor confinement layer 150 is located on the side of the first semiconductor confinement layer 110 opposite to the semiconductor substrate 100.

[0098] In one implementation, forming the gain structure A includes: a reference Figure 14 A first initial semiconductor confinement layer 110a, a first initial semiconductor waveguide layer 120a, an initial active layer 130a, a second initial semiconductor waveguide layer 140a, and a second initial semiconductor confinement layer 150a are sequentially formed on one side of the semiconductor substrate layer 100 along the fast axis direction Z; Reference Figure 15 A portion of the first initial semiconductor confinement layer 110a, a portion of the first initial semiconductor waveguide layer 120a, a portion of the initial active layer 130a, a portion of the second initial semiconductor waveguide layer 140a, and a portion of the second initial semiconductor confinement layer 150a are removed. The remaining first initial semiconductor confinement layer 110a forms the first semiconductor confinement layer 110, the remaining first initial semiconductor waveguide layer 120a forms the first semiconductor waveguide layer 120, the remaining initial active layer 130a forms the active layer 130, the remaining second initial semiconductor waveguide layer 140a forms the second semiconductor waveguide layer 140, and the remaining second initial semiconductor confinement layer 150a forms the second semiconductor confinement layer 150.

[0099] In one embodiment, the process of forming the first initial semiconductor confinement layer 110a, the first initial semiconductor waveguide layer 120a, the initial active layer 130a, the second initial semiconductor waveguide layer 140a, and the second initial semiconductor confinement layer 150a includes an epitaxial process.

[0100] In one embodiment, the process used to remove a portion of the first initial semiconductor confinement layer 110a, a portion of the first initial semiconductor waveguide layer 120a, a portion of the initial active layer 130a, a portion of the second initial semiconductor waveguide layer 140a, and a portion of the second initial semiconductor confinement layer 150a includes an etching process, which includes one or a combination of wet etching and dry etching processes.

[0101] refer to Figures 16 to 19 A grating waveguide dielectric structure B is formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z.

[0102] In one embodiment, forming the grating waveguide dielectric structure B includes: a reference Figure 16 and Figure 17 A dielectric waveguide structure B1 is formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z, and a slot C is formed between the dielectric waveguide structure B1 and the gain structure A; Reference Figure 18 and Figure 19 A grating 2301 is formed in the dielectric waveguide structure B1, so that the dielectric waveguide structure B1 and the grating 2301 constitute the grating waveguide dielectric structure B.

[0103] A dielectric waveguide structure B1 is formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z, including: Reference Figure 17 A first dielectric confinement layer 210, a dielectric waveguide layer 220, and a second dielectric confinement layer 230 are formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z. The dielectric waveguide layer 220 is located on the side of the first dielectric confinement layer 210 opposite to the semiconductor substrate 100, and the second dielectric confinement layer 230 is located on the side of the dielectric waveguide layer 220 opposite to the first dielectric confinement layer 210. The equivalent refractive index of the dielectric waveguide layer 220 is greater than the equivalent refractive index of the second dielectric confinement layer 230 and greater than the equivalent refractive index of the first dielectric confinement layer 210; Reference Figure 18 and Figure 19 A grating 2301 is formed in the dielectric waveguide structure B1. For example, the grating 2301 is formed in the second dielectric confinement layer 230, so that the dielectric waveguide structure B1 and the grating 2301 constitute the grating waveguide dielectric structure B. The grating is integrated in the grating waveguide dielectric structure B.

[0104] A first dielectric confinement layer 210, a dielectric waveguide layer 220, and a second dielectric confinement layer 230 are formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z, including: a reference layer 210, a dielectric waveguide layer 220, and a second dielectric confinement layer 230. Figure 16 A first initial dielectric confinement layer 210a, an initial dielectric waveguide layer 220a, and a second initial dielectric confinement layer 230a are formed on one side of the semiconductor substrate layer 100 along the fast axis direction Z. The first initial dielectric confinement layer 210a, the initial dielectric waveguide layer 220a, and the second initial dielectric confinement layer 230a are located on one side of the gain structure A along the cavity length direction X. Reference Figure 17 The first initial dielectric confinement layer 210a, the initial dielectric waveguide layer 220a, and the second initial dielectric confinement layer 230a are etched away to remove a portion of the first initial dielectric confinement layer 210a, the second initial dielectric waveguide layer 220a, and the third initial dielectric confinement layer 230a, which are oriented towards the gain structure A along the cavity length direction X. The remaining first initial dielectric confinement layer 210a forms the first dielectric confinement layer 210, the remaining initial dielectric waveguide layer 220a forms the dielectric waveguide layer 220, and the remaining second initial dielectric confinement layer 230a forms the second dielectric confinement layer 230.

[0105] In one embodiment, the process of etching away a portion of the first initial dielectric confinement layer 210a, the initial dielectric waveguide layer 220a, and the second initial dielectric confinement layer 230a along the cavity length direction X toward the gain structure A includes an etching process, which includes one or a combination of wet etching and dry etching processes.

[0106] refer to Figure 18 and Figure 19 The method for fabricating the semiconductor structure of the integrated grating further includes: forming an anti-reflection structure 240. Forming the anti-reflection structure 240 includes: forming the anti-reflection structure 240 in the slot C, wherein the refractive index of the anti-reflection structure 240 is greater than the equivalent refractive index of the grating waveguide dielectric structure B and less than the equivalent refractive index of the gain structure A.

[0107] In this embodiment, during the formation of the antireflection structure 240 in the slot C, a mask layer 250 is formed on the side of the dielectric waveguide structure B1 facing away from the semiconductor substrate layer 100. Forming the grating 2301 in the dielectric waveguide structure B1 includes etching the mask layer 250 and a portion of the second dielectric confinement layer 230, with the grating 2301 formed within the second dielectric confinement layer 230. The material of the mask layer 250 is the same as the material of the antireflection structure 240.

[0108] In this embodiment, the method for fabricating the semiconductor structure of the integrated grating further includes: forming an antireflection film and a reflective film.

[0109] In this embodiment, the end face of the grating waveguide dielectric structure B facing away from the gain structure A serves as the rear cavity face. The reflective film is located on the front cavity face of the gain structure A facing away from the grating waveguide dielectric structure B, and the antireflective film is located on the rear cavity face of the grating waveguide dielectric structure B facing away from the gain structure A. A resonant cavity is formed between the reflective film and the grating waveguide dielectric structure B, and the reflectivity of the reflective film is less than that of the grating.

[0110] In other embodiments, the end face of the grating waveguide dielectric structure B facing away from the gain structure A serves as the front cavity face. The reflective film is located on the rear cavity face of the gain structure A facing away from the grating waveguide dielectric structure B, and the antireflective film is located on the front cavity face of the grating waveguide dielectric structure B facing away from the gain structure A. A resonant cavity is formed between the reflective film and the grating waveguide dielectric structure B. The reflectivity of the reflective film is greater than that of the grating, and the reflectivity of the antireflective film is less than that of the reflective film. Furthermore, the reflectivity of the antireflective film can be less than that of the grating.

[0111] In this embodiment, the semiconductor light-emitting structure with integrated grating further includes: forming a front electrode and a back electrode, wherein the front electrode is located on the side of the gain structure A away from the semiconductor substrate 100, and the back electrode is located on the side of the semiconductor substrate 100 away from the gain structure A. The front electrode may not extend to the side of the grating waveguide dielectric structure B away from the semiconductor substrate 100. Alternatively, the front electrode may extend to the side of the grating waveguide dielectric structure B away from the semiconductor substrate 100.

[0112] It should be noted that, in this embodiment, the position of the grating in the second dielectric confinement layer 230 is to form Figure 19 The structure is used as an example. In other embodiments, the position of the grating in the second dielectric confinement layer may also be other positions described in the foregoing embodiments.

[0113] The following is for reference. Figures 20 to 25 This paper introduces another method for fabricating semiconductor structures with integrated gratings.

[0114] refer to Figure 20 A gain structure A is formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z. The gain structure A includes a first semiconductor confinement layer 110, a first semiconductor waveguide layer 120, an active layer 130, a second semiconductor waveguide layer 140, and a second semiconductor confinement layer 150 arranged sequentially along the fast axis direction Z. The second semiconductor confinement layer 150 is located on the side of the first semiconductor confinement layer 110 opposite to the semiconductor substrate 100.

[0115] refer to Figures 21 to 24 A grating waveguide dielectric structure B is formed on one side of a portion of the semiconductor substrate 100 along the fast axis direction Z. A slot C is formed between the grating waveguide dielectric structure B and the gain structure A.

[0116] refer to Figure 21 A first initial dielectric confinement layer 2100 is formed on one side of the semiconductor substrate 100 along the fast axis direction Z. A portion of the first initial dielectric confinement layer 2100 is located on one side of the gain structure A along the cavity length direction X, and another portion of the first initial dielectric confinement layer 2100 is located on the side of the gain structure A opposite to the semiconductor substrate 100. (Reference) Figure 22 A grating groove is formed on the surface of the first initial dielectric confinement layer 2100 on the side opposite to the semiconductor substrate layer 100; Reference Figure 23 An initial dielectric waveguide layer 2200 is formed on the side of the first initial dielectric confinement layer 2100 opposite to the semiconductor substrate layer 100; Reference Figure 23 A second initial dielectric confinement layer 2300 is formed on the side of the initial dielectric waveguide layer 2200 opposite to the semiconductor substrate layer 100; Reference Figure 24The first initial dielectric confinement layer 2100, the initial dielectric waveguide layer 2200, and the second initial dielectric confinement layer 2300 located on the side of the gain structure A away from the semiconductor substrate layer 100 are removed. A portion of the first initial dielectric confinement layer 2100, the initial dielectric waveguide layer 2200, and the second initial dielectric confinement layer 2300 near the gain structure A in the cavity length direction X are also removed. The remaining second initial dielectric confinement layer 2300 forms the second dielectric confinement layer 230, the remaining initial dielectric waveguide layer 2200 forms the dielectric waveguide layer 220, and the remaining first initial dielectric confinement layer 2100 forms the first dielectric confinement layer 210.

[0117] refer to Figure 24 A grating is integrated in the dielectric waveguide layer 220.

[0118] refer to Figure 25 This forms an anti-reflective structure 240.

[0119] In this embodiment, forming the anti-reflection structure 240 includes: forming the anti-reflection structure 240 in the slot C, wherein the refractive index of the anti-reflection structure 240 is greater than the equivalent refractive index of the grating waveguide dielectric structure B and less than the equivalent refractive index of the gain structure A.

[0120] In this embodiment, the method for fabricating the semiconductor structure of the integrated grating further includes: forming an antireflection film and a reflection film, the positions of the reflection film and the antireflection film, and the positional relationship between the grating waveguide dielectric structure B and the gain structure A as described in the foregoing embodiments.

[0121] In this embodiment, the method for fabricating the semiconductor light-emitting structure with integrated grating further includes: forming a front electrode and a back electrode, wherein the front electrode is located on the side of the gain structure A away from the semiconductor substrate 100, and the back electrode is located on the side of the semiconductor substrate 100 away from the gain structure A.

[0122] It should be noted that, in this embodiment, the position of the grating in the dielectric waveguide layer 220 is to form Figure 25 The structure is used as an example. In other embodiments, the grating may be located in other positions within the dielectric waveguide layer 220 as described in the foregoing embodiments.

[0123] The following is for reference. Figures 26 to 28 This paper introduces another method for fabricating semiconductor structures with integrated gratings.

[0124] refer to Figure 26 and Figure 27 , Figure 27 for Figure 26 Top view along the fast axis, Figure 26 For along Figure 27The cross-sectional view along cut line L1-L2 shows a gain structure A formed on one side of the semiconductor substrate 100 along the fast axis direction Z. Gain structure A includes a first semiconductor confinement layer 110, a first semiconductor waveguide layer 120, an active layer 130, a second semiconductor waveguide layer 140, and a second semiconductor confinement layer 150 arranged sequentially along the fast axis direction Z. The second semiconductor confinement layer 150 is located on the side of the first semiconductor confinement layer 110 opposite to the semiconductor substrate 100.

[0125] refer to Figure 26 and Figure 27 The gain structure A includes a gain main structure A-1 and a plurality of first protrusions A-2 arranged along the slow axis. The first protrusions A-2 are located on one side of the gain main structure A-1 along the cavity length direction X and are connected to the gain main structure A-1.

[0126] The shape and size of the first protrusion A-2 are as described in the foregoing embodiment.

[0127] In some embodiments, forming the gain structure A includes: sequentially forming a first initial semiconductor confinement layer, a first initial semiconductor waveguide layer, an initial active layer, a second initial semiconductor waveguide layer, and a second initial semiconductor confinement layer on one side of the semiconductor substrate layer 100 along the fast axis direction Z; removing a portion of the first initial semiconductor confinement layer 110a, a portion of the first initial semiconductor waveguide layer, a portion of the initial active layer, a portion of the second initial semiconductor waveguide layer, and a portion of the second initial semiconductor confinement layer, with the remaining first initial semiconductor confinement layer forming the first semiconductor confinement layer, the remaining first initial semiconductor waveguide layer forming the first semiconductor waveguide layer, the remaining initial active layer forming the active layer, the remaining second initial semiconductor waveguide layer forming the second semiconductor waveguide layer, and the remaining second initial semiconductor confinement layer forming the second semiconductor confinement layer.

[0128] refer to Figure 28 and Figure 31 A grating waveguide dielectric structure B is formed on one side of the semiconductor substrate 100 along the fast axis direction Z. The grating waveguide dielectric structure B is located on one side of the semiconductor substrate 100 along the fast axis direction and on one side of the gain structure A along the cavity length direction. A grating is integrated in the grating waveguide dielectric structure B.

[0129] refer to Figure 28 and Figure 31The grating waveguide dielectric structure B includes a main grating waveguide structure B-1 and a plurality of second protrusions B-2 arranged along the slow axis. The second protrusions B-2 are located on the side of the main grating waveguide structure B-1 facing the gain structure A and are connected to the main grating waveguide structure B-1. The main grating waveguide structure B-1 integrates a grating. The second protrusions B-2 are located between adjacent first protrusions A-2, and the first protrusions A-2 are located between adjacent second protrusions B-2. The plurality of first protrusions A-2 and the plurality of second protrusions B-2 constitute an anti-reflection structure 240.

[0130] The description of the first protrusion A-2 and the plurality of second protrusions B-2 refers to the description of the aforementioned embodiment.

[0131] refer to Figure 28 The formation of the grating waveguide dielectric structure B includes forming a first dielectric confinement layer 210, a second dielectric confinement layer 230, and a dielectric waveguide layer 220. The dielectric waveguide layer 220 is located on the side of the first dielectric confinement layer 210 away from the semiconductor substrate 100, and the second dielectric confinement layer 230 is located on the side of the dielectric waveguide layer 220 away from the first dielectric confinement layer 210. The equivalent refractive index of the dielectric waveguide layer 220 is greater than that of the second dielectric confinement layer 230 and greater than that of the first dielectric confinement layer 210. A grating is integrated in the grating waveguide dielectric structure. Figure 28 An example is the integrated grating in the dielectric waveguide layer 220.

[0132] In some embodiments, forming the grating waveguide dielectric structure B includes: sequentially forming a first initial dielectric confinement layer, an initial dielectric waveguide layer, and a second initial dielectric confinement layer on the semiconductor substrate layer 100 on the side of the gain structure A along the cavity length direction and on the side of the gain structure A away from the semiconductor substrate layer 100, with a portion of the first initial dielectric confinement layer, a portion of the initial dielectric waveguide layer, and a portion of the second initial dielectric confinement layer located in adjacent first protrusions A-2; removing the portions of the first initial dielectric confinement layer, the initial dielectric waveguide layer, and the second initial dielectric confinement layer located on the side of the gain structure A away from the semiconductor substrate layer 100, and the remaining first initial dielectric confinement layer, initial dielectric waveguide layer, and second initial dielectric confinement layer forming the grating waveguide dielectric structure B.

[0133] In other embodiments, the grating may be integrated in the first dielectric confinement layer 210. Preferably, the grating may be integrated in the second dielectric confinement layer 230.

[0134] In this embodiment, the method for fabricating the semiconductor structure further includes forming an antireflection coating and a reflective coating. The positions of the reflective coating and the antireflection coating, as well as the positional relationship between the grating waveguide dielectric structure B and the gain structure A, are as described in the foregoing embodiments.

[0135] In this embodiment, the semiconductor light-emitting structure with integrated grating further includes: forming a front electrode and a back electrode, wherein the front electrode is located on the side of the gain structure A away from the semiconductor substrate 100, and the back electrode is located on the side of the semiconductor substrate 100 away from the gain structure A.

[0136] It should be noted that, in this embodiment, the position of the grating in the dielectric waveguide layer 220 is to form Figure 28 The structure is used as an example. In other embodiments, the grating may be located in other locations within the dielectric waveguide layer as described in the foregoing embodiments.

[0137] The following is for reference. Figures 29 to 31 This paper introduces another method for fabricating semiconductor structures with integrated gratings.

[0138] refer to Figure 29 , Figure 30 and Figure 31 , Figure 29 In order to be in Figure 26 The schematic diagram shows that a grating waveguide dielectric structure B is formed on one side of the semiconductor substrate 100 along the fast axis direction Z. The grating waveguide dielectric structure B is located on one side of the semiconductor substrate 100 along the fast axis direction and on one side of the gain structure A along the cavity length direction. A grating is integrated in the grating waveguide dielectric structure B.

[0139] refer to Figure 30 and Figure 31 The grating waveguide dielectric structure B includes a main grating waveguide structure B-1 and a plurality of second protrusions B-2 arranged along the slow axis. The second protrusions B-2 are located on the side of the main grating waveguide structure B-1 facing the gain structure A and are connected to the main grating waveguide structure B-1. The main grating waveguide structure B-1 integrates a grating.

[0140] The first protrusion A-2 is located between adjacent second protrusions B-2, and the second protrusions B-2 are located between adjacent first protrusions A-2. The plurality of first protrusions A-2 and the plurality of second protrusions B-2 constitute an anti-reflective structure 240.

[0141] The description of the first protrusion A-2 and the plurality of second protrusions B-2 refers to the description of the aforementioned embodiment.

[0142] refer to Figure 29This forms a second dielectric confinement layer 230, a dielectric waveguide layer 220, and a first dielectric confinement layer 210, which are located on one side of the gain structure A along the cavity length direction X; Reference Figure 30 A grating 2301 is formed in the second dielectric confinement layer 230.

[0143] In this embodiment, the method for fabricating the semiconductor structure of the integrated grating further includes: forming an antireflection film and a reflection film, the positions of the reflection film and the antireflection film, and the positional relationship between the grating waveguide dielectric structure B and the gain structure A as described in the foregoing embodiments.

[0144] In this embodiment, the method for fabricating the semiconductor light-emitting structure with integrated grating further includes: forming a front electrode and a back electrode, wherein the front electrode is located on the side of the gain structure A away from the semiconductor substrate 100, and the back electrode is located on the side of the semiconductor substrate 100 away from the gain structure A.

[0145] It should be noted that, in this embodiment, the position of the grating in the second dielectric confinement layer 230 is to form Figure 30 The structure is used as an example. In other embodiments, the position of the grating in the second dielectric confinement layer may also be other positions described in the foregoing embodiments.

[0146] In the method for fabricating the semiconductor structure, the second dielectric confinement layer 230 can be a composite structure, or the dielectric waveguide layer 220 can be a composite structure, or the first dielectric confinement layer 210 can be a composite structure. Specific descriptions are as described in the foregoing embodiments and will not be repeated here.

[0147] Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the embodiments. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A semiconductor light-emitting structure with an integrated grating, characterized in that, It includes a semiconductor substrate, a gain structure, and a grating waveguide dielectric structure; the grating waveguide dielectric structure integrates a grating; wherein, an anti-reflection structure is provided at the interface between the grating waveguide dielectric structure and the gain structure; the refractive index temperature drift coefficient of the grating waveguide dielectric structure is smaller than that of the gain structure; The gain structure is located on one side of the semiconductor substrate along the fast axis direction. The gain structure includes a first semiconductor confinement layer, a first semiconductor waveguide layer, an active layer, a second semiconductor waveguide layer, and a second semiconductor confinement layer arranged sequentially along the fast axis direction. The second semiconductor confinement layer is located on the side of the first semiconductor confinement layer opposite to the semiconductor substrate. The grating waveguide dielectric structure is located on one side of the semiconductor substrate along the fast axis direction and on one side of the gain structure along the cavity length direction. The grating waveguide dielectric structure includes a first dielectric confinement layer, a dielectric waveguide layer, and a second dielectric confinement layer. The dielectric waveguide layer is located on the side of the first dielectric confinement layer away from the semiconductor substrate, and the second dielectric confinement layer is located on the side of the dielectric waveguide layer away from the first dielectric confinement layer. The equivalent refractive index of the dielectric waveguide layer is greater than the equivalent refractive index of the second dielectric confinement layer and greater than the equivalent refractive index of the first dielectric confinement layer.

2. The semiconductor light-emitting structure with integrated grating according to claim 1, characterized in that, The gain structure includes a main gain structure and a plurality of first protrusions arranged along the slow axis. The first protrusions are located on the side of the main gain structure facing the grating waveguide dielectric structure and are connected to the main gain structure. The grating waveguide dielectric structure includes a main grating waveguide structure and a plurality of second protrusions arranged along the slow axis. The second protrusions are located on the side of the main grating waveguide structure facing the gain structure and are connected to the main grating waveguide structure. A grating is integrated in the main grating waveguide structure. The first protrusion is located between adjacent second protrusions, and the second protrusion is located between adjacent first protrusions; the plurality of first protrusions and the plurality of second protrusions constitute the antireflective structure.

3. The semiconductor light-emitting structure with integrated grating according to claim 2, characterized in that, The first protrusion has a triangular cross-sectional shape along the direction perpendicular to the fast axis, and the second protrusion also has a triangular cross-sectional shape along the direction perpendicular to the fast axis.

4. The semiconductor light-emitting structure with integrated grating according to claim 2 or 3, characterized in that, The dimensions of the first protrusion in the cavity length direction and the dimensions of the second protrusion in the cavity length direction are K1, respectively; the distance between the centers of adjacent first protrusions in the slow axis direction and the distance between the centers of adjacent second protrusions in the slow axis direction are K2, respectively; wherein, K1 is less than or equal to 1 μm and K2 is less than or equal to 0.2 μm.

5. The semiconductor light-emitting structure with integrated grating according to claim 1, characterized in that, The anti-reflection structure is located between the grating waveguide dielectric structure and the gain structure; The refractive index of the antireflection structure is greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure.

6. The semiconductor light-emitting structure with integrated grating according to claim 5, characterized in that, The anti-reflective structure has a long strip shape in cross-section perpendicular to the fast axis.

7. The semiconductor light-emitting structure with integrated grating according to claim 1, characterized in that, The second dielectric confinement layer has a grating; or, the dielectric waveguide layer has a grating; or, the first dielectric confinement layer has a grating.

8. The semiconductor light-emitting structure with integrated grating according to claim 1, characterized in that, The second dielectric confinement layer has overlapping projections with the second semiconductor confinement layer and the second semiconductor waveguide layer in the cavity length direction, and the dielectric waveguide layer and the active layer have overlapping projections in the cavity length direction; the first dielectric confinement layer has overlapping projections with the first semiconductor waveguide layer and the first semiconductor confinement layer in the cavity length direction.

9. The semiconductor light-emitting structure with integrated grating according to claim 1, characterized in that, The equivalent refractive index of the first dielectric confinement layer is located between the equivalent refractive index of the second dielectric confinement layer and the equivalent refractive index of the dielectric waveguide layer.

10. The semiconductor light-emitting structure with an integrated grating according to claim 1 or 9, characterized in that, The dielectric waveguide layer includes a first sub-waveguide layer and a second sub-waveguide layer that are alternately stacked in the fast axis direction; Wherein, the refractive index of the first sub-waveguide layer is greater than the refractive index of the first dielectric confinement layer and greater than the refractive index of the second dielectric confinement layer; the refractive index of the second sub-waveguide layer is less than the refractive index of the first sub-waveguide layer.

11. The semiconductor light-emitting structure with an integrated grating according to claim 1 or 9, characterized in that, The first dielectric confinement layer includes a first sub-dielectric confinement layer and a second sub-dielectric confinement layer that are alternately stacked in the fast axis direction; Wherein, the refractive index of the first sub-dielectric confinement layer is less than the refractive index of the dielectric waveguide layer, and the refractive index of the second sub-dielectric confinement layer is greater than the refractive index of the first sub-dielectric confinement layer.

12. The semiconductor light-emitting structure with an integrated grating according to claim 1 or 9, characterized in that, The second dielectric confinement layer includes a third sub-dielectric confinement layer and a fourth sub-dielectric confinement layer that are alternately stacked in the fast axis direction. The refractive index of the third sub-dielectric confinement layer is less than that of the dielectric waveguide layer, and the refractive index of the fourth sub-dielectric confinement layer is greater than that of the third sub-dielectric confinement layer.

13. A method for fabricating a semiconductor light-emitting structure with an integrated grating, characterized in that, include: A gain structure is formed on one side of a portion of the semiconductor substrate along the fast axis direction. The gain structure includes a first semiconductor confinement layer, a first semiconductor waveguide layer, an active layer, a second semiconductor waveguide layer, and a second semiconductor confinement layer arranged sequentially along the fast axis direction. The second semiconductor confinement layer is located on the side of the first semiconductor confinement layer opposite to the semiconductor substrate. A grating waveguide dielectric structure is formed on one side of the semiconductor substrate along the fast axis direction, and the grating waveguide dielectric structure is located on one side of the gain structure along the cavity length direction; wherein, forming the grating waveguide dielectric structure includes forming a first dielectric confinement layer, a dielectric waveguide layer, and a second dielectric confinement layer, the dielectric waveguide layer being located on the side of the first dielectric confinement layer opposite to the semiconductor substrate, and the second dielectric confinement layer being located on the side of the dielectric waveguide layer opposite to the first dielectric confinement layer; wherein, the equivalent refractive index of the dielectric waveguide layer is greater than the equivalent refractive index of the second dielectric confinement layer and greater than the equivalent refractive index of the first dielectric confinement layer; a grating is integrated in the grating waveguide dielectric structure; the refractive index temperature drift coefficient of the grating waveguide dielectric structure is less than the refractive index temperature drift coefficient of the gain structure; An anti-reflection structure is formed, wherein the interface between the grating waveguide dielectric structure and the gain structure has an anti-reflection structure.

14. The method for fabricating the semiconductor light-emitting structure with integrated grating according to claim 13, characterized in that, Forming the gain structure includes: A first initial semiconductor confinement layer, a first initial semiconductor waveguide layer, an initial active layer, a second initial semiconductor waveguide layer, and a second initial semiconductor confinement layer are sequentially formed on one side of the semiconductor substrate along the fast axis direction. A portion of the first initial semiconductor confinement layer, a portion of the first initial semiconductor waveguide layer, a portion of the initial active layer, a portion of the second initial semiconductor waveguide layer, and a portion of the second initial semiconductor confinement layer are removed. The remaining first initial semiconductor confinement layer forms the first semiconductor confinement layer, the remaining first initial semiconductor waveguide layer forms the first semiconductor waveguide layer, the remaining initial active layer forms the active layer, the remaining second initial semiconductor waveguide layer forms the second semiconductor waveguide layer, and the remaining second initial semiconductor confinement layer forms the second semiconductor confinement layer.

15. The method for fabricating the semiconductor light-emitting structure with integrated grating according to claim 13, characterized in that, Forming the grating waveguide dielectric structure includes: forming the grating waveguide dielectric structure on one side of a portion of the semiconductor substrate along the fast axis direction, wherein a slot is provided between the grating waveguide dielectric structure and the gain structure; wherein forming the anti-reflection structure includes: forming the anti-reflection structure in the slot, wherein the refractive index of the anti-reflection structure is greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure; Alternatively, forming the grating waveguide dielectric structure includes: forming a dielectric waveguide structure on one side of a portion of the semiconductor substrate along the fast axis direction, having a slot between the dielectric waveguide structure and the gain structure, forming a grating in the dielectric waveguide structure, such that the dielectric waveguide structure and the grating constitute a grating waveguide dielectric structure; wherein forming the anti-reflection structure includes: forming the anti-reflection structure in the slot, wherein the refractive index of the anti-reflection structure is greater than the equivalent refractive index of the grating waveguide dielectric structure and less than the equivalent refractive index of the gain structure.

16. The method for fabricating the semiconductor light-emitting structure with integrated grating according to claim 13, characterized in that, The formation of the gain structure includes forming a gain main structure and a plurality of first protrusions arranged along the slow axis direction. The first protrusions are located on one side of the gain main structure along the cavity length direction and are connected to the gain main structure. The formation of the grating waveguide dielectric structure includes forming a main grating waveguide structure and a plurality of second protrusions arranged along the slow axis direction. The second protrusions are located on the side of the main grating waveguide structure facing the gain structure and are connected to the main grating waveguide structure. A grating is integrated in the main grating waveguide structure. The first protrusion is located between adjacent second protrusions, and the second protrusion is located between adjacent first protrusions; the plurality of first protrusions and the plurality of second protrusions constitute the antireflective structure.

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