Laser chip, method for manufacturing laser chip, and communication device

Abstract

The application provides a laser chip, a preparation method of the laser chip and a communication device, and relates to the technical field of chips.The laser chip comprises a multilayer epitaxial structure, an anode electrode, a cathode electrode and a third electrode;the anode electrode and the cathode electrode are arranged on the upper surface and the lower surface of the multilayer epitaxial structure;the third electrode is also arranged on the upper surface and is arranged in a spaced manner with the anode electrode, and the end surface of the third electrode close to the anode electrode is an arc surface;the edge of the upper surface is provided with a stepped surface, the stepped surface is filled with a current non-injection layer;the third electrode is covered on the current non-injection layer and extends to the upper surface from the current non-injection layer.The current non-injection layer is arranged on the cavity surface side, the third electrode is matched, the third electrode is widened, the coverage range of the third electrode is expanded, the carrier accumulation to the light emitting surface is effectively inhibited, and the heat accumulation of the cavity surface is avoided;further, the end surface of the third electrode close to the anode electrode is designed as an arc surface, the sharp end effect is avoided, and the heat accumulation is further reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chips, and in particular to a laser chip, a preparation method of the laser chip, and a communication device. BACKGROUND

[0002] The laser chip has wide application in the fields of optical communication, laser processing, medical equipment, etc., but is severely restricted by its self-heating effect. The diffusion of the carrier of the laser chip is difficult to effectively control, which causes the accumulation of the carrier and the gathering of heat near the light-emitting cavity surface, thereby causing the local temperature to rise sharply, causing the damage of the cavity surface, and leading to the failure of the device. SUMMARY

[0003] In view of the above problems, the present application provides a laser chip, a preparation method of the laser chip, and a communication device.

[0004] The present application provides the following technical solutions:

[0005] The present application provides a laser chip, which comprises: a multilayer epitaxial structure; and an anode electrode and a cathode electrode, which are respectively arranged on opposite upper and lower surfaces of the multilayer epitaxial structure along a first direction; a third electrode, which is arranged on the upper surface and is spaced from the anode electrode along a second direction, and an end surface of the third electrode close to the anode electrode is an arc surface; the upper surface intersects a first side surface of the multilayer epitaxial structure, and a recess is arranged at the intersection of the upper surface and the first side surface to form a stepped surface on the upper surface, and the stepped surface is filled with a current non-injection layer; the third electrode covers the current non-injection layer, and both ends of the third electrode along a third direction extend from the current non-injection layer to the upper surface; wherein the first direction, the second direction and the third direction are perpendicular to each other.

[0006] In an embodiment of the present application, the arc surface comprises a semicircular curved surface, an elliptical curved surface, a parabolic curved surface, a gradually changing curved surface or a wavy curved surface.

[0007] In an embodiment of the present application, the multilayer epitaxial structure comprises a substrate layer, a lower limiting layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper limiting layer and a ridge waveguide layer arranged in sequence; a surface of the ridge waveguide layer away from the upper limiting layer is the upper surface, and a surface of the substrate layer away from the lower limiting layer is the lower surface.

[0008] In an embodiment of the present application, the laser chip further comprises a reflective film and an anti-reflection film; the reflective film and the anti-reflection film are respectively arranged on the first side surface and a second side surface of the multilayer epitaxial structure opposite along the second direction.

[0009] In one embodiment of the present application, the laser chip further includes a passivation layer; the passivation layer is arranged on the third side surface and the fourth side surface of the multilayer epitaxial structure opposite to each other along the third direction; the passivation layer is also arranged on the area of ​​the upper surface other than the anode electrode; or, the passivation layer is also arranged on the upper surface and covers the edge of the anode electrode.

[0010] In one embodiment of the present application, the reflectivity of the reflective film is 50%-100%; the reflectivity of the antireflection film is less than or equal to 10%.

[0011] In one embodiment of the present application, the substrate layer is composed of GaAs with a thickness of 200 nm; the lower confinement layer is composed of AlGaAs with a thickness of 0.3 μm; the lower waveguide layer is composed of AlGaAs with a thickness of 0.5-3 μm; the quantum well active layer is composed of alternately grown AlGaAs well layer-AlGaAs barrier layer with a thickness of 0.1 μm; the upper waveguide layer is composed of AlGaAs with a thickness of 0.1-3 μm; the upper confinement layer is composed of AlGaAs with a thickness of 0.3-1 μm; the ridge waveguide layer is composed of AlGaAs with a thickness of 280 nm; the cathode electrode and the anode electrode are composed of one or more of Cr / Au, Ti / Au or Ni / Au; the current non-injection layer is composed of one or more of Al2O3, SiN or SiO2 with a thickness of 10-50 nm.

[0012] In one embodiment of the present application, the passivation layer is composed of SiO2 and has a thickness of 50nm-500nm.

[0013] The present application also provides a method for preparing a laser chip, which is used to prepare the laser chip described above, and includes:

[0014] A lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and a ridge waveguide layer are sequentially arranged on the substrate layer to obtain a multi-layer epitaxial structure;

[0015] Using a photoresist as a mask, dry etching is performed to form a step surface at the edge of the upper surface of the multilayer epitaxial structure;

[0016] Providing a current non-injection layer having the same step depth as that of the step surface on the step surface by using plasma enhanced chemical vapor deposition technology and magnetron sputtering technology, and removing the photoresist;

[0017] An anode electrode and a cathode electrode are respectively formed on the upper surface and the lower surface opposite to each other along the first direction of the multilayer epitaxial structure using photolithography technology and electron beam evaporation process, and a third electrode is formed on the upper surface. The third electrode is spaced from the anode electrode along the second direction, and the end surface of the third electrode close to the anode electrode is an arc-shaped surface. The third electrode covers the current non-injection layer, and the two ends of the third electrode along the third direction extend from the current non-injection layer to the upper surface.

[0018] An embodiment of the present application further provides a communication device, which includes the laser chip described above.

[0019] The laser chip provided in the embodiments of the present application has the following technical effects:

[0020] The laser chip provided in the embodiment of the present application can suppress the diffusion of carriers toward the light-emitting surface by setting a current non-injection layer on the cavity surface side and applying voltage in conjunction with the third electrode, thereby reducing the carrier concentration in the area near the cavity surface and thus lowering the cavity surface temperature.

[0021] At the same time, both ends of the third electrode along the third direction also extend from the current non-injection layer to the upper surface, thereby widening the third electrode and improving the coverage of the third electrode. Expanding the electrode coverage can significantly expand the range of movement of the depletion layer of the p-type semiconductor below the current non-injection layer toward the active region, forming a wider carrier suppression region, and ensuring effective blocking of carriers from gathering toward the light-emitting surface; the third electrode, as a good heat conduction medium, can increase the heat conduction path after widening, and can quickly conduct away the heat generated on the cavity surface, and transfer it to the outside through structures such as the ridge waveguide layer and the upper confinement layer, thereby avoiding heat accumulation on the cavity surface and improving heat dissipation capacity.

[0022] Furthermore, the end face of the third electrode close to the anode electrode is an arc-shaped surface, which avoids the tip effect from exacerbating the local electric field and carrier distribution, further reduces heat accumulation, improves heat dissipation capacity, and thereby enhances the photoelectric conversion efficiency and reliability of the laser chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0024] Figure 1 A cross-sectional view of the laser core provided in an embodiment of the present application along the front-to-back axis (x-axis);

[0025] Figure 2 for Figure 1Cross-sectional view of the laser core in area A along the left-right axis (y-axis);

[0026] Figure 3 A top view of the laser cell provided in an embodiment of the present application;

[0027] Figure 4 A cross-sectional view of the multi-layer epitaxial structure of the laser core provided in an embodiment of the present application along the front-to-back axis (x-axis);

[0028] Figure 5 A cross-sectional view of the multi-layer epitaxial structure of the laser core provided in an embodiment of the present application along the left-right axis (y-axis);

[0029] Figure 6 A cross-sectional view of a multi-layer epitaxial structure having a stepped surface provided in an embodiment of the present application;

[0030] Figure 7 A cross-sectional view of a non-current injection layer provided on a step surface according to an embodiment of the present application;

[0031] Figure 8 A cross-sectional view of an embodiment of the present application showing an anode, a cathode, and a third electrode disposed on a multilayer epitaxial structure.

[0032] Reference numerals:

[0033] 100-Multilayer epitaxial structure;

[0034] 101 - substrate layer; 102 - lower confinement layer; 103 - lower waveguide layer; 104 - quantum well active layer; 105 - upper waveguide layer; 106 - upper confinement layer; 107 - ridge waveguide layer; 108 - step surface;

[0035] 1011 - upper surface; 1012 - lower surface; 1013 - first side surface; 1014 - second side surface; 1015 - third side surface; 1016 - fourth side surface;

[0036] 200-photoresist;

[0037] 300-current non-injection layer;

[0038] 400-cathode electrode;

[0039] 500-anode electrode;

[0040] 600-third electrode;

[0041] 700-reflective film;

[0042] 800-AR coating;

[0043] 900-passivation layer.

[0044] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0045] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0046] refer to Figure 1-Figure 3 , a laser chip provided in an embodiment of the present application.

[0047] Among them, the first direction is the height direction of the laser chip, which is the z-axis shown in the figure; the second direction is the front-to-back length direction of the laser chip, which is the x-axis shown in the figure; the third direction is the left-to-right width direction of the laser chip, which is the y-axis shown in the figure; the first direction, the second direction and the third direction are perpendicular to each other.

[0048] The laser chip includes a multi-layer epitaxial structure 100 .

[0049] The multi-layer epitaxial structure 100 includes a substrate layer 101 , a lower confinement layer 102 , a lower waveguide layer 103 , a quantum well active layer 104 , an upper waveguide layer 105 , an upper confinement layer 106 and a ridge waveguide layer 107 , which are stacked in sequence.

[0050] The substrate layer 101 serves as a base, and is used to provide mechanical support and a crystal growth template.

[0051] The lower confinement layer 102 is used for carrier confinement and optical confinement. Carrier confinement refers to forming a potential barrier through high bandgap materials to prevent electrons from diffusing to the substrate; optical confinement refers to forming a lateral light field constraint through the refractive index difference between the lower confinement layer 102 and the active region.

[0052] The lower waveguide layer 103 confines photons near the active region by having a refractive index slightly lower than that of the active region, while also providing a diffusion path for electrons / holes to the active region.

[0053] The quantum well active layer 104 is used to confine the recombination of electrons and holes in the quantum well to generate stimulated radiation; and to adjust the emission wavelength by adjusting the well width and composition.

[0054] The upper waveguide layer 105 and the lower waveguide layer 103 are symmetrical and together form an optical resonant cavity, which constrains the longitudinal distribution of the light field and balances the carrier injection.

[0055] The upper confinement layer 106 prevents holes from leaking downward by using a high bandgap material and reduces contact resistance by using a doping gradient design.

[0056] The ridge waveguide layer 107 is a ridge-shaped structure formed by etching, so that carriers are injected only into the active area below the ridge. The ridge forms a refractive index difference with the low-refractive index materials on both sides, which laterally confines the optical mode.

[0057] The multilayer epitaxial structure 100 has an upper surface 1011 and a lower surface 1012 relative to each other along a first direction (the z-axis shown in the figure); the multilayer epitaxial structure 100 has a first side surface 1013 and a second side surface 1014 relative to each other along a second direction (the x-axis shown in the figure); the multilayer epitaxial structure 100 has a third side surface 1015 and a fourth side surface 1016 relative to each other along a third direction (the y-axis shown in the figure).

[0058] The surface of the ridge waveguide layer 107 away from the upper confinement layer 106 is an upper surface 1011 , and the surface of the substrate layer 101 away from the lower confinement layer 102 is a lower surface 1012 .

[0059] The laser chip further includes an anode electrode 500 and a cathode electrode 400 . The anode electrode 500 and the cathode electrode 400 are respectively disposed on the upper surface 1011 and the lower surface 1012 of the multi-layer epitaxial structure 100 .

[0060] The cathode electrode 400 is used to provide electron injection and is usually connected to the negative pole of the power supply; the anode electrode 500 is used to collect holes (positive charges) and is usually connected to the positive pole of the power supply.

[0061] The laser chip further includes a third electrode 600 .

[0062] The upper surface 1011 of the multilayer epitaxial structure 100 intersects with the first side surface 1013 of the multilayer epitaxial structure 100, and a pit is provided at the edge of the upper surface 1011, that is, a pit is provided at the intersection of the upper surface 1011 and the first side surface 1013 to form a step surface 108 at the edge of the upper surface 1011.

[0063] The step surface 108 is filled with a current non-injection layer 300 , and the thickness, length and width of the current non-injection layer 300 are the same as those of the step surface 108 , so that the two exposed surfaces of the step surface 108 are flush with the upper surface 1011 and the first side surface 1013 respectively.

[0064] The third electrode 600 is disposed on the upper surface 1011 and is spaced apart from the anode electrode 500 along the second direction (the x-axis shown in the figure). Meanwhile, the third electrode 600 also covers the current non-injection layer 300 .

[0065] That is to say, the laser chip provided in the embodiment of the present application can suppress the diffusion of carriers to the light-emitting surface by setting a current non-injection layer 300 on the cavity surface side and applying voltage in conjunction with the third electrode 600, thereby reducing the carrier concentration in the area near the cavity surface and thus lowering the cavity surface temperature.

[0066] At the same time, both ends of the third electrode 600 along the third direction (the y-axis shown in the figure) also extend from the current non-injection layer 300 to the upper surface 1011, so that the width of the third electrode 600 in the third direction is greater than the step surface 108 and greater than the current non-injection layer 300; thereby widening the third electrode 600 and improving the coverage range of the third electrode 600.

[0067] Expanding the electrode coverage can significantly extend the range of movement of the depletion layer of the p-type semiconductor below the current non-injection layer 300 toward the active region, forming a wider carrier suppression region and ensuring effective blocking of carrier aggregation toward the light-emitting surface. The third electrode 600, as a good heat conduction medium, can increase the heat conduction path after widening, and can quickly conduct away the heat generated on the cavity surface and transfer it to the outside through structures such as the ridge waveguide layer 107 and the upper confinement layer 106, thereby avoiding heat accumulation on the cavity surface and improving heat dissipation capacity.

[0068] Furthermore, the end face of the third electrode 600 close to the anode electrode 500 is an arc-shaped surface, which avoids the tip effect (the phenomenon of local enhancement of electric field strength caused by sharp corners or protrusions on the edge of the electrode or structure) from exacerbating the local electric field and carrier distribution, further reducing heat accumulation, improving heat dissipation capacity, and thereby enhancing the photoelectric conversion efficiency and reliability of the laser chip.

[0069] In the embodiment of the present application, the arc-shaped surface includes a semicircular surface, an elliptical surface, a parabolic surface, a gradient surface or a wavy surface.

[0070] The semicircular surface means that the end of the third electrode 600 is a standard semicircle, and the preparation process is simple, such as photoresist reflow; the electric field uniformity is optimal, and the tip effect can be effectively suppressed.

[0071] The elliptical curved surface means that the end of the third electrode 600 is an ellipse, and the ratio of the major axis to the minor axis of the ellipse can be adjusted according to actual conditions. By adjusting the curvature radius distribution, the electric field or current expansion can be directionally optimized.

[0072] The parabolic curved surface means that the end face shape of the third electrode 600 conforms to a parabola. The parabola can provide a relatively gentle electric field gradient and is suitable for ultra-high voltage scenarios.

[0073] The gradual curved surface refers to that the end of the third electrode 600 is formed into a smooth transition arc surface through chamfering or rounding, and the preparation process is simple, such as a conventional photolithography and etching process.

[0074] The wave-shaped curved surface refers to that the end surface shape of the third electrode 600 is wave-shaped, which is spliced by arc segments with different radii of curvature, and can realize double optimization of electric field and current in limited space.

[0075] With reference to Figure 1 In the embodiment of the present application, the laser chip further comprises a reflective film 700 and an anti-reflection film 800.

[0076] The reflective film 700 and the anti-reflection film 800 are respectively arranged on the first side surface 1013 and the second side surface 1014 of the multilayer epitaxial structure 100.

[0077] The reflective film 700 is formed by alternately stacking high and low refractive index materials, and uses interference of the multilayer dielectric film to enhance reflection, for retaining light energy; the anti-reflection film 800 uses interference cancellation or gradually changing refractive index to reduce reflection, for reducing light loss.

[0078] In the embodiment of the present application, the reflectivity of the reflective film 700 is 50%-100%; the reflectivity of the anti-reflection film 800 is less than or equal to 10%.

[0079] With reference to Figure 2 and Figure 3 In the embodiment of the present application, the laser chip further comprises a passivation layer 900.

[0080] The passivation layer 900 is arranged on the third side surface 1015 and the fourth side surface 1016 of the multilayer epitaxial structure 100, and is also arranged on the area of the upper surface 1011 except the anode electrode 500.

[0081] The passivation layer 900 is used for isolating impurities in the external environment and preventing cavity surface oxidation.

[0082] Alternatively, the passivation layer 900 is also arranged on the upper surface 1011, and the passivation layer 900 arranged on the upper surface 1011 also covers the edge of the anode electrode 500; the passivation layer 900 covering the edge of the anode electrode 500 can smooth the electric field distribution and reduce uneven carrier injection caused by local high electric field, thereby improving the device reliability.

[0083] In the embodiment of the present application, the substrate layer 101 can be composed of GaAs, with a thickness of 200 nm; the lower confinement layer 102 can be composed of AlGaAs, with a thickness of 0.3 μm; the lower waveguide layer 103 can be composed of AlGaAs, with a thickness of 0.5-3 μm; the quantum well active layer 104 can be composed of alternately grown AlGaAs well layer-AlGaAs barrier layer, with a thickness of 0.1 μm; the upper waveguide layer 105 can be composed of AlGaAs, with a thickness of 0.1-3 μm; the upper confinement layer 106 can be composed of AlGaAs, with a thickness of 0.3-1 μm; and the ridge waveguide layer 107 can be composed of AlGaAs, with a thickness of 280 nm.

[0084] The cathode electrode 400 and the anode electrode 500 can be composed of one or more of Cr / Au, Ti / Au or Ni / Au.

[0085] The current non-injection layer 300 can be composed of one or more of Al2O3, SiN or SiO2, with a thickness of 10-50 nm.

[0086] The passivation layer 900 can be composed of SiO2, with a thickness of 50 nm-500 nm.

[0087] It should be noted that the effect of the laser chip will be affected by the material, process and size variation of the lower confinement layer 102, the lower waveguide layer 103, the quantum well active layer 104, the upper waveguide layer 105, the upper confinement layer 106 and the ridge waveguide layer 107, so that the above-mentioned materials and sizes can be properly optimized according to different chip structures and process methods during actual preparation, so that the laser chip can play the best effect.

[0088] The embodiment of the present application also provides a preparation method of a laser chip, for preparing the above-mentioned laser chip, which comprises the following steps:

[0089] Step 1: referring to Figure 4 and Figure 5 , a substrate layer 101 is provided, and the substrate layer 101 is placed in a growth chamber of a metal organic chemical vapor deposition device (MOCVD, Metal-Organic Chemical Vapor Deposition), and the lower confinement layer 102, the lower waveguide layer 103, the quantum well active layer 104, the upper waveguide layer 105, the upper confinement layer 106 and the ridge waveguide layer 107 are sequentially grown on the substrate layer 101, to obtain a multilayer epitaxial structure 100.

[0090] It should be noted that by etching the ridge waveguide layer 107, the width of the ridge waveguide layer 107 in the third direction (the y-axis shown in the figure) is smaller than the widths of other layers, so as to form a ridge structure; wherein the thickness of the ridge waveguide layer 107 (the z-axis shown in the figure) can be 280 nm.

[0091] Step 2: Reference Figure 6 Using the photoresist 200 as a mask, a step surface 108 is formed at the edge of the ridge waveguide layer 107, that is, the edge of the upper surface 1011 of the multilayer epitaxial structure 100, and at the intersection of the upper surface 1011 and the first side surface 1013 by dry etching.

[0092] The step depth (z-axis shown in the figure) of the step surface 108 is 10 nm-50 nm.

[0093] Step 3: Reference Figure 7 A current non-injection layer 300 having the same step depth as the step surface 108 is disposed on the step surface 108 by plasma enhanced chemical vapor deposition technology and magnetron sputtering technology, and the photoresist 200 is removed.

[0094] The two exposed surfaces of the step surface 108 are flush with the upper surface 1011 and the first side surface 1013 respectively.

[0095] Step 4: Reference Figure 8 The anode electrode 500 and the cathode electrode 400 are respectively formed on the upper surface 1011 and the lower surface 1012 of the multilayer epitaxial structure 100 along the first direction (z-axis shown in the figure) using photolithography technology and electron beam evaporation process. That is, the anode electrode 500 and the cathode electrode 400 are respectively formed on the surface of the ridge waveguide layer 107 and the back surface of the substrate layer 101.

[0096] A third electrode 600 is formed on the upper surface 1011 . The third electrode 600 is spaced apart from the anode electrode 500 along the second direction (the y-axis shown in the figure). The end surface of the third electrode 600 close to the anode electrode 500 is an arc-shaped surface.

[0097] At the same time, the third electrode 600 also covers the non-current injection layer 300 , and both ends of the third electrode 600 along the third direction (the y-axis shown in the figure) extend from the non-current injection layer 300 to the upper surface 1011 .

[0098] The width of the third electrode 600 in the third direction is greater than the step surface 108 and greater than the current non-injection layer 300 , thereby widening the third electrode 600 and improving the coverage of the third electrode 600 .

[0099] Step 5: Reference Figure 2A passivation layer 900 with a thickness of 300 nm is deposited using plasma enhanced chemical vapor deposition technology, and the passivation layer 900 on the anode electrode 500, the cathode electrode 400, the third electrode 600, the first side surface 1013 and the second side surface 1014 is removed by photolithography technology and using BOE (Buffered Oxide Etch) etching solution to expose the electrical injection window.

[0100] Step 6: Reference Figure 1 The reflective film 700 and the anti-reflective film 800 are respectively plated on the first side surface 1013 and the second side surface 1014 by chemical plating, electroplating or other methods to obtain a laser chip.

[0101] An embodiment of the present application further provides a communication device, comprising the laser chip described above.

[0102] In summary, the embodiments of the present application provide a laser chip, a method for manufacturing a laser chip, and a communication device. The laser chip includes a multilayer epitaxial structure 100, an anode electrode 500, a cathode electrode 400, and a third electrode 600. The anode electrode 500 and the cathode electrode 400 are respectively arranged on the multilayer epitaxial structure 100 along a first direction (the z-axis shown in the figure) and have opposite upper surfaces 1011 and lower surfaces 1012. A step surface 108 is formed at the edge of the upper surface 1011 of the multilayer epitaxial structure 100, and the step surface 108 is filled with a current non-injection layer 300; the third electrode 600 is arranged on the upper surface 1011 and is spaced from the anode electrode 500 along the second direction (the x-axis shown in the figure). The end surface of the third electrode 600 close to the anode electrode 500 is an arc-shaped surface; at the same time, the third electrode 600 also covers the top of the current non-injection layer 300, and both ends of the third electrode 600 along the third direction (the y-axis shown in the figure) also extend from the current non-injection layer 300 to the upper surface 1011.

[0103] The laser chip provided in the embodiment of the present application can suppress the diffusion of carriers toward the light-emitting surface by setting a current non-injection layer 300 on the cavity surface side and applying voltage in conjunction with the third electrode 600, thereby reducing the carrier concentration in the area near the cavity surface and thus lowering the cavity surface temperature.

[0104] Meanwhile, the third electrode 600 also extends from the current non-injection layer 300 to the upper surface 1011 at both ends of the third direction (y-axis shown in the figure), thereby widening the third electrode 600, improving the coverage of the third electrode 600, expanding the range of the depletion layer of the p-type semiconductor below the current non-injection layer 300 to the active region, forming a wider carrier inhibition area, and ensuring effective blocking of the accumulation of carriers to the light-emitting surface; as a good heat conduction medium, the widened third electrode 600 can increase the heat conduction path, quickly conduct the heat generated on the cavity surface to the outside through the ridge waveguide layer 107, the upper limiting layer 106 and other structures, avoid heat accumulation on the cavity surface, and improve the heat dissipation capacity.

[0105] Further, the end surface of the third electrode 600 close to the anode electrode 500 is an arc surface, which avoids the intensification of local electric field and carrier distribution caused by the sharp end effect, further reduces heat accumulation, improves heat dissipation capacity, and further enhances the photoelectric conversion efficiency and reliability of the laser chip.

[0106] In the specification, each embodiment or embodiment is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0107] It should be noted that the terms "one embodiment", "an embodiment", "exemplary embodiment", "some embodiments", etc. in the specification mean that the described embodiment can include a specific feature, structure or property, but not necessarily every embodiment includes the specific feature, structure or property. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when a specific feature, structure or property is described in combination with an embodiment, it is within the knowledge of those skilled in the art to realize such feature, structure or property in combination with other embodiments described explicitly or implicitly.

[0108] Generally, the terms should be understood at least partly by the use in context. For example, at least partly according to the context, the term "one or more" used in the text can be used to describe any feature, structure or property of singular meaning, or can be used to describe the combination of features, structures or properties of plural meaning. Similarly, at least partly according to the context, terms such as "a" or "said" can be understood as conveying singular usage or conveying plural usage.

[0109] It should be readily understood that “on,” “above,” and “over” in this disclosure should be interpreted in the broadest manner, such that “on” means not only “directly on something,” but also includes “on something” with intervening features or layers therebetween, and “above” or “over” includes not only the meaning of “above” or “over,” but also includes “above” or “over” with no intervening features or layers therebetween (i.e., directly on something).

[0110] Additionally, spatially relative terms, such as "below," "beneath," "beneath," "above," and the like, may be used herein for ease of description to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be in other orientations (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A laser chip, characterized in that: include: Multilayer epitaxial structure; as well as, an anode electrode and a cathode electrode, the anode electrode and the cathode electrode being respectively arranged on an upper surface and a lower surface of the multilayer epitaxial structure that are opposite to each other along a first direction; a third electrode, the third electrode being disposed on the upper surface and spaced apart from the anode electrode along the second direction, wherein an end surface of the third electrode close to the anode electrode is an arc-shaped surface; The upper surface intersects with the first side surface of the multi-layer epitaxial structure, and a pit is provided at the intersection of the upper surface and the first side surface to form a step surface on the upper surface, and the step surface is filled with a current non-injection layer; The third electrode covers the current non-injection layer, and two ends of the third electrode along the third direction extend from the current non-injection layer to the upper surface; The first direction, the second direction and the third direction are perpendicular to each other.

2. The laser chip according to claim 1, characterized in that The arc-shaped surface includes a semicircular surface, an elliptical surface, a parabolic surface, a gradual surface or a wavy surface.

3. The laser chip according to claim 1, wherein The multi-layer epitaxial structure comprises a substrate layer, a lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and a ridge waveguide layer which are stacked in sequence; A surface of the ridge waveguide layer away from the upper confinement layer is the upper surface, and a surface of the substrate layer away from the lower confinement layer is the lower surface.

4. The laser chip according to claim 1, wherein: The laser chip further includes a reflective film and an anti-reflective film; The reflective film and the anti-reflection film are respectively disposed on the first side surface and the second side surface of the multi-layer epitaxial structure that are opposite to each other along the second direction.

5. The laser chip according to claim 1, wherein: The laser chip further includes a passivation layer; The passivation layer is provided on a third side surface and a fourth side surface of the multilayer epitaxial structure that are opposite to each other along the third direction; The passivation layer is further provided on the upper surface except for the anode electrode; or The passivation layer is further disposed on the upper surface and covers the edge of the anode electrode.

6. The laser chip according to claim 4, characterized in that The reflectivity of the reflective film is 50%-100%; The reflectivity of the antireflection film is less than or equal to 10%.

7. The laser chip according to claim 3, characterized in that The substrate layer is made of GaAs and has a thickness of 200 nm; The lower confinement layer is made of AlGaAs and has a thickness of 0.3 μm; The lower waveguide layer is made of AlGaAs and has a thickness of 0.5-3 μm; The quantum well active layer is composed of an alternately grown AlGaAs well layer and an AlGaAs barrier layer, and has a thickness of 0.1 μm; The upper waveguide layer is made of AlGaAs and has a thickness of 0.1-3 μm; The upper confinement layer is made of AlGaAs and has a thickness of 0.3-1 μm; The ridge waveguide layer is made of AlGaAs and has a thickness of 280 nm; The cathode electrode and the anode electrode are composed of one or more of Cr / Au, Ti / Au or Ni / Au; The current non-injection layer is made of one or more of Al2O3, SiN or SiO2, and has a thickness of 10-50nm.

8. The laser chip according to claim 5, characterized in that The passivation layer is made of SiO2 and has a thickness of 50nm-500nm.

9. A method for preparing a laser chip, for preparing the laser chip according to any one of claims 1 to 8, characterized in that: include: A lower confinement layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper confinement layer and a ridge waveguide layer are sequentially arranged on the substrate layer to obtain a multi-layer epitaxial structure; Using a photoresist as a mask, dry etching is performed to form a step surface at the edge of the upper surface of the multilayer epitaxial structure; Providing a current non-injection layer having the same step depth as that of the step surface on the step surface by using plasma enhanced chemical vapor deposition technology and magnetron sputtering technology, and removing the photoresist; An anode electrode and a cathode electrode are respectively formed on the upper surface and the lower surface opposite to each other along the first direction of the multilayer epitaxial structure using photolithography technology and electron beam evaporation process, and a third electrode is formed on the upper surface. The third electrode is spaced from the anode electrode along the second direction, and the end surface of the third electrode close to the anode electrode is an arc-shaped surface. The third electrode covers the current non-injection layer, and the two ends of the third electrode along the third direction extend from the current non-injection layer to the upper surface.

10. A communication device, characterized in that: The laser chip comprises the laser chip according to any one of claims 1 to 8.

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