Laser diode and method of manufacturing stacked high density laser diode array

Abstract

The invention discloses a laser diode and a method of manufacturing a stacked high density laser diode array wherein the laser diode comprises a substrate and a stacked layer, the stacked layer comprising a P-type layer with ridge strips, the laser diode having a waveguide surface, a light output surface, a reflective surface, and a bottom surface; the top surface of the P-type layer is a waveguide surface, the bottom surface of the substrate is a bottom surface, and the waveguide surface and the bottom surface are oppositely arranged; the bottom surface is provided with at least one groove, and the extending direction of the groove is perpendicular to the ridge-shaped strip. The two side edges of the waveguide surface, the light output surface and the reflection surface are all plated with coatings. According to the laser diode and the method for manufacturing the stacked high-density laser diode array, the structure of the laser diode is improved, and at least one groove is formed in the bottom surface of the laser diode, so that the two side edges, the light output surface and the reflecting surface of the waveguide surface are conveniently coated with coatings, and the light output surface and the reflecting surface are coated with the coatings; and the electrical performance of the laser diode is further ensured.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor light emitting diodes, in particular to a laser diode and a method for manufacturing a stacked high-density laser diode array. Background Art

[0002] The resonant mirror of the laser diode includes a light output surface and a reflection surface opposite thereto. A coating needs to be applied on the resonant mirror. The coating can prevent the resonant mirror of the laser diode from deteriorating during operation, and can change the reflectivity of the resonant mirror, thereby improving the electrical performance of the laser diode.

[0003] It can be seen that the mirror coating of the laser diode needs to maintain high purity and high cleanliness. Considering that the structure of the existing laser diode is a rectangular parallelepiped, its resonance mirror includes two opposite surfaces and needs double-sided coating. In the prior art, the laser diode is clamped by a fixture, and after coating the light output surface, the fixture is turned over and the coating is coated on the reflective surface. For details, please refer to Figure 1 , Figure 1 The structure diagram of one of the clamps in the prior art is shown as follows. Figure 1 It can be seen that several laser diode bars are arranged from bottom to top, the bottom laser diode bar is clamped by the first clamp a1, the top laser diode bar is clamped by the second clamp a2, the left side of all laser diode bars is clamped by the third clamp a3, the right side a4 of all laser diode bars is clamped by the fourth clamp, and a spacer a5 is provided between two adjacent laser diode bars, and the spacer a5 is used to separate adjacent laser diode bars. During the processing, the direction of the clamp is first adjusted so that the light output surface of the laser diode bar faces upward, and the light output surfaces of all laser diodes are vacuum coated to form a coating, and then the direction of the clamp is adjusted so that the light output surface of the laser diode bar faces downward, and the reflective surfaces of all laser diodes are vacuum coated to form a coating, so that the resonance mirrors of all laser diode bars have a coating.

[0004] Due to the small size of the laser diode, a large number of spacer bars are used in the fixture during actual coating, which greatly increases the processing cost of the entire product. Secondly, due to the influence of the material, the spacer bars will bend during use, resulting in an uneven surface formed by the spacer bars and the laser diode, which in turn affects the coating quality. More importantly, due to the existence of the third and fourth fixtures, the left side of the laser diode clamped by the third fixture cannot be coated, and the right side of the laser diode clamped by the fourth fixture cannot be coated. The left and right sides of the laser diode are not completely coated, and its electrical performance will be greatly affected.

[0005] It can be seen that the existing laser diodes have poor coating effects on the resonant mirrors due to limitations in their product structure. Therefore, how to solve the coating problem of the resonant mirrors of laser diodes has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0006] The present invention provides a laser diode and a method for manufacturing a stacked high-density laser diode array. By improving the structure of the laser diode, at least one groove is opened on the bottom surface of the laser diode, so that it is convenient to plate a coating on the two side edges of the waveguide surface, the light output surface and the reflection surface, thereby ensuring the electrical performance of the laser diode.

[0007] In order to solve the above technical problems, an embodiment of the present invention provides a laser diode, comprising a substrate and a stacked layer located on the substrate, wherein the stacked layer comprises an N-type layer, an active layer, and a P-type layer having a ridge strip on the surface, and the laser diode has a waveguide surface, a light output surface, a reflection surface, and a bottom surface;

[0008] The top surface of the P-type layer is the waveguide surface, the bottom surface of the substrate is the bottom surface, and the waveguide surface is arranged opposite to the bottom surface;

[0009] The bottom surface has at least one groove, and the extending direction of the groove is perpendicular to the ridge strip;

[0010] The light output surface and the reflection surface are located on opposite sides of the waveguide surface and are perpendicular to the waveguide surface;

[0011] A side edge of the waveguide surface connected to the light output surface, a side edge of the waveguide surface connected to the reflection surface, the light output surface and the reflection surface are all coated.

[0012] As one of the preferred solutions, the bottom surface has a first groove and a second groove, the first groove is located at one end of the bottom surface connected to the reflecting surface, and the second groove is located at one end of the bottom surface connected to the light output surface, and the first groove and the second groove form a strip-shaped protrusion extending downward on the bottom surface.

[0013] As a preferred solution, the height of the strip-shaped protrusions is 0.5 to 20 μm.

[0014] As a preferred solution, the width of the first groove is 5 to 50 μm, and the width of the second groove is 5 to 50 μm.

[0015] As a preferred solution, a difference between a width of a coating on an edge of the waveguide surface adjacent to the light output surface and a width of the second groove is greater than 2 μm.

[0016] Another embodiment of the present invention provides a coating method for a laser diode array resonant mirror, which is applicable to the laser diode as described above. The coating method for the laser diode array resonant mirror comprises:

[0017] Arrange at least two of the laser diodes, wherein the waveguide surface of each of the laser diodes faces the same direction and the waveguide surface of each of the laser diodes is located in the same plane, the bottom surface of each of the laser diodes faces the same direction and the bottom surface of each of the laser diodes is located in the same plane, the light output surface of each of the laser diodes faces the same direction and the light output surface of each of the laser diodes is located in the same plane, and the reflection surface of each of the laser diodes faces the same direction and the reflection surface of each of the laser diodes is located in the same plane, to form a laser diode bar;

[0018] stacking at least two of the laser diode bars to form a laser diode array, each of the laser diode bars is in contact with at least one other laser diode bar, and the light output surfaces of each of the laser diodes in each of the laser diode bars face the same direction and are located in the same plane; and the reflective surfaces of each of the laser diodes in each of the laser diode bars face the same direction and are located in the same plane;

[0019] An anti-reflection coating is plated on the light output surface of each of the stacked laser diode bars, a reflective coating is plated on the reflective surface of each of the stacked laser diode bars, a coating is plated on one side edge of the waveguide surface of each of the stacked laser diode bars that is adjacent to the light output surface, and a coating is plated on one side edge of the waveguide surface of each of the stacked laser diode bars that is adjacent to the reflective surface.

[0020] Another embodiment of the present invention provides a method for manufacturing a stacked high-density laser diode array, wherein the laser diode array is formed by stacking laser diode bars, each of which includes at least two laser diodes as described above. The method for manufacturing a stacked high-density laser diode array includes:

[0021] forming an epitaxial layer on a semiconductor wafer, the epitaxial layer comprising a quantum well;

[0022] Depositing a first metallization layer on a first surface of the semiconductor wafer and depositing a second metallization layer on a second surface of the semiconductor wafer opposite to the first surface;

[0023] applying a solder layer on the first metallization layer;

[0024] Coating a resist coating on the second metallization layer, and sequentially performing baking, exposure, development, dry etching and demolding to form a plurality of grooves on the second surface of the semiconductor wafer;

[0025] cutting the semiconductor wafer into a plurality of laser diode bars;

[0026] A plurality of the laser diode bars are stacked to form a laser diode array, wherein the waveguide surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; the bottom surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane, and the bottom surface of each of the laser diodes has at least one groove; the light output surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; and the reflective surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane;

[0027] The laser diode array is placed in a vacuum chamber for vacuum sputtering, an anti-reflection coating is plated on the light output surface of each laser diode in the laser diode bar, and a reflective coating is plated on the reflective surface of each laser diode in the laser diode bar; a coating is plated on the edge of one side of the waveguide surface of each laser diode in the laser diode bar that is connected to the light output surface; and a coating is plated on the edge of one side of the waveguide surface of each laser diode in the laser diode bar that is connected to the reflective surface.

[0028] Compared with the prior art, the beneficial effects of the embodiments of the present invention are at least one of the following: the structure of the laser diode is improved, at least one groove is provided on the bottom surface of the laser diode, and the groove enables the coating on the light output surface to spread to the edge of the waveguide surface connected to the light output surface when the laser diode is subjected to film coating, so that a portion of one end of the waveguide surface is coated with the coating; the groove also enables the coating on the reflection surface to spread to the edge of the waveguide surface connected to the reflection surface when the laser diode is subjected to film coating, so that a portion of the other end of the waveguide surface is coated with the coating. In the final processed product, in addition to the light output surface and the reflection surface being coated, a portion of the waveguide surface of the laser diode is also coated, so that it is convenient to coat the two side edges of the waveguide surface, the light output surface and the reflection surface, thereby ensuring the electrical performance of the laser diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of one of the clamps in the prior art;

[0030] Figure 2a is a schematic structural diagram of a laser diode having a groove in Embodiment 1 of the present invention;

[0031] Figure 2b is a schematic structural diagram of a laser diode having two grooves in Example 1 of the present invention;

[0032] Figure 3 is a side view schematic diagram of a laser diode having two grooves according to the present invention;

[0033] Figure 4 is a side view of a laser diode after a coating process in one embodiment of the present invention;

[0034] Figure 5a is a schematic diagram of the structure of the laser diode bar in the second embodiment of the present invention;

[0035] Figure 5b is a schematic diagram of the bottom surface structure of the laser diode bar in Example 2 of the present invention;

[0036] Figure 6 It is a cross-sectional schematic diagram of a process of processing a semiconductor wafer to obtain a groove according to the present invention;

[0037] Figure 7 is a schematic diagram of a processed semiconductor wafer of the present invention;

[0038] Figure 8 is a schematic diagram of cutting a semiconductor wafer according to the present invention;

[0039] Figure 9ais a side cross-sectional view of a clamp for fixing a laser diode bar according to Embodiment 5 of the present invention;

[0040] Figure 9b is a top view of a fixture for fixing a laser diode bar according to Embodiment 5 of the present invention;

[0041] Fig.9c is an enlarged structural view of a fixture for fixing a laser diode bar at position X according to Embodiment 5 of the present invention;

[0042] Fig.10a is a partial cross-sectional schematic diagram of a clamp including a support bar according to Embodiment 5 of the present invention;

[0043] Fig.10b is a schematic top view of a partial structure of a clamp including a support bar according to Example 5 of the present invention;

[0044] Reference numerals:

[0045] Among them, a1, first clamp; a2, second clamp; a3, third clamp; a4, fourth clamp; a5, spacer; 1, substrate; 2, stacked layer; 21, N-type layer; 22, active layer; 23, P-type layer; 24, ridge strip; 3, waveguide surface; 4, light output surface; 5, reflection surface; 6, bottom surface; 61, groove; 62, first groove; 63, second groove; 7, base; 8, stage; 91, first stop block; 92, second stop block; 10a, Fig.10a Support bar; 10b, Fig.10b Support bar; M, strip protrusion; D, extension height of the strip protrusion; L1, width of the first groove; L2, width of the second groove; N1, edge of the waveguide surface; N2, edge of the waveguide surface; J, first electrode surface; K, second electrode surface; P, first resonance mirror surface; Q, second resonance mirror surface; C, accommodating space; S1, difference between the coating width on the edge of one side of the waveguide surface 3 connected to the reflecting surface 5 and the width L1 of the first groove 62; S2, difference between the coating width on the edge of one side of the waveguide surface 3 connected to the light output surface 4 and the width L2 of the second groove 63. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0048] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0049] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0050] Laser diodes have been widely used in technical fields such as radar and medical treatment due to their easy mass production and low cost. Since laser diodes are small in size, when stacked, the protruding laser diodes cover the adjacent laser diodes, causing uneven mirror surface during coating, which affects the electrical performance of the laser diodes. Therefore, in the prior art, Figure 1As shown, a spacer bar is provided between two adjacent laser diodes to separate the two adjacent laser diodes. In this way, the adjacent laser diodes will not cover each other. However, the number of spacer bars used in the fixture is large, which will greatly increase the processing cost of the entire product. Therefore, the present invention designs a structure of a laser diode that no longer uses a spacer bar, thereby greatly reducing the processing cost of the product. The present invention improves the structure of the laser diode and opens at least one groove on the bottom surface of the laser diode, so as to facilitate coating on the two side edges of the waveguide surface, the light output surface and the reflection surface. The coating effect is good, thereby ensuring the electrical performance of the laser diode. Specifically, the embodiments of the present invention provide a coating method for a laser diode, a laser diode bar, a laser diode array resonant mirror, a method for manufacturing a stacked high-density laser diode array, and a fixture for fixing a laser diode bar.

[0051] Example 1

[0052] Embodiment 1 provides a laser diode. For details, see Figure 2a to Figure 2b , Figure 2a FIG. 1 is a schematic diagram showing the structure of a laser diode having a groove in Embodiment 1 of the present invention. Figure 2b The structure schematic diagram of the laser diode with two grooves in Example 1 of the present invention is shown. The laser diode in the embodiment includes a substrate 1 and a stacked layer 2 located on the substrate. The stacked layer 2 includes an N-type layer 21, an active layer 22 and a P-type layer 23 with a ridge strip 24 on the surface from bottom to top. The ridge strip 24 is arranged on the surface of the P-type layer 23 along the direction A. The laser diode has a waveguide surface 3, a light output surface 4, a reflection surface 5 and a bottom surface 6. It should be explained that the resonant mirror of the laser diode includes the light output surface 4 and the reflection surface 5 opposite thereto. In other materials, the light output surface 4 is also called the front facet of the laser diode, and the reflection surface 5 is also called the back facet of the laser diode. The facet is formed after sliding and cutting the wafer. Then, the laser diode is coated with a facet coating technology to form a coating, thereby ensuring the performance of the laser diode. The present invention is uniformly described with the light output surface 4 and the reflection surface 5, and no additional details are given here.

[0053] The top surface of the P-type layer 23 is the waveguide surface 3, the bottom surface of the substrate 1 is the bottom surface 6, the waveguide surface 3 is arranged opposite to the bottom surface 6; the bottom surface 6 has at least one groove. Figure 2a The number of grooves in the middle is 1 groove 61, Figure 2bThere are two grooves, namely a first groove 62 and a second groove 63. The first groove 62 is located at one end of the bottom surface 6, and the second groove 63 is located at the other end of the bottom surface 6. The first groove 62 and the second groove 63 form a strip-shaped protrusion M extending downward on the bottom surface 6.

[0054] The groove is arranged on the bottom surface 6 along the direction B, and the direction B is perpendicular to the direction A. The light output surface 4 and the reflection surface 5 are located on opposite sides of the waveguide surface 3 and are perpendicular to the waveguide surface 3. In the embodiment of the present invention, the light output surface 4 and the reflection surface 5 are both coated. In addition, since the laser diode has a groove structure, the edges of both sides of the waveguide surface 3 are also coated, which will be described in detail later.

[0055] Preferably, the N-type layer 21 of the laser diode in the above embodiment includes an N-type metal layer, and the P-type layer 23 includes a P-type metal layer.

[0056] by Figure 2b The structure of a laser diode having two trenches is shown for illustration, see Figure 3 , Figure 3 The figure shows a cross-sectional schematic diagram of a laser diode with two grooves, in which the top side is the waveguide surface 3 of the laser diode (the waveguide line is used as a schematic in the figure, and the waveguide line corresponds to the ridge-shaped strip formed by subsequent processing), the bottom side is the bottom surface 6 of the laser diode, the right side is the light output surface 4 of the laser diode, and the left side is the reflection surface 5 of the laser diode. It can be seen from the figure that the first groove 62 on the left and the second groove 63 on the right make the bottom surface 6 extend downward to form a strip-shaped protrusion M, which is equivalent to forming a cavity at the left and right positions of the bottom of the laser diode. When the laser diode is subjected to the coating process, the light output surface 4 and the reflection surface 5 are processed. The presence of the grooves prevents the bottom surface 6 of the laser diode from being coated, while the two side edges of the waveguide surface 3 (i.e., the dotted boxes N1 and N2 in the figure), the light output surface 4 and the reflection surface 5 are all coated.

[0057] For the strip-shaped protrusion M, its extended height D will affect the subsequent coating effect. In an optional implementation, in order to ensure the coating effect of the laser diode, the extended height D of the strip-shaped protrusion M in this embodiment is 0.5 to 20 μm, for example, 0.5 microns, 10 microns, 12 microns, 14 microns, 15 microns, etc. Of course, the extended height D of the strip-shaped protrusion can be set according to actual use requirements, and no further details are given here.

[0058] For the first groove 62 on the left, the width L1 of the first groove 62 on the left will affect the subsequent coating effect. In an optional implementation, in order to ensure the coating effect of the laser diode, the width L1 of the first groove 62 on the left in this embodiment is 5 to 50 μm, for example, 5 microns, 10 microns, 12 microns, 14 microns, 15 microns, etc. Of course, the width L1 of the first groove 62 on the left can be set according to actual use requirements, and no further details are given here.

[0059] For the second groove 63 on the right side, the width L2 of the second groove 63 on the right side will affect the subsequent coating effect. In an optional implementation, in order to ensure the coating effect of the laser diode, the width L2 of the second groove 63 on the right side in this embodiment is 5 to 50 μm, for example, 5 microns, 10 microns, 12 microns, 14 microns, 15 microns, etc. Of course, the width L2 of the second groove 63 on the right side can be set according to actual use requirements, and no further details are given here.

[0060] It should be noted that the width L1 of the first groove 62 on the left and the width L2 of the second groove 63 on the right do not need to be the same. By controlling the size of the groove, when processing the light output surface 4 and the reflection surface 5 of the laser diode, the plated coating can extend to the edges of the waveguide surface 3 on both sides (i.e., the dotted boxes N1 and N2 in the figure). In addition, due to the small size of the groove, during the actual processing, the residue of the coating will not spread to the bottom surface 6 of the laser diode, thereby ensuring the coating effect of the laser diode.

[0061] In the actual coating process, the coating on the light output surface 4 can spread to the edge of the waveguide surface 3 connected to the light output surface 4, so that a portion of one end of the waveguide surface 3 is coated with the coating, and the coating on the reflection surface 5 can spread to the edge of the waveguide surface 3 connected to the reflection surface 5, so that a portion of the other end of the waveguide surface 3 is coated with the coating. Preferably, see Figure 4 , Figure 4The cross-sectional schematic diagram of a laser diode after coating processing in one embodiment of the present invention is shown, and the side edge of the waveguide surface 3 connected to the light output surface 4, the side edge of the waveguide surface 3 connected to the reflective surface 5, the light output surface 4 and the reflective surface 5 are all coated. Preferably, the difference S2 between the coating width on the side edge of the waveguide surface 3 connected to the light output surface 4 and the width L2 of the second groove 63 is greater than 2μm. Furthermore, the difference S1 between the coating width on the side edge of the waveguide surface 3 connected to the reflective surface 5 and the width L1 of the first groove 62 is greater than 2μm. Of course, the actual coating width value can be set according to the actual use requirements, and no further elaboration is made here.

[0062] In practical applications, since one or two grooves can be provided on the bottom surface 6 of the laser diode in this embodiment, under the premise of providing only one groove, it is necessary to give priority to ensuring that a groove is provided on the side of the bottom surface 6 close to the light output surface 4, that is, the above-mentioned second groove 63. Correspondingly, it is also necessary to give priority to ensuring that the difference S2 between the coating width on the edge of the waveguide surface 3 connected to the light output surface 4 and the width L2 of the second groove 63 is greater than 2 μm.

[0063] Example 2

[0064] Embodiment 2 provides a laser diode bar, that is, an uncut laser diode bar. For details, see Figure 5a to Figure 5b , Figure 5a FIG. 2 is a schematic diagram showing the structure of a laser diode bar in Embodiment 2 of the present invention. Figure 5b The figure shows a schematic diagram of the bottom surface structure of the laser diode bar in Example 2 of the present invention (i.e., a schematic diagram equivalent to flipping the laser diode bar). It can be seen from the figure that the laser diode bar in Example 2 includes at least two laser diodes, each laser diode is in contact with at least one other laser diode, and the waveguide surface 3 of each of the laser diodes faces the same direction and is located in the same plane, forming the first electrode surface J of the laser diode bar; the bottom surface 6 of each of the laser diodes faces the same direction and is located in the same plane, forming the second electrode surface K of the laser diode bar; the light output surface 4 of each of the laser diodes faces the same direction and is located in the same plane, forming the first resonance mirror surface P of the laser diode bar; the reflection surface 5 of each of the laser diodes faces the same direction and is located in the same plane, forming the second resonance mirror surface Q of the laser diode bar.

[0065] In addition, the laser diode bar in this embodiment is generally made of various semiconductor materials such as GaAs, AlGaAs and InP, which are not specifically limited here. Similarly, the laser diode bar in this embodiment is a rectangular bar with a groove on the bottom surface as described above, which is not further explained here.

[0066] Example 3

[0067] Embodiment 3 provides a coating method for a laser diode array resonant mirror, which is applicable to the laser diode bar as described above. The coating method for the laser diode array resonant mirror comprises the following steps:

[0068] At least two of the laser diodes are arranged, the waveguide surface of each of the laser diodes faces the same direction, and the waveguide surface of each of the laser diodes is located in the same plane, the bottom surface of each of the laser diodes faces the same direction, and the bottom surface of each of the laser diodes is located in the same plane, the light output surface of each of the laser diodes faces the same direction, and the light output surface of each of the laser diodes is located in the same plane, and the reflective surface of each of the laser diodes faces the same direction, and the reflective surface of each of the laser diodes is located in the same plane, to form a laser diode bar.

[0069] The laser diode bars are stacked to form a laser diode array, each of the laser diode bars is in contact with at least one other laser diode bar, each of the laser diode bars is in contact with at least one other laser diode bar, the light output surface of each of the laser diodes in each of the laser diode bars faces the same direction; and the reflective surface of each of the laser diodes in each of the laser diode bars faces the same direction.

[0070] In other words, the first resonance mirror surface P of each laser diode bar faces the same direction; the second electrode surface K of each laser diode bar faces the same direction, that is, the second electrode surface K of each laser diode bar faces downward, the first electrode surface J of each laser diode bar faces upward, the first resonance mirror surface P of each laser diode bar faces the same side, and the second resonance mirror surface Q of each laser diode bar faces the same other side, thereby facilitating the subsequent coating process.

[0071] An anti-reflection coating is plated on the first resonance mirror surface P of the stacked laser diode bars, and a reflective coating is plated on the second resonance mirror surface Q of the stacked laser diode bars. Due to the presence of the grooves, there is a cavity between adjacent laser diode bars, and the cavity enables the coating to extend to the first electrode surface J, that is, the two side edges of the waveguide surface 3 of each laser diode have the coating. At the same time, since it is difficult for the coating material to penetrate the above-mentioned cavity, the residue of the coating will not spread to the second electrode surface K of the laser diode bar, that is, the bottom surface 6 of each laser diode has no coating, thereby ensuring the coating effect of the entire laser diode bar.

[0072] Example 4

[0073] The processing of the groove structure can be performed on a round wafer or before the wafer process. Specifically, Example 4 provides a method for manufacturing a stacked high-density laser diode array, comprising the following steps:

[0074] (1) An epitaxial layer is formed on a semiconductor wafer, wherein the epitaxial layer includes a quantum well. It should be noted that the wafer processing technology for producing laser diodes is the same as the prior art. The epitaxial layer on the substrate includes multiple layers of n-doped material, p-doped material and undoped material. The quantum well is formed in these layers and will not be further described here.

[0075] (2) Depositing a first metallization layer on the first surface of the semiconductor wafer, and depositing a second metallization layer on the second surface of the semiconductor wafer opposite to the first surface. The thickness of the first metallization layer and the second metallization layer is preferably 3 μm. The material of the metallization layer may be titanium, titanium tungsten, platinum, gold or other suitable metals.

[0076] (2) applying a solder layer on the first metallization layer;

[0077] (3) coating the second metallization layer with an anti-corrosion coating, and sequentially performing baking, exposure, development, dry etching, and demolding to form a plurality of grooves on the second surface of the semiconductor wafer. For details, see Figure 6 , Figure 6 FIG. 1 is a schematic cross-sectional view of a process for processing a semiconductor wafer to obtain a groove. It should be noted that since the groove is located on the bottom surface of the laser diode, in order to facilitate processing and display, Figure 6 The semiconductor wafer is flipped over, that is, Figure 6 In the cross-sectional view of FIG. 6 , the top portion corresponds to the bottom surface 6 of the laser diode. Figure 6 The bottom of the laser diode corresponds to the waveguide surface 3. Figure 6The difference between the drawings on the left and right sides is the difference in the angles of the semiconductor wafer during processing. The drawing on the right shows a cross-sectional view of the ridge of the semiconductor wafer in the direction of B→B', and the drawing on the left shows a cross-sectional view of the ridge of the semiconductor wafer in the direction of A→A'. After the above processing, the semiconductor wafer to be cut is obtained. For details, please refer to Figure 7 , Figure 7 This is a schematic diagram of a processed semiconductor wafer. Figure 7 The upper part shows the semiconductor wafer with the waveguide surface facing upward after processing in Example 5. Figure 7 The lower portion shows the semiconductor wafer of Example 5 after processing with the bottom surface facing upward.

[0078] (4) For details, please see Figure 8 , Figure 8 A schematic diagram showing cutting a semiconductor wafer into a plurality of laser diode bars is shown;

[0079] (5) Stacking a plurality of the laser diode bars to form a laser diode array, wherein the waveguide surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; the bottom surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane, and the bottom surface of each of the laser diodes has at least one groove; the light output surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; and the reflective surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane.

[0080] In other words, each of the laser diode bars has a first electrode surface J, on which a strip solder layer is provided, each of the laser diode bars has a first resonance mirror surface P and a second resonance mirror surface Q, the first resonance mirror surface P and the second resonance mirror surface Q are perpendicular to the first electrode surface J, each of the laser diode bars has a second electrode surface K, on ​​which at least one groove is provided (the groove is not shown in the figure due to size limitation);

[0081] (6) Placing the laser diode array in a vacuum chamber for vacuum sputtering. Plate an anti-reflection coating on the light output surface of each laser diode in the laser diode bar, plate a reflective coating on the reflective surface of each laser diode in the laser diode bar; plate a coating on the edge of one side of the waveguide surface of each laser diode in the laser diode bar that is connected to the light output surface; plate a coating on the edge of one side of the waveguide surface of each laser diode in the laser diode bar that is connected to the reflective surface

[0082] Since an anti-reflection coating is coated on the first resonance mirror P of the laser diode bar and a reflective coating is coated on the second resonance mirror Q of the laser diode bar, combined with the structure of the groove, the groove can make the coating on the light output surface spread to the side edge of the waveguide surface connected to the light output surface when the laser diode is coated, so that a portion of one end of the waveguide surface is coated; the groove can also make the coating on the reflective surface spread to the side edge of the waveguide surface connected to the reflective surface when the laser diode is coated, so that a portion of the other end of the waveguide surface is coated.

[0083] Preferably, after the coating process, the stacked plurality of laser diode bars may be subjected to vacuum reflow soldering to form a stacked high-density laser diode array.

[0084] Example 5

[0085] Embodiment 5 provides a fixture for fixing a laser diode bar, which is applicable to the laser diode bar as described above. For details, see Figure 9a to Figure 9c , Figure 9a A side cross-sectional view of a fixture for fixing a laser diode bar according to Embodiment 5 of the present invention is shown. Figure 9b FIG. 1 is a top view of a fixture for fixing a laser diode bar according to Embodiment 5 of the present invention, Fig.9c The figure shows an enlarged structural view of the fixture for fixing the laser diode bar at X according to Embodiment 5 of the present invention. The fixture for fixing the laser diode bar comprises:

[0086] The base 7, the top surface of the base 7 is preferably an inclined surface, which enables the device to be processed placed on the top surface to be clamped and fixed under the influence of its own gravity, thereby facilitating assembly and promoting subsequent coating processes. In addition, the top surface of the base 7 can also be a plane, which is determined by the actual processing design requirements and will not be repeated here.

[0087] The stage 8 is disposed on the top surface of the base 7, and stop blocks are disposed at both ends of the stage 8, and the stop blocks extend in a direction away from the inclined surface. In the present embodiment, a first stop block 91 is disposed at the left end of the stage 8, and a second stop block 92 is disposed at the right end of the stage 8, and the first stop block 91 and the second stop block 92 form an open accommodating space C on the stage 8, and a plurality of laser diode bars are sequentially arranged in the accommodating space C along their width direction, and the grooves of the laser diodes in each of the laser diode bars (shown as one groove in the present embodiment, i.e., the groove 61 in the figure) face the same direction.

[0088] Preferably, the cross-sectional shape of the first stop block 91 and the second stop block 92 is a trapezoid, and other shapes may also be selected. Those skilled in the art may select according to actual requirements of the product.

[0089] If the number of laser diode bars is too large, it is difficult to ensure linear processing on an inclined surface due to gravity or vibration. Therefore, the fixture for fixing the laser diode bars further includes:

[0090] A number of support bars are preferably fixed on the stage 8, and the support bars are parallel to the laser diode bars in the accommodating space C. The fixed support bars can ensure the stability of all laser diode bars and guarantee linear processing. Of course, the support bars can also be detachably mounted on the stage. For example, the support bars can be first adjusted on the stage and then fixed after being adjusted to a suitable position, so as to facilitate the picking process of the processing personnel. It should be noted that the material of the stop block and the support bar is determined by the actual product design requirements. For example, a single metal, plastic or alloy can be selected.

[0091] Preferably, the length of the support bar can be determined by the actual fixture design requirements and is not specifically limited here. Figure 10a to Figure 10b , Fig.10a FIG. 1 is a partial cross-sectional schematic diagram of a clamp including a support bar according to Embodiment 5 of the present invention, Fig.10b The diagram shows a partial top view of the structure of a fixture containing support bars according to Example 5 of the present invention. The introduction of the support bars can further ensure the stability of all laser diode bars on the stage.

[0092] The laser diode, laser diode bar, laser diode array resonant mirror coating method, and method for manufacturing a stacked high-density laser diode array provided by the embodiments of the present invention have the beneficial effects of at least one of the following:

[0093] The structure of the laser diode is improved, and at least one groove is provided on the bottom surface of the laser diode. The groove enables the coating on the light output surface to spread to the edge of the waveguide surface connected to the light output surface when the laser diode is subjected to film coating, so that a portion of one end of the waveguide surface is coated; the groove also enables the coating on the reflection surface to spread to the edge of the waveguide surface connected to the reflection surface when the laser diode is subjected to film coating, so that a portion of the other end of the waveguide surface is coated. In the final processed product, in addition to the light output surface and the reflection surface being coated, a portion of the waveguide surface of the laser diode is also coated, so that it is convenient to coat the two side edges of the waveguide surface, the light output surface and the reflection surface, thereby ensuring the electrical performance of the laser diode.

[0094] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A laser diode, comprising a substrate and a stacked layer located on the substrate, wherein the stacked layer comprises an N-type layer, an active layer and a P-type layer having a ridge strip on the surface, characterized in that: The laser diode has a waveguide surface, a light output surface, a reflective surface and a bottom surface; The top surface of the P-type layer is the waveguide surface, the bottom surface of the substrate is the bottom surface, and the waveguide surface is arranged opposite to the bottom surface; The bottom surface has at least one groove, and the extending direction of the groove is perpendicular to the ridge strip; The light output surface and the reflection surface are located on opposite sides of the waveguide surface and are perpendicular to the waveguide surface; A side edge of the waveguide surface connected to the light output surface, a side edge of the waveguide surface connected to the reflection surface, the light output surface and the reflection surface are all coated.

2. The laser diode according to claim 1, characterized in that The bottom surface has a first groove and a second groove, the first groove is located at one end of the bottom surface connected to the reflecting surface, and the second groove is located at one end of the bottom surface connected to the light output surface, and the first groove and the second groove form a strip-shaped protrusion extending downward on the bottom surface.

3. The laser diode according to claim 2, characterized in that The height of the strip-shaped protrusions is 0.5 to 20 μm.

4. The laser diode according to claim 2, characterized in that The width of the first groove is 5 to 50 μm, and the width of the second groove is 5 to 50 μm.

5. The laser diode according to claim 2, characterized in that A difference between a coating width on an edge of the waveguide surface adjacent to the light output surface and a width of the second groove is greater than 2 μm.

6. A coating method for a laser diode array resonant mirror, applicable to the laser diode as claimed in claim 1, characterized in that: The coating method of the laser diode array resonant mirror comprises: Arrange at least two of the laser diodes, wherein the waveguide surface of each of the laser diodes faces the same direction and the waveguide surface of each of the laser diodes is located in the same plane, the bottom surface of each of the laser diodes faces the same direction and the bottom surface of each of the laser diodes is located in the same plane, the light output surface of each of the laser diodes faces the same direction and the light output surface of each of the laser diodes is located in the same plane, and the reflection surface of each of the laser diodes faces the same direction and the reflection surface of each of the laser diodes is located in the same plane, to form a laser diode bar; stacking at least two of the laser diode bars to form a laser diode array, each of the laser diode bars is in contact with at least one other laser diode bar, and the light output surfaces of each of the laser diodes in each of the laser diode bars face the same direction and are located in the same plane; and the reflective surfaces of each of the laser diodes in each of the laser diode bars face the same direction and are located in the same plane; An anti-reflection coating is plated on the light output surface of each of the stacked laser diode bars, a reflective coating is plated on the reflective surface of each of the stacked laser diode bars, a coating is plated on one side edge of the waveguide surface of each of the stacked laser diode bars that is adjacent to the light output surface, and a coating is plated on one side edge of the waveguide surface of each of the stacked laser diode bars that is adjacent to the reflective surface.

7. A method for manufacturing a stacked high-density laser diode array, wherein the laser diode array is formed by stacking laser diode bars, each of which comprises at least two laser diodes according to claim 1, characterized in that: The method for manufacturing a stacked high-density laser diode array comprises: forming an epitaxial layer on a semiconductor wafer, the epitaxial layer comprising a quantum well; Depositing a first metallization layer on a first surface of the semiconductor wafer and depositing a second metallization layer on a second surface of the semiconductor wafer opposite to the first surface; applying a solder layer on the first metallization layer; Coating a resist coating on the second metallization layer, and sequentially performing baking, exposure, development, dry etching and demolding to form a plurality of grooves on the second surface of the semiconductor wafer; cutting the semiconductor wafer into a plurality of laser diode bars; A plurality of the laser diode bars are stacked to form a laser diode array, wherein the waveguide surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; the bottom surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane, and the bottom surface of each of the laser diodes has at least one groove; the light output surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; and the reflective surface of each of the laser diodes in each of the laser diode bars faces the same direction and is located in the same plane; The laser diode array is placed in a vacuum chamber for vacuum sputtering, an anti-reflection coating is plated on the light output surface of each laser diode in the laser diode bar, and a reflective coating is plated on the reflective surface of each laser diode in the laser diode bar; a coating is plated on the edge of one side of the waveguide surface of each laser diode in the laser diode bar that is connected to the light output surface; and a coating is plated on the edge of one side of the waveguide surface of each laser diode in the laser diode bar that is connected to the reflective surface.

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