Semiconductor laser chip and preparation method thereof

Abstract

The invention discloses a semiconductor laser chip and a preparation method thereof, which are mainly characterized in that an ion implantation region is formed on a ridge waveguide structure, so that current does not pass through the region, and only light passes through the region, thereby improving the reliability of a product. According to the main technical scheme, the semiconductor laser chip comprises a chip body, the chip body comprises a ridge waveguide structure, and ions are injected into the ridge waveguide structure to form an ion injection area. The laser generator is mainly used for generating laser.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor lasers, and in particular to a semiconductor laser chip and a preparation method thereof. Background Art

[0002] Semiconductor lasers are the core components of communication systems because of their small size, high conversion efficiency, high reliability, direct modulation, and easy integration with other semiconductor devices. In the field of semiconductor lasers, ridge waveguide structures are widely used in various semiconductor lasers due to the effects of light limitation and current limitation in the direction parallel to the junction.

[0003] In the field of optical communications, reliability is a very important indicator of products. Some products have always had problems such as failure or slow degradation, which will directly affect the subsequent development of the product. When the existing semiconductor laser is working, the optical power density of the laser's emission front face continues to increase, and carriers are injected into the emission front face. The temperature of the emission front face will increase, increasing light absorption. When the temperature further increases to a value greater than the threshold, the device will be prone to slow degradation or damage failure. Summary of the invention

[0004] In view of this, in order to solve at least one of the above technical problems, an embodiment of the present invention provides a semiconductor laser chip and a method for manufacturing the same.

[0005] In order to achieve the above object, the present invention mainly provides the following technical solutions:

[0006] On the one hand, an embodiment of the present invention provides a semiconductor laser chip, including:

[0007] The chip body (100) comprises a ridge waveguide structure (110), and ions are implanted into the ridge waveguide structure (110) to form an ion implantation region (200).

[0008] A thin film (300) is grown on the upper surface of the ridge waveguide structure (110), a window (301) is opened on the thin film (300), and ions are injected through the window (301) to form an ion injection region (200) on the ridge waveguide structure (110).

[0009] Wherein, the film (300) is a silicon oxide film, or the film (300) is a silicon carbide film.

[0010] The distance between the ion implantation area (200) and the emission front end surface of the chip body (100) is greater than or equal to 45 um and less than or equal to 55 um.

[0011] Wherein, the ions are phosphorus ions, boron ions or hydrogen ions.

[0012] The depth of the ion implantation region (200) is greater than or equal to 0.5 um and less than or equal to 1 um.

[0013] The length of the ion implantation region (200) in the extension direction parallel to the ridge waveguide structure (110) is greater than or equal to 18 um and less than or equal to 22 um.

[0014] The width of the ion implantation region (200) in a direction perpendicular to the extension of the ridge waveguide structure (110) is greater than or equal to 8 um and less than or equal to 12 um.

[0015] On the other hand, the present invention also provides a method for preparing a semiconductor laser chip, comprising:

[0016] Providing a substrate, and epitaxially growing each growth layer on the substrate in sequence;

[0017] Etching to form a ridge waveguide structure;

[0018] Ions are implanted on the ridge waveguide structure to form an ion implantation region.

[0019] After the step of etching to form a ridge waveguide structure and before implanting ions on the ridge waveguide structure to form an ion implantation region, the method further includes:

[0020] grow a thin film;

[0021] forming a window on the film on the upper surface of the ridge waveguide structure, and removing the window film;

[0022] The ion implantation region is formed by implanting ions on the ridge waveguide structure as follows:

[0023] Ions are implanted onto the ridge waveguide structure through the window to form an ion implantation region.

[0024] A semiconductor laser chip and a preparation method thereof proposed in an embodiment of the present invention mainly improve the reliability of the product by forming an ion implantation area on a ridge waveguide structure, so that current does not pass through the area but only light passes through the area. When the existing semiconductor laser is working, the optical power density of the laser's emission front end surface continues to increase, and carriers are injected into the cavity surface. The temperature of the emission front end surface will increase, which increases light absorption. When the temperature rises to a value greater than the threshold, it will cause the device to fail slowly or be damaged. In the present application, an ion implantation area is formed on the ridge waveguide structure by ion implantation, which can reduce or block the carriers from passing through the ion implantation area, limit the carrier injection into the emission front end surface, reduce the carrier concentration at the emission front end surface, and reduce the temperature at the emission front end surface, thereby ensuring the reliability of the chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1A schematic structural diagram of a semiconductor laser chip provided by an embodiment of the present invention at a first viewing angle;

[0026] Figure 2 A schematic structural diagram of a semiconductor laser chip provided by an embodiment of the present invention at a second viewing angle;

[0027] Figure 3 A flowchart of a method for preparing a semiconductor laser chip provided by an embodiment of the present invention;

[0028] Figure 4 A flow chart of another method for preparing a semiconductor laser chip provided by an embodiment of the present invention;

[0029] Among them, there are a chip body-100, a ridge waveguide structure-110, an ion implantation area-200, a film-300, and a window-301. DETAILED DESCRIPTION

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "width", "length", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like 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 an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of a semiconductor laser chip proposed according to the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0034] In one embodiment, if Figure 1-2 As shown, the present invention provides a semiconductor laser chip, comprising:

[0035] The chip body (100) comprises a ridge waveguide structure (110), and ions are implanted into the ridge waveguide structure (110) to form an ion implantation region (200).

[0036] The chip body is a main structure for realizing the chip function, which may further include a substrate and various growth layers grown on the substrate, and each growth layer may further include a buffer layer, a lower confinement layer, a lower waveguide layer, an active layer, an electron blocking layer, an upper waveguide layer and an upper confinement layer grown in sequence from the substrate to the top. Among them, a ridge waveguide structure (110) is formed on the upper confinement layer, such as a wafer can be used to etch a double groove on the upper confinement layer to form the ridge waveguide structure (110). The substrate may be an indium phosphide (InP) substrate or a silicon-based (InGaAs) substrate. The upper confinement layer may be P-type doped aluminum gallium nitride. The buffer layer may be N-type doped gallium nitride, which is used to buffer the stress generated by lattice mismatch, so as to facilitate the formation of the upper growth layer. The lower confinement layer may be N-type doped aluminum gallium nitride, and the lower confinement layer is used to limit the extension of the light field to the substrate. The upper confinement layer may be P-type doped aluminum gallium nitride, and the upper confinement layer is used to limit the extension of the light field away from the substrate. The lower waveguide layer can be made of N-type doped gallium nitride, and the upper waveguide layer can be made of P-type doped gallium nitride. The lower waveguide layer and the upper waveguide layer are used to limit the diffusion of carriers, so as to limit the carriers in the active area, thereby improving the luminous efficiency. The active layer is a quantum well for optical gain. The electron blocking layer can be made of P-type doped aluminum gallium nitride to prevent electron overflow from the active layer. The above structure is only an embodiment provided by the present application, and the material of each layer and whether it is grown can be selected as needed.

[0037] The ridge waveguide structure (110) destroys the lattice of the ion implantation area (200) through ion implantation, causing the conductivity of the area to drop significantly, and the ion implantation area (200) can be approximately considered to be non-conductive. When the semiconductor laser chip is working, the density of carriers in the ion implantation area (200) is greatly reduced, and the carriers cannot be injected into the emission front end face of the chip body (100) in large quantities, thereby reducing the carrier concentration at the emission front end face, reducing the non-radiative recombination of carriers at the emission front end face, and reducing the heat generated at the emission front end face. The emission front end face is located at the front end of the chip body (100) along the laser emission direction, that is, the laser light is output from the emission front end face. The ion implantation area (200) is an area that passes through both sides of the ridge waveguide structure (110) in the width direction of the ridge waveguide structure (110), or in a direction perpendicular to the laser light emission direction. In other words, the width of the ion implantation area (200) is consistent with the width of the ridge waveguide structure (110), thereby achieving consistent carrier blocking in the width direction.

[0038] It is worth noting that in the present application, ion implantation is to form a carrier high resistance region by ion bombardment. After selecting the ion type, the dopant is placed in an ion source, heated and voltage is applied, and then the dopant is ionized to form high-energy ions. After the ions are accelerated, an ion beam is formed and accurately injected into the ridge waveguide structure (110). Compared with the method of etching a deep terrace on the ridge waveguide structure (110) and growing a carrier blocking region, damage that may be caused by etching can be avoided. For example, when etching a deep terrace, the undercutting of the mask edge may be quite serious, resulting in difficulties in subsequent resist application and coverage of the metal step.

[0039] In addition, ion implantation doping technology has high regional position accuracy, uniform doping measurement and process repeatability, and the doping process is not affected by solid solubility and diffusion factors. Compared with other methods such as diffusion, it has better doping effect.

[0040] A semiconductor laser chip and a preparation method thereof proposed in an embodiment of the present invention mainly improve the reliability of the product by forming an ion implantation area on a ridge waveguide structure, so that current does not pass through the area but only light passes through the area. When the existing semiconductor laser is working, the optical power density of the laser's emission front end surface continues to increase, and carriers are injected into the cavity surface. The temperature of the emission front end surface will increase, which increases light absorption. When the temperature rises to a value greater than the threshold, it will cause the device to be easily damaged, fail, or slowly degrade. In the present application, an ion implantation area is formed on the ridge waveguide structure by ion implantation, which can reduce or block the carriers from passing through the ion implantation area, limit the carrier injection into the emission front end surface, reduce the carrier concentration at the emission front end surface, and reduce the temperature at the emission front end surface, thereby ensuring the reliability of the chip.

[0041] In one embodiment, a thin film (300) is grown on the upper surface of the ridge waveguide structure (110), a window (301) is opened on the thin film (300), and ions are injected through the window (301) to form an ion injection region (200) on the ridge waveguide structure (110).

[0042] The film (300) is used to block the ion beam flow at the non-ion implantation position, so as to prevent the non-ion implantation position on the chip body (100) from being bombarded and damaged and leaking. After the film (300) is grown, photolithography is added to open a window, and the film (300) corresponding to the window (301) is removed. The ridge waveguide structure (110) will be exposed at the window (301), and then ion implantation can be performed through the window (301), thereby ensuring the accuracy of ion implantation.

[0043] In one embodiment, the film (300) may be a silicon oxide or silicon nitride film covering the upper limiting layer. Alternatively, the film (300) may also be a photoresist, a metal film or other forms of composite multilayer masks. Masks that can be used for ion implantation in the prior art can be used in this application. It is understood that the window (301) is formed in different ways for masks of different components, which is known to those skilled in the art and will not be described in detail here.

[0044] In one embodiment, the distance S between the ion implantation region (200) and the emission front end surface of the chip body (100) is greater than or equal to 45 um and less than or equal to 55 um.

[0045] The distance S between the ion implantation area (200) and the emission front face refers to the distance S between the side of the ion implantation area (200) closest to the emission front face and the emission front face. Or it can be said that it is the distance S between the side of the window (301) closest to the emission front face and the emission front face. S is greater than or equal to 45um and less than or equal to 55um, ensuring that the ion implantation area (200) is not set close to the emission front face, thereby avoiding damage to the emission front face, thereby avoiding affecting the reliability of the chip. In addition, due to process requirements, some existing chips will corrode the emission front face during the manufacturing process, while the present application uses the ion implantation area (200) to separate the emission front face by a distance, thereby avoiding the ion implantation area (200) from being corroded and failing. For example, the distance S between the side of the window (301) closest to the emission front face and the emission front face can be specifically 50um.

[0046] In one embodiment, the implanted ions are cations with a single energy, such as boron ions or hydrogen ions, which form a P-type semiconductor after implantation. Alternatively, they may be phosphorus ions.

[0047] There is no limitation on the depth of the ion implantation region (200). For example, in one embodiment, the depth H of the ion implantation region (200) is greater than or equal to 0.5 um and less than or equal to 1 um. The ion implantation region (200) may be only within the ridge waveguide structure (110), or may penetrate into the upper confinement layer located below the ridge waveguide structure (110), or may penetrate the entire upper confinement layer to reach the upper waveguide layer.

[0048] In one embodiment, the length D of the ion implantation region (200) or the window (301) in the extension direction parallel to the ridge waveguide structure (110) is greater than or equal to 18um, and less than or equal to 22um, such as 20um. In one embodiment, the width H of the ion implantation region (200) or the window (301) in the extension direction perpendicular to the ridge waveguide structure (110) is greater than or equal to 8um, and less than or equal to 12um. It can be understood that the window (301) runs through both sides of the width direction of the ridge waveguide structure (110), such as the ridge waveguide structure (110) can be 10um wide, and the width of the window (301) is also 10um.

[0049] The length and width of the ion implantation region (200) or the window (301) are uniform, and the entire window (301) is rectangular, thereby ensuring the consistency of blocking carriers in all directions of the ridge waveguide structure (110).

[0050] In addition, it should be noted that the structures in the drawings of the present application are intended to illustrate positional relationships, and the sizes shown are not actual proportions but are merely schematic representations of a position.

[0051] On the other hand, Figure 3 As shown, the present invention also provides a method for preparing a semiconductor laser chip, comprising:

[0052] S1-1. Provide a substrate, and sequentially epitaxially grow various growth layers on the substrate.

[0053] For example, a buffer layer, a lower confinement layer, a lower waveguide layer, an active layer, an electron blocking layer, an upper waveguide layer and an upper confinement layer are sequentially grown on an InP substrate or an InGaAs substrate.

[0054] S1-2, etching to form a ridge waveguide structure (110).

[0055] A double groove is formed on the upper confinement layer by wafer etching to form a ridge waveguide structure (110).

[0056] S1-3, implanting ions on the ridge waveguide structure (110) to form an ion implantation region (200).

[0057] For example, the ion implantation region (200) is formed by hydrogen ion bombardment, which destroys the lattice of the ion implantation region (200), causing the conductivity of the region to drop significantly. It can be approximately considered that the ion implantation region (200) is non-conductive, thus achieving carrier isolation.

[0058] like Figure 4 As shown, the present invention also provides another method for preparing a semiconductor laser chip, comprising:

[0059] S2-1. Provide a substrate, and sequentially epitaxially grow various growth layers on the substrate.

[0060] S2-2, etching to form a ridge waveguide structure (110) Etching to form a ridge waveguide structure.

[0061] S2-3, growing a thin film (300).

[0062] A silicon oxide film or a silicon nitride film is grown on the above restriction layer.

[0063] S2-4. Form a window (301) on the thin film (300) on the upper surface of the ridge waveguide structure (100), and remove the thin film (300) of the window (301).

[0064] For example, a window (301) is opened by photolithography, and the thin film (300) in the window (301) area is removed, so that the upper surface of the ridge waveguide structure (110) is exposed through the window (301). In some embodiments, the ridge waveguide structure (110) is not directly exposed in the window (301), but has a protective film, which may be different depending on the specific structure of the thin film (300) or the mask.

[0065] S2-5. Ions are implanted onto the ridge waveguide structure (110) through the window (301) to form an ion implantation region (200).

[0066] After the ion implantation region (200) is formed, the film (300) is removed, and subsequent steps such as forming an upper electrode and a lower electrode are continued.

[0067] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A semiconductor laser chip, characterized in that: include: A chip body (100) comprises a ridge waveguide structure (110), and ions are implanted into the ridge waveguide structure (110) to form an ion implantation region (200).

2. The semiconductor laser chip according to claim 1, characterized in that: A thin film (300) is grown on the upper surface of the ridge waveguide structure (110), a window (301) is opened on the thin film (300), and ions are injected through the window (301) to form an ion injection region (200) on the ridge waveguide structure (110).

3. The semiconductor laser chip according to claim 1, characterized in that: The film (300) is a silicon oxide film, or the film (300) is a silicon carbide film.

4. The semiconductor laser chip according to claim 1, characterized in that: The distance between the ion implantation area (200) and the emission front end surface of the chip body (100) is greater than or equal to 45 um and less than or equal to 55 um.

5. The semiconductor laser chip according to claim 1, characterized in that: The ions are phosphorus ions, boron ions or hydrogen ions.

6. The semiconductor laser chip according to claim 1, characterized in that: The depth of the ion implantation area (200) is greater than or equal to 0.5 um and less than or equal to 1 um.

7. The semiconductor laser chip according to claim 1, characterized in that: The length of the ion implantation region (200) in the extension direction parallel to the ridge waveguide structure (110) is greater than or equal to 18 um and less than or equal to 22 um.

8. The semiconductor laser chip according to claim 1, characterized in that: The width of the ion implantation region (200) in a direction perpendicular to the extension of the ridge waveguide structure (110) is greater than or equal to 8 um and less than or equal to 12 um.

9. A method for preparing a semiconductor laser chip, characterized in that: include: Providing a substrate, and epitaxially growing each growth layer sequentially on the substrate; Etching to form a ridge waveguide structure; Ions are implanted on the ridge waveguide structure to form an ion implantation region.

10. The method for preparing a semiconductor laser chip according to claim 9, characterized in that: After the step of etching to form a ridge waveguide structure and before the step of implanting ions on the ridge waveguide structure to form an ion implantation region, the method further comprises: grow a thin film; forming a window on the film on the upper surface of the ridge waveguide structure, and removing the film corresponding to the window; The step of implanting ions on the ridge waveguide structure to form an ion implantation region is specifically as follows: Ions are implanted onto the ridge waveguide structure through the window to form an ion implantation region.

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