阅读说明：本技术 一种高亮度条型半导体激光器及其制备方法 (High-brightness strip-shaped semiconductor laser and preparation method thereof ) 是由 周坤 何林安 杨鑫 杜维川 李弋 贺钰雯 高松信 唐淳 于 2021-06-30 设计创作，主要内容包括：本发明公开了一种高亮度条型半导体激光器及其制备方法,属于半导体激光器件的技术领域,该结构的激光器制备在衬底层上,由衬底层往上依次为下限制层、下波导层、量子阱有源层、上波导层、上限制层、接触层和金属电极,其中,上限制层的部分区域进行离子注入,接触层的部分区域进行腐蚀去除,通过离子注入限制激光器注电区域,通过欧姆接触控制电流的扩展,在控制电流分布的同时降低慢轴方向的波导限制,可提高慢轴亮度,同时,在制备条型半导体激光器时无需使用绝缘膜,无需进行绝缘膜电极窗口工艺,减小芯片中的应力,避免电极窗口光刻时的对准问题,改善芯片的散热,提高芯片偏振度,提高条型半导体激光器的一致性和可靠性。(The invention discloses a high-brightness strip-shaped semiconductor laser and a preparation method thereof, belonging to the technical field of semiconductor laser devices, the laser with the structure is prepared on a substrate layer, a lower limiting layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper limiting layer, a contact layer and a metal electrode are sequentially arranged from the substrate layer to the top, wherein, ion injection is carried out on partial area of the upper limiting layer, corrosion removal is carried out on partial area of the contact layer, the laser injection area is limited through ion injection, the waveguide limitation in the slow axis direction is reduced while the current distribution is controlled through the expansion of ohmic contact, the slow axis brightness can be improved, meanwhile, an insulating film is not needed when preparing the strip-shaped semiconductor laser, an insulating film electrode window process is not needed, the stress in a chip is reduced, the alignment problem when photoetching an electrode window is avoided, and the heat dissipation of the chip is improved, the polarization degree of the chip is improved, and the consistency and the reliability of the strip-shaped semiconductor laser are improved.)

1. A high-brightness stripe type semiconductor laser comprising a substrate layer, characterized by further comprising: the lower limiting layer, the lower waveguide layer, the quantum well active layer, the upper waveguide layer, the upper limiting layer, the contact layer and the metal electrode are sequentially stacked above the substrate layer;

ion injection regions are oppositely arranged in the upper limiting layer, and each ion injection region penetrates from the front cavity surface to the rear cavity surface of the semiconductor laser;

the width of the contact layer in the slow axis direction is smaller than the width between the two ion implantation areas, and the contact layer is embedded into the metal electrode.

2. A high brightness stripe type semiconductor laser according to claim 1, wherein the substrate layer, the lower confinement layer, the lower waveguide layer, the quantum well active layer, the upper waveguide layer, the upper confinement layer, the contact layer and the metal electrode are located on a same symmetry line, and each of the ion implantation regions is symmetrically arranged at both sides of the symmetry line.

3. A high brightness stripe type semiconductor laser as claimed in claim 1, wherein the ion implantation region is stripe shaped and is oriented perpendicular to the slow axis direction of the semiconductor laser.

4. A high brightness stripe type semiconductor laser according to claim 1, wherein the depth of the ion implanted region is larger than the thickness of the upper confinement layer and smaller than the sum of the thicknesses of the upper confinement layer and the upper waveguide layer.

5. A high brightness stripe type semiconductor laser according to claim 1 wherein the metal electrode forms an ohmic contact with the contact layer and a schottky contact with the upper confinement layer.

6. A method for manufacturing a high-brightness stripe-type semiconductor laser is characterized by comprising the following steps:

s1: sequentially growing a lower limiting layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper limiting layer and a contact layer on the substrate layer to form an epitaxial structure;

s2: photoetching the surface of the epitaxial structure through first photoresist to define an ohmic contact electrode pattern;

s3: corroding the contact layer by taking the first photoresist as a mask to form an ohmic contact electrode area, and removing the first photoresist after the corrosion is finished;

s4: continuing to perform photoetching on the surface of the epitaxial structure through second photoresist, and defining an ion implantation area which penetrates from the front cavity surface to the rear cavity surface of the epitaxial structure and is distributed on two sides of the ohmic contact electrode area;

s5: taking the second photoresist as a mask, carrying out ion implantation on the ion implantation area, and removing the second photoresist after the ion implantation is finished;

s6: and evaporating a metal electrode on the surface of the epitaxial structure.

7. The method of claim 6 wherein the ion implanted region is in the shape of a stripe and the direction of the ion implanted region is perpendicular to the slow axis of the epitaxial structure.

8. A method of fabricating a high brightness stripe type semiconductor laser as claimed in claim 6 wherein the depth of the ion implanted region is greater than the thickness of the upper confinement layer and less than the sum of the thicknesses of the upper confinement layer and the upper waveguide layer.

9. A method of fabricating a high brightness stripe type semiconductor laser as claimed in claim 6 wherein ohmic contact is formed between the metal electrode and the ohmic contact electrode region and schottky contact is formed between the metal electrode and the upper limiting layer.

10. The method of claim 6 wherein the upper confinement layer is of AlGaAs, AlGaInP or GaInP material and the upper confinement layer has a dopant concentration of less than 2 x 10¹⁸cm^-3(ii) a The contact layer is made of GaAs material, and the doping concentration of the contact layer is more than 1 × 10²⁰cm^-3。

Technical Field

The invention belongs to the technical field of semiconductor laser devices, and particularly relates to a high-brightness strip-type semiconductor laser and a preparation method thereof.

Background

The semiconductor laser has the advantages of compact structure, low cost, easy regulation of light field, etc., and is widely applied to pumping solid and fiber lasers, material processing, laser medical treatment, etc. For a strip laser with a wide light emitting area, although the power is high (a single chip can reach 10-25W), the lateral width is large (100-200 μ M), so that the strip laser is easily influenced by multi-side mode and filiform light emitting effects, and the beam quality is poor (M)² _x> 10), low brightness. The poor quality of the slow axis light beam greatly limits the semiconductor laser in the application of high-energy laser, and in order to realize the application of high-quality and wide-range semiconductor laser, the semiconductor laser must simultaneously meet the requirements of high power and high light beam quality, namely, the realization of high-brightness laser so as to meet the application requirements of various high-energy lasers.

In the fabrication of semiconductor lasers, it is necessary to limit the injection region of current to improve the electro-optical conversion efficiency or to limit the size of the beam waist. P-type material with higher epitaxial conductivity is usually removed by etching, and ohmic contact electrode regions are prepared in the non-etched regions for current injection. However, although the removal of the material can limit the current well, the removal of the material brings a waveguide effect in the slow axis direction, increases the waveguide mode of the current injection region, and enhances the filament-like luminescence, so that the slow axis divergence angle becomes large, the beam quality deteriorates, and the luminance is difficult to improve.

Disclosure of Invention

In view of the above, in order to solve the above problems of the prior art, the present invention provides a high-brightness stripe type semiconductor laser and a method for fabricating the same, so as to achieve the purpose of reducing the slow-axis divergence angle while controlling the current injection region.

The technical scheme adopted by the invention is as follows: a high brightness stripe type semiconductor laser comprising a substrate layer, further comprising: the lower limiting layer, the lower waveguide layer, the quantum well active layer, the upper waveguide layer, the upper limiting layer, the contact layer and the metal electrode are sequentially stacked above the substrate layer;

ion injection regions are oppositely arranged in the upper limiting layer, and each ion injection region penetrates from the front cavity surface to the rear cavity surface of the semiconductor laser;

the width of the contact layer in the slow axis direction is smaller than the width between the two ion implantation areas, and the contact layer is embedded into the metal electrode.

Furthermore, the substrate layer, the lower limiting layer, the lower waveguide layer, the quantum well active layer, the upper waveguide layer, the upper limiting layer, the contact layer and the metal electrode are located on the same symmetrical line, and the ion injection regions are symmetrically arranged on two sides of the symmetrical line so as to ensure the consistency and the reliability of the strip-shaped semiconductor laser.

Furthermore, the ion implantation area is in a strip shape, the direction of the ion implantation area is perpendicular to the slow axis direction of the semiconductor laser, a strong waveguide effect cannot be formed while current is limited, and current cannot be accumulated at the edge of the implantation area.

Furthermore, the depth of the ion implantation region is greater than the thickness of the upper limiting layer and less than the sum of the thicknesses of the upper limiting layer and the upper waveguide layer, so that the ion implantation region has the function of limiting current expansion and cannot damage the quantum well material on the lower layer.

Furthermore, ohmic contact is formed between the metal electrode and the contact layer, and good ohmic contact is favorable for current injection; and Schottky contact is formed between the metal electrode and the upper limiting layer so as to limit the direct injection of current from the limiting layers on two sides.

The invention also provides a preparation method of the high-brightness strip-type semiconductor laser, which comprises the following steps:

s1: sequentially growing a lower limiting layer, a lower waveguide layer, a quantum well active layer, an upper waveguide layer, an upper limiting layer and a contact layer on the substrate layer to form an epitaxial structure;

s2: photoetching the surface of the epitaxial structure through first photoresist to define an ohmic contact electrode pattern;

s3: corroding the contact layer by taking the first photoresist as a mask to form an ohmic contact electrode area, and removing the first photoresist after the corrosion is finished;

s4: continuing to perform photoetching on the surface of the epitaxial structure through second photoresist, and defining an ion implantation area which penetrates from the front cavity surface to the rear cavity surface of the epitaxial structure and is distributed on two sides of the ohmic contact electrode area;

s5: taking the second photoresist as a mask, carrying out ion implantation on the ion implantation area, and removing the second photoresist after the ion implantation is finished;

s6: and evaporating a metal electrode on the surface of the epitaxial structure.

Furthermore, the ion implantation area is in a strip shape, the direction of the ion implantation area is perpendicular to the slow axis direction of the epitaxial structure, a strong waveguide effect cannot be formed while current is limited, and current cannot be accumulated at the edge of the implantation area.

Furthermore, the depth of the ion implantation region is greater than the thickness of the upper limiting layer and less than the sum of the thicknesses of the upper limiting layer and the upper waveguide layer, so that the ion implantation region has the function of limiting current expansion and cannot damage the quantum well material on the lower layer.

Further, ohmic contact is formed between the metal electrode and the ohmic contact electrode area, and good ohmic contact is favorable for current injection; a Schottky contact is formed between the metal electrode and the upper confinement layer to confine current injected directly from the confinement layers on both sides.

Further, the upper limiting layer is made of AlGaAs, AlGaInP or GaInP material, and the doping concentration of the upper limiting layer is less than 2 x 10¹⁸cm^-3(ii) a The contact layer is made of GaAs material, and the doping concentration of the contact layer is more than 1 × 10²⁰cm^-3。

The invention has the beneficial effects that:

1. when the high-brightness strip-type semiconductor laser provided by the invention is used, current is injected through the contact layer and expands towards two sides in the upper limiting layer outside the two sides of the contact layer, the edge of the current expansion is limited by the ion injection region, the semiconductor laser with the structure can not form a strong waveguide effect while limiting the current, the current can not be accumulated at the edge of the ion injection region, and the waveguide limitation in the slow axis direction is reduced while controlling the current distribution, so that the slow axis brightness is improved.

2. According to the preparation method of the high-brightness strip-shaped semiconductor laser, the photoresist is adopted to define the ohmic contact electrode pattern and the ion injection region in the preparation process, an insulating film is not needed, an insulating film electrode window process is not needed, the stress in a chip is reduced, the alignment problem in the photoetching of an electrode window is avoided, the heat dissipation of the chip is improved, the polarization degree of the chip is improved, and the consistency and the reliability of the strip-shaped semiconductor laser are improved.

Drawings

Fig. 1 is a schematic structural diagram of S1 in the method for manufacturing a high-luminance stripe type semiconductor laser according to the present invention;

fig. 2 is a schematic structural diagram of S2 in the method for manufacturing a high-luminance stripe type semiconductor laser according to the present invention;

fig. 3 is a schematic structural diagram of S3 in the method for manufacturing a high-luminance stripe type semiconductor laser according to the present invention;

fig. 4 is a schematic structural diagram of S4 in the method for manufacturing a high-luminance stripe type semiconductor laser according to the present invention;

fig. 5 is a schematic structural diagram of S5 in the method for manufacturing a high-luminance stripe type semiconductor laser according to the present invention;

fig. 6 is a schematic structural diagram of S6 in the method for manufacturing a high-luminance stripe type semiconductor laser according to the present invention;

the drawings are labeled as follows:

101-N type substrate layer, 102-N type lower limiting layer, 103-N type lower waveguide layer, 104-quantum well active layer, 105-P type upper waveguide layer, 106-P type upper limiting layer, 107-P type contact layer, 208-first photoresist, 409-second photoresist, 501-upper limiting layer with ion implantation, 502-ion implantation region, 601-metal electrode, 701-ohmic contact electrode region.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that the indication of the orientation or the positional relationship is based on the orientation or the positional relationship shown in the drawings, or the orientation or the positional relationship which is usually placed when the product of the present invention is used, or the orientation or the positional relationship which is usually understood by those skilled in the art, or the orientation or the positional relationship which is usually placed when the product of the present invention is used, and is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the indicated device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, cannot be understood as limiting the present invention. Furthermore, the terms "first" and "second" are used merely to distinguish one description from another, and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be further noted that the terms "disposed" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, unless explicitly stated or limited otherwise; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases by those skilled in the art; the drawings in the embodiments are used for clearly and completely describing the technical scheme in the embodiments of the invention, and obviously, the described embodiments are a part of the embodiments of the invention, but not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Example 1

The invention also provides a preparation method of the high-brightness strip-type semiconductor laser, which comprises the following steps:

s1: as shown in fig. 1, a lower confinement layer, a lower waveguide layer, a quantum well active layer 104, an upper waveguide layer, an upper confinement layer and a contact layer are sequentially grown on a substrate layer to form an epitaxial structure of a semiconductor laser; specifically, the method comprises the following steps: an N-type lower confinement layer 102, an N-type lower waveguide layer 103, a quantum well active layer 104, a P-type upper waveguide layer 105, a P-type upper confinement layer 106, a P-type contact layer 107, and a metal electrode 601 are sequentially grown above the N-type substrate layer 101.

In practical application, the design is as follows: the N-type substrate layer 101 is made of GaAs material; the N-type lower confinement layer 102 has a thickness of 1000nm and is Al_0.42Ga_0.58An As material; the N-type lower waveguide layer 103 has a thickness of 1600nm and is Al_0.15Ga_0.85An As material; the quantum well active layer 104 has a thickness of 8nm and is In_0.2Ga_0.8An As material; the P-type upper waveguide layer 105 has a thickness of 700nm and is Al_0.15Ga_0.85An As material; the thickness of the P-type upper confinement layer 106 is 700nm and is Al_0.42Ga_0.58An As material; the P-type contact layer 107 is 200nm thick and is a GaAs material. Wherein, the doping concentration of the P-type upper limiting layer 106 is 1 × 10¹⁸cm^-3The doping concentration of the P-type contact layer 107 is 5 × 10²⁰cm^-3。

S2: as shown in fig. 2, a first photoresist 208 is prepared and the pattern width of the first photoresist 208 is 80 μm and the thickness is 1500nm, and photolithography is performed on the surface of the epitaxial structure through the first photoresist 208 to define an ohmic contact electrode pattern.

S3: as shown in fig. 3, the first photoresist 208 is used as a mask, and phosphoric acid: hydrogen peroxide: water 1: 1: the solution of 50 etches the contact layer, partially etching the contact layer to form an ohmic contact electrode region 701, and removing the first photoresist 208 after etching.

S4: as shown in fig. 4, a second photoresist 409 is prepared, the image width of the second photoresist 409 is 100 μm, the thickness of the second photoresist 409 is 5100nm, and the photolithography is continuously performed on the surface of the epitaxial structure through the second photoresist 409, so as to define an ion implantation region 502 penetrating from the front cavity surface (the front cavity surface is the opposite surface in fig. 4, and the back cavity surface is the opposite surface) of the epitaxial structure to the back cavity surface, and the ion implantation region 502 is distributed on both sides of the ohmic contact electrode region 701. The ion implantation region 502 is in a strip shape, the direction of the ion implantation region 502 is perpendicular to the slow axis direction of the epitaxial structure, so that the edge of current expansion is limited by the ion implantation region 502, the depth of the ion implantation region 502 is greater than the thickness of the upper limiting layer and less than the sum of the thicknesses of the upper limiting layer and the upper waveguide layer, the ion implantation region 502 is ensured to have the function of limiting current expansion, and the quantum well material on the lower layer is not damaged.

S5: as shown in fig. 5, the second photoresist 409 is used as a mask to perform ion implantation on the ion implantation region 502 (after the ion beam is irradiated to the solid material, the speed is slowly reduced due to the resistance of the solid material, and the phenomenon that the ion beam finally stays in the solid material is called as ion implantation), and the second photoresist 409 is removed after the ion implantation is completed; the ion source for ion implantation is He + ion, the implantation energy is 150keV, and the implantation depth is 1000nm, so as to form the upper confinement layer 501 with ion implantation.

S6: as shown in fig. 6, a metal electrode 601 is evaporated on the surface of the epitaxial structure, the metal electrode 601 adopts Ti/Pt/Au of 30nm/70nm/1000nm, and the metal electrode 601 forms ohmic contact on the contact layer by annealing, the extension of current is controlled by the ohmic contact, the waveguide limit in the slow axis direction is reduced while the current distribution is controlled by matching with the ion implantation region 502, and the slow axis brightness can be improved; schottky contacts are formed between the upper confinement layers at the metal electrodes 601 to confine the current injected directly from the confinement layers on both sides.

Example 2

As shown in fig. 1 to 6, another method for manufacturing a high-brightness stripe type semiconductor laser is provided in the present invention, the method comprising:

s1: as shown in fig. 1, a lower confinement layer, a lower waveguide layer, a quantum well active layer 104, an upper waveguide layer, an upper confinement layer and a contact layer are sequentially grown on a substrate layer to form an epitaxial structure of a semiconductor laser; specifically, the method comprises the following steps: an N-type lower confinement layer 102, an N-type lower waveguide layer 103, a quantum well active layer 104, a P-type upper waveguide layer 105, a P-type upper confinement layer 106, a P-type contact layer 107, and a metal electrode 601 are sequentially grown above the N-type substrate layer 101.

In practical application, the design is as follows: the N-type substrate layer 101 is made of GaAs material; the thickness of the N-type lower confinement layer 102 is 1000nm and is made of AlGaInP material; the thickness of the N-type lower waveguide layer 103 is 1200nm and is made of GaInP material; the quantum well active layer 104 is 8nm thick and is GaAsP material; the P-type upper waveguide layer 105 is 500nm thick and is of GaInP material; the thickness of the P-type upper confinement layer 106 is 1000nm and is an AlGaInP material; the P-type contact layer 107 is 200nm thick and is a GaAs material. Wherein, at the same time, the doping concentration of the P-type upper limiting layer 106 is 1.5 × 10¹⁸cm^-3The doping concentration of the P-type contact layer 107 is 5 × 10²⁰cm^-3。

S2: as shown in fig. 2, a first photoresist 208 is prepared and the pattern width of the first photoresist 208 is 100 μm and the thickness is 1500nm, and photolithography is performed on the surface of the epitaxial structure through the first photoresist 208 to define an ohmic contact electrode pattern.

S3: as shown in fig. 3, the first photoresist 208 is used as a mask, and phosphoric acid: hydrogen peroxide: water 1: 1: the solution of 50 etches the contact layer to form an ohmic contact electrode region 701 after etching a partial region of the contact layer, and removes the first photoresist 208 after etching.

S4: as shown in fig. 4, a second photoresist 409 is prepared, the image width of the second photoresist 409 is 200 μm, the thickness of the second photoresist 409 is 5100nm, and the second photoresist 409 is used to perform photolithography on the surface of the epitaxial structure, so as to define an ion implantation region 502 penetrating from the front cavity surface to the back cavity surface of the epitaxial structure, and the ion implantation region 502 is distributed on two sides of the ohmic contact electrode region 701, so that the ion implantation region 502 limits the implantation region of the semiconductor laser. The ion implantation region 502 is in a strip shape, the direction of the ion implantation region 502 is perpendicular to the slow axis direction of the epitaxial structure, so that the edge of current expansion is limited by the ion implantation region 502, the depth of the ion implantation region 502 is greater than the thickness of the upper limiting layer and less than the sum of the thicknesses of the upper limiting layer and the upper waveguide layer, the ion implantation region 502 is ensured to have the function of limiting current expansion, and the quantum well material on the lower layer is not damaged.

S5: as shown in fig. 5, the second photoresist 409 is used as a mask to perform ion implantation on the ion implantation region 502, and the second photoresist 409 is removed after the implantation is completed; the ion source for ion implantation is He + ion, the implantation energy is 200keV, and the implantation depth is 1200nm, so as to form the upper confinement layer 501 with ion implantation.

S6: as shown in fig. 6, a metal electrode 601 is deposited on the surface of the epitaxial structure, the metal electrode 601 adopts Ti/Pt/Au of 30nm/70nm/1000nm, the metal electrode 601 forms ohmic contact on the contact layer by annealing, the extension of current is controlled by the ohmic contact, the waveguide limit in the slow axis direction is reduced while the current distribution is controlled by matching with the ion implantation region 502, the slow axis brightness can be improved, and the metal electrode 601 forms schottky contact between the upper limit layers to limit the current to be directly injected from the limit layers at both sides.

Example 3

As shown in fig. 6, in this example, a high-luminance stripe-type semiconductor laser device is provided, which is manufactured by applying the manufacturing methods provided in the above-described examples 1 and 2. The N-type semiconductor laser device comprises an N-type substrate layer 101, and an N-type lower limiting layer 102, an N-type lower waveguide layer 103, a quantum well active layer 104, a P-type upper waveguide layer 105, a P-type upper limiting layer 106, a P-type contact layer 107 and metal electrodes 601 which are sequentially stacked on the N-type substrate layer 101, wherein the substrate layer, the lower limiting layer, the lower waveguide layer, the quantum well active layer 104, the upper waveguide layer, the upper limiting layer, the contact layer and the metal electrodes 601 are located on the same symmetry line, and the ion injection regions 502 are symmetrically arranged on two sides of the symmetry line.

When the metal electrode 601 and the upper limiting layer are in contact, the energy band of a semiconductor at the interface is bent to form a Schottky barrier, and the limiting current is directly injected from the limiting layers at two sides.

The invention is not limited to the above alternative embodiments, and any other various forms of products can be obtained by anyone in the light of the present invention, but any changes in shape or structure thereof, which fall within the scope of the present invention as defined in the claims, fall within the scope of the present invention.