Semiconductor laser element and light-emitting device

Abstract

The invention provides a semiconductor laser element and a light-emitting device. An electron blocking layer is arranged between a second coating layer and a second waveguide layer of the semiconductor laser element; the second semiconductor layer is doped with a P-type dopant, the P-type dopant in the electron blocking layer has at least one doping concentration peak, the doping concentration of Mg at the doping concentration peak is smaller than the maximum doping concentration of the P-type dopant in the second semiconductor layer, and the P-type dopant in the electron blocking layer gradually approaches the direction of the electron blocking layer. The doping concentration of the P-type dopant in the second coating layer is provided with a plurality of subareas, and the doping concentration curve of the P-type dopant is gradually reduced along the plurality of subareas. Due to the descending trend of the Mg doping concentration in the second semiconductor layer, it can be guaranteed that the second semiconductor layer can provide enough holes, the hole injection efficiency in the quantum well layer is improved, and the light emitting efficiency is improved. Meanwhile, due to the arrangement of the second semiconductor layer, light absorption can be reduced, and the light emitting effect of the device is improved.

Description

Technical Field

[0001] The present application relates to the field of semiconductor manufacturing technology, and in particular to a semiconductor laser element and a light-emitting device. Background Art

[0002] III-group nitrides represented by gallium nitride are direct-transition wide-bandgap semiconductor materials with a wide energy band, making them ideal materials for making lasers from the ultraviolet band to the green band. GaN-based blue-green lasers have the advantages of small size, high integration, high brightness, and high resolution. The distribution of the light field and the ability to confine photons are key factors affecting the performance of GaN-based blue-green lasers.

[0003] In laser products, the P-type semiconductor layer is usually doped with Mg. The doping and diffusion of Mg concentration will produce unnecessary optical absorption, affecting the photoelectric efficiency (carrier injection) of the laser device. At the same time, when the device is exposed to high temperature and high current density for a long time, the diffusion of Mg will damage the AR cavity surface and cause catastrophic optical damage (COD) to the device, thereby causing a decline in device performance and affecting the reliability of the device.

[0004] Therefore, it is necessary to reduce unnecessary optical absorption caused by doping while ensuring sufficient carriers for effective carrier recombination. Summary of the invention

[0005] In view of the above defects and deficiencies in the prior art, the purpose of the present application is to provide a semiconductor laser element and a light-emitting device to solve one or more of the above problems.

[0006] According to one aspect of the present application, a semiconductor laser element is provided, comprising at least:

[0007] A semiconductor stack, the semiconductor stack comprising a first semiconductor layer, a first waveguide layer, an active layer, a second waveguide layer and a second semiconductor layer stacked in sequence from bottom to top, wherein the first semiconductor layer is an N-type doped layer, the second semiconductor layer is a P-type doped layer, in a direction away from the active layer, the second semiconductor layer is sequentially provided with an electron blocking layer and a second cladding layer, in the electron blocking layer, the P-type dopant has at least one doping concentration peak, the doping concentration of the P-type dopant at the doping concentration peak is less than the maximum doping concentration of the P-type dopant in the second semiconductor layer, and, in a direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer has a plurality of partitions, and the doping concentration curve of the P-type dopant decreases along the plurality of partitions.

[0008] According to one aspect of the present application, the present application also provides a light-emitting device, which includes the semiconductor laser element described in the above technical solution.

[0009] Compared with the prior art, the semiconductor laser element and light-emitting device provided by the present application have at least the following beneficial effects:

[0010] In the technical solution of the present application, an electron blocking layer is arranged between the second cladding layer and the second waveguide layer of the semiconductor laser element; wherein the second semiconductor layer is doped with a P-type dopant, and the P-type dopant has at least one doping concentration peak in the electron blocking layer, the doping concentration of Mg at the doping concentration peak is less than the maximum doping concentration of the P-type dopant in the second semiconductor layer, and in the direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer has multiple partitions, and the doping concentration curve of the P-type dopant has different downward trends in the multiple partitions. The downward trend setting of the Mg doping concentration in the second semiconductor layer can ensure that the second semiconductor layer can provide sufficient holes, improve the hole injection efficiency in the quantum well layer, and improve the luminous efficiency. At the same time, the above-mentioned setting of the second semiconductor layer can reduce the absorption of light and improve the light-emitting effect of the device.

[0011] In addition, it can be arranged that in the direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer has multiple partitions, and the doping concentration curves of the P-type dopant in the multiple partitions have different change trends, that is, different slopes. For example, in the direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer has a fourth partition, a third partition, a second partition and a first partition in sequence. Among them, the first partition has the minimum slope value, the fourth partition has the maximum slope value, the slope value of the second partition is greater than the slope value of the third partition, and the concentration range and concentration decrease trend of Mg are controlled in the third partition to reduce the blocking of the series resistance of the light-emitting diode, and at the same time, there is a probability to activate more magnesium to provide more holes, thereby improving the hole injection efficiency of the quantum well of the active layer.

[0012] In some embodiments, the thickness of the first partition is controlled to be smaller than the thickness of the second partition and smaller than the thickness of the third partition, thereby controlling the hole injection depth, improving the hole injection efficiency, and further improving the electron-hole recombination efficiency. Properly increasing the thickness of the second partition and the third partition is conducive to improving the production of ridges in laser diode processing.

[0013] In addition, the light-emitting device provided in the present application includes the semiconductor laser element provided by the above technical solution, and therefore, the above light-emitting device also has the above good technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. The positional relationships described in the drawings in the following description are based on the directions in which the components are drawn in the diagrams, unless otherwise specified.

[0015] For the purpose of convenience or clarity, the thickness and size of each layer shown in the drawings can be exaggerated, omitted or roughly drawn. In addition, the size of the light emitting device does not completely reflect the actual size.

[0016] Figure 1 Shown is a schematic cross-sectional structure diagram of a semiconductor laser element provided in Example 1 of the present application.

[0017] Figure 2 The diagram shows the relationship between the doping concentration, ion intensity and depth of some elements of the semiconductor laser element provided in the first embodiment.

[0018] Figure 3 Display as Figure 2 A locally enlarged schematic diagram of the portion of the semiconductor stack with a depth of 0 to 0.5 μm.

[0019] Figures 4 to 9 Shown are the performance simulation results of the laser element of the present application.

[0020] Fig.10 The graph shows the relationship between the doping concentration of the elements, the ion strength and the depth in the semiconductor stacking layer of the semiconductor laser element provided in the first embodiment with a depth of 0.4 μm to 1 μm.

[0021] Fig.11 Display as Fig.10 A local enlarged schematic diagram of the portion with a depth of 0.6μm to 0.7μm.

[0022] List of reference numerals:

[0023] 100, substrate; 200, first semiconductor layer; 210, buffer layer; 220, first cladding layer; 230, electron supply layer; 240, first waveguide layer; 300, active layer; 400, second semiconductor layer; 410, second waveguide layer; 420, electron blocking layer; 430, second cladding layer; 440, ohmic contact layer; 500, contact electrode; 600, insulating layer; 700, second electrode; 800, first electrode. DETAILED DESCRIPTION

[0024] The following specific embodiments illustrate the implementation of the present application, and those familiar with the technology can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0025] According to one aspect of the present application, a semiconductor laser element is provided, which at least includes: a semiconductor stack, the semiconductor stack includes a first semiconductor layer, a first waveguide layer, an active layer, a second waveguide layer and a second semiconductor layer stacked in sequence from bottom to top, wherein the first semiconductor layer is an N-type doped layer, the second semiconductor layer is a P-type doped layer, and in a direction away from the active layer, the second semiconductor layer is sequentially provided with an electron blocking layer and a second cladding layer; in the electron blocking layer, the P-type dopant has at least one doping concentration peak, the doping concentration of the P-type dopant at the doping concentration peak is less than the maximum doping concentration of the P-type dopant in the second semiconductor layer, and, in a direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer has a plurality of partitions, and the doping concentration curve of the P-type dopant decreases along the plurality of partitions.

[0026] The downward trend of the Mg doping concentration in the second semiconductor layer can ensure that the second semiconductor layer can provide sufficient holes, improve the hole injection efficiency in the quantum well layer, and improve the luminous efficiency. At the same time, the above setting of the second semiconductor layer can reduce the absorption of light and improve the light emission effect of the device.

[0027] Optionally, in a direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer tends to decrease.

[0028] The concentration of the P-type dopant in the second cladding layer can ensure the hole concentration on one side of the second semiconductor layer, thereby improving the hole injection efficiency, which is beneficial to improving the luminous efficiency of the laser diode. The gradually decreasing doping concentration can effectively control the diffusion depth of Mg and prevent it from affecting the light-emitting effect.

[0029] Optionally, the second cladding layer is adjacent to one side of the electron blocking layer, and the doping concentration of the P-type dopant is less than the doping concentration of the P-type dopant at the doping concentration peak in the electron blocking layer.

[0030] A slight increase in the Mg doping concentration in the electron blocking layer can provide an additional barrier to effectively block electrons from overflowing the active region, thereby improving the luminescence efficiency and operating temperature range of the device.

[0031] Optionally, in a direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer sequentially includes a fourth partition, a third partition, a second partition and a first partition, wherein the doping concentration of the P-type dopant in the fourth partition is between 8E18atom / cm 3 ~1E20atom / cm 3 The doping concentration of the P-type dopant in the third partition is between 6E18atom / cm 3 ~8E18atom / cm 3 The doping concentration of the P-type dopant in the second partition is between 3E18atom / cm 3 ~6E18atom / cm 3 The doping concentration of the P-type dopant in the first partition is between 2E18atom / cm 3 ~4E18atom / cm 3 .

[0032] Optionally, the doping concentration curve of the P-type dopant is in the first partition, the second partition, the third partition and the fourth partition, wherein the first partition has a minimum slope value and the fourth partition has a maximum slope value.

[0033] Optionally, the slope values ​​of the second partition and the third partition range from 0.5E19atom / cm 3 / μm~6E19atom / cm 3 / μm.

[0034] Optionally, the slope value of the second partition is greater than the slope value of the third partition.

[0035] Controlling the reduction of the Mg doping concentration in the third partition is beneficial to reducing the impedance of the series resistor, and at the same time has the probability of activating more Mg to provide more holes, thereby improving the hole injection efficiency of the quantum well.

[0036] Optionally, the slope value of the first partition is between 1E19atom / cm 3 / μm~4E19atom / cm 3 / μm.

[0037] Optionally, the slope value of the fourth partition is between 1E21atom / cm 3 / μm~9E21atom / cm 3 / μm.

[0038] Controlling the concentration range and thickness range in which the Mg doping concentration drops sharply can reduce unintentional Mg doping in the active layer, thereby reducing non-radiative recombination centers in the active layer and reducing non-radiative recombination in the active layer, thereby improving the quantum efficiency of the laser.

[0039] Optionally, the thickness of the first partition is between 0.05 μm and 0.3 μm, and the doping concentration of the P-type dopant in the first partition on the side adjacent to the electron blocking layer is 3E18 atom / cm 3 ±10%.

[0040] The thickness setting of the first partition is helpful for the diffusion of holes, reduces the diffusion depth of holes, and ensures that there are enough holes in the active layer to radiate and recombine with electrons.

[0041] Optionally, the thickness of the second partition is between 0.05 μm and 0.3 μm, and the thickness of the third partition is between 0.05 μm and 0.4 μm.

[0042] Optionally, the thickness of the fourth partition is between 0.01 μm and 0.05 μm.

[0043] Optionally, the thickness of the first partition is smaller than the thickness of the second partition, and smaller than the thickness of the third partition.

[0044] The thickness of the second and third partitions is greater than that of the first partition, which is beneficial to improving the subsequent production yield of the laser diode ridge, and thus is beneficial to improving the overall yield of the laser diode. By setting the thickness of the second and third partitions and the Mg doping concentration reduction rate, it is ensured that there is a probability to activate more magnesium to provide more holes, thereby improving the hole injection efficiency of the quantum well.

[0045] Optionally, the doping concentration of the P-type dopant in the electron blocking layer is between 1E18 atom / cm3 and 1E19 atom / cm3.

[0046] Optionally, after the electron blocking layer enters the second waveguide layer, the doping concentration of the P-type dopant is reduced to 1E18atom / cm 3 the following.

[0047] A slight increase in the Mg doping concentration in the electron blocking layer can provide an additional barrier to effectively block electrons from overflowing the active area, thereby improving the luminous efficiency and operating temperature range of the device. In addition, the Mg doping concentration in the electron blocking layer continues to decrease, which helps to reduce the barrier for hole injection, thereby improving the hole injection efficiency and further improving the performance of the device.

[0048] Optionally, the thickness of the second semiconductor layer is between 250 nm and 500 nm, the thickness of the electron blocking layer is between 5 nm and 10 nm, and the thickness of the second cladding layer is between 200 nm and 400 nm.

[0049] The thickness of each material layer is set to ensure the optical performance of the laser element, for example, to ensure that it can provide sufficient hole recombination efficiency; at the same time, it reduces the absorption of light by the material layer and improves the light output effect.

[0050] Optionally, the P-type dopant is magnesium.

[0051] Optionally, the light emission wavelength of the active layer is between 440nm and 470nm, or between 505nm and 540nm.

[0052] Another aspect of the present application provides a light emitting device, characterized by comprising the semiconductor laser element described in the present application.

[0053] The composition and dopant of each layer included in the semiconductor laser device of the present application can be analyzed by any suitable method, such as secondary ion mass spectrometer (SIMS). The thickness of each layer included in the semiconductor laser device of the present application can be analyzed by any suitable method, such as transmission electron microscopy (TEM) or scanning electron microscopy (SEM), for example, to match the depth position of each layer on the SIMS map.

[0054] In this application, unless otherwise specified, the term "peak shape" refers to a line profile comprising two line segments having slopes of opposite signs, i.e., one line segment has a positive slope and the other line segment has a negative slope. "Doping concentration peak" refers to the highest concentration value between the two line segments of the peak shape having slopes of opposite signs.

[0055] For ease of description, the growth direction of the semiconductor stack is defined as upward, and the opposite direction is defined as downward. Figure 1As shown, this embodiment provides a semiconductor laser element, which includes at least a semiconductor stack, which includes a first semiconductor layer 200, a first waveguide layer 240, an active layer 300, a second waveguide layer 410 and a second semiconductor layer 400 stacked in sequence; the first semiconductor layer 200 in this embodiment is an N-type semiconductor layer, and the second semiconductor layer 400 is a P-type semiconductor layer. The semiconductor laser element is an end-face emitting laser element having a light emitting end face and a light reflecting end face intersecting with the main surface of the semiconductor layer such as the active layer 300, and the semiconductor stack has a ridge of a mesa structure at the top, and the ridge is formed in the second cladding layer 430 of the second semiconductor layer 400 and above, and the extension direction of the ridge is the propagation direction of the laser. An insulating layer 600 is provided on the side of the ridge and on the surface of the second semiconductor layer 400 continuous from the side of the ridge.

[0056] Alternatively, if Figure 1 As shown, the above-mentioned laser element may further include a substrate 100. The substrate 100 has a relative upper surface and a lower surface, and a first electrode 800 is provided on the lower surface thereof, and the first electrode 800 is electrically connected to the first semiconductor layer 200. In addition, a contact electrode 500 is provided on the upper surface of the ridge, and the contact electrode 500 forms an ohmic contact with the second semiconductor layer 400. The semiconductor laser element further includes a second electrode 700 provided on the upper surface of the contact electrode 500, and the second electrode 700 is electrically connected to the contact electrode 500. The first electrode 800 and the second electrode 700 act together on the PN junction, and release energy and generate photons through the recombination of electrons and holes. These photons are reflected and amplified by the resonant cavity to form a laser beam, thereby realizing the laser emission function of the laser diode.

[0057] Continue to see Figure 1-2 , the substrate 100 can be a growth substrate, including but not limited to nitride semiconductors, SiC or high-impedance substrates such as sapphire substrates. The substrate containing nitride semiconductors can improve the heat dissipation efficiency because the thermal conductivity is higher than that of sapphire, thereby reducing defects such as dislocations and making the crystallinity good. In an optional embodiment, the substrate 100 can be a supporting substrate, and the growth substrate originally used for epitaxial growth of the semiconductor stack can be selectively removed according to the needs of the application, and then the semiconductor stack is transferred to the aforementioned supporting substrate. Furthermore, the thickness of the substrate 100 ranges from 40μm to 400μm, for example 50μm, 80μm, 100μm, 150μm, 200μm and 300μm.

[0058] like Figure 1As shown, the first waveguide layer 240 is formed below the active layer 300, and the first semiconductor layer 200 is formed below the first waveguide layer 240. In the direction gradually away from the active layer, the first semiconductor layer 200 includes a buffer layer 210 and a first cladding layer 220 sequentially stacked on the substrate 100. The first semiconductor layer 200 may also be configured with other layers other than the above layers, and a part of the layers may also be omitted. For example, in an optional embodiment, in order to reduce lattice defects caused by lattice constant mismatch, a stress release layer or the like may be formed between the first waveguide layer 240 and the active layer 300.

[0059] like Figure 1 As shown, the second waveguide layer 410 is formed above the active layer 300, and the p-type second semiconductor layer 400 is formed above the second waveguide layer 410. The second semiconductor layer 400 may be a single layer or a multilayer structure formed of a nitride material layer. As a p-type nitride semiconductor layer, the second semiconductor layer 400 may, for example, include a semiconductor material layer formed of a nitride material containing p-type impurities such as Mg and C. For example, the second semiconductor layer 400 may be an AlGaInN material layer. In this embodiment, the p-type dopant in the second semiconductor layer 400 is Mg element, wherein the doping concentration of Mg is between 1E18atom / cm 3 ~1E20atom / cm 3 . Also refer to Figure 1 In this embodiment, in the direction gradually away from the active layer, the second semiconductor layer 400 includes an electron blocking layer 420 and a second cladding layer 430 stacked in sequence. The second semiconductor layer 400 may also be configured with other layers in addition to the above layers, such as an ohmic contact layer 440 formed on the second cladding layer 430, or a part of the material layer may be omitted.

[0060] like Figure 1 As shown, the second waveguide layer 410 is arranged adjacent to the active layer 300, and its material may be InGaN. The thickness of the second waveguide layer 410 is between 50nm and 500nm. Further, the thickness of the second waveguide layer 410 is between 100nm and 250nm. The thickness setting of the second waveguide layer 410 can achieve a balance between the carrier injection efficiency, the refractive index and the layer structure strength. The addition of the In component in the second waveguide layer 410 can make it have a higher refractive index to form a contrast with the refractive index of the active layer 300, thereby limiting the propagation path of light and making it propagate in the waveguide layer, thereby achieving directional emission of light. In addition, the addition of the In component in the second waveguide layer 410 and the adjustment of the content can also well suppress electron leakage, increase hole injection, and help improve the electron-hole recombination efficiency in the active layer 300.

[0061] Likewise Figure 1As shown, an electron blocking layer 420 is formed on the second waveguide layer 410, and a second cladding layer 430 is formed on the electron blocking layer 420. The material of the electron blocking layer 420 can be a wide bandgap material such as AlN, AlGaN or AlInGaN to effectively block the leakage of electrons from the active layer 300 to the second semiconductor layer 400, while allowing holes to pass through. The second waveguide layer 410 and the electron blocking layer 420 work together in the laser to jointly achieve the limitation of the light field and carriers, which helps to more effectively recombine the electrons and holes in the active area, thereby improving the luminous efficiency. The material of the second cladding layer 430 can be a wide bandgap material such as AlGaN, and the second cladding layer 430 limits the propagation of light in the waveguide layer by providing a lower refractive index than the second waveguide layer 410. The thickness of the second cladding layer 430 is between 100 nm and 500 nm, and further between 300 nm and 350 nm, so as to provide sufficient carrier diffusion to the active layer 300 , while not being too thick to avoid increasing excessive series resistance.

[0062] Reference Figure 2 The doping concentration of Mg in the second semiconductor layer 400 is between 1E18atom / cm 3 ~1E21atom / cm 3 , wherein the doping concentration of Mg in the electron blocking layer 420 has at least one doping concentration peak, and the doping concentration of Mg at the doping concentration peak is less than the maximum doping concentration of Mg in the second semiconductor layer 400. Optionally, the doping concentration of Mg in the electron blocking layer 420 is between 3E18atom / cm 3 ~8E18atom / cm 3 .like Figure 2 As shown, the maximum doping concentration of Mg in the second semiconductor layer 400 is between 1E19atom / cm 3 ~1E21atom / cm 3 The Mg doping concentration at the Mg concentration peak in the electron blocking layer 420 is obviously lower than the above-mentioned maximum doping concentration of Mg in the second semiconductor layer 400. The Mg concentration in the electron blocking layer 420 is set so that the Mg doping concentration can be strictly controlled within the range from the electron blocking layer 420 to the active layer 300, so that the Mg doping concentration is reduced to 1E18atom / cm after the electron blocking layer 420 enters the second waveguide layer 410. 3 As described above, by controlling the diffusion of Mg toward the active layer 300 , it is helpful to reduce the non-radiative centers associated with Mg defects in the active region 300 , and the trap-assisted tunneling current can be suppressed, thereby improving the performance of the diode.

[0063] In an alternative embodiment, if Figure 2 and Figure 3As shown in FIG. 1 , in the second semiconductor layer 400, the doping concentration of Mg in the second cladding layer 430 shows a decreasing trend as it gradually approaches the electron blocking layer 420, wherein the overall slope value of the doping curve is between 2E18atom / cm 3 / μm~4E18atom / cm 3 / μm. In an optional embodiment, in the process of reducing the Mg doping concentration as a whole, the Mg doping concentration may slightly increase within a very small thickness range. Furthermore, the Mg doping concentration on the side of the second cladding layer 430 adjacent to the electron blocking layer 420 is less than the Mg doping concentration at the Mg doping concentration peak in the electron blocking layer 420. Near the surface of the second semiconductor layer 400 away from the active layer 300, that is, near the surface of the ohmic contact layer 440, the Mg doping concentration is the largest, greater than 1E19atom / cm 3 , further, greater than 1E20atom / cm 3 Less than 1E21atom / cm 3 The high concentration of Mg doping in the ohmic contact layer 440 can increase the hole concentration in the second semiconductor layer 400, thereby reducing the contact resistance with the metal, and at the same time can reduce the barrier height of the metal-semiconductor contact, which is helpful to achieve better ohmic contact; in addition, the high concentration of Mg doping can increase the number of holes in the second semiconductor layer 400, thereby improving the hole injection efficiency, which is beneficial to improving the luminous efficiency of the laser diode.

[0064] In an optional embodiment, in the direction gradually approaching the electron blocking layer 420, the Mg doping concentration curve in the second cladding layer 430 can be divided into a plurality of sub-areas with different change trends, and the plurality of sub-areas of the Mg doping concentration curve have different slopes, that is, in the direction approaching the electron blocking layer 420, the Mg doping concentration in the second cladding layer 430 gradually decreases as a whole, but the reduction range or concentration change range of the Mg doping concentration in different sub-areas is not the same. For example, in the direction approaching the electron blocking layer 420, the Mg doping concentration in the second cladding layer 430 may be always in a downward trend, or on the basis of the overall downward trend, the Mg doping concentration in some areas may be substantially unchanged or slightly increased.

[0065] In a specific embodiment of this embodiment, if Figure 3 As shown, in the direction gradually approaching the electron blocking layer 420, the Mg doping concentration curve in the second cladding layer 430 has the fourth partition L4, the third partition L3, the second partition L2 and the first partition L1 in sequence. From the fourth partition L4 to the first partition L1, and from the fourth partition L4 to the first partition L1, the Mg doping concentration decreases as a whole. Specifically, the Mg doping concentration of the fourth partition L4 is between 1E19atom / cm3 ~1E20atom / cm 3 The Mg doping concentration of the third partition L3 is between 6E18atom / cm 3 ~1E19atom / cm 3 The Mg doping concentration of the second partition L2 is between 3E18atom / cm 3 ~6E18atom / cm 3 The Mg doping concentration of the first partition L1 is between 2E18atom / cm 3 ~4E18atom / cm 3 After entering the electron blocking layer 420 from the second cladding layer 430, the Mg doping concentration suddenly rises and then suddenly drops, forming at least one doping concentration peak in the electron blocking layer. As described above, the Mg doping concentration at the concentration peak is higher than the Mg doping concentration in the first subarea L1 adjacent to the electron blocking layer 420, but lower than the Mg doping concentration in the fourth subarea L4.

[0066] The doping concentration curve of the P-type dopant has a first slope, a second slope, a third slope and a fourth slope in the first partition L1, the second partition L2, the third partition L3 and the fourth partition L4, respectively, wherein the first slope has a minimum slope value and the fourth slope has a maximum slope value. It should be noted that in the coating layer 430, the doping concentration of Mg is generally decreasing, so the slope of the doping curve is a negative value, and the negative sign indicates the direction of the doping curve. For the sake of convenience, only the value after removing the negative sign (i.e., the slope value) is compared. The larger the value, the faster the rate of decline, and the smaller the value, the slower the rate of decline.

[0067] Specifically, refer to Figure 3 The thickness of the first partition L1 is between 0.05 μm and 0.3 μm, and further between 0.05 μm and 0.15 μm. The thickness setting of the first partition L1 is conducive to the diffusion of holes, reduces the diffusion depth of holes, and ensures that there are enough holes and electrons in the active layer 300 for radiation recombination. Within the thickness range of the first partition L1, the slope value of the Mg doping concentration curve is between 0.5E19atom / cm 3 / μm~2E19atom / cm 3 / μm. Combined Figure 3 It can be seen that on the side adjacent to the electron blocking layer 420 and the side adjacent to the second subarea L2, the doping concentration of Mg in the first subarea L1 is approximately (3±0.5)E18atom / cm 3 In the range of 2.5E18atom / cm2, between the electron blocking layer 420 and the second partition L2, the Mg doping concentration is 2.5E18atom / cm2. 3 ~3.5E18atom / cm 3That is, within the first partition L1, the change trend of Mg doping concentration gradually becomes flat, always at 3E18atom / cm 3 Fluctuates within a small range up and down.

[0068] Also combined Figure 2 and Figure 3 , the thickness of the second partition L2 is between 0.05μm and 0.3μm, and further, between 0.09μm and 0.2μm. The thickness of the third partition L3 is between 0.05μm and 0.4μm, and further, between 0.12μm and 0.3μm. In an optional embodiment, the thickness of the second partition L2 is greater than the thickness of the first partition L1, and the thickness of the third partition L3 is also approximately the thickness of the first partition L1. The thickness of the second partition L2 and the third partition L3 being greater than the thickness of the first partition L1 is beneficial to improving the subsequent production yield of the ridge of the laser diode, and thus is beneficial to improving the overall yield of the laser diode.

[0069] In an optional embodiment, in the second subarea L2 and the third subarea L3, the doping concentration of Mg has a similar downward trend, such as Figure 3 As shown, the overall slope value of the second partition L2 and the third partition L3 is between 0.5E19atom / cm 3 / μm~6E19atom / cm 3 By setting the thickness of the second partition L2 and the third partition L3 and the rate at which the doping concentration of Mg decreases, it is ensured that there is a probability to activate more magnesium to provide more holes, thereby improving the hole injection efficiency of the quantum well.

[0070] In a further optional embodiment, if Figure 3 As shown, the slope value of the second partition L2 is between 1E19atom / cm 3 / μm~6E19atom / cm 3 / μm, the slope value of the third partition L3 is between 0.5E19atom / cm 3 / μm~4E19atom / cm 3 / μm, and the slope value of the second partition L2 is greater than the slope value of the third partition L3. As described above, controlling the Mg doping concentration of the second partition L2 closer to the active layer 300 to decrease faster is beneficial to reducing the impedance of the series resistance, and at the same time, there is a probability to activate more Mg to provide more holes, thereby improving the hole injection efficiency of the quantum well.

[0071] Likewise Figure 2 and Figure 3As shown, the thickness of the fourth subarea L4 is between 0.01 μm and 0.05 μm, and further, between 0.02 μm and 0.05 μm. The doping concentration of Mg in the fourth subarea L4 is 1E21 atom / cm 3 Dropped to 1E19atom / cm 3 , the slope of the fourth partition L4 is between 1E22atom / cm 3 / μm~1E23atom / cm 3 / μm, that is, the doping concentration of Mg decreases significantly in the fourth subarea L4. Controlling the concentration range and thickness range in which the Mg doping concentration decreases sharply can reduce the unintentional doping of Mg in the active layer 300, thereby reducing the non-radiative recombination centers in the active layer 300 and reducing the non-radiative recombination in the active layer 300, thereby improving the quantum efficiency of the laser.

[0072] Refer again Figure 3 The thickness of the electron blocking layer 420 is between 0.05 μm and 0.2 μm, and further between 0.1 μm and 0.15 μm. The doping concentration of Mg in the electron blocking layer 420 is between 1E18 atom / cm 3 ~1E19atom / cm 3 , and a doping concentration peak is formed. That is, after entering the electron blocking layer 420 from the first partition, the doping concentration of Mg will first rise, and then drop sharply, forming a doping concentration peak. After the doping concentration peak, the doping concentration of Mg drops significantly in the direction of entering the second waveguide layer 410 and the active layer 300, and drops to 1E18atom / cm after entering the second waveguide layer 410. 3 Below, further, down to 1E17atom / cm 3 The increase in the Mg doping concentration in the electron blocking layer 420 can increase the hole concentration in the electron blocking layer 420, thereby enhancing the blocking effect on electrons, effectively blocking electrons from overflowing the active area 300, thereby improving the luminous efficiency of the device. In addition, the Mg doping concentration in the electron blocking layer 420 continues to decrease, which helps to reduce the barrier for hole injection, thereby improving the hole injection efficiency and further improving the performance of the device.

[0073] The thickness of the second cladding layer 430 and the electron blocking layer 420 and the setting of the Mg doping concentration enable the second semiconductor layer 400 to provide sufficient holes to the active layer 300; at the same time, the unintentional doping of impurities such as Mg, C, H, O, etc. in the active layer 300 is reduced, especially the unintentional doping of Mg and C, thereby reducing the non-radiative recombination centers in the active layer 300 and reducing the non-radiative recombination in the active layer 300, thereby improving the quantum efficiency of the laser. Reduce the efficiency of the laser.

[0074] In an optional embodiment, an ohmic contact layer 440 may be formed on the second cladding layer 430. The material of the ohmic contact layer 440 may be GaN or InGaN, which matches the lattice constant of the second cladding layer 430. The Mg doping concentration in the ohmic contact layer 440 is relatively high, for example, between 1E20atom / cm 3 ~1E21atom / cm 3 The high doping can improve the conductivity, thereby reducing the resistance of the contact with the metal electrode, forming a good ohmic contact, reducing the voltage value of the laser diode and promoting uniform injection of current.

[0075] In one embodiment of the present invention, the semiconductor laser element can form a ridge by etching part of the second semiconductor layer 400. The width of the ridge is adjusted to 1 μm to 5 μm. A contact electrode 500 is provided on the upper surface of the ridge. Specifically, the main function of the contact electrode 500 is to improve the lateral expansion capability and expand the area where the current acts. The material of the contact electrode 500 can be a transparent conductive film such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), gallium oxide (GaO3), etc. The material of the contact electrode 500 can also be a metal such as nickel and gold. The contact electrode 500 is a transparent conductive film having a refractive index smaller than that of the active layer 300. Further, an insulating layer 600 is formed on the side of the exposed ridge, the side of the contact electrode 500, and the surface of the second cladding layer 430 exposed by etching. The film thickness of the insulating layer 600 is between 100 nm and 500 nm, and it can be formed by a single layer or a multilayer film of materials such as oxides or nitrides of Si, Al, Zr, Ti, Nb, Ta, etc.

[0076] Also refer to Figure 1 , the active layer 300 is located between the first semiconductor layer 200 and the second semiconductor layer 400, specifically, the active layer 300 is located between the first waveguide layer 240 and the second waveguide layer 410. The active layer 300 can be set to a multilayer structure composed of nitride semiconductors such as GaN and InGaN. The active layer 300 has a single quantum well structure or a multiple quantum well structure. In the case where the active layer 300 includes a multiple quantum well structure, if the potential well layer and the potential barrier layer are alternately stacked, the starting layer and the termination layer can be either a potential well layer or a potential barrier layer. Further, the multiple quantum well structure includes 2 to 15 pairs of potential barrier layers and potential well layers arranged alternately. In an optional embodiment, the thickness of each barrier layer in the active layer 300 can be the same or different, and the thickness of each potential well layer can also be the same or different.

[0077] Furthermore, for a semiconductor laser element that emits blue-green light, the potential well layer and the potential barrier layer in the active layer 300 include an InGaN / GaN material layer. The emission wavelength of the laser element can be controlled by adjusting the In content of the well layer to emit blue light or green light. Optionally, the output wavelength of the laser diode can be tested by an integrating sphere measurement method. In this embodiment, the measured output wavelength range of the laser diode is 440nm to 540nm, more specifically, between 440nm and 470nm, or between 505nm and 540nm.

[0078] Continue to see Figure 1 , the first semiconductor layer 200 is an AlGaInN material layer. For example, it can be set as a multilayer structure composed of nitride semiconductors such as GaN, InGaN, and AlGaN. The first semiconductor layer 200 includes a first cladding layer 220 and a first waveguide layer 240 stacked on the substrate 100 in sequence. In an optional embodiment, in order to improve the lattice quality of the epitaxial stack, a buffer layer 210 can also be formed between the substrate 100 and the first cladding layer 120.

[0079] In an optional embodiment, the first semiconductor layer 200 may also be formed with an electron supply layer 230, which is located between the first cladding layer 220 and the first waveguide layer 240, and may be an AlGaN material layer. By adjusting the refractive index and thickness of the first cladding layer 220, the light field is limited so that the light is mainly concentrated between the waveguide layers of the laser, thereby improving the efficiency and performance of the laser. The first cladding layer 220 needs to have a certain thickness to effectively limit carriers and prevent electron overflow, and its thickness is usually between 100nm and 500nm.

[0080] In an optional embodiment, the n-type doping concentration of the electron supply layer 230 is greater than or equal to 3×10 18 atom / cm 3 , which is used to effectively increase the electron injection efficiency and improve the recombination efficiency of carriers in the active layer 300. The thickness of the electron supply layer 230 is less than or equal to 500nm. Specifically, the thickness of the electron supply layer 230 is between 10nm and 100nm, preferably between 10nm and 50nm, and the doping concentration is between 2×10 18 atom / cm 3 ~1.5×10 19 atom / cm 3. The n-type impurity doping concentration of the electron supply layer 230 is generally greater than the n-type impurity doping concentration of the first cladding layer 220. It is understandable that since the laser in the waveguide layer will cause the gain coefficient to decrease due to doping, the carrier recombination efficiency will be affected, which will in turn affect the luminous brightness, and the insertion of the electron supply layer 230 can effectively inject electrons from the first cladding layer 220 into the active layer 300, thereby accumulating sufficient non-equilibrium electron concentration in the well layer of the active layer 300, optimizing the number and distribution of electrons in the active layer 300, and improving the quantum efficiency of the laser; in addition, the electron supply layer 230 can also limit the diffusion of electrons in the horizontal direction, reduce electron overflow, reduce non-radiative recombination of carriers, and ensure that they are mainly concentrated in the active area, thereby improving the efficiency of the laser.

[0081] In the above embodiment, the thickness of the electron supply layer 230 is less than the thickness of the first waveguide layer 240, which ensures good light confinement capability and provides a relatively flat surface as the growth basis of the first waveguide layer 240, which is beneficial to improving the crystal quality of the first waveguide layer 240. The thickness of the electron supply layer 230 is between 10nm and 30nm, for example, it can be 10nm, 15nm, 20nm, 25nm or 30nm. An overly thick layer may introduce more defects or stresses in the subsequent material deposition process, affecting the reliability and stability of the device, while an overly thin layer cannot withstand the stress or temperature changes in the subsequent process, resulting in the cracking or failure of the layer structure, and requiring higher precision for the doping process. Further, the thickness of the electron supply layer 230 is between 15nm and 25nm, for example, 20nm, to achieve a good balance between the electron supply capability and the quality of the layer structure.

[0082] In the above embodiment, the electron supply layer 230 is a GaN material highly doped with Si elements, and its doping concentration is greater than the doping concentrations of the first cladding layer 220 and the first waveguide layer 240. By setting a higher Si doping concentration, the electron concentration is increased to ensure sufficient carrier recombination in the active layer 300. Further, along the thickness growth direction of the semiconductor stack, the Si element and the like in the electron supply layer 230 are doped, and the initial doping concentration of the lower surface to the doping concentration of the upper surface are substantially consistent. The constant doping concentration is conducive to simplifying the preparation process, and also keeps the electron concentration in the electron supply layer 230 stable, which can improve the performance stability of the semiconductor laser element.

[0083] like Figure 1As shown, the first waveguide layer 240 is located between the electron supply layer 230 and the active layer 300, and its material can be InGaN. By introducing different proportions of IN components into InGaN, the refractive index and band gap of the waveguide layer are adjusted, so that the refractive index of the first waveguide layer 240 is higher than that of the first cladding layer 220. The first waveguide layer 240 and the second waveguide layer 410 work together to confine the light to propagate in the waveguide layer, thereby achieving an effective light gain effect. At the same time, the electron supply layer 230 below the first waveguide layer 240 can also play a certain role in reducing electron overflow. The thickness of the first waveguide layer 240 is between 50nm and 500nm to achieve a balance between electron injection efficiency, refractive index and layer structure strength. Further, the thickness of the first waveguide layer 240 is similar to that of the second waveguide layer 410, both between 50nm and 500nm. Further, the thickness of the first waveguide layer 240 is between 200nm and 400nm. In an optional embodiment, as Figure 2 As shown, the content of the In component in the first waveguide layer 240 gradually increases as it approaches the active layer 300, thereby improving the electron-hole recombination efficiency.

[0084] In order to verify the relevant performance of the laser diode of the second semiconductor layer 400 having the above-mentioned doping characteristics of this embodiment, a photoelectric performance simulation was performed. Figures 4 to 6 As shown in FIG. 1 , PI and VI simulation curves and life simulation results of the blue and green laser diodes having the second semiconductor layer 400 are shown respectively. Figures 4 to 6 As shown in the simulation of the blue light diode, the light wavelength is defined as ~450nm, the ridge width RW of the laser diode is 30μm, and the length of the resonant cavity is L=1200μm. It can be seen from the PI and VI curves of the blue light diode that the threshold current Ith of the blue light laser diode with the second semiconductor layer structure is about 300mA, and the threshold current density Jth is about 0.83kA / cm 2 , the rate at which the diode power increases with current, i.e. the slope efficiency SE, is about 1.55W / A. From the time-P / P0 curve of the blue light diode, it can be seen that after 6000 hours of continuous operation, the percentage of the optical output power (P) of the blue laser diode relative to its initial power (P0) as a function of time (hours) remains above 85%.

[0085] like Figures 7 to 9 As shown in FIG. 1 , in the simulation of the green light diode, the light wavelength is defined as 515 nm, the ridge width RW of the laser diode is 15 μm, and the length of the resonant cavity is 1200 μm. From the PI and VI curves of the green light diode, it can be seen that the threshold current Ith of the green light laser diode with the second semiconductor layer structure is about 300 mA, and the threshold current density Jth is about 1.66 kA / cm 2, the rate at which the power of the diode increases with the current, that is, the slope efficiency SE is about 0.72W / A. From the duration-P / P0 curve of the green diode, it can be seen that after 4000 hours of continuous operation, the percentage of the change in the optical output power (P) of the green laser diode with time (hours) relative to its initial power (P0) remains above 95%.

[0086] It can be seen from the above simulation results that the laser diode having the second semiconductor layer 400 of this embodiment has a lower threshold current and good photoelectric conversion efficiency. At the same time, the power attenuation of the laser diode is small over time, and it has good stability. The device has a long service life and high reliability.

[0087] like Fig.10 and Fig.11 As shown, within the range from the first waveguide layer 240 to the second waveguide layer 410, the In component has an ion strength curve, and the ion strength curve includes a first part S1, a second part S2, a third part S3 and a fourth part S4 connected in sequence; wherein the ion strength of the In component of the first part S1 gradually increases in the direction from the first waveguide layer to the second waveguide layer and reaches a maximum value at the connection with the second part S2; the second part S2 includes a first trough T1, a second trough T2 and a middle section T3 located between the first trough T1 and the second trough T2, the ion strength of the middle section T3 is greater than the ion strength of the first trough T1 and greater than the ion strength of the second trough T2, the first trough T1 is connected to the first part S1, the second trough T2 is connected to the third part S3, and the ion strength of the In component of the third part S3 has two significant peaks; at the connection with the third part S3, the initial intensity of the In component ion strength of the fourth part S4 is the maximum value and gradually decreases along the direction from the first waveguide layer 240 to the second waveguide layer 410.

[0088] Likewise Fig.10 and Fig.11As shown, the ion intensity of the In component in the second part S2 is less than the maximum ion intensity of the In component in the first part S1, and the ion intensity of the In component in the middle section T3 of the second part S2 is less than the maximum ion intensity of the fourth part S4, thereby avoiding the carrier overflow phenomenon caused by the excessively high content of the In component in the middle section T3. Specifically, for the second part S2, the In ion intensity in the middle section T3 is greater than the In ion intensity in the first valley T1 and the second valley T2, and the semiconductor material corresponding to the middle section T3 can be, for example, InGaN, and the valleys on both sides contain a small amount of In component or no In component, and the semiconductor material corresponding to the valleys on both sides can be, for example, GaN. It can be understood that the signal duration of the In component ion intensity corresponds to the thickness of different semiconductor layers to a certain extent, and the layer thickness of the first part S1 is greater than the layer thickness corresponding to the second part S2; for the second part S2, the layer thickness of the middle section T3 is greater than the layer thickness corresponding to the first valley T1, and is also greater than the layer thickness corresponding to the second valley T1.

[0089] In this embodiment, the first waveguide layer 240 corresponds to Figure 1 The first portion S1 of the ion intensity curve L shown in FIG. 1 , the thickness of the first waveguide layer 240 corresponding to the first portion S1 is between 50 nm and 500 nm, so as to achieve a balance between electron injection efficiency, refractive index and layer structure strength. Further, the thickness of the first waveguide layer 240 is between 200 nm and 400 nm.

[0090] After testing, under the condition that other semiconductor layer parameters are the same, the In content percentage in the active layer is 10% and the maximum In content percentages of the first waveguide layer 240 and the second waveguide layer 410 are both within the range of 2% to 10%.

[0091] It is understandable that for semiconductor lasers of other wavelengths, the emission wavelength can be adjusted by adjusting the In content in the active layer 300, thereby achieving light emission of different colors. Taking the green light semiconductor laser element as an example, the wavelength of green light is greater than the wavelength of blue light, and the In content in its active layer 300 is also relatively high. In order to confine the light between the waveguide layers, the difference in refractive index between the waveguide layer and the cladding layer should also be large, so the In content in the waveguide layer is also high relative to the blue light component.

[0092] Continue to see Figure 2 and Fig.10, it can be seen that the Si element has a concentration curve along the direction from the first semiconductor layer 200 to the active layer, and the concentration curve includes a first segment D1, a second segment D2 and a third segment D3 connected in sequence; wherein the first segment D1 corresponds to the area of ​​the first semiconductor layer 200 far away from the active layer 300, the third segment D3 corresponds to the area of ​​the first semiconductor layer 200 close to the active layer 300, the concentration value of the second segment D2 is lower than the concentration value of the first segment D1, and the Si element has a peak concentration in the third segment D3, and the concentration of the first segment D1 is lower than the peak concentration. The doping concentration of Si in the first segment D1 is between 9×10 17 atom / cm 3 ~4×10 18 atom / cm 3 , which can effectively increase the electron injection efficiency and improve the quantum efficiency of the laser.

[0093] In one embodiment, the peak concentration of the third segment D3 is less than or equal to 1E19 atom / cm 3 The third segment D3 is a semiconductor layer close to the active layer 300. Limiting its peak concentration can prevent defects in the crystal caused by excessive doping concentration. It is understandable that by optimizing the distribution of Si elements, the third segment D3 may have more than one peak concentration to optimize the performance of the semiconductor laser element. In an optional embodiment, when the third segment D3 corresponds to a multiple stacked structure composed of different materials, such as a GaN / InGaN / GaN multilayer structure, the doping peak concentration can be generated in any semiconductor layer corresponding to the third segment D3.

[0094] In the above embodiment, the first segment D1 can be AlGaN material with high Si doping concentration between 9×10 17 atom / cm 3 ~4×10 18 atom / cm 3 By inserting the highly doped first segment D1 before the second segment D2, sufficient electron concentration is provided to improve the electron-hole recombination efficiency and thus enhance the luminous brightness. The concentration of the second segment D2 is between 5×10 17 atom / cm 3 ~2×10 18 atom / cm 3 The doping concentration of the third segment D3 is between 1×10 18 atom / cm 3 ~9×10 18 atom / cm 3 The third segment D3 has a relatively high Si doping concentration to reduce the influence of the polarization field on the carrier recombination efficiency in the active layer 300.

[0095] In the above embodiment, the Si concentration of the semiconductor layer corresponding to the first section D1, that is, the electron supply layer 230, is less than the peak concentration of Si in the third section D3, and the Si element is uniformly doped in the electron supply layer 230 along the direction from the first semiconductor layer 200 to the active layer, and the initial doping concentration of the lower surface to the doping concentration of the upper surface is basically consistent. The constant doping concentration is conducive to simplifying the preparation process, and also keeps the electron concentration in the electron supply layer 230 stable, which can improve the performance stability of the semiconductor laser element. The insertion of the electron supply layer 230 can optimize the number and distribution of electrons in the active layer 300 and improve the quantum efficiency of the laser. The doping concentration in the layer is between 1×10 18 atom / cm 3 ~4×10 18 atom / cm 3 In order to provide enough electrons to the quantum well layer for effective recombination. In an optional embodiment, the doping concentration of the first segment D1 can also be uniformly graded doping or gradient graded doping.

[0096] In an optional embodiment, if Figure 1 As shown, the laser element further includes a first electrode and a second electrode. The second electrode 700 is formed on the ridge, contacts the contact electrode 500 and is electrically connected to the second semiconductor layer 400. The thickness of the second electrode 700 is between 0.1 μm and 2 μm, and generally, as long as it is a thickness that can function as an electrode of a semiconductor laser element, its material can be a metal or alloy such as Ni, Rh, Cr, Au, W, Pt, Ti, Al, etc. The first electrode 800 is disposed on the lower surface of the substrate 100 and is electrically connected to the first semiconductor layer 200. The material of the first electrode 800 includes any one or a combination of two or more of Ni, Ti, Pd, Pt, Au, Al, TiN, ITO, and IGZO, but is not limited thereto.

[0097] Embodiment 2

[0098] This embodiment provides a light-emitting device, which includes a driving substrate and a light-emitting element fixed on the driving substrate, wherein the light-emitting element may include the semiconductor laser element provided in the first embodiment, so the light-emitting device also has the above-mentioned excellent effects.

[0099] In summary, the semiconductor laser element and light-emitting device provided by the present application effectively overcome various shortcomings in the prior art and have high industrial utilization value.

[0100] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A semiconductor laser element, characterized in that: At least: A semiconductor stack, the semiconductor stack comprising a first semiconductor layer, a first waveguide layer, an active layer, a second waveguide layer and a second semiconductor layer stacked in sequence from bottom to top, wherein the first semiconductor layer is an N-type doped layer, the second semiconductor layer is a P-type doped layer, and in a direction away from the active layer, the second semiconductor layer is sequentially provided with an electron blocking layer and a second cladding layer; in the electron blocking layer, the P-type dopant has at least one doping concentration peak, the doping concentration of the P-type dopant at the doping concentration peak is less than the maximum doping concentration of the P-type dopant in the second semiconductor layer, and, in a direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer has a plurality of partitions, and the doping concentration curve of the P-type dopant decreases along the plurality of partitions.

2. The semiconductor laser element according to claim 1, wherein In a direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer tends to decrease.

3. The semiconductor laser element according to claim 1, wherein The second cladding layer is adjacent to one side of the electron blocking layer, and the doping concentration of the P-type dopant is lower than the doping concentration of the P-type dopant at the doping concentration peak in the electron blocking layer.

4. The semiconductor laser element according to claim 1, wherein In the direction gradually approaching the electron blocking layer, the doping concentration of the P-type dopant in the second cladding layer sequentially includes a fourth subarea, a third subarea, a second subarea and a first subarea, wherein the doping concentration of the P-type dopant in the fourth subarea is between 8E18atom / cm 3 ~1E20 atom / cm 3 The doping concentration of the P-type dopant in the third partition is between 6E18atom / cm 3 ~8E18atom / cm 3 The doping concentration of the P-type dopant in the second partition is between 3E18atom / cm 3 ~6E18 atoms / cm 3 The doping concentration of the P-type dopant in the first partition is between 2E18atom / cm 3 ~4E18 atoms / cm 3 .

5. The semiconductor laser element according to claim 4, characterized in that The doping concentration curve of the P-type dopant is in the first partition, the second partition, the third partition and the fourth partition, wherein the first partition has a minimum slope value and the fourth partition has a maximum slope value.

6. The semiconductor laser element according to claim 4, characterized in that The slope values ​​of the second partition and the third partition range from 0.5E19 atom / cm 3 / μm~6E19 atom / cm 3 / μm.

7. The semiconductor laser element according to claim 6, characterized in that The slope value of the second partition is greater than the slope value of the third partition.

8. The semiconductor laser element according to claim 4, characterized in that The slope value of the first partition is between 0.5E19 atom / cm 3 / μm~2E19 atom / cm 3 / μm.

9. The semiconductor laser element according to claim 4, characterized in that The slope value of the fourth partition is between 1E21atom / cm 3 / μm~9E21 atom / cm 3 / μm.

10. The semiconductor laser element according to claim 4, characterized in that The thickness of the first partition is between 0.05 μm and 0.3 μm. On the side adjacent to the electron blocking layer, the doping concentration of the P-type dopant in the first partition is 3E18 atom / cm 3 ±10%.

11. The semiconductor laser device according to claim 4, characterized in that The thickness of the second partition is between 0.05 μm and 0.3 μm, and the thickness of the third partition is between 0.05 μm and 0.4 μm.

12. The semiconductor laser element according to claim 4, characterized in that The thickness of the fourth subarea is between 0.01 μm and 0.05 μm.

13. The semiconductor laser element according to claim 4, characterized in that The thickness of the first partition is smaller than the thickness of the second partition, and smaller than the thickness of the third partition.

14. The semiconductor laser element according to claim 1, wherein The doping concentration of the P-type dopant in the electron blocking layer is between 1E18 atom / cm 3 ~1E19 atom / cm 3 .

15. The semiconductor laser device according to claim 1, wherein After the electron blocking layer enters the second waveguide layer, the doping concentration of the P-type dopant is reduced to 1E18 atom / cm 3 the following.

16. The semiconductor laser element according to claim 1, wherein The thickness of the second semiconductor layer is between 250 nm and 500 nm, the thickness of the electron blocking layer is between 5 nm and 10 nm, and the thickness of the second cladding layer is between 200 nm and 400 nm.

17. The semiconductor laser device according to claim 1, wherein The P-type dopant is magnesium.

18. The semiconductor laser device according to claim 1, wherein The light emission wavelength of the active layer is between 440nm and 470nm, or between 505nm and 540nm.

19. A light emitting device, characterized in that: A semiconductor laser element comprising the semiconductor laser element according to any one of claims 1 to 18.

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