Wide-strip diode laser with integrated pn tunnel junction

Abstract

Broad-strip diode laser, including: an active layer (20) formed between an n-doped semiconductor material (10, 12, 14) and a p-doped semiconductor material (30, 32, 34), wherein the active layer (20) forms an active zone along a longitudinal axis for generating electromagnetic radiation; wherein at least one n-doped intermediate layer (50, 54) is arranged between a p-sided metal contact (52) and the p-doped semiconductor material (30, 32, 34), wherein in the at least one n-doped intermediate layer (50, 54) a pn tunnel junction (40) is formed in the area above the active zone adjacent to the p-doped semiconductor material (30, 32, 34); characterized by the fact that a residual layer thickness d res between the active layer (20) and the pn tunnel junction (40) is less than 0.5 µm; an n-doped shell layer (54) is arranged on the pn tunnel junction (40), and the pn tunnel junction (40) is arranged on a p-doped cladding layer (32) of the p-doped semiconductor material (30, 32, 34) and an n-doped contact layer (50) rests on the n-doped cladding layer (54).

Description

[0001] The present invention relates to a broad-area diode laser (BAL) with an integrated pn tunnel junction. In particular, the present invention relates to a high-power broad-area diode laser in which a reverse-biased pn tunnel junction is integrated into the layer system of the diode laser to improve beam quality and reduce thermal resistance. State of the art

[0002] Broadband diode lasers (BALs) can exhibit particularly high efficiency and brilliance. These emitters can reliably achieve output powers of >15 W. BALs are the most efficient light source for near-infrared (NIR) radiation, making them widely used as pump sources for solid-state and fiber lasers. They are also the key element of fiber-coupled laser systems designed to deliver high-radiation-density beams for material processing at high conversion efficiencies. To increase the output power of these systems and reduce their cost, it is important to improve the beam quality, especially on the slow axis, as this enables the coupling of a greater number of emitters in low numerical aperture (NA) fibers.

[0003] At high optical output powers and the associated operating currents, however, a significant deterioration in beam quality generally occurs, which has a particularly negative impact on coupling in fibers. It has been shown that thermal lensing (and not charge carrier or gain-induced guiding) in the slow axis is one of the predominant causes of beam quality deterioration at increased operating currents (Bai, JG et al., Mitigation of Thermal Lensing Effect as a Brightness Limitation of High-Power Broad Area Diode Lasers, Proc. SPIE 7953, 79531F (2011) & Crump, P. et al., Experimental Studies Into the Beam Parameter Product of GaAs High-Power Diode Lasers, IEEE J. Sel. Top. Quantum Electron., vol. 28, no. 1 (2022)).The decisive factor for the deterioration of beam quality at high output powers is therefore the formation of a lateral temperature gradient due to a temperature increase in the central area under the laser stripe, which leads to a local increase in the refractive index and thus to additional lateral wave propagation and consequently to a larger divergence angle.

[0004] In particular, previous studies on GaAs-based wide-strip diode lasers (e.g., Rieprich, J. et al., Thermal boundary resistance between GaAs and p-side metal as limit to high power diode lasers, IEEE High Power Diode Lasers and Systems Conf. (Coventry, UK), pp. 35-36 (2019)) have shown that a significant thermal barrier forms at the interface between the highly p-doped GaAs contact layer and the metal contact deposited above it. The reduced heat dissipation caused by this barrier intensifies the effect of the resulting thermal lens, leading to lower beam quality and increased thermal resistance. In contrast, no such thermal barrier could be detected at the other semiconductor-metal interface within the device, i.e., between n-doped GaAs and metal.

[0005] From US 2018 / 0337513A1, it is known that improved heat dissipation from a high-performance optical semiconductor device can be achieved via an np-type tunnel junction to form an alloyed contact junction directly between the np-type tunnel junction and a metal contact layer. This alloyed contact junction exhibits lower thermal and electrical resistance than a metallurgically abrupt junction in a conventional p-type contact. The n-doped region of the np-type tunnel junction itself forms the metal-semiconductor junction required for contacting.

[0006] DE 10 2009 015 314 A1 also relates to a semiconductor laser device with an integrated pn tunnel junction formed between a waveguide layer made of p-doped material and an n-doped cladding layer. By using a buried tunnel junction, magnesium-doped layers can be advantageously omitted in the p-side cladding layer. This, in particular, reduces aging effects in the semiconductor laser device that could otherwise be caused by magnesium diffusion.

[0007] JP 2002 319 703 A discloses a laminated group III nitride semiconductor layer structure comprising tunnel diodes, with at least one first laminated group III nitride semiconductor layer structure of n-type, one laminated group III nitride semiconductor layer structure of p-type and one second laminated group III nitride semiconductor layer structure of n-type, which are formed on a substrate.

[0008] CN 104 682 195 A shows an edge-emitting semiconductor laser with a tunnel transition structure integrated into a strip-shaped ribbed waveguide and a corresponding manufacturing process.

[0009] From Winterfeldt et al. (Winterfeldt, M.; et al.: “Assessing the influence of the vertical epitaxial layer design on the lateral beam quality of high-power broad area diode lasers”, in: Proc. SPIE 9733, 2016, p. 97330O) laser structures with a strong asymmetry in the waveguide thickness are known, which feature a very thin p-waveguide for minimal electrical resistance and suppression of bias-induced charge carrier loss. Disclosure of the invention

[0010] It is therefore an object of the present invention to provide a wide-strip diode laser in which, in order to improve the beam quality and reduce the thermal resistance, the thermal barrier occurring between a highly p-doped contact layer and the metal contact deposited above it is to be reduced or completely prevented.

[0011] These problems are solved according to the invention by the features of independent claim 1. Advantageous embodiments of the invention are contained in the dependent claims.

[0012] The present invention relates to a wide-strip diode laser comprising an active layer formed between an n-doped semiconductor material and a p-doped semiconductor material, wherein the active layer forms an active zone for generating electromagnetic radiation along a longitudinal axis; wherein at least one n-doped intermediate layer is arranged between an overlying p-sided metal contact and the p-doped semiconductor material, wherein in the at least one n-doped intermediate layer, in the region above the active zone, a pn tunnel junction is formed directly adjacent to the p-doped semiconductor material, wherein a residual layer thickness d res(i.e., the actual minimum distance) between the active layer and the pn tunnel junction is less than 0.5 µm, wherein an n-doped cladding layer is arranged on the pn tunnel junction, and wherein the pn tunnel junction is arranged on a p-doped cladding layer of the p-doped semiconductor material, and an n-doped contact layer rests on the n-doped cladding layer. The at least one n-doped intermediate layer comprises a p-side n-contact layer. The p-side metal contact is arranged on the p-side n-contact layer.

[0013] The n-doped semiconductor material typically comprises an n-doped substrate (referred to as the n-substrate), an n-sided n-cladding layer arranged on the n-substrate, and an n-waveguide layer arranged on the n-sided n-cladding layer. The p-doped semiconductor material typically comprises a p-waveguide layer and a p-cladding layer arranged on the p-waveguide layer. In the prior art, a p-contact layer is usually arranged on the p-cladding layer. The active layer, which is designed for light generation, is located between the two differently doped semiconductor materials. The active zone is the region of the active layer in which light generation actually takes place through charge carrier injection during operation of the laser diode. The longitudinal axis points in the longitudinal direction and preferably corresponds to the resonator axis of the laser.

[0014] The charge carriers are typically supplied on the n-side via the n-substrate and on the p-side via an overlying metal contact, whereby this p-side metal contact then forms a semiconductor-metal interface with an underlying p-contact layer. As described above, this interface represents a significant thermal barrier. Since such a thermal barrier could not be demonstrated for an n-side semiconductor-metal interface, according to the invention, at least one n-doped intermediate layer is arranged between the overlying p-side metal contact and the underlying p-doped semiconductor material. Furthermore, to further facilitate charge carrier injection in the at least one n-doped intermediate layer, a pn tunnel junction is formed directly adjacent to the p-doped semiconductor material in the region above the active zone.Thus, a preferred interface between an n-type semiconductor material and a metal can also be realized on the p-side, i.e., without the formation of a significant thermal barrier. The pn tunnel junction preferably has a total thickness of less than 100 nm.

[0015] The present invention is based on the finding that a semiconductor-metal interface with an n-doped semiconductor on both sides of the BAL is particularly advantageous. To achieve this, the p-side contact layer of the BAL can be designed to be more n-doped than p-doped. However, this results in a reverse-biased pn junction, which acts as a current barrier. To avoid this, a reverse-biased pn tunnel junction (or simply "tunnel junction," TJ) is formed at this pn interface. This tunnel junction consists, for example, of highly doped semiconductor layers and allows charge carriers to tunnel between a corresponding p-side n-contact layer and the other p-side semiconductor layers.In such a design, it is crucial that the tunnel junction has a very low turn-on voltage and a very low series resistance so that the conversion efficiency of the BAL is not impaired. The BALs according to the invention are also referred to as TJ-BALs.

[0016] Besides reducing or eliminating the thermal barrier that would otherwise form at the p-side semiconductor-metal interface, this approach offers further advantages. The high electrical conductivity of the highly doped n-contact and TJ layers can lead to a very low series resistance between the active zone and the epi-side contact, especially in vertical structures with thin p-side waveguide and cladding layers, as in the ETAS design (ETAS - Extreme Triple Asymmetric Structure). This low series resistance results in higher conversion efficiency, particularly at higher currents (Crump, P. et al., Efficient High-Power Laser Diodes, IEEE J. Sel. Top. Quantum Electron., vol. 19, no. 4 (2013)).Furthermore, the planar TJ layers are so highly doped that they tend towards an equipotential, which means that any voltage differences occurring between different areas of the laser chip cannot be maintained and immediately equalize. The low epi-side resistance and the presence of an equipotential have the advantage of reducing spatial hole burning and suppressing higher-order lateral modes, thereby further improving beam quality, output power, and conversion efficiency (Zeghuzi, A. et al., Traveling wave analysis of non-thermal far-field blooming in high-power broad-area lasers, IEEE J. Quantum Electron., vol. 55, no. 2 (2019) & Zeghuzi, A. et al., Influence of nonlinear effects on the characteristics of pulsed high-power broad-area distributed Bragg reflector lasers, Opt. Quant. Electron., vol. 50, no. 88 (2018)).

[0017] Another advantage of the very low resistivity of highly n-doped p-side semiconductor layers and the equipotential is that the thickness of the p-side n-contact layer grown over the pn tunnel junction can be significantly increased without substantially degrading the electrical resistance. This protects the active zone in structures with a thin p-side from process- and design-related mechanical stresses that can impair polarization purity, output power, and device lifetime, and can lead to unwanted waveguiding, which in turn reduces beam quality.

[0018] Preferably, the pn tunnel junction comprises a p arranged on the p-doped semiconductor material + -tunnel layer and a n arranged on it +-tunnel layer. Due to the high doping of the two tunnel layers of the pn tunnel junction, the charge carriers can tunnel through the reverse-biased pn junction formed at the interface between the at least one p-sided n-doped intermediate layer and the p-doped semiconductor material, so that the electrical resistance during charge carrier injection remains low. The doping concentration of the n- and p-doped layers of the pn tunnel junction is preferably N D,A ≥ 10 19 cm -3 (typical doping concentration in the environment up to about 10 18 cm -3 ).

[0019] Preferably, the pn tunnel junction is arranged on a p-doped sub-contact layer (p-sub-contact layer) of the p-doped semiconductor material. The p-sub-contact layer essentially corresponds to the p-contact layer in the prior art. However, according to the invention, no metal contact is arranged on the p-sub-contact layer; instead, it is separated from the p-sub-contact layer by at least one n-doped intermediate layer. The p-sub-contact layer can be distinguished from the underlying p-cladding layer either by the semiconductor material or its composition, or by a discontinuity in the refractive index / refractive index gradient at the layer boundary.

[0020] In an embodiment of the present invention not covered by the claims, the pn tunnel junction is arranged on a p-doped cladding layer of the p-doped semiconductor material. In this case, no p-sub-contact layer is arranged between the p-doped cladding layer and the pn tunnel junction. Preferably, an n-doped cladding layer is arranged on the pn tunnel junction. This means that the p-side cladding layer comprises a p-doped and an n-doped region, between which the pn tunnel junction is arranged. Since the optical modes guided in the waveguide layer also extend into the cladding layers, this means that the optical modes can extend on the p-side beyond the pn tunnel junction into the p-side n-doped cladding layer. Any subsequent contact layer, however, no longer participates significantly in wave guidance.

[0021] Preferably, the strip width of the diode laser is defined by a lateral width W of the pn tunnel junction. The injection region can be defined by the geometric definition of the pn tunnel junction, which is a blocking pn junction everywhere outside of it. Thus, the current path can be determined by the size and shape of the pn tunnel junction.

[0022] Alternatively, the pn tunnel junction can be formed as a layer, and the stripe width of the diode laser is determined by the lateral width W of an opening in an n-current aperture embedded in the p-doped semiconductor material. In this case, the pn tunnel junction largely cancels the effect of the blocking pn junction, and structuring of individual stripes must therefore be achieved by other means. The proposed n-current apertures for limiting current flow are well known in the prior art. The current path can thus be determined by the size and shape of the opening of the n-current aperture (aperture aperture) in a manner completely analogous to the embodiment described above. The n-current aperture preferably has a total thickness of less than 100 nm, with the doping concentration of the n-current aperture preferably being N D ≥ 10 18 cm -3 is.

[0023] If the pn tunnel junction is formed as a layer, the strip width of the diode laser can be determined not only by an n-current aperture but also by a lateral width W of a region between two adjacent deep implantation areas (e.g., by means of ion implantation). Deep implantation allows the resistance in the treated areas to be increased so significantly that current effectively flows only through the non-deep-implanted areas. Preferably, the deep implantation extends from the metal contact into the p-cladding layer. The series resistance of the deep implantation area is preferably at least twice that of the surrounding area.

[0024] Preferably, the semiconductor material is GaAs-based. For example, an n-substrate can comprise GaAs, an n-sided n-cladding layer AlGaAs, an n-waveguide layer AlGaAs, a p-waveguide layer AlGaAs, and a p-cladding layer AlGaAs. A p-sub-contact layer can comprise GaAs. A pn-tunnel junction can be a p+ tunnel layer p + -GaAs and as n + -tunnel layer n + -GaAs. An n-contact layer can comprise GaAs. A p-sided n-cladding layer can comprise AlGaAs.

[0025] The minimum distance between the active layer and the pn tunnel junction is less than 0.5 µm. The advantage of a minimal distance between the active layer and the pn tunnel junction is the reduction of series resistance and spatial hole burning, thereby improving laser properties (e.g., beam quality, power, efficiency).

[0026] In the TJ-BALs according to the invention, various lateral structuring techniques can be implemented to limit the current to the center of the device (i.e., below the laser strips or above the active zone). The resulting current limitation minimizes losses at the stripe edges and limits the adverse effects of lateral current propagation and lateral carrier accumulation (LCA) on beam quality. Current limitation is more important in these TJ-BALs than in standard BALs because current propagation in an n-contact layer is significantly stronger than in a p-contact layer due to the higher mobility of electrons compared to holes.

[0027] The remaining layer thickness d res The gap between the active zone and a current aperture is preferably less than 1 µm. This is achieved by minimizing the residual layer thickness d. resThis can reduce adverse current expansion. The total p-side thickness d tot The total thickness d, including the pn tunnel junction and the p-side n-contact layer, is preferably greater than 2 µm. WL The thickness of the waveguide layers is preferably greater than 1 µm. The thickness of the p-side waveguide layer d p-WL The wavelength is preferably less than 350 nm. The strip width W is preferably greater than or equal to 50 µm. The resonator length L is preferably greater than or equal to 3 mm.

[0028] Further preferred embodiments of the invention result from the features mentioned in the respective dependent claims.

[0029] Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another. Brief description of the drawings

[0030] The invention is explained below using exemplary embodiments with reference to the accompanying drawing. The drawing shows: Fig. 1 an exemplary schematic representation of a first embodiment of a laser diode according to the invention, Fig. 2 an exemplary schematic representation of a second embodiment of a laser diode according to the invention, Fig. 3 an exemplary schematic representation of a third embodiment of a laser diode according to the invention, Fig. 4 an exemplary schematic representation of a fourth embodiment of a laser diode according to the invention Fig. 5 an exemplary schematic representation of a fifth embodiment of a laser diode according to the invention, and Fig. 6 an exemplary schematic representation of a sixth embodiment of a laser diode according to the invention. Detailed description of the drawings

[0031] Fig. Figure 1 shows an exemplary schematic representation of a first embodiment of a laser diode according to the invention.The laser diode shown comprises an active layer 20 formed between an n-doped semiconductor material (n-substrate 10, n-sided n-cladding layer 12, n-waveguide layer 14) and a p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32, p-sub-contact layer 34), wherein the active layer 20 forms an active zone for generating electromagnetic radiation along a longitudinal axis; wherein an n-contact layer 50 is arranged between an overlying p-sided metal contact 52 and the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32, p-sub-contact layer 34), wherein in the n-contact layer 50 in the region above the active zone a pn-tunnel junction 40 is formed directly adjacent to the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32, p-sub-contact layer 34).The pn tunnel junction 40 shown comprises a p arranged on the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32, p-sub-contact layer 34). + -Tunnel layer 42 and a n arranged on it + -Tunnel layer 44. In this embodiment, the pn tunnel junction 40 is arranged on a p-doped sub-contact layer 34 of the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32, p-sub-contact layer 34). A strip width of the diode laser is defined by a lateral width W of the pn tunnel junction 40. The residual layer thickness d res is defined as the minimum distance between the active layer 20 and the pn tunnel junction 40.

[0032] This embodiment of the invention can be produced via a two-stage epitaxial growth process with an intermediate etching step. In a first growth step, the structure can be grown up to the pn tunnel junction 40. Subsequently, the tunnel junction layers (42, 44) can be selectively etched away outside the strip. After subsequent epitaxial growth of the n contact layer 50, a reverse-biased pn junction is formed in the outer regions of the structure, while the central pn tunnel junction 40 allows current flow. This is a known method for current and optical confinement in vertical-axis surface-emitting lasers (VCSELs).

[0033] Fig. Figure 2 shows an exemplary schematic representation of a second embodiment of a laser diode according to the invention. The basic layer structure corresponds to that shown in Figure 2. Fig. The individual reference numerals and their respective assignments apply accordingly to the arrangement shown in Figure 1. In contrast to the embodiment shown there, the pn tunnel junction 40 is formed as a layer, and the strip width of the diode laser is determined by a lateral width W of an opening in an n-current aperture 60 embedded in the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32, p-sub-contact layer 34). In particular, in the example shown, the n-current aperture 60 is arranged within the p-sub-contact layer 34. The residual layer thickness d res In this embodiment, is defined as the minimum distance between the active layer 20 and the current aperture 60.

[0034] In this embodiment of the invention, current confinement can also be achieved through a two-step epitaxy process with an intermediate etching step. The current blocking at the component edges is realized here by the so-called (enhanced) self-aligned lateral structure, independent of the tunnel junction. For this purpose, highly n-doped layers can be integrated near the underside of the p-side contact layer (i.e., the p-sub-contact layer 34), creating a blocking pn junction with reverse bias. The first growth step ends after these layers have been grown. Subsequently, these layers can be selectively etched away in the center to create a corresponding opening for current flow. The remainder of the p-sub-contact layer 34, as well as the pn tunnel junction 40 and the n-contact layer 50, can then be grown over the structured n-current aperture 60.

[0035] Fig. Figure 3 shows an exemplary schematic representation of a third embodiment of a laser diode according to the invention. The basic layer structure corresponds to that in Figure 3. Fig. The individual reference numerals and their respective assignments apply accordingly to the arrangement shown in Figure 2. The pn tunnel junction 40 is also designed as a layer. In contrast to the embodiment shown there, a strip width W of the diode laser is defined by a lateral width W of a region between two adjacent depth implantation areas 70. In particular, in the example shown, the two peripheral depth implantation areas 70 extend from the metal contact 52 into the p-cladding layer 32. Since an opening for current flow can also be created through the depth implantation areas 70, the additional integration of an n-current aperture 60 is not necessary. The residual layer thickness d resIn this embodiment, is defined as the minimum distance between the active layer 20 and the underside of the deep implantation areas 70.

[0036] In contrast to the previously described embodiments, this embodiment can be realized via a single-step epitaxial growth process, reducing the complexity of the manufacturing process and thus its costs. Current limiting is achieved, for example, by deep, high-energy ion implantation at the device edges. Furthermore, current flow can be prevented by increasing the series resistance and introducing point defects where charge carriers rapidly recombine. Deep implantation through the active zone effectively prevents current spreading and LCA, which could significantly improve beam quality, but would also severely compromise performance and efficiency. Therefore, an implantation profile tailored to terminate above the active zone (e.g., within the p-cladding layer) is preferred with regard to overall performance.

[0037] Fig. Figure 4 shows an exemplary schematic representation of a fourth embodiment of a laser diode according to the invention. The laser diode shown comprises an active layer 20 formed between an n-doped semiconductor material (n-substrate 10, n-sided n-cladding layer 12, n-waveguide layer 14) and a p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32), wherein the active layer 20 forms an active zone for generating electromagnetic radiation along a longitudinal axis; wherein an n-contact layer 50 and a p-side n-cladding layer 54 are arranged between a p-side metal contact 52 and the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32), wherein a pn-tunnel junction 40 is formed in the p-side n-cladding layer 54 in the area above the active zone, directly adjacent to the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32).The pn tunnel junction 40 shown comprises a p arranged on the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32). + -Tunnel layer 42 and a n arranged on it + -Tunnel layer 44. In this embodiment, the pn tunnel junction 40 is arranged on a p-doped cladding layer 32 of the p-doped semiconductor material (p-waveguide layer 30, p-cladding layer 32). Additionally, an n-doped cladding layer 54 is formed on the pn tunnel junction 40. A strip width of the diode laser is defined by a lateral width W of the pn tunnel junction 40. The residual layer thickness d res is defined as the minimum distance between the active layer 20 and the pn tunnel junction 40.

[0038] The main difference to in Fig. The embodiment shown in Figure 1 thus consists in the fact that the pn tunnel junction 40 is located on the p-doped shell layer 32 and therefore closer to the active zone. The integration of an additional p-sub-contact layer 34 can be omitted. While this proximity of the pn tunnel junction 40 to the active zone makes the fabrication technologically more complex (especially in the variants with two-step epitaxy growth), significant performance advantages can be achieved.

[0039] Fig. Figure 5 shows an exemplary schematic representation of a fifth embodiment of a laser diode according to the invention. The basic layer structure corresponds to that in Figure 5. Fig. The arrangement shown in Figure 4, the individual reference symbols and their respective assignments apply accordingly. The actual functional principle and a possible manufacturing process, however, can be found in Figure 4. Fig. 2 can be removed. This embodiment differs from the one in Fig. 2 the embodiment shown differs only by the position of the tunnel transition 40 and the absence of a p-sub contact layer 34.

[0040] Fig. Figure 6 shows an exemplary schematic representation of a sixth embodiment of a laser diode according to the invention. The basic layer structure corresponds to that shown in Fig. The arrangement shown in Figure 5, the individual reference symbols and their respective assignments apply accordingly. The actual functional principle and a possible manufacturing process, however, can be found in Figure 5. Fig. 3 can be removed. This embodiment differs from the one in Fig. 3 shown embodiment also differs only by the position of the tunnel transition 40 and the absence of a p-sub-contact layer 34. Reference symbol list 10 n substrate (e.g. GaAs) 12 n-cladding layer (n-sided, e.g. AlGaAs) 14 n-waveguide layer (e.g. AlGaAs) 20 active layer (includes active zone) 30 p-waveguide layer (e.g. AlGaAs) 32p cladding layer (e.g. AlGaAs) 34 p-sub-contact layer (e.g. GaAs) 40 pn tunnel transition 42 p + -tunnel layer (e.g. p + -GaAs) 44 n + -tunnel layer (e.g. n + -GaAs) 50 n-(sub-)contact layer (p-side, e.g. GaAs) 52 Metal contact (p-side) 54 n-cladding layer (p-side, e.g. AlGaAs) 60 n-flow aperture 70 Deep implantation area W strip width d res Remaining layer thickness

Claims

[1] Broad-strip diode laser, comprising: an active layer (20) formed between an n-doped semiconductor material (10, 12, 14) and a p-doped semiconductor material (30, 32, 34), wherein the active layer (20) forms an active zone along a longitudinal axis for generating electromagnetic radiation; wherein at least one n-doped intermediate layer (50, 54) is arranged between a p-sided metal contact (52) and the p-doped semiconductor material (30, 32, 34), wherein in the at least one n-doped intermediate layer (50, 54) a pn tunnel junction (40) is formed in the area above the active zone adjacent to the p-doped semiconductor material (30, 32, 34); characterized by , that a residual layer thickness d res between the active layer (20) and the pn tunnel junction (40) is less than 0.5 µm; an n-doped shell layer (54) is arranged on the pn tunnel junction (40), and the pn tunnel junction (40) is arranged on a p-doped cladding layer (32) of the p-doped semiconductor material (30, 32, 34) and an n-doped contact layer (50) rests on the n-doped cladding layer (54). [2] Broad-strip diode laser according to claim 1, wherein the pn tunnel junction (40) is a p arranged on the p-doped semiconductor material (30, 32, 34). + -tunnel layer (42) and a n arranged thereon + -Tunnel layer (44) includes. [3] Wide-strip diode laser according to claim 1 or 2, wherein a strip width of the diode laser is defined via a lateral width W of the pn tunnel junction (40). [4] Wide-strip diode laser according to claim 1 or 2, wherein the pn tunnel junction (40) is formed as a layer and a strip width of the diode laser is determined via a lateral width W of an opening of an n current aperture (60) introduced into the p-doped semiconductor material (30, 32, 34). [5] Broadband diode laser according to claim 1 or 2, wherein the pn tunnel transition (40) is formed as a layer and a strip width of the diode laser is defined over a lateral width W of a region between two adjacent deep implantation areas (70). [6] Broad-strip diode laser according to any of the preceding claims, wherein the semiconductor material is based on GaAs.

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