DE102008014092A1 - Edge-emitting semiconductor laser chip with a structured contact strip - Google Patents

Abstract

An edge-emitting semiconductor laser chip is specified, with an active zone (14) in which electromagnetic radiation is generated during operation of the semiconductor laser chip (1) and - at least one structured contact strip (2) which is structured in such a way that a charge carrier injection into ide active Zone (14) decreases towards one side of the semiconductor laser chip (1), at which a Auskoppelfacette (3) of the semiconductor laser chip (1) is located.

Description

It an edge-emitting semiconductor laser chip is specified.

The publication US 6,947,464 B2 describes an edge-emitting semiconductor laser chip and a method for its production.

A to be solved task is an edge-emitting Specify semiconductor laser chip, wherein the emitted laser radiation a reduced beam divergence, especially in the slow-axis Direction.

At least an embodiment of the edge emitting semiconductor laser chip The edge-emitting semiconductor laser chip comprises an active zone. The active zone of the semiconductor laser chip is for generating electromagnetic Radiation suitable. That is, in the operation of the edge-emitting Semiconductor laser chips become electromagnetic in the active zone Radiation generated and amplified, which the semiconductor laser chip at least partially by a Auskoppelfacette leaves. The active zone comprises for this purpose one or more quantum well structures, which upon injection of electrical current by stimulated recombination provide optical amplification.

The Designation Quantum well structure includes in particular any structure in the case of charge carriers by confinement can experience a quantization of their energy states. In particular, the term quantum well structure does not include any Statement about the dimensionality of the quantization. It thus includes, among other things, quantum wells, quantum wires and quantum dots and any combination of these structures.

At least an embodiment of the edge emitting semiconductor laser chip The edge-emitting semiconductor laser chip further comprises a Contact strips. About the contact strip is electrical Electricity in the form of charge carriers, which subsequently for generating electromagnetic radiation in the active zone is injected into the active zone. This means, the semiconductor laser chip is electrically conductive by means of the contact strip contacted. The contact strip can be on the top and / or the bottom of the edge emitting semiconductor laser chip are located. Preferably, the contact strip is structured. This means, the contact strip is not homogeneous, for example as a metal layer uniform width and / or thickness, but the contact strip has structures. Alternatively or in addition to a structured contact strip also other means for structured charge carrier injection such as quantum well intermixing or structured implantation or alloying of foreign atoms possible.

The Means for structured charge carrier injection, for example the contact strip is structured such that a charge carrier injection decreases in the active zone to one side of the semiconductor laser chip, where the Auskoppelfacette of the semiconductor laser chip is located.

With In other words, for example, the contact strip extends for example on the top of the semiconductor laser chip in the emission direction generated by the edge emitting semiconductor laser chip in operation Laser radiation. That is, the main extension direction of the contact strip is, for example, parallel to the emission direction. The contact strip extends approximately from the Auskoppelfacette opposite side of the edge emitting semiconductor laser chip to the side of the semiconductor laser chip, at which the Auskoppelfacette of the Semiconductor laser chips is located. The contact strip is such structured that in areas of the contact strip in the vicinity the decoupling facet injected less current into the active zone is considered to be in areas of the contact strip, which is far from the Auskoppelfacette are removed. The structured charge carrier injection in the active zone therefore increases to the side of the semiconductor laser chip from where the output coupling of the semiconductor laser chip located.

At least an embodiment of the edge emitting semiconductor laser chip The semiconductor laser chip includes an active zone in operation the semiconductor laser chip electromagnetic radiation is generated. Furthermore, the edge-emitting semiconductor laser chip comprises at least a means for structured carrier injection in the active zone, in particular at least one structured contact strip, wherein the means is structured such that a charge carrier injection decreases in the active zone to one side of the semiconductor laser chip, at which a Auskoppelfacette of the semiconductor laser chip is located.

In accordance with at least one embodiment of the edge emitting semiconductor laser chip, the contact strip is structured into regions of high and regions of low charge carrier injection. That is, the contact strip has areas from which little current is injected into the active zone. It is possible that no current is injected into the active zone from these areas. These areas of the contact strip are the areas of low charge carrier injection and thus low current density. In addition, the contact strip has areas from which a higher current is injected into the active zone. From these areas, the ak tive zone, for example, energized as if the contact strip was not structured. These areas are the areas of high charge carrier injection and thus high current density.

At least an embodiment of the edge emitting semiconductor laser chip is the contact strip in a direction along the longitudinal central axis of the contact stripe into areas of high and areas of low charge carrier injection structured. For example, the contact strip runs from the side of the semiconductor laser chip, which the Auskoppelfacette is turned away, to the side of the semiconductor laser chip, at the itself the decoupling facet is located. The longitudinal center axis is an imaginary line which runs in the contact strip in the middle and also from the side of the semiconductor laser chip, which is the Auskoppelfacette facing away, to the side of the semiconductor laser chip extends, at which the Auskoppelfacette of the semiconductor laser chip located. For example, the longitudinal central axis is parallel to the emission direction of the laser radiation generated by the semiconductor laser chip. The longitudinal central axis may have an axis of symmetry of the contact strip form. Now you drive over the contact strip along the longitudinal central axis, so is the contact strip in areas of high and low charge carrier injection areas structured. The areas can be, for example each a rectangular or differently shaped base exhibit. The areas can be this way for example be formed by strips which have the same width as the Have contact strip.

At least an embodiment of the edge emitting semiconductor laser chip takes the area fraction of the areas of high charge carrier injection with decreasing distance to the side of the semiconductor laser chip down from where a Auskoppelfacette the semiconductor laser chip located. In this way, the charge carrier injection decreases into the active zone towards the side of the semiconductor laser chip, where the Auskoppelfacette of the semiconductor laser chip is located.

Of the Area fraction of the areas of high current injection relates For example, the total area of the contact strip.

At least an embodiment of the edge emitting semiconductor laser chip is the contact strip in a direction transverse to the longitudinal central axis of the contact stripe into areas of high and areas of low charge carrier injection structured. That is, you drive over the contact strip in a direction transverse to the direction of the longitudinal central axis, that is, for example, perpendicular to the longitudinal central axis, So you drive over areas higher and lower Charge carrier injection.

At least an embodiment of the edge emitting semiconductor laser chip takes the area fraction of the areas of high charge carrier injection with increasing distance to the longitudinal central axis towards. That means in the middle of the contact strip will open this way, little or no electrical current in the active Zone injected. In the outer areas of the contact strip In contrast, more current than in the middle of the contact strip in injected the active zone. Preferably, such is located in Direction transverse to the longitudinal central axis structured section the contact strip near the side of the semiconductor laser chip, where the Auskoppelfacette of the semiconductor laser chip is located. In other sections of the contact strip, which further from the Auskoppelfacette lie away, the contact strip can then For example, be unstructured, so there is a high current injected into the active zone. That is, the current density in the active zone is high there.

At least an embodiment of the edge emitting semiconductor laser chip takes the area fraction of the areas of high charge carrier injection with decreasing distance to the longitudinal center axis and with decreasing distance to the side of the semiconductor laser chip down from where a Auskoppelfacette the semiconductor laser chip located. This can be achieved, for example, by the fact that the Areas of high carrier injection are formed by stripes are, which along the longitudinal central axis of Contact strip extend and towards the Auskoppelfacette out rejuvenate.

At least an embodiment of the edge emitting semiconductor laser chip is the contact strip in a direction transverse to the longitudinal central axis the contact strip and in a direction parallel to the longitudinal central axis of the contact stripe into areas of high and areas of low charge carrier injection structured. This can be achieved, for example, by the fact that the contact strip in areas of high and low carrier injection is structured, which are longitudinal and transverse to the longitudinal central axis extend the contact strip.

In accordance with at least one embodiment of the edge-emitting semiconductor laser chip, the contact strip in the regions of high charge carrier injection consists of a first material and in regions of low charge carrier injection of a second material. In this case, the first material is selected such that its electrical contact resistance to the semiconductor material of the edge-emitting semiconductor laser chip, to which the contact strip is applied, is selected smaller than the contact resistance of the second material. In this way, a structuring of the contact strip into areas of high and low charge carrier injection realized. For example, the first and second materials contain or consist of first and second metals. As a result, both the high and the low charge carrier regions have approximately the same thermal conductivity, since they each consist of or contain metals. Consequently, the thermal conductivity does not vary spatially and thus the heat removal from the semiconductor laser chip via the contact strip hardly or not at all.

Further it is possible that the contact strip third, fourth, and so on has further areas, which consist of third, fourth, and so forth further materials are formed. The height the charge carrier injection from these areas can then between the height of the charge carrier injection the areas with the first metal and the height of the charge carrier injection lie with the areas of the second metal. That means the Contact strip then has areas high, areas lower and Areas where the charge carrier injection between these two extremes lies. In this way, another, more precise and finer structuring and thus an even more accurate Adjustment of carrier injection into the active zone allows.

At least an embodiment are located both on the upper and the bottom of the edge emitting semiconductor laser chip Contact strip structured in the manner described here are.

in the The following is the edge-emitting semiconductor laser chip described here based on embodiments and the associated Figures explained in more detail.

1 shows plotted measured values of the beam divergence in angular degrees versus the output power W of an edge-emitting semiconductor laser chip.

2 shows a schematic plan view of the coupling of laser radiation in a fiber optic.

3A shows a schematic perspective view of a simulated temperature distribution in an edge-emitting semiconductor laser chip.

3B shows an edge-emitting semiconductor laser chip described here in a schematic sectional view.

4 to 8th show schematic plan views of embodiments of edge-emitting semiconductor laser chips described herein with different configurations of the contact strip.

9A and 9B show a further possibility for structuring the charge carrier injection on the basis of a schematic sectional representation.

In The embodiments and figures are the same or like-acting components each with the same reference numerals Mistake. The illustrated elements are not to scale On the contrary, individual elements can be better Understanding shown exaggeratedly large be.

The technical progress in the realization of fiber lasers and fiber-coupled lasers, which allow excellent beam quality and high achievable output powers, allow their use, for example, in new industrial applications such as "remote" welding. As the pumping light source, edge-emitting semiconductor laser diodes will usually be used. They offer a very high efficiency in the conversion of electrical power used in usable radiation power with high optical output power. On the other hand, they show a strong ellipticity of the far field. An efficient coupling of the laser radiation into the round fiber cross-section of a fiber optic 103 is only possible with the help of expensive and complex micro-optics 101 to reach (see also the 2 ). Simplifying and improving fiber coupling of the laser diodes would result in lower cost and more reliable laser systems. The adjustment effort of the micro-optics is reduced drastically if the beam divergence, at least in the already narrower horizontal direction - the so-called slow axis direction - would be smaller and the beam for efficient fiber coupling only in the vertical direction - that is in the direction perpendicular to the plane for example, the top 1a of the semiconductor laser chip is - must be heavily transformed.

The 1 shows plotted measured values of the beam divergence in angular degrees versus the output power W of an edge-emitting semiconductor laser chip. The beam divergence was determined at 95% power inclusion. The beam divergence was in the horizontal direction, that is, in a plane parallel to the top 1a (compare to that too 2 ), determined. "95% power confinement" means that only the area of the laser beam that includes 95% of the output power was considered for determining the beam divergence.

As can be seen in figure, the horizon grows tale beam divergence with increasing output power W of the laser strong. This complicates the above-described use of the edge emitting semiconductor laser chip for high light outputs, since the preferably used small micro-optics 101 can then be outshined laterally and light is lost.

The 2 shows a schematic plan view of the coupling of laser radiation 10 , which by an edge-emitting semiconductor laser chip 1 is produced in a fiber optic 103 , The 2 shows an edge-emitting semiconductor laser chip 1 , which is designed as a laser bar with five individual emitters. The edge-emitting semiconductor laser chip has for this purpose at its top 1a five contact strips 2 on. At the Auskoppelfacette 3 become five laser beams 10 decoupled, which first by a micro-optics 101 to step. By another optical element 102 , which is for example a converging lens, the laser radiation is brought together and into the fiber optic 103 coupled.

The 3A shows a schematic perspective view of a simulated temperature distribution in an edge-emitting semiconductor laser chip 1 which is used as a laser bar 24 Single emitters is executed. For reasons of symmetry, only half the bar with twelve emitters is shown in the illustration. The left edge in the 3A corresponds to the middle of the laser bar. The dark spots in the 3A symbolize areas 30 high temperature T9. The reference symbols T1 to T9 mark temperature ranges, T1 denoting the region of lowest temperature and T9 the region of highest temperature.

The high power dissipation density in high-performance edge-emitting semiconductor laser chips generates a temperature gradient in the semiconductor laser chip. How out 3A can be seen forms at high output power of several watts and narrow strip widths of the individual emitter of the edge-emitting semiconductor laser chip 1 an inhomogeneous temperature distribution in the resonator of the edge-emitting semiconductor laser chip 1 out. Here are local maxima of the temperature T9 - the areas of high temperature 30 - in the middle of the Auskoppelfacette 3 every single emitter detected. This is also true for edge-emitting semiconductor laser chips with more or fewer emitters than the laser in the 3A or even lasers with a single emitter. As the refractive index of the semiconductor material from which the semiconductor laser chip 1 is formed, is temperature-dependent, arises in each emitter, a thermal converging lens which distorts the phase front of the laser light propagating in the resonator. As a result, the far field of the laser expands in a horizontal (slow axis) direction compared to the undistorted case. As the output power increases or the pumping current increases, the beam divergence increases due to the phase front distortion becoming more intense with the power loss (cf. 1 ).

The maximum temperature reached and thus the strength of the thermal lens increases with that in the semiconductor laser chip 1 generated electrical power loss. Higher efficiency lasers produce less power dissipation in the semiconductor laser chip with the same optical output power, and generally exhibit lower horizontal beam divergences.

The 3B shows an edge-emitting semiconductor laser chip described here 1 in a schematic sectional view. The edge-emitting semiconductor laser chip can be manufactured in different material systems. For example, it is a semiconductor laser chip based on one of the following semiconductor materials: GaP, GaAsP, GaAs, GaAlAs, AlGaInAs, InGaAsP, GaN, InGaN, AlGaInAsSb. In addition, other semiconductor materials from the III-V or II-VI semiconductor systems are conceivable. The semiconductor chip is preferably based, for example, on the AlGaInAs material system. In the edge emitting semiconductor laser chip 1 it is, for example, a diode laser bar with a plurality of emitters, for example with four to six emitters, which has a resonator length greater than or equal to 100 microns, for example between 3 and 6 mm. The width of the laser radiation emitted by the individual emitters is preferably between 50 μm and 150 μm. The edge-emitting semiconductor laser chip 1 For example, it can produce laser radiation with a central wavelength of 915 nm or 976 nm. However, depending on the semiconductor material used, the generation of short-wave or longer-wave laser light is also possible. Between the contact strips 2 can become electricity barriers 4 which the current injection into the active zone 14 in directions parallel to the emission direction of the semiconductor laser chip 1 restrict. It is also possible that between two contact strips two or more current barriers 4 are located.

The semiconductor laser chip 1 includes a substrate 11 which may, for example, be a growth substrate and which may form a p-contact layer. Furthermore, the edge-emitting semiconductor laser chip comprises 1 an active zone 14 , which is intended to generate electromagnetic radiation. The active zone 14 is in waveguide layers 13 embedded, which has a higher band gap and a lower refractive index than the active zone 14 exhibit. Each of the waveguiding layers is adjoined by a coating layer 12 which have a higher bandgap and a lower refractive index than the waveguide layers 13 having. On the substrate 11 remote side of the semiconductor laser chip 1 is on the overcoat layer 12 a final contact layer 15 , On the contact layer 15 there are contact strips 3 , about which electrical current in the active zone 14 can be injected. The width of the contact strips 3 is preferably between 10 microns and several 100 microns.

The 4 shows a contact strip 2 an edge-emitting semiconductor laser chip described here 1 in a schematic plan view. The contact strip 2 can be on the top 1a and / or at the bottom 1b of the semiconductor laser chip 1 are located. The contact strip 2 is structured such that a charge carrier injection into the active zone 14 to one side of the semiconductor laser chip 1 decreases, where the Auskoppelfacette 3 of the semiconductor laser chip 1 located.

A structured charge carrier injection on the top and / or bottom of the semiconductor laser chip 1 leads via the likewise structured distribution of the ohmic power dissipation density in the semiconductor laser chip 1 for a targeted influencing of the thermal lens in the resonator of the semiconductor laser chip 1 , The resonator is through the coupling-out facet 3 and that of the Auskoppelfacette 3 opposite side of the semiconductor laser chip 1 educated. Particularly advantageous is a structuring of the contact strip 2 in the longitudinal direction, ie in the direction along the longitudinal center axis 23 of the contact strip 2 , and / or in the lateral direction, ie in the direction transverse or perpendicular to the longitudinal central axis 23 of the contact strip 2 , Surprisingly, it has been found that in these cases the temperature distribution is homogenized and this counteracts the distortion of the phase fronts due to the thermal lens. This reduces the divergence of the laser beam generated in the emitter in the horizontal direction. The contact strip 2 is in low carrier injection regions 22 as well as high charge carrier injection 21 divided up. Through the areas of low charge carrier injection 22 little or no electricity gets into the active zone 14 imprinted. On the other hand, in the areas of high charge carrier injection 21 Current similar to the active zone 14 imprinted as in the unstructured case.

The structuring of the charge carrier injection can be done as follows:
One possibility of structuring the charge carrier injection is that a correspondingly structured passivation layer on the semiconductor laser chip 1 is applied, such that the passivation layer only in the areas of high carrier injection 21 is removed, so there is a contact between the material of the contact strip 2 - Usually a metal - and the semiconductor material of the semiconductor laser chip 1 consists.

Furthermore, it is possible that the structuring by means of structured removal of the uppermost semiconductor layer of the semiconductor laser chip 1 before applying the contact layer 2 and thereby structuring the contact resistance between the semiconductor material and the metal of the contact strip 2 is generated.

Furthermore, a structured implantation or alloying of foreign atoms to change the contact resistance between the contact layer 2 and the semiconductor material of the semiconductor laser chip 1 respectively. As an alternative to changing the contact resistance or in addition to changing the contact resistance, the conductivity of the semiconductor material below the contact strip can also be achieved by implantation or alloying 2 to be changed.

Another possibility for structuring the charge carrier injection is before the deposition of the contact strip 2 via the example p-doped contact layer 15 to apply an n-doped semiconductor layer, which is then removed in a structured manner. In this way, at the locations where the n-doped layer is still present, pn diodes which are blocked during operation and effectively hinder the flow of current are formed. Only where the n-doped layer is removed can current be injected. These areas form the areas of high charge carrier injection 21 ,

Similarly, a p-type semiconductor layer over an n-doped contact layer 15 are applied, whereby after structured removal of the p-doped layer, the same effect occurs.

Another possibility for structuring the charge carrier injection is that the charge carrier recombination in the active zone by quantum well intermixing 14 and thus the generation of heat loss in the active zone 14 is prevented in these places. Structured performance of quantum well intermixing allows high and low carrier injection into the active zone 14 be generated.

Another possibility for structuring the charge carrier injection is to locally the contact layer 2 of different metals or other materials, which have different electrical contact resistances at the interface between these materials and the contact layer 15 of the semiconductor laser chip. This also leads to a structured charge carrier injection and a distribution of contact layer 2 in areas of high charge carrier injection 21 and low carrier injection areas 22 , This method simultaneously avoids a variation of the thermal conductivity of the contact strip 2 and hence a variation of the heat dissipation from the semiconductor laser chip 1 , A spatial modulation of the thermal lenses, which could affect the homogeneity of the laser light generated, is thereby avoided. For example, the contact layer 15 thereby formed from p-doped GaAs. In areas of high current injection, the contact strip is then formed of Cr / Pt / Au, where Cr is the metal critical to low contact resistance. In areas of low impact injection, for example, aluminum is used.

In the embodiment of 4 the charge carrier injection varies near the output coupling facet 3 in the longitudinal direction, parallel to the longitudinal axis 23 of the contact strip 2 , In this way, the temperature rise at the Auskoppelfacette 3 decreases and the temperature distribution in the semiconductor laser chip 1 balanced.

The 5 shows the contact strip 2 an edge-emitting semiconductor laser described here. In this embodiment, the charge carrier injection varies in the lateral direction, that is to say in the direction transverse to the longitudinal axis 23 , The structuring is preferably carried out only in the vicinity of the Auskoppelfacette 3 , Over the remaining length of the contact strip 2 there is no structuring. Due to the structuring, the current density of the current impressed into the active zone in the middle of the resonator of the semiconductor laser chip at the output coupling facet becomes 3 minimized locally. The structuring consists of areas of high charge carrier injection 21 and stripe-like regions of low carrier injection 22 , being in the middle of the contact strip 2 particularly little current is injected and the area fraction of the areas of high charge carrier injection 21 There is especially small.

The 6 shows the contact strip 2 an edge-emitting semiconductor laser chip described here 1 , In this embodiment, the current density is in the active zone 14 by structuring the contact strip 2 in the longitudinal and lateral directions near the decoupling facet 3 given a softer transition from the unstructured to the structured area. In this case, the areas of high charge carrier injection are tapered 21 in the direction of the decoupling facet 3 while the areas of high carrier injection 22 widen in this direction.

The 7 shows the contact strip 2 an edge-emitting semiconductor laser chip described here 1 , In this embodiment, the structuring measures of the contact strip 2 from the embodiments of the 4 and to 6 combined. This will make an even stronger change in the active zone 14 reached injected current density.

In conjunction with the 8th is a halftone structuring of the contact strip 2 described. The rectangles in the 9 close areas of low carrier injection 22 on average, therefore, the injected current density decreases to the output coupling facet 3 towards and to the central axis 23 down. The structuring is given by one of the structuring measures described above. That is, for example, in the areas of low injection 22 a passivation layer may be present.

The 9A and 9B show a further possibility for structuring the charge carrier injection on the basis of a schematic sectional representation through a part of the semiconductor laser chip 1 ,

The structuring of the contact strip 2 takes place via a tunnel contact. A very highly doped pn junction, in particular in the reverse direction, forms a tunnel junction. This tunnel contact can be ohmic with appropriate design, that is, he then has a linear current-voltage characteristic.

In 9A It is shown that a highly p-doped tunnel layer 11a on the p-contact layer 11 of the semiconductor laser chip 1 is applied. The highly p-doped tunnel contact layer 11a follows a highly n-doped tunnel contact layer 11b to. The tunnel contact layers are preferably at least where later a contact strip 2 should be located over the entire surface of the p-contact layer 11 applied and removed in places after their epitaxy.

Due to the different electrical contact resistance between the metal of the contact strip 2 and n- or p-doped semiconductors results in the areas with tunnel layers and the areas without tunnel layers in each case a different charge carrier injection. In this way, therefore, areas of low charge carrier injection 22 as well as high charge carrier injection 21 generated.

With poor contact between metal and p-doped semiconductor and good contact between metal and n-doped semiconductor results in the region of the tunnel layers, a high current density in the active zone and in the area without tunnel layers, a low current density. On the other hand, poor contact between metal and n-doped region and good contact between metal and p-doped region results in low current density, that is, a region of low charge carrier injection 22 , in the area of the tunnel layers and a high current density, where the tunnel layers have been removed.

The same structuring option also exists on the n-side of the semiconductor laser chip 1 , This is in conjunction with the 9B described. Here's on the n-contact layer 15 a highly n-doped tunnel layer 15a and on this a highly p-doped tunnel layer 15b applied. With poor metal-to-p-doped area contact and metal-to-n-doped metal contact, where the tunneling layers were left, a low current density results in the active zone, whereas where the tunneling layers were removed and contact between the metal and the n-doped contact layer 15 exists, a high current density. Furthermore, with poor contact of metal to the n-doped region and good contact of metal to the p-doped region, high current density in the region of the tunnel layers and low current density where a metal was made to n-contact.

The The invention is not by the description based on the embodiments limited. Rather, the invention includes every new feature as well any combination of features, especially any combination includes features in the claims, also if this feature or combination itself is not explicit specified in the patent claims or exemplary embodiments is.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6947464 B2 [0002]

Claims (10)

Edge-emitting semiconductor laser chip with - an active zone ( 14 ), in which during operation of the semiconductor laser chip ( 1 ) electromagnetic radiation is generated and - at least one means for structured charge carrier injection, in particular a structured contact strip ( 2 ), which is structured such that the charge carrier injection into the active zone ( 14 ) to a side of the semiconductor laser chip ( 1 ) decreases, at which a Auskoppelfacette ( 3 ) of the semiconductor laser chip ( 1 ) is located. Edge-emitting semiconductor laser chip according to the preceding claim, in which the contact strip ( 2 ) into areas of high ( 21 ) and areas ( 22 ) low charge carrier injection is structured. Edge-emitting semiconductor laser chip according to at least one of the preceding claims, in which the contact strip ( 2 ) in a direction along the longitudinal central axis ( 23 ) of the contact strip ( 2 ) into areas of high ( 21 ) and areas ( 22 ) low charge carrier injection is structured. Edge-emitting semiconductor laser chip according to the preceding claim, in which the area fraction of the regions of high ( 21 ) Carrier injection with decreasing distance to the side of the semiconductor laser chip ( 1 ) decreases, at which a Auskoppelfacette ( 3 ) of the semiconductor laser chip ( 1 ) is located. Edge-emitting semiconductor laser chip according to at least one of the preceding claims, in which the contact strip ( 2 ) in a direction transverse to the longitudinal central axis ( 23 ) of the contact strip ( 2 ) into areas of high ( 21 ) and areas lower ( 22 ) Carrier injection is structured. Edge-emitting semiconductor laser chip according to the preceding claim, in which the area fraction of the regions of high ( 21 ) Carrier injection with increasing distance to the longitudinal central axis ( 23 ) increases. An edge-emitting semiconductor laser chip according to claim 5, wherein the area ratio of the regions of high ( 21 ) Carrier injection with decreasing distance to the longitudinal central axis ( 23 ) and with decreasing distance to the side of the semiconductor laser chip ( 1 ) decreases, at which a Auskoppelfacette ( 3 ) of the semiconductor laser chip ( 1 ) is located. Edge-emitting semiconductor laser chip according to at least one of the preceding claims, in which the contact strip ( 2 ) in a direction transverse to the longitudinal central axis ( 23 ) of the contact strip ( 2 ) and in a direction parallel to the longitudinal central axis ( 23 ) of the contact strip ( 2 ) into areas of high ( 21 ) and areas lower ( 22 ) Carrier injection is structured. Edge-emitting semiconductor laser chip according to at least one of the preceding claims, in which the contact strip ( 2 ) in areas of high ( 21 ) Carrier injection consists of a first metal and in areas lower ( 22 ) Carrier injection consists of a second metal, wherein the contact resistance to the semiconductor material, to which the contact strip ( 2 ), the first metal is smaller than the second metal. Edge-emitting semiconductor laser chip according to at least one of the preceding claims, in which the structured contact strip ( 2 ) on the upper ( 1a ) and the underside ( 1b ) of the semiconductor laser chip ( 1 ) is applied.