DE102004032696A1 - Surface-emitting semiconductor laser with lateral heat dissipation - Google Patents

Abstract

The invention relates to a surface-emitting semiconductor laser with vertical resonator and with lateral heat dissipation. A laser according to the invention has on a substrate 10 a first Bragg mirror stack 11, an active laser emitting layer 13 and a second Bragg mirror stack 16 and is characterized in that the second Bragg mirror stack, the active layer and the first Bragg mirror stack a mesa is etched, which at the level of the first Brag mirror stack, the active layer and the second Bragg mirror stack forms a side surface 2, on which an electrical insulation layer 30 of a non-conductive and non-semiconducting material is arranged.

Description

The The present invention relates to a surface emitting Semiconductor laser and a method for producing such Semiconductor laser, in particular on the heat dissipation of such surface emitting Semiconductor lasers.

A surface Semiconductor lasers are already known from the prior art. The maximum output power of such surface emitting semiconductor lasers is due to the heat development limited during operation of the laser.

In a first group of semiconductor lasers according to the prior art the heat dissipation takes place via heat sinks on the substrate or surface, the heat sinks are here on the surface of the laser or arranged on the substrate base. In this group of prior art lasers, there is also the idea that Isolation of individual lasers on a wafer with each other wet oxidation through holes in the surface of the To ensure wafers. In this case results in a relatively good heat dissipation through the semiconductor material. However, in this case all individual lasers are electric connected in parallel and a single operation of each laser is not possible. Generally leaves through heat sinks on the surface just a big one Part of that heat dissipate, which also arrives at the surface. However, this is for a not inconsiderable part of the in the active zone of a laser generated heat does not apply, the temperature of the active zone is in such surface-emitting semiconductor lasers or laser matrices up to 80 ° above the Temperature of the heat sink. This is for optimal operation of the laser is not sufficient.

In the patent EP 0 653 823 B1 the heat dissipation takes place by means of a diamond-like layer. However, the heat is also removed only above the active zone of the laser. The arrangement described in the patent already significantly improves the heat dissipation compared to the first group of semiconductor lasers according to the prior art. However, there is still no heat removal directly from the active zone and the areas below possible.

Out the prior art, it is already known, several p-n junctions with active zones to increase to integrate the output power. In a first group of thus integrated laser structures, this is done by in-series circuit the individual p-n junctions. The electrical connection takes place via a tunnel junction or over Tunnel diodes. Such tunnel diodes for the series connection of several p-n transitions condition However, a high doping and an increase in the operating voltage or an increase in the Voltage drop, resulting in increased heat generation near the active zone and the absorption of light in the resonator (high internal absorption), so that the optical output power is not increased significantly can.

Out The prior art also includes a surface emitting semiconductor laser with two antiserial p-n junctions in Parallel connection known. Because of the heat dissipation through the surface results but here, too, no significant increase in output power. In addition, the contacting takes place via a multi-level mesa. A surface Semiconductor laser with antiserial p-n junctions in parallel, the above Although a multi-level mesa can be contacted, in principle, the available output power increase, However, the problem here is the Stromeinschnürung: becomes the Stromeinschnürung generated by implantation, the current can only ever be active Zone be effectively concentrated. For wet-chemical oxidation is first a very large diameter auxiliary mesa required to evenly achieve the current constriction for all active areas. The oxidation over size However, depths are not sufficiently accurate today. Then then have to All mesa steps are etched out one at a time, causing problems in lithography leads, since the individual steps are at different depths. Will the Stepped mesa instead made in advance, can not be uniform stream constriction over the Achieve depth as the oxidation always starts from the edge of the mesa and always invades equally. The concept of multilevel mesa makes a significant increase the number of active zones with good current constriction at the same time the current state of the art thus impossible.

Also in the two cases described the Integration of several active zones or several individual surface emitting Semiconductor laser, the heat dissipation in the prior art through the substrate and the laser surface.

The object of the present invention is to enable an increase in the optical output power of surface-emitting semiconductor lasers with simultaneously good beam quality by optimizing the heat dissipation. The object of the present invention is furthermore to provide a surface-emitting semiconductor laser in an arrangement with a plurality of active zones, which has a high optical output power with simultaneously good beam quality and sufficient Heat dissipation allows.

This object is achieved by a surface emitting semiconductor laser according to claim 1, an arrangement according to claim 22 and by a corresponding manufacturing method according to claim 41 solved. Advantageous developments of the laser according to the invention and of the corresponding production method are described in the respective dependent claims.

The The object described above is achieved by a lateral heat dissipation from the active zone (s) of the surface emitting semiconductor laser solved, which makes it possible that a reinforcing Zone or a profit zone of several p-n junctions with active zones are created may be antiserial at which the individual p-n junctions are switched and operated in parallel.

essential Point of the present invention is the etching of a mesa from the upper Bragg mirror stack, from the active zone and from the bottom Bragg mirror stack of a surface emitting Semiconductor laser and then making an electrical insulating layer over the exposed p-n junction, whereby the heat dissipation from the sides of the active zone. The heat dissipation thus takes place not only above the active zone, but also laterally of it and below. Due to the lateral heat dissipation surface-emitting Semiconductor laser with vertical resonators possible, their profit zones off several antiseries switched p-n junctions with active zones or consist of stacks of active zones. Alternative to the concept of Bragg mirror stack is also simplified in the following the term the Bragg mirror or simply the mirror used.

By etching a such deep mesa, which extends the active zone into the underlying Bragg mirror stack cuts through, thus a side surface is generated, which for heat dissipation is being used. It is necessary for this that there is a zone for Stromeinschnürung is, with the help of which the current largely kept away from the surface of the mesa becomes. To electrically isolate the exposed p-n junctions made an insulating layer. The production of the insulation layer either by applying such an insulating layer by means of deposition (for example by sputtering or vapor deposition) or directly by oxidation (for example by anodic oxidation, wet-chemical oxidation or oxidation in water vapor). The manufactured Oxide layer must be enough thin and be stable.

On the insulation layer or on the oxide layer is any heat-carrying Medium applied. This can be made of a solid such as gold or another good thermal conductor, but it is also possible, gases (such as compressed air) or liquids (such as Water or glycol) for cooling to use. becomes a solid as heat-carrying Medium used, so must a heat sink, for example in the form of an air-cooled volume, to the solid body the heat can give off or radiate (convection). Be gases or liquids the heat transferring media used, so the heat dissipation also by heat conduction and delivery to a heat sink be carried out, or also by the fact that the heat in the gas or in the liquid is stored and removed by permanent convection. For this For example, the heat-carrying Permanently led past the insulating layer, causing the heat is withdrawn (for example, by coupling to a water cooling).

in the The following will be under a surface emitting semiconductor laser element both the surface emitting Semiconductor laser itself, as well as a corresponding arrangement without understood the mirrors. For an active layer with a laser-emitting zone is possibly including the adjacent layers used the term profit block. The active etalon of the laser then has one or more gain blocks (with each active layer). The active etalon or the sum from one another arranged profit blocks with the two mirrors or Bragg mirror stacks is also called a laser block designated. Compared to the active etalon, a passive etalon has no profit and can in order to form a resonator with the mirrors, a laser action but is not possible with a passive etalon.

in the following will be first advantageous variants of a surface emitting semiconductor laser according to the invention or laser element described. These variants described limit the Scope of the claims given protection not. In the following examples be further preferred variants of the semiconductor laser according to the invention described.

A surface-emitting semiconductor laser according to the invention (also referred to below as a laser for short) with a vertical resonator advantageously has a substrate and a first laser block for generating laser radiation. The laser block in this case has a arranged on a surface of the substrate first Bragg mirror stack (which a plurality of individual Schich comprising semiconductor materials having different refractive indices, the individual layers being disposed substantially parallel to the surface of the substrate), an active layer having a laser emitting zone and one on the active layer disposed on the first Bragg mirror substantially parallel to its layers arrange second Bragg mirror stack (also of a plurality of layers which are arranged substantially parallel to the active layer) on. This embodiment is inventively characterized in that the second Bragg mirror, the active layer and at least a subset of the layers of the first Bragg mirror parallel to the surface of the substrate have a smaller extent than the substrate so that the second Bragg mirror stack active layer and the subset of the layers of the first Bragg mirror one over the plane parallel to the surface of the substrate, which separates the subset of the layers from the non-expanded layers of the first Bragg mirror stack or from the substrate, in the direction of the substrate side facing away form protruding elevation with at least one non-parallel to the surface of the substrate side surface and that directly on or on this side surface, an electrical isolation region of a non-conductive and non-semiconductive material is arranged. The aforementioned survey is preferably a ridge, a spine or a mesa. In the case of a mesa this is preferably substantially cylindrical or frusto-conical, wherein the axis of rotation of the mesa is arranged substantially perpendicular to the surface of the substrate. Equally, however, elliptical cylinders or truncated cones or square truncated pyramids or other geometric formations can also be used. On the side surface of the truncated cone or on the side surface of the cylinder, the electrical insulation region is then arranged. The ratio of the mean mesa diameter d and the mesa height h is preferably less than 100/8, in a particularly preferred embodiment less than 40/8. The arranged on the side surface Isola tion region is preferably a substantially parallel to the side surface extending insulation layer. This preferably has a thickness of less than 500 nm, in particular a layer thickness of less than 300 nm, particularly preferably a thickness of 50 to 200 nm.

In In another advantageous embodiment, the isolation area is adjacent directly to the second Bragg mirror stack, the active layer and the first Bragg mirror stack. The isolation area covers the side surface in relation to a to the surface of the substrate in a substantially vertical direction in the area above, at the height of and in the area below the active layer then at least partially extends or extends with respect to a surface of the Substrate in substantially vertical direction from the second Bragg mirror stack over the active layer up to the first Bragg mirror stack.

In a further advantageous embodiment, the second Bragg mirror stack on a p-doped zone and the first Bragg mirror stack has an n-doped zone, between which the laser emitting Zone of the active layer is then arranged so that a p-n junction is formed, wherein the isolation region then arranged is that he is moving towards the p-n junction of the p-doped Zone extends into the n-doped zone.

As already described, the insulation region or the insulation layer in an advantageous embodiment, an oxide layer, which for example Silica, alumina, silicon nitride and / or silicon oxynitride (And / or other Pas sivierungsschicht materials, which at low Layer thickness sufficient isolate) or consists of.

In a further advantageous embodiment of the laser according to the invention, a heat dissipation region is arranged directly on or on the insulation region. This heat removal region is preferably designed as a solid with high thermal conductivity (preferably greater than 40 Wm ^-1 K ^-1 ) or contains a liquid or a gas.

In a further embodiment variant is directly to the heat dissipation area a heat sink arranged. The heat dissipation area can about that Be arranged or designed in such a way that heat via convection or supply and removal of the gas and / or the liquid can be discharged. Becomes a solid used, it is advantageously made of gold or contains this. As a liquid Advantageously, water and / or glycol is used. As gas can be used advantageously compressed air.

In order to realize an embodiment with several active zones, the elevation of the semiconductor laser in a further embodiment according to the invention has at least two gain blocks arranged one above the other in the emission direction or in the direction perpendicular to the surface of the substrate. Each additional gain block, like the first gain block, has a smaller extent than the substrate parallel to the surface of the substrate and thus forms the already mentioned side surface with the first gain block as a common side wall. Each gain block in this case has a first contact layer and ei ne second contact layer including interposed (having a laser emitting zone) active layer on. In this case, the gain blocks of the survey are then arranged so that in the direction perpendicular to the surface of the substrate on a gain block with an arrangement sequence of the first contact layer and second contact layer, a gain block with an arrangement sequence of second contact layer and first contact layer and vice versa follows. According to the invention, such a semiconductor laser having a plurality of active zones is advantageously characterized in that the isolation region directly adjoins the second contact layers, the active layers and the first contact layers, and / or that the isolation region has the common side surface or sidewall of the gain blocks with respect to the surface of the substrate in a substantially vertical direction in the region above, in the region of and in the region below the active layers at least partially covers and / or that the isolation region with respect to a surface of the substrate substantially perpendicular direction of the farthest from the substrate arranged contact layer extends over the active layers into the substrate disposed closest to the contact layer. Advantageously, the second contact layers each have a p-doped zone and the first contact layers each have an n-doped zone, wherein between the first and second contact layer of a gain block each have a laser emitting zone of an active layer is arranged so that in each of these winning blocks a pn junction is formed. However, the doping can also be reversed (second contact layers n-doped). The isolation region is then arranged so that it extends in the direction of the pn junctions from the n-doped or p-doped zone farthest from the substrate into the n-doped or p-doped zone closest to the substrate. It should be noted that there is no connection between p-type and n-type zones (eg via a heat sink) to avoid short circuits. Bragg mirror stacks may then be applied above the uppermost contact layer and below the lowermost contact layer or in the emission direction on both sides of the active etalon.

In a further advantageous embodiment variant is between one of the first contact layers and the adjacent active layer one arranged first spacer layer and / or between one of the active Layers and the adjacent second contact layer a second Spacer layer arranged.

In a further embodiment variant in this case has one of the spacer layers a high impedance or electrically blocking current confinement layer on.

In According to a further advantageous embodiment, the surface emitting according to the invention Semiconductor laser electrical contacts for electrical control on, wherein the electrical contacts are arranged so that the gain blocks can be controlled in parallel. Advantageously, beyond the individual profit blocks as well as the contacts arranged so that an antiserial electrical Connection is realized: The p-doped zone of a gain block is with the p-doped zone of one adjacent to this winning block arranged profit block connected and the n-doped zone of a Profit block is with the n-doped zone of an angren zend of these Winning block arranged profit block connected. In another Design variant are the contacts ring contacts or partial ring contacts. In a further embodiment variant, a heat dissipating area designed as a solid body is used also used as a contact or for contacting.

In An advantageous embodiment is the relative position at least two profit blocks adjustable with the help of a guide device. The guiding device This can be a hole and a plug in the hole pin (In particular a glass fiber pen) or a hole and have a plug in the hole or press-in ball.

The have surface-emitting semiconductor laser according to the invention described above the advantage of an increase the optical output power at the same time good steel quality due the improved heat dissipation on.

Of the Surface emitting according to the invention Semiconductor lasers can as described in one of the following examples, be executed or be used. Same or similar Components or components of the laser are described in the following Figures provided with identical reference numerals.

1 shows the structure of a surface emitting semiconductor laser according to the invention with lateral heat dissipation and with a gain block.

2 shows the basic structure of a surface emitting semiconductor laser according to the invention with stacked active zones to increase the output power.

3 shows a gain block for producing the gain zone of a multi-stacked block surface emitting semiconductor laser according to the invention.

4 , shows a monolithic grown Profit zone of a surface emitting semiconductor laser according to the invention with antiserial pn junctions, lateral contact and lateral heat dissipation.

directory the reference numbers used in the figures:

1

survey Mesa

2

Side surface of the Survey or mesa

8th

external mirror

10

substratum

11

first Bragg mirror stack

12

First Leveling layer or first distance

layer

13

active Zone

14

Second Leveling layer or second distance

layer

15

insulation layer or current or current

pinch layer

16

second Bragg mirror stack

17

contact layer

18

lower metal contact

19

Oberer metal contact

20

lateral metal contact

21

First contact layer

22

Second contact layer

30

insulation layer

31

Wärmeabführbereich

• – Auf dem Substrat 10 ist ein unterer Bragg-Spiegelstapel 11 aufgewachsen. Dieser besteht aus einer Vielzahl einzelner, parallel zur Oberfläche des Substrats 10 angeordneter Schichten aus einem halbleitenden Material, wobei die einzelnen Schichten unterschiedliche Brechungsindizes aufweisen. Der untere Bragg-Spiegel 11 ist hier n-dotiert. Die Dotierung des unteren Spiegels 11 ist bevorzugt so, wie die des Substrats, also hier n, kann somit aber auch p sein, wenn das Substrat p-dotiert ist.
• – Auf dem Bragg-Spiegel 11 ist ein Spacer 12 bzw. eine Abstandsschicht 12 aufgebracht.
• – Oberhalb des Spacers 12 befindet sich die aktive Zone 13 bzw. eine entsprechende aktive Schicht mit laseremittierender Zone.
• – Oberhalb der aktiven Zone 13 ist eine weitere Abstandsschicht 14 bzw. ein weiterer Spacer 14 angeordnet.
• – Auf dem Spacer 14 ist ein oberer Bragg-Spiegel 16 aufgebracht, der analog zum Bragg-Spiegel 11 aufgebaut ist. Der obere Bragg-Spiegel 16 ist hier jedoch p-dotiert (kann jedoch, wenn der un tere Spiegel p-dotiert ist, auch n-dotiert sein).
• – Auf dem Bragg-Spiegel 16 ist eine Kontaktschicht 17 aufgebracht.

1 shows a section perpendicular to the substrate surface, the basic structure of a surface emitting semiconductor laser according to the invention with lateral heat dissipation. To better illustrate the individual components of the laser, two identical laser units or laser blocks L1 and L2 are shown in the figure. In each of the illustrated laser blocks or each laser are parallel to a substrate surface on a substrate 10 the layers or components described below are arranged in the order described below:

• - on the substrate 10 is a lower Bragg mirror stack 11 grew up. This consists of a plurality of individual, parallel to the surface of the substrate 10 arranged layers of a semiconductive material, wherein the individual layers have different refractive indices. The lower Bragg mirror 11 is here n-doped. The doping of the lower mirror 11 is preferably the same as that of the substrate, that is to say n here, but can thus also be p when the substrate is p-doped.
• - On the Bragg mirror 11 is a spacer 12 or a spacer layer 12 applied.
• - Above the spacer 12 is the active zone 13 or a corresponding active layer with laser emitting zone.
• - Above the active zone 13 is another spacer layer 14 or another spacer 14 arranged.
• - on the spacer 14 is an upper Bragg mirror 16 Applied, analogous to the Bragg mirror 11 is constructed. The upper Bragg mirror 16 is here, however, p-doped (but can also be n-doped if the lower level is p-doped).
• - On the Bragg mirror 16 is a contact layer 17 applied.

The lower Bragg mirror 11 (here n-doped) is realized in the present case of AlGaAs layers of different composition. The thickness of the individual layers is in each case λ / (4n) of the desired resonant wavelength of the laser resonator. This wavelength is also the wavelength at which the laser emits. λ / (4n) here means the vacuum wavelength divided by 4 and the refractive index n of the material. The layer 12 or the lower spacer 12 (which is also n-doped here) serves the power supply to the active zone. It is made of AlGaAs. Together with the active zone described below 13 and the upper spacer 14 is the bottom spacer 12 about λ / (2n) thick. He can also be chosen thicker. The active zone (layer 13 ), which is undoped here, consists in the present case of quantum wells and barrier material, eg as GaInAs quantum wells and GaAs barriers. It may also be a pure volume material or the active zone may contain Quantum Dots or Quantum Wires. In the present case, preferably three to five wells are used. The layer thicknesses result from the function (quantum wells up to about 20 nm). The upper spacer 14 is constructed like the lower spacer 12 , but here is p-doped. The upper Bragg mirror 16 is constructed like the lower Bragg mirror 11 , here however p-doped. The contact layer 17 (here also p-doped) is in the present case (as usually) as part of the upper Bragg mirror 16 executed. The contact layer 17 is required for a good ohmic contact. She is heavily doped, otherwise there is a Schottky contact. Their thickness is similar to the thickness of a layer in the Bragg mirror.

The layer thicknesses and / or layer materials described in this example can as well in the other embodiments described by way of example or in others embodiments be used.

The enumerated sequence of layers or components taken together forms a frustum-shaped mesa or a corresponding elevation 1 (Which in the present case (but not necessarily) a round cross-section points) on the substrate 10 is arranged so that the axis of rotation or axis of symmetry of the truncated cone is perpendicular to the substrate surface.

The mesa has a height h of 8 μm and a mean diameter d of 40 μm. The side surface 2 the mesa 1 or the corresponding truncated cone is completely of an insulating layer 30 surround. This isolation layer 30 also covers the surface of the substrate 10 or as in the present case the next to the mesa 1 located, formed by the etching process surface of the lower Bragg mirror 11 , The insulation layer 30 is here arranged so that they are exposed by the etching process side surfaces of the upper Bragg mirror stack 16 , the active zone 13 and partly also the exposed by the etching process side surface of the lower Bragg mirror 11 covered. The the mesa side surface 2 covering part of the insulation layer 30 is thus directly on the mesa side surface and parallel to this arranged so that the insulating layer in the region of the side surface 2 passing through the exposed side portions of the upper Bragg mirror 16 , the active zone 13 and the lower Bragg mirror 11 is formed, directly to the upper Bragg mirror 16 , the active zone 13 and the lower Bragg mirror 11 borders. It is thus an electrically insulating layer 30 arranged directly on the side surfaces of the pn junction forming constituents of the laser (the two Bragg mirror stack and the active zone) so that the electrically insulating layer along the pn junction is placed over this. The insulation layer 30 also covers the portions of the side surface exposed by the etching process 2 passing through the contact layer 17 , the spacer 14 and the spacer 12 be formed. The spacer 14 has a layer 15 on, which is either high impedance or blocking and which serves to Strominschnürung (current aperture). This layer is in the form of a ring, which is parallel to the surface of the substrate 10 in the upper spacer 14 is arranged. The layer 15 is generated by introducing impurities by implantation or oxidation. The insulating panel 15 in the present case is produced by wet-chemical oxidation or ion implantation with protons. In the first case, Al (Ga) As (with low Ga content) is oxidized in hot steam (conversion to alumina). The layer thickness is in the range of about 20 to 100 nm.

On the mesa 1 opposite side of the insulation layer 30 is a heat transferring layer of gold 31 or a corresponding heat dissipation area 31 arranged from gold. This gold layer 31 surrounds the mesa or the on the side surface 2 the mesa arranged sub-layer of the insulation layer 30 sideways completely. On the mesa or partly on the contact layer 17 , partly on the upper end of the insulation layer 30 and partly on the upper end of the heat dissipation layer 31 is an annular metallic contact layer 19 arranged. These and another on the surface of the substrate opposite the mesa 10 arranged contact 18 are used for electrical control of the laser.

The essential point is the etching of the mesa 1 through the active zone 13 in the lower mirror 11 and subsequently producing the insulating layer 30 , The production of the insulation layer 30 takes place as already described, either by applying a layer by means of deposition (for example sputtering or vapor deposition) or directly by oxidation (for example anodic oxidation, wet-chemical oxidation or oxidation in steam). The applied insulation layer or the oxide layer must be sufficiently thin and stable in this case. Sufficiently thin means that the heat flow is hindered as little as possible (insulators tend to conduct the heat poorly). Stable means that the layer loses its insulation function when it becomes too thin. The layer must therefore not be too thin. In addition, it must be able to withstand the convection of a heat carrier (liquid or gas) mechanically.

Put it on the contacts 18 and 19 a voltage, so flows an injection current, which in the active layer 13 Generates electrons and holes. These then recombine in the active zone of the active layer 13 under the stimulated emission of photons in the direction perpendicular to the surface of the substrate 10 or in the direction of the substrate 10 to the upper contact layer 17 (Emitting direction). The generated heat associated with recombination becomes laterally out of the mesa 1 through the side surface 2 with the help of the insulation layer 30 and the heat-carrying medium (of gold) 31 dissipated. Alternatively to the use of a solid or of gold as a heat transfer medium 31 It is also possible to use a liquid such as water or glycol or a gas (such as compressed air). In the case shown, the area forms laterally of the heat-carrying medium 31 a heat sink to which the heat-carrying medium releases the heat by convection.

2 Figure 12 shows a pn-block as it can be used to make a gain zone from multiple active layers by stacking several pn-blocks. The basic geometric structure of the block in the form of a mesa is analogous to that in 1 shown construction. On the surface of the substrate 10 however, parallel to the substrate surface is an n-doped first contact layer 21 arranged above which a spacer layer 12 , an active zone 13 , a spacer layer 14 with current constriction layer 15 (annular) and a p-doped second contact layer 22 are arranged. The layers mentioned again form a frustum-shaped mesa on the surface of the substrate 10 , On the side surface of the truncated cone is like in 1 shown the insulation layer 30 which also covers the exposed substrate surface on the mesaside. The insulation layer 30 surrounds the side surfaces 2 the mesa completely. Side of that portion of the insulation layer 30 which surrounds the mesa is the heat-carrying medium 31 (A gold layer) arranged so that it is the mesa surrounding portion of Isolati onsschicht 30 completely surrounds. On the mesa surface or on the p-doped layer 22 , the upper edge of the insulation layer 30 as well as the upper edge of the gold layer 31 is a first annular contact 19 arranged. This serves together with the second contact 18 (on the opposite side of the mesa of the substrate 10 ) for the electrical control of the laser. The essential components of the illustrated single block for producing a gain zone by stacking many such individual blocks are the n-doped zone 21 , the p-doped zone 22 and the intermediate active zone 13 , To Strominschnürung is in turn again as at 1 described, a high-resistance or electrically blocking layer 15 used. The side surfaces 2 the mesa will be with the insulation layer 30 For example, provided by anodic oxidation, deposition of an insulator or wet chemical oxidation. The heat-carrying medium 31 (Gold layer) on the mesa flank 2 allows lateral heat dissipation from the profit zone. If a layer stack for a surface-emitting semiconductor laser is produced from blocks such as those shown by subsequent stacking of the individual blocks, the substrate can 10 largely remain for easier handling. On both sides of such a block then the ring contacts 18 and 19 attached and the blocks connected together antiserially. The adjustment of the blocks to each other then takes place by means of guides in the form of guided through the blocks holes and inserted into these holes glass fiber pins. Alternatively, glass balls can also be used for adjustment, which are pressed into the holes.

3 shows in a simplified schematic representation (which does not show all components) a surface-emitting semiconductor laser according to the invention with several stacked active zones to increase the output power. The pn junctions are connected in parallel with each other. The figure shows in the present case four (it can, of course, any number ≥ 2 are used) arranged parallel to each other in the direction of the emission direction stacked profit blocks of in 2 shown construction. The individual winning blocks are stacked on top of each other and each winning block consists of a p-doped zone 22 , an n-doped zone 21 (both not visible) from an intermediate active zone 13 , made of two spacer layers 12 and 14 (with current shutter 15 in layer 14 ) as well as a substrate 10 and two ring contacts 18 and 19 , Above and below the profit zone formed from the four profit blocks or the active etalon are two external mirrors 8a and 8b arranged, with which the active etalon forms a resonator, so that laser action is possible. The four profit blocks show the numerical suffix a to d for their respective elements. Between the active zone 13 a winning block and the p-doped zone 22 The same gain block is each a Stromeinschnürungsschicht 15 as they are already in 1 is shown arranged. The individual profit blocks are arranged so that a p-doped zone 22 of a gain block as the nearest contact layer, the p-doped zone 22 of the adjacent arranged gain block or with the p-doped zone 22 the adjacent gain block is connected and that in each case an n-doped zone 21 a winning block with the n-doped zone 21 is connected to the adjacent gain block or has this as the closest contact layer. At the junctions of two profit blocks are annular metallic contact layers 18 . 19 arranged. The ring contacts 18 . 19 are alternately on two lines 5a and 5b connected. The administration 5a lies at a positive potential, the line 5b at a negative potential. The arrangement of the individual profit blocks or their p-doped zones 22 and their n-doped zones 21 as well as the contacts 18 . 19 This is done so that four antiserial pn junctions are connected in parallel. The profit zone of the surface emitting semiconductor laser shown is thus given as a stack of several pn blocks with active zones with parallel control. The p-doped zones and the n-doped zones can either be produced monolithically by epitaxial growth or produced by subsequent stacking of individual prefabricated pn blocks with active zones. The Bragg mirrors can be represented by external mirrors as shown.

Important is here that in each case the p- or the n-sides of the p-n blocks are connected to each other (Anti-series). The connection points are then for the electrical Control used.

4 shows a monolithically grown gain zone of a surface emitting semiconductor laser with antiserial pn junctions, lateral contact and lateral heat dissipation. The profit zone here consists of a total of four pn-transitions or profit blocks, but it can also be more or less. The basic en Arrangement of the mesa 1 including side surface 2 , the insulation layer 30 and the heat-carrying medium 31 corresponds to the in the 1 to 3 shown arrangements. In contrast to the 1 and 2 However, the mesa shown is cylindrical and not designed in the form of a truncated cone. The electrical contacting of the laser shown here takes place as in 3 shown. The diameter d of the mesa 1 (without heat-carrying medium 31 ) is between 40 and 100 microns, the height h is per block of profit a material wavelength, here 300 nm per gain block, so a total of 1200 nm (without substrate 10 ).

Due to the antiserial arrangement of the individual pn blocks or profit blocks that points to the substrate 10 arranged mesa 1 seen from the substrate surface, the following layer sequence (the individual layers are parallel to the substrate surface 10 arranged): first n-doped contact layer 21a , first lower spacer 12a , first active zone 13a , first upper spacer 14a including electricity constriction 15a and first p-doped contact layer 22a , Arranged on it is the second block of profit (which, to be more precise, also the contact layer 22a includes) with the spacer 14b including electricity constriction 15b , the second active zone or layer 13b , the spacer 12b and the second n-type contact layer 21b , On the second winning block, the third winning block is located with the spacer 12c , the third active zone 13c , the spacer 14c including electricity constriction 15c and the p-doped layer 22b , Arranged thereon is the fourth gain block (with the p-doped zone 22b ), the spacer 14d including electricity constriction 15d , the fourth active layer 13d , the spacer 12d and the n-doped zone 21c , Laterally next to the cylindrical mesa, consisting of the four winning blocks described above 1 is directly on the side surface of the mesa cylinder 2 the insulation layer 30 arranged so as to directly adjoin the p-doped layers, the n-doped layers and the active layers of the individual gain blocks and the mesa cylinder 1 on the entire height h completely surrounds. Immediately on the opposite side of the mesa insulation layer 30 is a heat transferring layer 31 arranged from gold. This surrounds the mesa cylinder 1 including insulation layer 30 in the form of two half-shells approaching each other except for a narrow gap (to avoid a short circuit between p and n) and over the entire height h. One of the insulation layer 30 corresponding insulation layer 30a is on the exposed (ie not covered by the mesa cylinder) surface of the substrate 10 arranged. In the illustrated case of direct epitaxial growth of the layer stacks, the mesa must be etched through the entire stack (here, by four pn junctions with four active zones). The Stromeinschnürung 15 This is done in one step for all active zones 13 made and is thus self-adjusting, so that no further guidance is required. Self-adjusting means here that the apertures of all current stops 15a to 15d exactly on top of each other, as they are produced in the same step. In contrast, the panels would be in the assembly of individual elements with high probability because of the adjustment tolerances not exactly on top of each other.

The insulation layer 30 serves also in the present case, the electrical passivation of the mesa side surface or the exposed pn junctions. The involved p- or n-layers are contacted laterally 20 , The contacts 20 For this purpose, they are arranged laterally of the adjoining p-doped or n-doped layers of two adjacent gain blocks and immediately adjacent to these p-doped or n-doped layers. The contacts are partial ring contacts. Each with an n-doped zone 21 connected contact (contacts 20a -C) is here with the one half-shell of the heat-carrying layer (shell 31a ), each with a p-doped zone 22 connected contact (contacts 20d -E) with the other half shell 31b ,

Both shells are not electrically connected, ie they do not touch (gap) to avoid a short circuit between p and n. In the case shown are the contacts 20 also made of gold and with the gold of the heat dissipation area 31 as described directly connected (the heat-carrying medium 31 serves in the case illustrated thus simultaneously as electrical connection of the respective p- or n-layers). The parallel connection of the four antiserial pn junctions takes place as in 3 described.

Claims (50)

Surface-emitting semiconductor laser element with vertical resonator with an active layer ( 13 ), which has a laser-emitting zone, wherein the laser-emitting zone is substantially perpendicular to the active layer (FIG. 13 ), one on a first surface of the active layer ( 13 ) substantially parallel to this and adjacent to this first adjacent layer and on a second, the first surface opposite surface of the active layer ( 13 ) substantially parallel to this and adjacent to this second adjacent layer characterized in that the second adjacent layer, the active layer ( 13 ) and at least a part of the first neighboring layer at least one not parallel to the active layer ( 13 ) running side surface ( 2 ), where directly on this side surface ( 2 ) adjacent at least partially an electrical isolation area ( 30 ) is arranged from a non-conductive and non-semiconducting material. Surface emitting semiconductor laser element according to the preceding claim, characterized in that adjacent to one of the adjacent layers a substrate ( 10 ) is arranged. Surface emitting semiconductor laser element according to one of the preceding claims, characterized in that the first and / or the second adjacent layer a Bragg mirror stack ( 11 . 16 ) and / or a spacer layer ( 12 . 14 ) and / or a contact layer ( 21 . 22 ) having. Surface emitting semiconductor laser element according to the preceding claim, characterized in that the first and / or the second adjacent layer adjacent to the active layer ( 13 ) a spacer layer ( 12 . 14 ) and adjacent thereto on the active layer ( 13 ) facing away from a Bragg mirror stack ( 11 . 16 ) or a contact layer ( 21 . 22 ) having. Surface-emitting semiconductor laser element according to one of the preceding claims, characterized in that the second adjacent layer has a p-doped zone and the first adjacent layer has an n-doped zone, or that the second adjacent layer has an n-doped zone and the first adjacent layer has a p-doped zone such that a pn junction is formed, the isolation region ( 30 ) is arranged so that it extends in the direction of the pn junction from the p-doped zone to the n-doped zone. Surface emitting semiconductor laser element according to claim 5 and according to one of claims 3 or 4, characterized in that the contact layer ( 21 ) of the first neighboring layer is p-doped and that the contact layer ( 22 ) of the second neighboring layer is n-doped or vice versa. Surface emitting semiconductor laser element according to one of the preceding claims, characterized in that on the active layer ( 13 ) opposite side of the first adjacent layer and / or the second adjacent layer, a mirror, in particular a Bragg mirror stack is arranged. A surface emitting semiconductor laser element according to any one of the preceding claims and claim 2 including a first laser block for generating laser radiation, comprising: one on a surface of the substrate ( 10 ) arranged as a first neighboring layer first Bragg mirror stack ( 11 ) of a plurality of layers, wherein the individual layers substantially parallel to the surface of the substrate ( 10 ) arranged on the first Bragg mirror stack ( 11 ) disposed substantially parallel to its layers, the laser emitting zone having active layer ( 13 ), and one on the active layer ( 13 ) arranged as a second neighboring layer second Bragg mirror stack ( 16 ) of a plurality of layers, wherein the individual layers are substantially parallel to the active layer (FIG. 13 ), wherein the second Bragg mirror stack ( 16 ), the active layer ( 13 ) and at least a subset of the layers of the first Bragg mirror stack ( 11 ) parallel to the surface of the substrate ( 10 ) a smaller extent than the substrate ( 10 ) such that the second Bragg mirror stack ( 16 ), the active layer ( 13 ) and the subset of the layers of the first Bragg mirror stack ( 11 ) one over the surface of the substrate ( 10 ) and / or the plane parallel to this surface which divides the subset of the layers from the non-thinned layers of the first Bragg mirror stack ( 11 ) or from the substrate ( 10 ) separates, in the direction of the side facing away from the substrate protruding elevation ( 1 ) with the at least one not parallel to the surface of the substrate ( 10 ) running side surface ( 2 ) train. Surface emitting semiconductor laser element according to the preceding claim, characterized in that between the first Bragg mirror stack ( 11 ) and the active layer ( 13 ) a spacer layer ( 12 ) and / or that between the second Braggspiegelstapel ( 16 ) and the active layer ( 13 ) a spacer layer ( 14 ) is arranged. Semiconductor laser element according to one of the two preceding claims, characterized in that the elevation ( 1 ) has a ridge, a spine or a mesa and / or that the survey ( 1 ) has a substantially cylindrical or truncated cone-shaped mesa, wherein the cylinder or truncated cone axis of the mesa or the axis of symmetry of the mesa substantially perpendicular to the surface of the substrate ( 10 ) and wherein the ratio of mean meso diameter d and mesahole h is preferably d / h <100/8, more preferably d / h <40/8. Semiconductor laser element according to one of Claims 8 to 10, characterized in that the isolation region ( 30 ) directly to the second Bragg mirror stack ( 16 ), the active layer ( 13 ) and the first Bragg mirror stack ( 11 ) and / or that the isolation area ( 30 ) the side surface ( 2 ) with respect to the surface of the substrate ( 10 ) in the substantially vertical direction in Above, at and below the active layer ( 13 ) at least partially and / or that the isolation area ( 30 ) with respect to the surface of the substrate ( 10 ) in substantially vertical direction from the second Bragg mirror stack ( 16 ) over the active layer ( 13 ) to the first Bragg mirror stack ( 11 ). Semiconductor laser element according to one of Claims 8 to 11, characterized in that the second Bragg mirror stack ( 16 ) has a p-doped zone and that the first Bragg mirror stack ( 11 ) has an n-doped zone or that the second Bragg mirror stack ( 16 ) has an n-doped zone and that the first Bragg mirror stack ( 11 ) has a p-doped zone, wherein between the two zones the laser-emitting zone of the active layer ( 13 ) is arranged so that a pn junction is formed, and that the isolation region ( 30 ) is arranged so that it extends in the direction of the pn junction from the p-doped zone to the n-doped zone. Semiconductor laser element according to one of claims 8 to 12, characterized in that on the second Bragg mirror stack ( 16 ) a contact layer ( 17 ) is arranged. Surface-emitting semiconductor laser element according to one of the preceding claims and according to claim 3 or 4 or 9, characterized in that the spacer layer ( 14 ) a high-impedance or electrically blocking Stromeinschnürungsschicht ( 15 ) having. Surface-emitting semiconductor laser element according to one of the preceding claims and according to claim 2, characterized in that on the side facing away from the substrate of the active layer ( 13 ) on or at the surface emitting semiconductor laser element a metallic contact layer ( 19 ), in particular a ring contact, and / or that on the active layer ( 13 ) facing away from the surface of the substrate ( 10 ) a metallic contact layer ( 18 ), in particular a ring contact, is arranged. Semiconductor laser element according to one of the preceding claims, characterized in that the isolation region ( 30 ) one substantially parallel to the side surface ( 2 ) contains or consists of insulating layer. Semiconductor laser element according to the preceding claim, characterized in that the insulation layer has a layer thickness of less than 500 nm, in particular of less than 300 nm, in particular of more than 50 nm and / or below 200 nm. Semiconductor laser element according to one of the preceding claims, characterized in that the isolation region ( 30 ) comprises an oxide layer and / or contains or consists of aluminum oxide and / or silicon nitride and / or silicon oxynitride. Semiconductor laser element according to one of the preceding claims, characterized in that directly on or at the isolation region ( 30 ) a heat removal area ( 31 ) is arranged. Semiconductor laser element according to the preceding claim, characterized in that the heat dissipation region ( 31 ) contains or consists of a solid with high thermal conductivity, preferably greater than 40 Wm ^-1 K ^-1 , and / or that the heat removal area ( 31 ) contains a liquid and / or a gas or can be filled with a liquid and / or a gas. Semiconductor laser element according to the preceding claim, characterized in that directly to the heat dissipation region ( 31 ) a heat sink, for example an air-filled volume, is arranged and / or that the heat dissipation area ( 31 ) is arranged and / or designed so that heat via convection and / or supply and removal of the gas and / or the liquid can be discharged, for example by means of a gas or liquid cooling, in particular a water cooling, and / or that the solid gold contains or consists of and / or that the liquid contains water and / or glycol or consists thereof and / or that the gas contains compressed air or consists thereof. Arrangement comprising at least two surface-emitting semiconductor laser elements according to any one of claims 1 to 21, characterized in that an active etalon is formed from at least two gain blocks by the at least two active layers ( 13 ) are arranged substantially parallel to one another in the direction perpendicular to the layer planes or in the emission direction one above the other. Arrangement according to the preceding claim, characterized in that the isolation area ( 30 ) on one of the active etalon, not parallel to the active layers ( 13 ) running side surface ( 2 ) is formed at least in regions such that it extends in the emission direction from below the lowest to the uppermost active layer ( 13 ). Arrangement according to one of claims 22 or 23 and according to claim 5, characterized in that the isolation region in the emission direction at least partially from the top, p- or n-doped zone of the uppermost pn junction extends into the lowest, n- or p-doped zone of the lowest pn junction. Arrangement according to one of claims 22 to 24 and according to claim 5, characterized in that the active etalon or from the gain blocks having formed profit zone several antiserial switched p-n junctions. Arrangement according to the preceding claim by an antiserial electrical connection, in each case the p-doped zone of a gain block with the p-doped zone a profit block located adjacent to this winning block and in each case the n-doped zone of a winning block with the n-doped zone of one adjacent to this winning block Profit block is connected. Arrangement according to one of claims 22 to 26, characterized in that the arrangement on a substrate ( 10 ) is arranged. Arrangement according to one of Claims 22 to 27, characterized in that the active etalon or the gain zone has at least two profit blocks arranged one above the other, the first of these profit blocks having, in the following order in the emission direction: a first contact layer ( 21 ), an active layer ( 13 ) with laser-emitting zone and a second contact layer arranged thereon ( 22 ), wherein the second gain block arranged on the first gain block has, in the following order in the emission direction: a further active layer ( 13 ) with laser-emitting zone and a further first contact layer arranged thereon ( 21 ) and optionally further thereon arranged profit blocks in the emission direction are alternately constructed as the first gain block without first contact layer ( 21 ) and the second winning block. Arrangement according to the preceding claim, characterized in that between at least one of the active layers ( 13 ) and the adjacent first contact layer ( 21 ) and / or the adjacent second contact layer ( 22 ) a spacer layer ( 12 . 14 ) is arranged. Arrangement according to the preceding claim, characterized in that one of the spacer layers ( 14 ) a high-impedance or electrically blocking Stromeinschnürungsschicht ( 15 ) having. Arrangement according to one of claims 28 to 30, characterized by at least one metallic contact ( 20 ) for electrical control, wherein such a contact ( 20 ) preferably adjacent to a connection region between two gain blocks and / or with respect to the emission direction laterally from a first contact layer ( 21 ) or a second contact layer ( 22 ) and is disposed adjacent to this contact layer. Arrangement according to one of claims 22 to 27, characterized in that the active etalon or the profit zone comprises at least two superposed profit blocks, each of the profit blocks comprising: a metallic contact ( 18 ), in particular a ring contact, a substrate arranged thereon ( 10 ), a first contact layer ( 21 ), an active layer ( 13 ) with laser-emitting zone and a second contact layer arranged thereon ( 22 ) and optionally a second metallic contact ( 19 ), in particular a ring contact, and wherein the stacked profit blocks the said elements ( 18 . 10 . 21 . 13 . 22 . 19 ) in the emission direction alternately in the said and in the reverse order. Arrangement according to the preceding claim, characterized in that between at least one of the first contact layers ( 21 ) and the adjacent active layer ( 13 ) a first spacer layer ( 12 ) and / or that between at least one of the second contact layers ( 22 ) and the adjacent active layer ( 13 ) a second spacer layer is arranged. Arrangement according to the preceding claim, characterized in that at least one of the spacer layers ( 14 ) a high-impedance or electrically blocking Stromeinschnürungsschicht ( 15 ) having. Arrangement according to one of claims 28 to 34, characterized in that the first contact layers ( 21 ) are n-doped and that the second contact layers ( 22 ) are p-doped or vice versa. Arrangement according to one of Claims 32 to 34 and according to Claim 35, characterized in that the electrical contacts ( 18 . 19 ) are connected so that the individual pn junctions are connected in parallel to each other. Arrangement according to one of claims 22 to 36, characterized in that in the emission direction on both sides of the arrangement in each case a mirror ( 8a . 8b ), in particular a Bragg mirror stack is arranged. Arrangement according to one of claims 28 to 37, characterized in that each gain block on a non-parallel to the active layers ( 13 ) formed side surface ( 2 ) in the emission direction of the first contact layer ( 21 ) to the second contact layer ( 22 ) at least partially an electrical isolation area ( 30 ) having. Arrangement according to one of Claims 22 to 38, characterized that the relative position of at least two of the profit blocks to each other Help a guide device is adjustable. Arrangement according to the preceding claim, characterized characterized in that the guiding device at least one hole and at least one insertable in the hole Pen, in particular a glass fiber pen and / or that the guiding device at least one ball that can be inserted or pressed into the hole, in particular a glass ball. Method for producing a laser-active etalon for vertical-cavity surface-emitting semiconductor lasers, wherein an active layer (3) is formed on a first adjacent layer substantially parallel to it 13 ), which has a laser-emitting zone, is arranged so that the laser-emitting zone is substantially perpendicular to the active layer (FIG. 13 ), and wherein on one of the first adjacent layer opposite surface of the active layer ( 13 ) substantially parallel to the active layer ( 13 ) and a second neighboring layer is arranged adjoining this, characterized in that the arrangement takes place such that the second neighboring layer, the active layer ( 13 ) and at least a part of the first neighboring layer at least one not parallel to the active layer ( 13 ) running side surface ( 2 ) and that directly to this side surface ( 2 ) adjacent at least partially an electrical isolation area ( 30 ) is arranged from a non-conductive and non-semiconducting material. Method according to the preceding claim, characterized characterized in that an element or an arrangement according to a the claims 1 to 40 is made. Method according to one of the two preceding claims, characterized in that adjacent to one of the adjacent layers a substrate ( 10 ) is arranged. Method according to one of claims 41 to 43, characterized in that the side surface ( 2 ) is formed by etching. Method according to one of claims 41 to 44, characterized in that on the surface of a substrate ( 10 ) substantially parallel to the surface of the substrate ( 10 ) a first contact layer ( 21 ) is arranged on the first contact layer ( 21 ) substantially parallel to this a first spacer layer ( 12 ) is arranged on this spacer layer ( 12 ) substantially parallel to this one having a laser emitting zone active layer ( 13 ) is arranged on this active layer ( 13 ) substantially parallel to this a second spacer layer ( 14 ), which has a current diaphragm ( 15 ) and that on this second spacer layer ( 14 ) substantially parallel to this a second contact layer ( 22 ), wherein from the second contact layer ( 22 ), the second spacer layer ( 14 ), the active layer ( 13 ), the first spacer layer ( 12 ) and at least a portion of the first contact layer ( 21 ) a survey ( 1 ) which is projected over the plane parallel to the surface of the substrate ( 10 ), which covers the etched part of the first contact layer ( 21 ) of the unetched part of the first contact layer ( 21 ) or the substrate ( 10 ), protrudes in the direction of the side facing away from the substrate and which at least one not parallel to the surface of the substrate ( 10 ) running side surface ( 2 ) and directly on or on this side surface ( 2 ) the electrical isolation area ( 30 ) is arranged from a non-conductive and non-semiconducting material. Method according to one of claims 41 to 45, characterized in that the isolation region ( 30 ) contains or consists of an insulating layer which is applied by means of deposition methods, such as, for example, sputtering methods or vapor deposition methods, or which is applied by oxidation, such as, for example, anodic oxidation, wet-chemical oxidation or oxidation in water vapor. Method according to one of claims 41 to 46, characterized in that directly on or at the isolation area ( 30 ) a solid body and / or a gas and / or a liquid containing or consisting of existing heat removal area ( 31 ) is arranged. Method according to the preceding claim, characterized in that the heat removal area ( 31 ) is arranged so that in the laser operation heat from the heat dissipation area ( 31 ) by means of heat conduction, delivery to a heat valley or by means of convection. Method according to one of claims 41 to 48, characterized in that in one of the neighboring layers one to the active layer ( 13 ) adjacent spacer layer ( 14 ) is produced in which by introducing impurities by implantation or oxidation, a high-resistance or electrically blocking layer ( 15 ) or current aperture is generated. Method according to one of claims 41 to 49, characterized in that the first and / or the second adjacent layer and / or the active layer ( 13 ) is grown epitaxially.