DE102022118351A1 - METHOD FOR MAKING AN EDGE EMISSION SEMICONDUCTOR LASER DIODE - Google Patents

Abstract

A method of manufacturing an edge emission semiconductor laser diode is provided, comprising the following steps:
- Providing an edge emission semiconductor body (2) configured to generate electromagnetic laser radiation during an operation in a chamber (12), the edge emission semiconductor body (2) having two opposing facets (4, 4', 4''),
- increasing a temperature (T) of the edge emission semiconductor body (2) from a first temperature (T1) to a second temperature (T2) during a first time interval (Δt1),
- treating the edge emission semiconductor body (2) with the second temperature (T2) during a second time interval (Δt2),
- Treating the edge emission semiconductor body (2) with an ion plasma (16) in the chamber (12) during the first time interval (Δt1) and the second time interval (Δt2).

Description

A method of manufacturing an edge emission semiconductor laser diode is provided.

An improved method for manufacturing an edge emission semiconductor laser diode is to be provided. In particular, an improved cleaning process for the facets of an edge emission semiconductor laser diode is to be provided.

This problem is solved by a method with the method steps according to claim 1.

Further developments and embodiments of the method are given in the dependent claims.

According to an embodiment of the method for producing an edge emission semiconductor laser diode, an edge emission semiconductor body is provided in a chamber. In particular, the chamber has a closed volume in which a vacuum can be generated. The edge emission semiconductor body is configured to generate electromagnetic laser radiation during operation. In particular, the edge emission semiconductor body comprises or consists of a semiconductor layer sequence with an active region, the active region being configured to generate electromagnetic radiation during operation of the edge emission semiconductor laser diode. Furthermore, the edge emission semiconductor body has two opposite facets. The facets are formed from side surfaces of the edge emission semiconductor body. Furthermore, the facets are arranged on two opposite side surfaces of the edge emission semiconductor body. The facets are perpendicular to a main plane of extent of the active region. Electromagnetic laser radiation is emitted via a facet during operation by the edge emission semiconductor laser diode.

The facets, coated, for example, with a highly reflective coating on one facet and an anti-reflective coating on the other facet, form a resonator for the electromagnetic laser radiation. In particular, the active region acts as an active laser medium and is arranged within the resonator.

A population inversion associated with the resonator is generated in the active region during operation of the edge emission semiconductor laser diode. Due to population inversion, the electromagnetic radiation in the active region is generated by stimulated emission, leading to the formation of electromagnetic laser radiation. Due to the generation of the electromagnetic laser radiation by stimulated emission, the electromagnetic laser radiation usually has a longer coherence length, a narrower emission spectrum and/or a high degree of polarization compared to electromagnetic radiation generated by spontaneous emission.

According to a further embodiment of the method, a temperature of the edge emission semiconductor body is increased from a first temperature to a second temperature during a first time interval. For example, the temperature is continuously increased from the first temperature to the second temperature. In particular, an increase in temperature from the first temperature to the second temperature is constant.

According to a further embodiment of the method, the edge emission semiconductor body is treated with the second temperature during a second time interval. In particular, the second temperature is constant as much as possible during the second time interval. However, it is possible that the second temperature may inadvertently vary slightly due to process variations. For example, the variation of the second time interval does not exceed 3%, preferably 1%. The second time interval preferably follows immediately after the first time interval.

According to a further embodiment of the method, an ion plasma is ignited in the chamber before or during the first time interval. In particular, the ion plasma burns continuously throughout the first time interval and the entire second interval. For example, the ion plasma includes or consists of hydrogen ions.

According to a further embodiment of the method, the edge emission semiconductor body is treated with an ion plasma in the chamber during the first time interval and the second time interval. In other words, the edge emission semiconductor body is treated with an ion plasma not only when the second temperature is achieved by heating the edge emission semiconductor body, but also during heating of the edge emission semiconductor body to the second temperature. For example, the edge emission semiconductor body is treated with an ion plasma throughout the heating step. In such a way, cleaning of the facets of the edge emission semiconductor body can be improved.

According to a further embodiment of the method, at least one of the facets is carried out the ion plasma is cleaned so that at least one cleaned facet is achieved. In other words, cleaning of one or both facets occurs during the firing of the ion plasma. Both facets are preferably cleaned during the firing of the ion plasma. In particular, as the ion plasma cleans the facets, foreign matter and contaminants are removed from one or both facets. Oxides are preferably removed during cleaning.

• - Bereitstellen eines Kantenemissionshalbleiterkörpers, der zum Erzeugen elektromagnetischer Laserstrahlung während einer Operation in einer Kammer konfiguriert ist, wobei der Kantenemissionshalbleiterkörper zwei gegenüberliegende Facetten aufweist,
• - Erhöhen einer Temperatur des Kantenemissionshalbleiterkörpers von einer ersten Temperatur auf eine zweite Temperatur während eines ersten Zeitintervalls,
• - Behandeln des Kantenemissionshalbleiterkörpers mit der zweiten Temperatur während eines zweiten Zeitintervalls,
• - Behandeln des Kantenemissionshalbleiterkörpers mit einem Ionenplasma in der Kammer während des ersten Zeitintervalls und des zweiten Zeitintervalls.

According to a preferred embodiment, the method comprises the following steps:

• - providing an edge emission semiconductor body configured to generate electromagnetic laser radiation during surgery in a chamber, the edge emission semiconductor body having two opposing facets,
• - increasing a temperature of the edge emission semiconductor body from a first temperature to a second temperature during a first time interval,
• - treating the edge emission semiconductor body with the second temperature during a second time interval,
• - Treating the edge emission semiconductor body with an ion plasma in the chamber during the first time interval and the second time interval.

The previously given method steps are preferably carried out in the given order.

Preferably, several edge emission semiconductor bodies are treated in the same way. In other words, the process is a batch process, with the same process steps being carried out in parallel on several edge emission semiconductor bodies. In the present case, for the sake of simplicity, the method steps are often described for only one edge emission semiconductor body in the singular.

According to a further embodiment of the method, the ion plasma burns continuously during the first time interval and the second time interval. In particular, the ion plasma continuously impinges on the facets of the edge emission semiconductor body during the first time interval and the second time interval.

According to a further embodiment of the method, the temperature of the edge emission semiconductor body is reduced from the second temperature to a third temperature during a third time interval. In particular, the third time interval follows the second time interval, preferably immediately. In particular, there is no further time interval between the second time interval and the third time interval. For example, a decrease in temperature is constant during the third time interval. For example, the temperature decreases continuously down to the third temperature.

According to a further embodiment of the method, the temperature decrease during the third time interval is between 2 ° C / min and 40 ° C / min, each included.

According to a further embodiment of the method, the ion plasma is deleted after the second time interval, particularly preferably immediately after the second time interval. In particular, the ion plasma does not burn during the third time interval when the temperature of the edge emission semiconductor body is reduced from the second temperature to the third temperature in this embodiment of the method. In this embodiment of the method, the edge emission semiconductor body is not treated with the ion plasma during the third time interval when cooling of the edge emission semiconductor body takes place.

Alternatively, it is also possible for the ion plasma to be deleted after the third time interval, particularly preferably immediately afterwards. In other words, in this embodiment of the method, the ion plasma burns, preferably continuously, during the first time interval, the second time interval and the third time interval.

According to a further embodiment of the method, a passivation layer is deposited on the facet, in particular after the second time interval or the third time interval. In other words, after cleaning the facet using the ion plasma, the passivation layer is deposited during the first time interval and the second time interval and optionally during the third time interval.

For example, the passivation layer is deposited on the facet by epitaxial growth. The passivation layer is particularly preferably in direct contact with the facet and completely covers the facet. In particular, the passivation layer is deposited on both facets of the edge emission semiconductor body. For example, the passivation layer includes or consists of ZnSe. For example, the passivation layer has a thickness between 10 nanometers and 100 nanometers, inclusive.

According to a further embodiment of the method, the edge emission semiconductor body is based on an arsenide compound semiconductor material. For example, the edge emission semiconductor body includes or consists of one or more arsenide compound semiconductor materials.

Arsenide compound semiconductor materials are compound semiconductor materials containing arsenic, such as the materials from the system In _x Al _y Ga _1-xy As with 0 ≤ x ≤ 1, 0 ≤ y ≤ 1 and x+y ≤ 1. In particular, an active region is created based on an arsenide compound semiconductor material electromagnetic radiation of the infrared spectral range.

According to a further embodiment of the method, the facet of the edge emission semiconductor body comprises AlGaAs or consists of AlGaAs. In particular, if the edge emission semiconductor body is based on an arsenide compound semiconductor material, the facet of the edge emission semiconductor body comprises or consists of AlGaAs.

According to a further embodiment of the method, an oxide content of the facet is reduced. Particularly preferably, the facet is free of an oxide, in particular free of an oxide of As, such as As ₂ O ₃ , of an oxide of Al and/or of an oxide of Ga. In particular, As ₂ O ₃ exists on the facet if the facet includes or consists of AlGaAs. In particular, oxides are removed by cleaning the facets with the ion plasma during the first time interval and the second time interval. In particular, removing oxides from the facets avoids burning of the oxides within the facets during cleaning. Furthermore, removing the oxides from the facets reduces the oxygen content of the facet, resulting in fewer crystal defects near the active region.

For example, the facets are formed by cleaving adjacent edge-emitting semiconductor bodies that are part of a wafer. If the facets are exposed to ambient air after cleaving, oxidation of the facets occurs, so that oxides, for example As ₂ O ₃ in the case of an edge emission semiconductor body based on an arsenide compound semiconductor material, are formed. Before further coatings, such as a passivation layer and/or a highly reflective coating and/or an anti-reflective coating, are deposited, the oxide content must be reduced in order to achieve high quality coatings and to ensure maximum passivation of dangling bonds on the semiconductor surface to achieve improved interfaces. In particular, the passivation layer preferably has a crystal quality if an oxide content is reduced before the passivation layer is deposited.

The method is based on the idea that to clean the facets with an ion plasma, the plasma burns while the edge emission semiconductor body is being heated to a process temperature and not just during a time interval at the process temperature. In such a way, cleaning can be improved and process time can be reduced. In particular, the oxide content of the facets is reduced by the process, so that a passivation layer with improved quality can be deposited on the facets. Further, a high hydrogen pressure of the ion plasma could create a back pressure and could avoid outgassing of material from the facet and also serves as a shielding gas to prevent oxidation during the first and second time intervals and optionally also during the third time interval if an ion plasma is burning.

According to a further embodiment of the method, the second temperature is between 250 ° C and 500 ° C, inclusive.

According to a further embodiment of the method, a duration of the second time interval does not exceed 100 minutes.

According to a further embodiment of the method, a temperature increase during the first time interval is between 2 ° C / min and 40 ° C / min, each included.

According to a further embodiment of the method, the first temperature and/or the third temperature are between 50 ° C and 200 ° C, each included.

According to a further embodiment of the method, the edge emission semiconductor body is arranged in the chamber such that one facet faces away from an ion plasma source that generates the ion plasma, and the other facet faces the ion plasma source during treatment with the ion plasma. With the method, it is possible to dispense with turning the edge emission semiconductor laser body so that both facets face the ion plasma source during treatment with the ion plasma for cleaning.

This is possible due to the high efficiency of the cleaning, since the ion plasma is already burning during the heating of the edge emission semiconductor body to the second temperature. On a In this way, process time can be reduced.

According to a further embodiment of the method, an anti-reflection coating, which has an anti-reflection effect for the electromagnetic laser radiation, is deposited on the facet facing the ion plasma source during a treatment. In particular, the anti-reflection coating reflects at most 5% of the electromagnetic radiation of the active area, preferably at most 2% of the electromagnetic radiation of the active area, particularly preferably at most 0.2% of the electromagnetic radiation of the active area or at most 0.1% of the electromagnetic radiation of the active area .

Furthermore, a highly reflective coating that is highly reflective of the electromagnetic laser radiation is deposited on the other facet facing away from the ion plasma source during treatment. In particular, the highly reflective coating reflects at least 90%, preferably at least 95%, particularly preferably at least 98% of the electromagnetic radiation of the active area.

In particular, the edge emission semiconductor laser diode produced by the method is a high-power infrared laser.

The edge emission semiconductor laser diode can be used, for example, for cutting, welding, soldering, hair removal or defense purposes.

• 1 zeigt ein Flussdiagramm eines Verfahrens zum Herstellen einer Halbleiterkantenemissionslaserdiode gemäß einem Ausführungsbeispiel.
• 2 bis 8 zeigen schematisch unterschiedliche Stufen des Verfahrens des Ausführungsbeispiels aus 1.
• 9 zeigt ein Temperaturprofil und ein Ionenplasmaprofil während des Verfahrens des Ausführungsbeispiels aus 1 schematisch.
• 10 zeigt ein Flussdiagramm eines Verfahrens zum Herstellen einer Halbleiterkantenemissionslaserdiode gemäß einem weiteren Ausführungsbeispiel.
• 11 zeigt ein Temperaturprofil und ein Ionenplasmaprofil während eines Verfahrens eines weiteren Ausführungsbeispiels schematisch.
• 12 zeigt Messungen der optischen Ausgabe in Abhängigkeit von der Betriebszeit einiger Kantenmissionslaserdioden, die mit einem üblichen Verfahren hergestellt wurden.
• 13 zeigt Messungen der optischen Ausgabe in Abhängigkeit von der Betriebszeit einiger Kantenmissionslaserdioden, die mit einem Verfahren gemäß einem Ausführungsbeispiel hergestellt wurden.
• 14 zeigt XRD-Spektren von Testproben, die mit einem Verfahren gemäß einem Ausführungsbeispiel gereinigt wurden, bevor sie mit einer ZnSe-Passivierungsschicht bedeckt wurden, sowie ein XRD-Spektrum von Testproben, die mit einem üblichen Verfahren gereinigt wurden, bevor sie mit einer ZnSe-Passivierungsschicht bedeckt wurden.
• 15 zeigt Laufzeit-Sekundärionen-Massenspektrometrie(ToF-SIMS: Time-of-Flight Secondary Ion Mass Spectometry)-Analysen einer Testprobe, die mit üblichen Verfahren gereinigt wurde, bevor sie mit einer ZnSe-Passivierungsschicht bedeckt wurde, und die mit einem Verfahren gemäß einem Ausführungsbeispiel gereinigt wurde, bevor sie mit einer ZnSe-Passivierungsschicht bedeckt wurde.

Further advantageous embodiments and developments of the method result from the exemplary embodiments described below in connection with the figures.

• 1 shows a flowchart of a method for producing a semiconductor edge emission laser diode according to an exemplary embodiment.
• 2 until 8th show schematically different stages of the method of the exemplary embodiment 1 .
• 9 shows a temperature profile and an ion plasma profile during the method of the exemplary embodiment 1 schematic.
• 10 shows a flowchart of a method for producing a semiconductor edge emission laser diode according to a further exemplary embodiment.
• 11 schematically shows a temperature profile and an ion plasma profile during a method of a further exemplary embodiment.
• 12 shows measurements of optical output versus operating time of some edge emission laser diodes fabricated using a common method.
• 13 shows measurements of optical output versus operating time of some edge emission laser diodes fabricated using a method according to an embodiment.
• 14 shows XRD spectra of test samples that were cleaned using a method according to an embodiment before being covered with a ZnSe passivation layer, as well as an XRD spectrum of test samples that were cleaned using a conventional method before being covered with a ZnSe passivation layer were covered.
• 15 shows time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyzes of a test sample that was cleaned using conventional methods before being covered with a ZnSe passivation layer and which was prepared using a method according to one Embodiment was cleaned before it was covered with a ZnSe passivation layer.

The same or similar elements and elements with the same function are designated with the same reference numerals in the figures. The figures and the proportions of the elements shown in the figures are not considered to be to scale. Rather, individual elements, in particular individual layers, can be shown with an exaggerated size for better presentation and/or better understanding.

During the procedure of the exemplary embodiment 1 until 9 In a first step S1, a wafer 1, which comprises a plurality of edge emission semiconductor bodies 2, is separated into separate edge emission semiconductor bodies 2 by splitting in clean room air along separation lines 3 ( 2 ). The splitting produces facets 4 of the edge emission semiconductor bodies.

3 schematically shows a sectional view of an edge emission semiconductor body 2 after splitting. The edge emission semiconductor laser body 2 includes an epitaxial semiconductor layer sequence 5 with an active region 6 configured to generate electromagnetic radiation during operation. An electrical contact layer 9 is deposited on each of two opposite main surfaces of the epitaxial semiconductor layer sequence 5.

Side surfaces 10 of the edge emission semiconductor bodies are formed by the splitting generated facets 4 formed. The facets 4 are perpendicular to a main plane of expansion of the edge emission semiconductor body 2.

The edge emission semiconductor body 2 includes a resonator 7 which is formed by the opposing facets 4. The resonator 7 has an optical axis 8 parallel to a main plane of expansion of the active region 6 and also perpendicular to the facets 4 of the edge emission semiconductor body 2.

The edge emission semiconductor body 2 of the present embodiment is based on an arsenide compound semiconductor material. In particular, the active region includes 6 AlGaAs. After cleaving, oxides 11 are formed on the facets 4 by oxidation in clean room air.

In a next step S2, the isolated edge emission semiconductor bodies 2 are transferred to a molecular beam epitaxy ultra-high vacuum plasma chamber 12 with a first temperature T1. For example, the first temperature T1 is approximately 150°C. The first temperature T1 is also a transfer temperature at which the edge emission semiconductor bodies can be transferred into the molecular beam epitaxy ultrahigh vacuum plasma chamber 12.

The edge emission semiconductor bodies 2 are secured in a holder 13 with a ring-like geometry. The holder 13 is in physical and/or radiation contact with a heating element 14 configured to heat the edge emission semiconductor bodies 2. Furthermore, an ion plasma source 15 is provided in the chamber 12. The ion plasma source 15 is configured to produce an ion plasma 16 during operation. Currently, the ion plasma source 15 produces a hydrogen ion plasma. The edge emission semiconductor bodies 2 are arranged in the chamber 12 in such a way that facets 4′ face the ion plasma source 15, while the other facets 4″ face away from the ion plasma source 15 ( 4 ).

In a next step S3, the edge emission semiconductor bodies 2 are heated by the heating element 14 from the first temperature T1 of approximately 150 ° C to a second temperature T2 of approximately 400 ° C during a first time interval Δt1. During the first time interval Δt1, when the temperature of the edge emission semiconductor bodies 2 is increased from the first temperature T1 to the second temperature T2, the ion plasma source 15 is ignited so that an ion plasma 16 is generated in the entire first time interval Δt1 and the entire second time interval Δt2 Chamber 12 is present. The ion plasma 16 cleans the edge emission semiconductor bodies 2 and in particular the facets 4.

In a next step S4, the ion plasma 16 within the chamber 12 is extinguished and in a further step S5 the edge emission semiconductor bodies 2 are cooled to a third temperature T3 of approximately 150 ° C during a third time interval Δt3. Currently, the third temperature T3 is also the transfer temperature.

In a next step S6, the edge emission semiconductor bodies 2 are transferred to a turning chamber in which the edge emission semiconductor bodies 2 are turned over by rotating the annular holder and transferred again to the molecular beam epitaxy ultra-high vacuum plasma chamber 12 (not shown). Due to the turning of the edge emission semiconductor bodies 2 in the annular holder 13, the facets 4", which faced away from the ion plasma source 15 during steps S3, S4 and S5, now face the ion plasma source 15 ( 5 ).

Then in step S7, steps S3 to S5, as already described, are repeated.

6 shows a sectional view of the edge emission semiconductor body 2 after method step S7 of the method of the flowchart 1 schematic. Compared to the edge emission semiconductor body 2 3 the facets 4 are cleaned and in particular largely free of oxides 11.

After cooling the edge emission semiconductor bodies 2 to the third temperature T3 of about 150 ° C in the second step S5, the edge emission semiconductor bodies 2 are transferred to a growth chamber (not shown) in step S8.

In a further step S9, a passivation layer 17, which comprises or consists of ZnSe, is deposited on the facets 4 of the edge emission semiconductor bodies 2, which are to be covered with an anti-reflection coating 18 in step S12.

Then, in step S10, the edge emission semiconductor bodies 2 are transferred to the turning chamber, in which the edge emission semiconductor bodies 2 are turned over so that the facets 4 are accessible, which are to be covered with a highly reflective coating 19 in step S13.

In a next step S11, a passivation layer 17, which comprises or consists of ZnSe, is grown on the facets 4, which in step S13 are coated with a highly reflective coating 19 should be covered. The ZnSe passivation layer 17 is deposited on the facets 4 by epitaxial growth.

7 shows a schematic sectional view of an edge emission semiconductor body 2 after process step S11. A passivation layer 17, which comprises or consists of ZnSe, is deposited on both facets 4 in direct contact with the epitaxial semiconductor layer sequence 5. The passivation layer 17 preferably covers the facets 4 completely.

In a next step S12, an anti-reflection coating 18 is deposited on one of the facets 4 in direct contact with the passivation layer 17.

In a further step S13, a highly reflective coating 19 is deposited on the other facet 4, also in direct contact with the passivation layer 17.

8th shows a schematic sectional view of an edge emission semiconductor body 2 after process step S13. In direct contact with the passivation layer 17 over one of the facets 4, an anti-reflection coating 18, which has an anti-reflection effect for the electromagnetic radiation generated within the active region 6, is applied. On the other facet 4, a highly reflective coating 19 is applied to the passivation layer 17. The highly reflective coating 19 is highly reflective for the electromagnetic radiation of the active area 6.

9 shows a temperature profile of the edge emission semiconductor bodies 2 during the process steps S3, S4 and S5 of the method according to the flowchart 1 schematic. When the edge emission semiconductor bodies 2 are provided within the chamber 12 that includes the ion plasma source 15, the edge emission semiconductor bodies 2 have a first temperature T1, which currently corresponds to the transfer temperature of about 150 ° C.

During a first time interval Δt1, the edge emission semiconductor bodies 2 are heated to a second temperature T2 of approximately 400 ° C. In other words, the temperature T of the edge emission semiconductor bodies 2 is raised to a second temperature T2 during the first time interval Δt1, particularly preferably in a continuous manner. After heating the edge emission semiconductor bodies 2 to the second temperature T2, the temperature T of the edge emission semiconductor bodies 2 is kept constant at the second temperature T2 during a second time interval Δt2.

After the second time interval Δt2, a third time interval Δt3 follows immediately. During the third time interval Δt3, the temperature T of the edge emission semiconductor bodies 2 is reduced to a third temperature T3. Currently, the third temperature T3 is the transfer temperature of about 150 °C.

As in 9 indicated by the hatched areas, the ion plasma source 15 is ignited upon starting to increase the temperature T and the ion plasma 16 burns within the chamber 12 continuously during the first time interval Δt1 and the second time interval Δt2.

During the process of the flowchart 10 will be steps S1, S2 and S3, as already mentioned in connection with 1 described, carried out. In comparison to the method of the exemplary embodiment 1 Steps S5 and S4 are swapped. In other words, according to the procedure of the flowchart 10 the edge emission semiconductor bodies 2 are cooled to a third temperature T3, which is the transfer temperature of about 150 ° C, before the ion plasma 16 is quenched. Therefore, the ion plasma 16 also burns during the third time interval Δt3 in which the temperature T of the edge emission semiconductor bodies 2 is reduced to the third temperature T3, and not only during the first time interval Δt1 and the second time interval Δt2.

The method further comprises according to the flowchart 10 not steps S6 and S7. In other words, the edge emission semiconductor bodies 2 are made during the process of the flowchart 10 not turned over, so that all facets 4 face the ion plasma source 15 for cleaning.

However, steps S8 to S13 are as already mentioned in connection with the flowchart 1 described, carried out.

In particular, the method according to the flowchart can be used 10 turning over the edge emission semiconductor bodies 2 can be avoided because cleaning is improved. In particular, the facets 4 of the edge emission semiconductor bodies 2 facing away from the ion plasma source 15 are efficiently cleaned, so that the inversion does not have to be carried out.

11 shows the temperature profile during the process of the flowchart 10 . Compared to 9 the ion plasma 16 also burns during a decrease in the temperature T of the edge emission semiconductor bodies from the second temperature T2 to the third temperature T3.

For example, the temperature increase ΔT during the first time interval Δt1 and the temperature decrease ΔT during the third time interval Δt3 are approximately 20 °C/min. The second time interval T2 has a duration of approximately 50 minutes, for example.

12 shows results of life tests of edge emission semiconductor laser diodes produced using a conventional process. During this process, the ion plasma source 15 produces an ion plasma 16 only during the second time interval Δt2, while the ion plasma 16 is extinguished during the first time interval Δt1 and the third time interval Δt3. The edge emission semiconductor laser diodes used for the life test emitted electromagnetic laser radiation with a wavelength of approximately 920 nanometers. Further, a width of the resonator 7 of the edge emission semiconductor laser diodes was about 200 micrometers and a length of the resonator 7 was about 4 millimeters.

To stress the edge emission semiconductor laser diodes to simulate a lifetime, the edge emission semiconductor laser diodes were driven under extreme overload conditions with a very high electrical current of approximately 29 A to 30 A.

The electrical output power P was measured from some edge emission semiconductor laser diodes as a function of time t. How out 12 can be seen, which shows the relative optical output power P as a function of the operating time t, the output power P of the edge emission semiconductor laser diodes drops significantly after about 400 hours of operation. Therefore, edge emission semiconductor laser diodes produced by a conventional method in which the ion plasma 16 burns only during the second time interval Δt2 have a life of about 400 hours under extreme overload conditions.

13 shows results of the same life test of edge emission semiconductor laser diodes using a method according to the exemplary embodiment 1 were produced. In other words, the ion plasma 16 also burned during the first time interval Δt1 when the temperature T of the edge emission semiconductor bodies 2 is increased to the second temperature T2, and not only during the second time interval Δt2 when the temperature T of the edge emission semiconductor bodies is constantly at an increased second temperature T2 is held.

It can be off 13 It can be seen that the life of the edge emission semiconductor laser diodes using a method according to the flowchart 1 were produced, approximately 2500 hours for the same overload conditions as for the reference devices 12 amounts. Therefore, the present disclosed manufacturing method significantly improves the lifetime of the edge emission semiconductor laser diodes.

In order to investigate cleaning properties of the present method, measurements were carried out on test samples. Wafers with a surface made of AlGaAs with an aluminum content of 2% to 40% were used as test samples. The surface of these test samples was covered with a ZnSe passivation layer 17 after cleaning the surface using the method described here.

14 shows an X-ray diffraction (XRD) pattern of a test sample covered with the ZnSe passivation layer 17. The diagram shows the intensity I of the X-rays as a function of the specific angle 2θ. In particular, the diagram shows the peak resulting from the ZnSe of the passivation layer 17. This tip is marked by a dashed circle 14 specified.

In 14 different XRD measurements are shown. Curves C1 and C2 show the XRD measurement on a test sample that was cleaned by a conventional method only during the second time interval Δt2. The second time interval Δt2 of curve C1 had a duration of approximately 25 minutes, while the second time interval of curve C2 had an extended duration of 75 minutes. During the two usual processes, the ion plasma 16 burned only during the second time interval Δt2 and not during the heating and/or cooling of the edge emission semiconductor bodies 2.

Furthermore shows 14 a curve C3 of a test sample that was cleaned by a method according to an exemplary embodiment, wherein the ion plasma 16 burned at a substantially constant second temperature T2 not only during the second time interval Δt2, but also during the first time interval Δt1 and the third time interval Δt3, therefore during heating and cooling. It can be off 14 It can be seen that the ZnSe peak of the test sample cleaned with the present method has increased, indicating better crystal quality of the ZnSe passivation layer 17.

15 shows ToF-SIMS analyzes of test samples based on an AlGaAs compound semiconductor material, the surface of the test samples being covered with a ZnSe passivation layer 17. On the left axis are the counts C, O ₂ and H are shown (solid lines), while on the right axis the counts corresponding to O (dashed line) are plotted.

Test samples were analyzed with the AlGaAs surface cleaned using a conventional method before deposition of a ZnSe passivation layer 17 (left and middle values). During the usual process, the ion plasma 16 burned only during the second time interval Δt2 and not during the first time interval Δt1 and the third time interval Δt3. The second time interval Δt2 of the left values (circles) was 25 minutes and the second time interval Δt2 of the middle values was 75 minutes (squares).

Furthermore shows 15 Values of a test sample cleaned with an ion plasma 16 that burned during the first time interval Δt1 and the second time interval Δt2 (right values, stars). An increase in temperature ΔT during the first time interval Δt1 was 5 °C/min, while the duration of the first time interval Δt1 together with the second time interval Δt2 was 50 minutes. It can be seen that C, O ₂ , H and O at the ZnSe/AlGaAs interface are greatly reduced by the disclosed method.

The invention is not limited to the description of the embodiments. Instead, the invention encompasses any new feature as well as any combination of features, in particular any combination of features of the claims, even if the feature or combination of features itself is not explicitly given in the claims or embodiments.

Reference symbols

1

wafers

2

Edge emission semiconductor body

3

Separation line

4, 4', 4"

facet

5

Epitaxial semiconductor layer sequence

6

active area

7

resonator

8th

optical axis

9

electrical contact layer

10

side surface

11

oxide

12

chamber

13

bracket

14

Heating element

15

Ion plasma source

16

Ion plasma

17

passivation layer

18

Anti-reflective coating

19

highly reflective coating

T1

first temperature

Δt1

first time interval

T2

second temperature

Δt2

second time interval

T3

third temperature

Δt3

third time interval

ΔT

Temperature increase/decrease

Claims (18)

A method of manufacturing an edge emission semiconductor laser diode, comprising the following steps: - Providing an edge emission semiconductor body (2) configured to generate electromagnetic laser radiation during an operation in a chamber (12), the edge emission semiconductor body (2) having two opposing facets (4, 4', 4"), - increasing a temperature (T) of the edge emission semiconductor body (2) from a first temperature (T1) to a second temperature (T2) during a first time interval (Δt1), - treating the edge emission semiconductor body (2) with the second temperature (T2) during a second time interval (Δt2), - Treating the edge emission semiconductor body (2) with an ion plasma (16) in the chamber (12) during the first time interval (Δt1) and the second time interval (Δt2). Method according to the preceding claim, wherein at least one of the facets (4, 4', 4") is cleaned by the ion plasma (16), so that at least one cleaned facet (4, 4', 4") is achieved. Method according to one of the preceding claims, wherein the ion plasma (16) burns continuously during the first time interval (Δt1) and the second time interval (Δt2). Method according to one of the preceding claims, wherein after the second time interval (Δt2), the temperature (T) of the edge emission semiconductor body (2) is reduced from the second temperature (T2) to a third temperature (T3) during a third time interval (Δt3). A method according to the preceding claim, wherein a decrease in a temperature T during the third time interval (Δt3) is between 2°C/min and 40°C/min, inclusive. Method according to one of the preceding claims, wherein the ion plasma (16) is deleted after the second time interval (Δt2). Procedure according to Claim 4 until 5 , whereby the ion plasma (16) is deleted after the third time interval (Δt3). Method according to one of the preceding claims, wherein a passivation layer (17) is deposited on the facet (4, 4', 4"). Method according to the preceding claim, wherein the passivation layer (17) comprises ZnSe. Method according to one of the preceding claims, wherein the edge emission semiconductor body (2) is based on an arsenide compound semiconductor material. Method according to one of the preceding claims, wherein the facet (4, 4', 4") of the edge emission semiconductor body (2) comprises AlGaAs. Method according to one of the preceding claims, wherein an oxide content of the facet (4, 4', 4") is reduced. A method according to any one of the preceding claims, wherein the second temperature (T2) is between 250°C and 500°C, inclusive. Method according to one of the preceding claims, wherein a duration of the second time interval (Δt2) does not exceed 100 minutes. Method according to one of the preceding claims, wherein an increase in a temperature (T) during the first time interval (Δt1) is between 2 °C/min and 40 °C/min, both inclusive. Method according to one of the preceding claims, wherein the first temperature (T1) and/or the third temperature (T3) is between 50 °C and 200 °C, each included. Method according to one of the preceding claims, wherein the edge emission semiconductor body (2) is arranged in the chamber (12) in such a way that a facet (4, 4 ', 4") faces away from an ion plasma source (15) which produces the ion plasma (16). generated, and the other facet (4, 4 ', 4'') faces the ion plasma source (15) during treatment with the ion plasma (16). Method according to the preceding claim, wherein - an anti-reflection coating (18), which has an anti-reflection effect for the electromagnetic laser radiation, is deposited on the facet (4, 4 ', 4'') that faced the ion plasma source (15) during a treatment, and - a highly reflective coating (19), which is highly reflective for the electromagnetic laser radiation, is deposited on the other facet (4, 4', 4'') which was turned away from the ion plasma source (16) during a treatment.

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