Vertical cavity surface emitting laser device with integrated photodiode
阅读说明:本技术 具有集成光电二极管的垂直腔面发射激光器装置 (Vertical cavity surface emitting laser device with integrated photodiode ) 是由 P·H·格拉赫 于 2019-01-09 设计创作,主要内容包括:本发明描述一种垂直腔面发射激光器(VCSEL)装置、包括VCSEL装置的光学传感器以及制造这样的VCSEL装置的方法。VCSEL装置包括第一电接触体(105)、第三电接触体(130)、第四电接触体(150)和光学谐振器。光学谐振器包括第一分布式布拉格反射器(115)、光电二极管、第二分布式布拉格反射器和用于发光的有源层(120)。有源层(120)被布置在第一分布式布拉格反射器(115)与第二分布式布拉格反射器之间。第二分布式布拉格反射器包括第一部分(125)、第二部分(135)和第三部分(145)。第一部分(125)包括具有不同折射率的至少一对成对层。所述至少一对成对层的特征在于是第二导电类型的。第二部分(135)包括具有不同折射率的至少一对成对层。所述至少一对成对层的特征在于是与第二导电类型不同的第一导电类型的。第三部分包括具有不同折射率的至少一对成对层,其中,所述至少一对成对层的特征在于是第二导电类型的。光电二极管的光吸收结构(140)被布置在第二部分(135)与第三部分(145)之间。第一电接触体(105)和另一电接触体被布置为能够提供电驱动电流,以电泵浦光学谐振器。光吸收结构(140)被布置在电驱动电流的电流路径之外。第三电接触体(130)和第四电接触体(150)被布置为能够电接触光电二极管。(A Vertical Cavity Surface Emitting Laser (VCSEL) device, an optical sensor including the VCSEL device, and a method of fabricating such VCSEL device are described. The VCSEL device includes a first electrical contact (105), a third electrical contact (130), a fourth electrical contact (150), and an optical resonator. The optical resonator includes a first distributed bragg reflector (115), a photodiode, a second distributed bragg reflector, and an active layer (120) for emitting light. An active layer (120) is disposed between the first distributed Bragg reflector (115) and the second distributed Bragg reflector. The second distributed Bragg reflector includes a first portion (125), a second portion (135), and a third portion (145). The first portion (125) includes at least one pair of dyads having different indices of refraction. The at least one pair of pairs of layers is characterized as being of the second conductivity type. The second portion (135) includes at least one pair of dyads having different indices of refraction. The at least one pair of pairs of layers is characterized by a first conductivity type different from a second conductivity type. The third portion includes at least one pair of dyads having different indices of refraction, wherein the at least one pair of dyads is characterized as being of the second conductivity type. The light absorbing structure (140) of the photodiode is arranged between the second portion (135) and the third portion (145). The first electrical contact (105) and the further electrical contact are arranged to be able to provide an electrical driving current to electrically pump the optical resonator. The light absorbing structure (140) is arranged outside a current path of the electrical driving current. The third electrical contact (130) and the fourth electrical contact (150) are arranged to be able to electrically contact the photodiode.)
1. A VCSEL device comprising a first electrical contact (105), a third electrical contact (130), a fourth electrical contact (150), and an optical resonator, wherein the optical resonator comprises a first distributed Bragg reflector (115), a photodiode, a second distributed Bragg reflector, and an active layer (120) for emitting light, wherein the active layer (120) is arranged between the first distributed Bragg reflector (115) and the second distributed Bragg reflector, wherein the second distributed Bragg reflector comprises a first portion (125), a second portion (135), and a third portion (145), wherein the first portion (125) comprises at least one pair of first dyad layers having different refractive indices, wherein the at least one pair of first dyad layers are of a second conductivity type, wherein the second portion (135) comprises at least one pair of second dyad layers having different refractive indices, wherein the at least one pair of second dyad layers is of a first conductivity type different from the second conductivity type, wherein the third portion comprises at least one pair of third dyad layers having different refractive indices, wherein the at least one pair of third dyad layers is of a second conductivity type, wherein the light absorbing structure (140) of the photodiode is arranged between the second portion (135) and the third portion (145), wherein the first electrical contact (105) and the further electrical contact are arranged to be able to provide an electrical driving current for electrically pumping the optical resonator, wherein the light absorbing structure (140) is arranged outside a current path of the electrical driving current, wherein the third electrical contact (130) and the fourth electrical contact (150) are arranged to be able to electrically contact the photodiode, wherein the further electrical contact is a second electrical contact (127), wherein the second electrical contact (127) electrically contacts the first portion (125), wherein the third electrical contact (130) electrically contacts the second portion (135), wherein the second electrical contact (127) and the third electrical contact (130) are separated by the semiconductor layer structure.
2. The VCSEL device of claim 1, comprising a base (110), wherein the first DBR is disposed between the base (110) and the active layer (120).
3. The VCSEL device of claim 1, comprising a base (110), wherein the base (110) is of a first conductivity type, wherein the first distributed Bragg reflector (115) is of the first conductivity type.
4. A vcsel device in accordance with claim 2 or 3, wherein the first conductivity type is characterized as having n-doped material, and wherein the second conductivity type is characterized as having p-doped material.
5. A vertical cavity surface emitting laser device according to any preceding claim, wherein the semiconductor layer structure is an isolation structure (128) arranged to electrically isolate the third electrical contact (130) from the second electrical contact (127).
6. The VCSEL device of claim 5, wherein the isolation structure (128) includes at least one pair of pairs of layers, each of the pairs of layers including a first layer having a first refractive index and a second layer having a second refractive index different from the first refractive index.
7. The VCSEL device of claim 6, wherein the isolation structure (128) includes a plurality of pairs including first and second layers, wherein at least two of the first layers are of a first conductivity type and wherein at least two of the second layers are of a second conductivity type.
8. The VCSEL device of claim 1, wherein the VCSEL device is arranged to be capable of lasing through a first distributed Bragg reflector (115).
9. The VCSEL device of claim 8, comprising a first current distributing layer (106) disposed between the base (110) and the first DBR (115), wherein the first current distributing layer is electrically connected to the first electrical contact (105), wherein the base (110) comprises an undoped semiconductor material.
10. The VCSEL device of any of the preceding claims, wherein the first portion (125) and the second portion (135) of the second DBR include more pairs of layers having different refractive indices than the third portion (145) of the second DBR.
11. The VCSEL device of any of the preceding claims, wherein the absorbing structure (140) includes an intrinsic layer (141) having a thickness less than 100 nanometers.
12. The VCSEL device of claim 11, wherein the intrinsic layer (141) is disposed in an antinode of a standing wave pattern in the optical resonator during operation of the VCSEL device.
13. An optical sensor comprising a vertical cavity surface emitting laser device according to any preceding claim.
14. A method of fabricating a vertical cavity surface emitting laser device, the method comprising:
a base body (110) is arranged,
providing a first electrical contact (105), wherein the first electrical contact (105) and the further electrical contact are arranged to be able to provide an electrical driving current for electrically pumping the vertical cavity surface emitting laser device,
a first distributed bragg reflector (115) is provided,
an active layer (120) is provided such that a first distributed Bragg reflector (115) is arranged between the active layer (120) and the base body (110),
arranging a first portion (125) of a second distributed Bragg reflector such that the active layer (120) is arranged between the first distributed Bragg reflector (115) and the first portion (125), wherein the first portion (125) comprises at least one pair of first dyad layers having different refractive indices, wherein the at least one pair of first dyad layers is of a second conductivity type,
providing a second portion (135) of a second distributed Bragg reflector, wherein the second portion (135) comprises at least one pair of second dyads having different refractive indices, wherein the at least one pair of second dyads is of a first conductivity type different from the second conductivity type,
providing a third portion (145) of the second distributed Bragg reflector, wherein the third portion (145) comprises at least one third pair of layers having different refractive indices, wherein the at least one third pair of layers is of the second conductivity type,
a light absorbing structure (140) of the photodiode is arranged between the second portion (135) and the third portion (145), wherein the light absorbing structure (140) is arranged outside a current path of the electrical driving current,
-providing a third electrical contact (130),
providing a fourth electrical contact (150), wherein the third electrical contact (130) and the fourth electrical contact (150) are arranged to be able to electrically contact the photodiode, wherein the further electrical contact is the second electrical contact (127), the method further comprising electrically contacting the first portion (125) through the second electrical contact (127) and the second portion (135) through the third electrical contact (130), and separating the second electrical contact (127) and the third electrical contact (130) through the semiconductor layer structure.
Technical Field
The present invention relates to a Vertical Cavity Surface Emitting Laser (VCSEL) device with an integrated photodiode. The invention also relates to a corresponding method of manufacturing such a VCSEL device.
Background
WO2009/136348a1, corresponding to US2011/0064110a1, discloses a vertical cavity surface emitting laser device comprising a VCSEL having a monolithically integrated photodiode arranged between a substrate and a first Distributed Bragg Reflector (DBR) of the VCSEL. The photodiode is formed by a layer sequence of a first n-doped region, a p-doped region, an intrinsic region and a second n-doped region of semiconductor material. The photodiode and the laser share a common electrode realized as an ohmic n-contact at said first n-doped region.
US5757837A discloses a VCSEL configured with an intracavity quantum well photodetector. EP0993087a1 discloses a combination of a light-emitting device and a photodetector having such a structure: the layer of the photodetector in contact with the light emitting device has a semiconductor conductivity type polarity opposite to that of the light emitting device. US5892786A discloses an intracavity sensor based output power control for microcavity light emitting devices.
Disclosure of Invention
It is an object of the present invention to provide an improved vertical cavity surface emitting laser device with an integrated photodiode.
According to a first aspect, a Vertical Cavity Surface Emitting Laser (VCSEL) device is provided. The VCSEL device includes a first electrical contact, a base, a third electrical contact, a fourth electrical contact, and an optical resonator. The optical resonator includes a first Distributed Bragg Reflector (DBR), a photodiode, a second DBR, and an active layer for emitting light. The active layer is disposed between the first DBR and the second DBR. The first DBR may be disposed between the substrate and the active layer. The second DBR includes a first portion, a second portion, and a third portion. The first portion includes at least one pair of dyad layers having different refractive indices. The at least one pair of pairs of layers is characterized as being of the second conductivity type. The second portion includes at least one pair of dyads having different refractive indices. The at least one pair of pairs of layers is characterized by a first conductivity type different from a second conductivity type. The third portion includes at least one pair of dyads having different refractive indices. The at least one pair of dyad layers of the third portion is characterized as being of the second conductivity type. The light absorbing structure of the photodiode is disposed between the second portion and the third portion. The first electrical contact and the further electrical contact are arranged to be able to provide an electrical driving current to electrically pump the optical resonator. The light absorbing structure is arranged outside the current path of the electrical driving current. The third electrical contact and the fourth electrical contact are arranged to be able to electrically contact the photodiode. The further electrical contact may be a third electrical contact or a further second electrical contact.
The arrangement of the light absorbing structure between the second and third portions of the second (upper as seen from the distance to the substrate) DBR of the photodiode may reduce the absorption of the light spontaneously emitted by the active layer compared to prior art solutions. Thus, the signal-to-noise ratio can be improved. Furthermore, the processing can be simplified and in particular the processing time can be reduced, since it is avoided to etch back (through a few micrometers of semiconductor material) to contact the photodiode, which is usually placed in the first (lower seen from the distance to the substrate) DBR. Finally, the electrical isolation between the active layer and the photodiode can be improved by arranging the light absorbing structure outside the current path for the driving current for electrically pumping the active layer.
The second DBR may include four, five, or more portions. Each of the pairs of layers may be characterized by a thickness of one quarter of the emission wavelength of the VCSEL device in the respective material of the layer. VCSEL devices may include other layers such as current distribution layers and current confinement layers (e.g., oxide apertures). Each of the layers may include two, three, four, or more sub-layers of the build layer. The active layer may, for example, comprise a plurality of sub-layers building a quantum well structure or layer.
VCSEL devices can be bottom emitters (lasing through the first DBR or through the substrate) or top emitters (lasing away from the first DBR or substrate).
According to one embodiment, the substrate, or more particularly the semiconductor substrate (e.g., gallium arsenide substrate) and the first DBR may be of the first conductivity type. According to an alternative embodiment, the substrate may be substantially electrically non-conductive. The matrix may, for example, comprise or consist of an undoped semiconductor material. The concentration of the material for the n-doped or p-doped semiconductor material in the undoped semiconductor is preferably less than 1017/cm3. Contamination of the corresponding semiconductor material by any doping material (background doping) may not be avoided.
The first conductivity type may be characterized as having an n-doped material and the second conductivity type may be characterized as having a p-doped material.
The further electrical contact is a further second electrical contact. A second electrical contact electrically contacts the first portion. A third electrical contact electrically contacts the second portion. The second electrical contact and the third electrical contact are separated by the semiconductor layer structure. The semiconductor layer structure may be, for example, a material of the first conductivity type.
The provision of a separate and further second electrical contact between the first electrical contact and the second electrical contact may also improve the electrical isolation between the electrical drive current provided by means of the first electrical contact and the second electrical contact and the e.g. self-mixing interferometric sensor signal generated by the photodiode, which may be measured via the third electrical contact and the fourth electrical contact.
The semiconductor layer structure may be an isolation structure arranged to electrically isolate the third electrical contact from the second electrical contact. The isolation structure provides electrical isolation but does not provide optical isolation. The isolation structure is thus substantially transparent in the wavelength range of the emission wavelength of the VCSEL structure. The isolation structure may be a separate semiconductor layer structure disposed between the first portion of the second DBR and the second portion of the second DBR.
The isolation structure may include at least one pair of pairs of layers. Each of the one or more pairs of layers includes a first layer having a first refractive index and a second layer having a second refractive index different from the first refractive index. The first and second layers may be quarter-wave layers that contribute to the reflectivity of the second DBR. The isolation structure may increase the distance between the active layer and the absorption structure of the photodiode. Accordingly, the thickness of the isolation structure in the direction perpendicular to the active layer may reduce the probability of detecting light spontaneously emitted through the active layer due to an increase in the distance between the active layer and the photodiode.
The at least one pair of layers comprised by the isolation structure may for example comprise undoped semiconductor material to increase the electrical isolation. This results in a strong heterogeneous shift in the energy band diagram that can increase the electrical isolation between the second electrical contact and the third electrical contact.
The material of the first layer may comprise a first aluminum concentration and the material of the second layer comprises a second aluminum concentration lower than the first aluminum concentration, wherein the aluminum concentration determines the refractive index of the respective layer, wherein an interface between the first layer and the second layer, wherein the first aluminum concentration changes to the second aluminum concentration, is characterized as having a thickness of less than lnm. The sharp grading between the first layer and the second layer supports electrical isolation. Sharp grading may be limited by surface roughness and production tolerances.
The isolation structure may alternatively or additionally comprise a plurality of pairs of layers comprising first and second layers, wherein at least two of the first layers are of a first conductivity type and wherein at least two of the second layers are of a second conductivity type. The isolation structure may for example comprise alternating p-n-p-n (or n-p-n-p) doping to increase the electrical isolation.
The second electrical contact may be in electrical contact with a highly conductive p-doped contact layer arranged in a node of a standing wave pattern of the optical resonator during operation of the VCSEL device. The highly conductive p-doped contact layer may be characterized as having a thickness preferably greater than 1019/cm3More preferably greater than 1020/cm3The carbon doping concentration of (c). The high conductivity of the p-doped contact layer can provide good current distribution across the active layer. Placing a highly doped p-doped contact layer in the nodes of the standing wave pattern may avoid or at least reduce laser mode absorption that occurs during operation of the VCSEL device.
The further electrical contact may alternatively be a third electrical contact. The third electrical contact is in electrical contact with the first portion of the second DBR. The junction between the first portion of the second DBR and the second portion of the second DBR may be a pn junction disposed between the third electrical contact and the fourth electrical contact. The pn-junction is contacted in the forward direction (direction bias) during operation of the VCSEL device. The pn junction may increase the electrical isolation between the electrical drive current used to pump the active layer of the VCSEL device and the photodiode.
According to one embodiment, the VCSEL device may be arranged to be able to emit laser light through or in the direction of the substrate (bottom emitter). A doped matrix (e.g. an n-doped GaAs matrix, which is commonly used because it is available in high quality) may cause absorption of the laser light. Therefore, it may be preferable to thin the substrate or alternatively use an undoped semiconductor substrate to reduce the absorption of the laser light. In this case, the VCSEL device may include a first current distribution layer disposed between the base and the first DBR. The first current distribution layer is electrically connected to the first electrical contact. The first electrical contact is typically an n-contact of the active layer of the VCSEL device. The first current-distributing layer is characterized by a high electrical conductivity (e.g. a high n-doping). The absorption of the laser light may be reduced by arranging the first current distributing layer in a node of a standing wave pattern of the VCSEL device. Alternatively, the matrix may be partially or even completely removed after processing the VCSEL device.
The third portion of the second DBR may comprise pairs of layers of different refractive index, preferably between 2 and 20 pairs of layers of different refractive index, more preferably between 5 and 15 pairs of layers of different refractive index and most preferably between 8 and 12 pairs of layers of different refractive index. For example, AlGaAs (Al)xGa(1-x)As) layer may vary between 15% and 90% Al concentration to provide different refractive indices. The paired layers of the second DBR increase the intensity of the intra-cavity standing wave pattern.
The second portion of the second DBR may include at least two dyad layers of the first conductivity type. The first and second portions of the second DBR may include more pairs of layers of different refractive index than the third portion of the second DBR. As the distance between the active layer and the absorbing structure increases, the intensity of light spontaneously emitted by the active layer may be reduced as the number of pairs of layers increases.
The absorbing structure may comprise an intrinsic layer having a thickness of less than 100 nm. The intrinsic layer of the photodiode may comprise an undoped absorbing semiconductor having a low bandgap, for example undoped GaAs. The absorbing structure may be placed such that it is located in the antinode (maximum) of the standing wave pattern in the laser cavity to have a high absorption of the laser light during operation of the VCSEL device. A representative thickness of the absorbing structure may be 100 nm. Placing a relatively thin absorbing structure in an antinode of the standing wave pattern may increase the likelihood of laser light absorption compared to absorption of light spontaneously emitted by the active layer. A disadvantage of a thin absorbing layer may be a relatively high capacity, limiting the switching speed of the VCSEL device. Thus, according to an alternative embodiment, the absorbing structure may be characterized by having a thickness that covers two, three or more antinodes of the standing wave pattern within the laser cavity. An increase in the thickness of the absorbent structure can reduce the capacity, but it can make this design more sensitive to self-luminescence, since the total absorption of self-luminescence increases with increasing thickness of the absorbing layer.
The VCSEL device may be comprised by an optical sensor. The optical sensor may be comprised by a mobile communication device. Optical sensors can be used for distance detection, speed detection, particle density detection (PM 2.5 measurement), gesture control and all sensor applications based in particular on self-mixing interferometry.
According to another aspect, a method of fabricating a VCSEL device with an integrated photodiode is provided. The method comprises the following steps:
the base body is arranged on the base body,
providing a first electrical contact, wherein the first electrical contact and the further electrical contact are arranged to be able to provide an electrical driving current to electrically pump the VCSEL device,
a first DBR is provided which has a first DBR,
an active layer is provided such that the first DBR is disposed between the active layer and the substrate,
providing a first portion of the second DBR such that the active layer is arranged between the first DBR and the first portion, wherein the first portion comprises at least one pair of dyads having different refractive indices, wherein the at least one pair of dyads is characterized by a second conductivity type,
providing a second portion of the second DBR, wherein the second portion includes at least one pair of dyads having different refractive indices, wherein the at least one pair of dyads is characterized as being of a first conductivity type different from the second conductivity type,
providing a third portion of the second DBR, wherein the third portion includes at least one pair of dyads having different refractive indices, wherein the at least one pair of dyads is characterized as being of a second conductivity type,
a light absorbing structure of the photodiode is arranged between the second portion and the third portion, wherein the light absorbing structure is arranged outside a current path of the electric drive current,
a third electrical contact is provided which,
providing a fourth electrical contact, wherein the third and fourth electrical contacts are arranged to be able to electrically contact the photodiode,
wherein the further electrical contact is a second electrical contact (127), the method further comprising electrically contacting the first portion (125) through the second electrical contact (127) and the second portion (135) through the third electrical contact (130), and separating the second electrical contact (127) and the third electrical contact (130) by the semiconductor layer structure.
These steps need not be performed in the order given above. The different layers may be deposited by epitaxial methods, such as MOCVD, MBE, etc. The matrix may be removed in a subsequent processing step.
It shall be understood that the VCSEL device and the method of manufacturing a VCSEL device according to any of the embodiments described above have similar and/or identical embodiments, in particular as defined in the dependent claims.
It shall be understood that preferred embodiments of the invention may also be any combination of the dependent claims with the respective independent claims.
Further advantageous embodiments are defined below.
Drawings
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.
The invention will now be described by way of example based on embodiments with reference to the accompanying drawings.
In the drawings:
fig. 1 shows a schematic diagram of a first VCSEL device with integrated photodiode.
Fig. 2 shows a schematic diagram of a second VCSEL device with integrated photodiode.
Fig. 3 shows a schematic diagram of a third VCSEL device with integrated photodiode.
Fig. 4 shows a schematic diagram of a part of the standing wave pattern of the fourth VCSEL device in relation to the layer arrangement of the integrated photodiode.
Fig. 5 shows a schematic diagram of a top view of a fifth VCSEL device with integrated photodiode.
Fig. 6 shows an equivalent circuit of a fifth VCSEL device.
Fig. 7 shows a schematic diagram of a sixth VCSEL device with integrated photodiode.
FIG. 8 illustrates one embodiment of an optical sensor.
Fig. 9 illustrates one embodiment of a mobile communication device including an optical sensor.
Fig. 10 shows a schematic diagram of a process flow of a method of manufacturing a VCSEL according to the present invention.
In the drawings, like reference numerals refer to like elements throughout. The objects in the drawings are not necessarily to scale.
Detailed Description
Various embodiments of the invention will now be described with the aid of the accompanying drawings.
Fig. 1 shows a schematic diagram of a first VCSEL device with integrated photodiode. The first VCSEL is a top-emitting VCSEL device that emits laser light in a direction away from the base 110 as indicated by the arrow. The
Fig. 2 shows a schematic diagram of a second VCSEL device with integrated photodiode. The construction of the second VCSEL device is similar to that described in relation to figure 1. The main difference is that the electrical contacts of the light emitting part of the VCSEL device are separated from the electrical contacts of the photodiode. The
Fig. 3 shows a schematic diagram of a third VCSEL device with integrated photodiode. The construction of the third VCSEL device is similar to that described in relation to figure 2. The main difference is that there is an isolation structure 128 disposed between the
Fig. 4 shows a schematic diagram of a part of the standing wave pattern of the fourth VCSEL device in relation to the layer arrangement of the integrated photodiode. The fourth VCSEL device is also a top emitter as discussed with respect to fig. 1-3. The fourth VCSEL device comprises an n-doped GaAs substrate and Al with an aluminum content that varies as a function of the distance 203 from left to right to the laser facet as shown by the y-axis showing the aluminum concentration 201xGa(1-x)And an As layer. Fig. 4 shows an upper part of the semiconductor layer stack discussed in fig. 1 to 3 starting with the fourth
Fig. 5 shows a schematic diagram of a top view of a fifth VCSEL device with integrated photodiode. The semiconductor layer structure of the fifth VCSEL device is similar to that discussed with respect to fig. 3. A first electrical contact (n-contact) 105 of the light emitting structure of the VCSEL device is arranged on the back side of the base body and is in contact with a first bond pad, not shown in fig. 5. The
Fig. 6 shows an equivalent circuit of a fifth VCSEL device. The light emitting laser diodes of the VCSEL device are contacted by means of the first bonding pad 325 and the
Fig. 7 shows a schematic diagram of a sixth VCSEL device with integrated photodiode. The sixth VCSEL device is a bottom emitting VCSEL device comprising two VCSELs with integrated photodiodes arranged on the
Fig. 8 shows a cross section of an
Fig. 9 shows a schematic diagram of a
Fig. 10 shows a schematic diagram of a process flow of a method of manufacturing a VCSEL according to the present invention. In step 410, the
The provision of electrical contacts may comprise one or more than two steps of etching down to the respective contact layers using a suitable etching technique (dry etching, wet etching, etc.) as described above in relation to figure 4. The fabrication process may also include an oxidation process to provide an oxide aperture in each VCSEL of the VCSEL device. The manufacturing process may also include a passivation or planarization process to provide a smooth surface for depositing the bond pads (see, e.g., fig. 5). The
The layers of the first DBR, the active layer and any other layers that are current injection layers, etc. may be deposited by an epitaxial method, such as MOCVD or MBE.
While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive.
Other modifications will be apparent to persons skilled in the art upon reading this disclosure. Such modifications may involve other features which are already known in the art and which may be used instead of or in addition to features already described herein.
Variations to the disclosed embodiments can be understood and effected by those skilled in the art from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the singular form does not exclude the plural elements or steps. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
Any reference signs in the claims shall not be construed as limiting the scope of the claims.
List of reference numerals:
105 first electric contact
106 first current distribution layer
110 base body
112 optical structure
115 first DBR
120 active layer
125 first portion of the second DBR
127 second electrical contact
128 isolation structure
130 third electrical contact
135 second portion of the second DBR
140 absorbent structure
141 intrinsic layer
145 third portion of the second DBR
148 grating
150 fourth electrical contact
201 aluminum concentration
203 to laser facet distance
211 aluminum distribution
213 standing wave pattern
300 optical sensor
310 transmission window
315 emitting laser
317 reflection laser
320 driving circuit
323 analysis evaluator
325 first bonding pad
327 second bonding pad
330 third bond pad
350 fourth bond pad
362 underetch structure to photodiode cathode contact layer
364-UNDER ETCHING STRUCTURE TO VCSEL ANODE CONTACT LAYER
366 to the lower etch structure of the aperture layer
380 mobile communication device
410 step of disposing a substrate
415 step of setting a first electrical contact
420 step of setting the first DBR
425 step of providing source layer
430 step of setting the first portion of the second DBR
435 step of setting the second portion of the second DBR
440 step of disposing a third portion of the second DBR
445 step of disposing a light absorbing structure
450 setting the third electrical contact
455 setting fourth Electrical contact
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