Title: Carrier plate for opto-electronic elements having a photodiode with a thickness that absorbs a portion of incident light
Abstract: A carrier for opto-electronic elements has a carrier plate that is transparent to emitted or absorbed light of an opto-electronic element that is allocated to the carrier. At least one semiconductor structure is inventively deposited on the carrier plate and forms at least one photodiode, whereby the semiconductor structure at least partly absorbs light impinging on the carrier plate. This makes light detection possible in a simple and highly integrated fashion. A transmitting device and a receiving device can be formed with this kind of carrier.
Patent Number: 6,989,554 Issued on 01/24/2006 to Schrödinger
| Inventors:
|
Schrödinger; Karl (Berlin, DE)
|
| Assignee:
|
Infineon Technologies, AG (Munich, DE)
|
| Appl. No.:
|
281023 |
| Filed:
|
October 25, 2002 |
Foreign Application Priority Data
| Aug 02, 2002[DE] | 102 36 376 |
| Current U.S. Class: |
257/79; 257/81; 257/82 |
| Current Intern'l Class: |
H01L 27/15 (20060101) |
| Field of Search: |
257/79,81,82,184-201
|
References Cited [Referenced By]
U.S. Patent Documents
| 3946423 | Mar., 1976 | Augustine.
| |
| 4689652 | Aug., 1987 | Shimada et al.
| |
| 5701374 | Dec., 1997 | Makiuchi.
| |
| 6037644 | Mar., 2000 | Daghighian et al.
| |
| 6483130 | Nov., 2002 | Yang et al.
| |
| 6591754 | Jul., 2003 | Baur et al.
| |
| Foreign Patent Documents |
| 195 27 026 | Feb., 1997 | DE.
| |
| 101 42 531 | Mar., 2003 | DE.
| |
| 0 388 161 | Sep., 1990 | EP.
| |
| 63 269 580 | Nov., 1988 | JP.
| |
| 03/019659 | Mar., 2003 | WO.
| |
Primary Examiner: Abraham; Fetsum
Attorney, Agent or Firm: Greenberg; Laurence A., Stemer; Werner H., Locher; Ralph E.
Claims
I claim:
1. A carrier for opto-electronic elements, comprising:
a carrier plate being transparent to emitted light from an opto-electronic element
associated with said carrier plate; and
at least one semiconductor structure deposited on said carrier plate, said semiconductor
structure forming at least one photodiode and having a thickness such that less
than 20% of incident light is absorbed and partly transmits the incident light.
2. The carrier according to claim 1, wherein:
said carrier plate has a side; and
said semiconductor structure includes a layer having good conductivity disposed
at least partly on said side of said carrier plate, a first semiconductor layer,
and a second semiconductor layer.
3. The carrier according to claim 2, wherein said first semiconductor layer and
said second semiconductor layer form a PN junction, and said layer with good conductivity
forms a backside contact for said first semiconductor layer and adjoins said carrier plate.
4. The carrier according to claim 2, wherein said layer with good conductivity
and said first and second semiconductor layers form a p-doped semiconductor layer,
an n-doped semiconductor layer, and one of an intermediate lightly doped layer
and an intrinsic layer.
5. The carrier according to claim 2, wherein said layer with good conductivity
is formed from a doped semiconductor material.
6. The carrier according to claim 5, wherein said doped semiconductor material
is a doped silicon.
7. The carrier according to claim 2, wherein said layer, said first semiconductor
layer and said second semiconductor layer are formed from silicon.
8. The carrier according to claim 1, further comprising at least one metallization
contact disposed on each of said layer and said second semiconductor layer, respectively,
by way of which an electrical contacting of said layer and said second semiconductor
layer is achieved.
9. The carrier according to claim 1, wherein attenuation of light impinging on
said carrier plate is set by a thickness of said semiconductor structure.
10. The carrier according to claim 1, wherein said photodiode is a monitor diode
of an optical transmitter, and said semiconductor structure only partially absorbs
the incident light impinging on said carrier plate.
11. The carrier according to claim 1, wherein said carrier plate contains a beam
shaping element.
12. The carrier according to claim 11, wherein said beam shaping element is a lens.
13. The carrier according to claim 1, wherein said carrier plate is formed of
glass, quartz, plastic, sapphire, diamond or a semiconductor material which is
transparent to radiation of the opto-electronic element.
14. The carrier according to claim 1, further comprising an antireflection layer
applied on at least one side of said carrier plate.
15. The carrier according to claim 1, wherein said carrier plate and said semiconductor
structure form a cuboidal carrier block.
16. The carrier according to claim 1, further comprising conductive tracks and
appertaining contact pads formed on at least one of said carrier plate and said
semiconductor structure, and serving for mounting at least one of electrical elements
and the opto-electronic elements on the carrier.
17. The carrier according to claim 1, wherein said semiconductor structure is
deposited on said carrier plate by at least one method selected from the group
consisting of chemical deposition methods, physical deposition methods, epitaxy
methods, chemical vapor deposition methods, vapor deposition methods, and sputtering methods.
18. The carrier according to claim 1, wherein said semiconductor structure forms
a plurality of photodiodes in a one-dimensional or two-dimensional array.
19. The carrier according to claim 1, further comprising a beam shaping element
connected to said carrier plate.
20. The transmitting device according to claim 19, wherein said beam shaping
element is a lens.
21. The carrier according to claim 1, further comprising an antireflection layer
applied on at least one side of said semiconductor structure.
22. The carrier according to claim 1, further comprising an antireflection layer
applied on at least one side of said carrier plate and one side of said semiconductor structure.
23. An optical transmitting device, comprising:
at least one light-emitting opto-electronic element; and
a carrier, containing:
a carrier plate being transparent to emitted or received light from said light-emitting
opto-electronic element associated with said carrier; and
at least one semiconductor structure deposited on said carrier plate, said semiconductor
structure forming at least one monitor diode and having a thickness such that less
than 20% of incident light is absorbed and partly transmits the incident light;
said light-emitting opto-electronic element having an emitting surface facing
said carrier, so that light emitted by said light-emitting opto-electronic element
passes through said monitor diode and said carrier plate.
24. The transmitting device according to claim 23, further comprising a beam
shaping element, and said carrier plate has a side being averted from said semiconductor
structure and connected with said beam shaping element.
25. The transmitting device according to claim 24, wherein said beam shaping
element is a lens.
26. The transmitting device according to claim 24, wherein said carrier has interconnects
and said light-emitting opto-electronic element is fastened on said carrier and
conductively connected to said interconnects of said carrier by one of a flip chip
mounting process and a conventional bonding process.
27. The transmitting device according to claim 26, further comprising additional
components selected from the group consisting of electrical components and opto-electronic
components, said additional components fastened to said carrier and conductively
connected to said interconnects of said carrier.
28. The transmitting device according to claim 23, wherein said carrier plate
has a side being averted from said semiconductor structure and a beam shaping element
disposed on said side.
29. The transmitting device according to claim 28, wherein said beam shaping
element is a lens.
30. The transmitting device according to claim 23, wherein said light-emitting
opto-electronic element is one of a plurality of light-emitting semiconductor elements
forming a transmitting array element, and said monitor diode is one of a plurality
of monitor diodes disposed in said carrier, said monitor diodes being allocated
to said transmitting array element, and each of said monitor diodes receives light
from one of light-emitting semiconductor elements.
Description
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a carrier for opto-electronic elements, an optical
transmitter, and an optical receiver with such a carrier. The opto-electronic element
contains a carrier plate that is transparent to emitted or received light of the
opto-electronic element that is allocated to the carrier.
The monitoring of transmission power and wavelength of a laser diode by a monitor
diode is known. For edge-emitting lasers, a monitor diode is typically mounted
on the back-side mirror of the resonator. But for vertically emitting lasers (VCSEL),
this is impossible. With vertically emitting lasers it is therefore necessary to
divert a portion of the emitted light onto the monitor diode. This is disadvantageously
associated with a relatively large outlay. Accordingly, in multi-channel transmitter
modules (parallel optical link) it has not been possible to utilize a separate
monitor diode for each channel for monitoring purposes.
As an alternative to diverting a portion of the emitted light, what is known
as
a reference laser can be utilized, which has the same characteristics as the actual
laser that transmits a signal. But in this case, aging characteristics cannot be compensated.
German Patent DE 195 27 026 C2 describes an opto-electronic transducer in
which a semiconductor component that transmits or receives light is mounted on
a carrier plate in which the beam shaping structures are integrated.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a carrier for opto-electronic
elements, an optical transmitter, and an optical receiver that overcomes the above-mentioned
disadvantages of the prior art devices of this general type, with which the transmitted
or received light of an opto-electronic component can be detected in a simple fashion.
In particular, a transmitting device and a receiving device will be proposed, which
make photo detection possible for a number of opto-electronic elements easily and
optimally independently.
With the foregoing and other objects in view there is provided, in accordance
with the invention, a carrier for opto-electronic elements. The carrier contains
a carrier plate that is transparent to emitted or received light from an opto-electronic
element associated with the carrier plate, and at least one semiconductor structure
deposited on the carrier plate. The semiconductor structure forms at least one
photodiode and at least partly absorbs incident light.
The inventive solution is based on the idea of expanding the functionality of
the carrier that usually serves for fastening and conductively contacting opto-electronic
elements, such that a structure that is deposited on the carrier plate forms one
or more photodiodes. Because the carrier is transparent and is penetrated by the
light being emitted or received by an opto-electronic element, light can be easily
detected by the photodiode without additional beam branching devices or the like.
The desired light absorption can be set by suitably setting the layer thickness
of the semiconductor structure.
The semiconductor structure contains at least two semiconductor layers, which
form at least one photodiode. In a preferred development, the semiconductor structure
has a layer with good conductivity, which is formed at least partly on one side
of the carrier plate, a first semiconductor layer, and a second semiconductor layer.
The first semiconductor layer and the second semiconductor layer thus form the
PN junction of the photodiode. The layer with good conductivity supplies the backside
contact for the semiconductor layer adjoining the carrier plate.
The layer with good conductivity is preferably formed by a heavily doped semiconductor
material, particularly a heavily doped silicon. Together with the two other semiconductor
layers, it can form respective heavily doped p and n layers and an intermediate
lightly doped or intrinsic semiconductor layer as in PIN photodiodes. But the layer
with good conductivity can also be a simple metallization contact that is adjoined
by a PN-diode.
At least one respective metallization contact is advantageously provided on individual
layers of the semiconductor structure, by way of which the respective layer and
the overall photodiode are conductively contacted. To the extent that the semiconductor
structure forms several photodiodes, each photodiode, specifically the relevant
layers, contains separate contacts, so that the signal of each photodiode can be
detected independently.
In a preferred development, the photodiode is part of an optical receiver. Because
such a photodiode should completely absorb incident light, the thickness of the
semiconductor layer is selected such that incident light is substantially fully
absorbed. In an alternative development, the photodiode is a monitor diode of an
optical transmitter, whereby the semiconductor structure only partly absorbs light
impinging on the carrier plate.
The carrier plate preferably is formed of glass, quartz, plastic, sapphire, diamond
or a semiconductor material that is transparent to the radiation of the allocated
opto-electronic element.
The invention provides that an antireflection layer may be applied to at least
one side of the carrier plate and/or the semiconductor structure, namely on the
outside surfaces of the carrier and between the semiconductor structure and the
carrier plate. This minimizes losses due to reflection and backscatter.
Conductive tracks and appertaining contact pads are advantageously formed
on the carrier plate and/or on the semiconductor structure, which serve for the
mounting and conductive contacting of the electrical and/or opto-electronic elements
on the carrier. To the extent that the conductive tracks are formed on the semiconductor
structure, an isolating layer, for instance an oxide layer, is advantageously deposited
on the semiconductor structure.
The semiconductor structure can be deposited on the carrier plate by any chemical
and/or physical deposition technique, for instance epitaxy, chemical vapor deposition
(CVD), vapor deposition or sputtering. What is essential is that the semiconductor
structure is an integral component of the carrier and not merely mounted on the
carrier plate.
In a preferred development, the carrier forms a plurality of photodiodes in a
one-dimensional or two-dimensional array, with a transmission element allocated
to each. The plurality of photodiodes is advantageously provided by isolating individual
regions of the semiconductor structure following its deposition on the carrier
plate by sawing, etching or the like, and separately contacting the regions. It
is also imaginable for several semiconductor structures to be separately deposited
next to one another on the carrier plate.
The invention also relates to an optical transmitting device with at least one
light-emitting opto-electronic element and at least one monitor diode. The carrier
is provided, whereby the monitor diode is integrated in the semiconductor structure
of the carrier, and the beam emission surface of the light-emitting element faces
the carrier, so that light that is emitted by the element passes through the photodiode
and the transparent carrier plate. The emitted light can pass through the semiconductor
layer or the carrier first, depending on the orientation of the carrier. A monitoring
of the light passing though the carrier occurs automatically to a certain extent
and without additional light deflecting devises, beam splitters, etc.
The invention also provides that the carrier plate forms or contains a beam shaping
element, particularly a lens, on the side which is averted from the semiconductor
structure, so that light exiting the carrier plate undergoes beam shaping, for
instance being focused onto the butt of the optical waveguide.
The element is advantageously fastened on the carrier and conductively connected
to tracks of the carrier, for instance by flip chip mounting or conventional bonding
techniques. In principle, however, the element can also be fastened to some other
structure. The invention provides that additional electrical or opto-electronic
components may also be fastened to the carrier and conductively connected to interconnects
of the carrier.
In a preferred development, several light emitting semiconductor elements are
combined into a transmission array, and an array of monitor diodes in the semiconductor
structure is allocated to the transmission array, whereby each monitor diode receives
the light from a semiconductor element, respectively. This makes possible an individual
monitoring of the individual lasers of the array.
Lastly, the invention relates to an optical receiving device with at least
one optical receiver containing a photodiode and an electrical preamplifier. The
inventive carrier is provided. The photodiode is integrated into the semiconductor
structure of the carrier, and the electrical preamplifier is fastened to the carrier.
The semiconductor structure absorbs incident light substantially completely. A
plurality of photodiodes is again disposed in a one-dimensional or two-dimensional array.
Other features which are considered as characteristic for the invention are
set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in
a carrier for opto-electronic elements, an optical transmitter, and an optical
receiver, it is nevertheless not intended to be limited to the details shown, since
various modifications and structural changes may be made therein without departing
from the spirit of the invention and within the scope and range of equivalents
of the claims.
The construction and method of operation of the invention, however, together
with additional objects and advantages thereof will be best understood from the
following description of specific embodiments when read in connection with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic, side-elevational view of a principal structure of
a transmitting device with a carrier that forms a semiconductor structure according
to the invention;
FIG. 2 is an enlarged sectional view of the semiconductor structure shown in
FIG. 1;
FIG. 3 is a side-elevational view of the transmitting device with the carrier
that forms the semiconductor structure, whereby a laser diode and an integrated
circuit are fastened on the semiconductor structure;
FIG. 4 is a side-elevational view of the transmitting device shown in FIG. 3,
in which a Fresnel lens is employed as a beam-shaping element; and
FIG. 5 is a side-elevational view of the transmitting device in which an array
of laser diodes is allocated to an array of monitor diodes.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly,
to FIG. 1 thereof, there is shown a diagrammatic representation of an optical transmitting
device with a light-emitting optical radiation element
1 and a carrier
2.
The carrier
2 contains a transparent carrier plate
21 and a semiconductor
structure
22. A lens
3 is also provided, and disposed on a side of
the transparent carrier plate
21 that is averted from the optical radiation
element
1, or being formed in one piece with the plate
21. A beam
path
4 of light that is emitted by the optical radiation element
1
is schematically represented.
The optical radiation element
1 is advantageously a light-emitting semiconductor
component, particularly a surface imitating laser diode (VCSEL) that provides a
coherent light source. A driver module is allocated to the laser diode
1,
which is not represented but which modulates the light of the laser diode
1
in correspondence to a data signal that is to be transmitted. The optical radiation
element
1 can be directly fastened on the carrier
2 and conductively
connected to interconnects that are constructed on the carrier
2, as represented
in FIGS. 3 to
5. But it is also possible for the optical radiation element
1 to be fastened to some other structure, such as a housing that also includes
the transparent carrier
2.
The carrier plate
21 of the carrier
2 is transparent to the light
that is emitted by the optical radiation element
1. To that end, the carrier
plate
21 is formed of glass, quartz, plastic sapphire, diamond, or a semiconductor
material that is permeable to the radiation that is emitted by the optical radiation
element
1. GaAs can be utilized for wavelengths above 900 μm, and
silicon for wavelengths above 1100 μm.
The carrier plate
21 has a cuboidal shape and contains a top side
21a
which faces the optical radiation element
1 and a bottom side
21b
which is averted from the optical radiation element
1. The collecting
lens
3 is constructed on the bottom side
21b of the carrier
plate
21. The collecting lens
3 can be formed of the same material
as the carrier plate
21 and can have a monolithic structure with the carrier
plate
21. But it is just as possible for the lens
3 to be provided
as a separate part which is fastened on the bottom side
21b of the
carrier plate
21, for instance by gluing. The lens
3 can also have
a different relative refractive index than the carrier plate
21.
At the top side
21a of the carrier plate
21, the semiconductor
structure
22 is revealed. The structure
22 contains several layers
that are deposited on the transparent carrier plate
21. Known chemical and/or
physical deposition techniques can be employed to deposit or apply the individual
layers of the semiconductor structure
22. For instance, the individual layers
of the semiconductor structure can be applied to the carrier plate by epitaxy.
But other methods, such as CVD, vapor deposition, or sputtering, are also possible.
The semiconductor structure
22 that is deposited on the carrier plate
21 forms at least one photodiode.
The semiconductor structure
22 is partly transparent to the light that
is emitted by the optical radiation element
1. The photodiode that is formed
in the semiconductor structure
22 advantageously represents a monitor diode,
which partially detects the light which is emitted by the optical radiation element
1 and feeds it to a non-illustrated control device for controlling the wavelength
and/or intensity of the light that is emitted by the optical radiation element
1. Integrating the monitor diode into the carrier
2 that receives
the light from the optical radiation element
1 makes it possible to monitor
the emitted light without substantially influencing the optical path. The occurring
attenuation can even be used with advantage to the optical characteristics of the
module in certain circumstances. An example of this derives from the fact that
lasers for higher speeds are driven with high currents. The correspondingly higher
light power must then be reduced, because the power must have an upper limit for
purposes of laser safety. The required attenuation can be produced by the semiconductor
structure instead of a separate attenuating disk.
The measure of attenuation (i.e. absorption) is determined by the thickness of
the semiconductor structure
22. For instance, the depth of penetration is
approximately 10 μm for silicon. Accordingly, when the semiconductor structure
is made from silicon, it has a thickness of less than 10 μm, whereby merely
a small fraction (less than 20%) of the light that is emitted by the optical radiation
element
1 is absorbed.
It should be noted that the semiconductor structure
22 does not have to
cover the top side
21a of the transparent carrier plate
21
completely. This being the case shown in FIG. 2, the carrier
2 as a whole
is cuboidal.
FIG. 2 exemplarily represents the semiconductor structure
22 of the carrier
2. It should be noted that the semiconductor structure
22 can also
be constructed some other way. What is essential is that the individual layers
of the semiconductor structure
22 form the photodiode.
According to FIG. 2, the semiconductor structure
22 contains a layer
with good conductivity
221, a first semiconductor layer
222, and
a second semiconductor layer
223. The layer
221 with good conductivity
is applied directly on the transparent carrier plate
21, whereby an additional
antireflection layer
224 can be applied between the conductive layer
221
and the carrier plate
21 in order to minimize losses owing to reflection
and backscatter.
In this exemplifying embodiment, the layer
221 with good conductivity
is
a heavily doped silicon layer or other semiconductor layer such as an n+ doped
layer. It contains a metallization contact
51 by way of which the layer
221 is charged with an electrical voltage or ground. The contact
51
represents one or both of the contacts of the photodiode that is formed by the
semiconductor structure
22. Owing to the good conductivity, the layer
221
forms the backside contact for the adjoining semiconductor layer
222.
The two semiconductor layers
222,
223 that are applied on the conductive
layer
221 form a PN junction. They are applied to the carrier plate
21
and the layer with good conductivity
221, respectively, by epitaxy or some
other method. The middle semiconductor layer
222 is lightly n-doped or forms
an intrinsic layer, for example. The outer semiconductor layer
223 is p-doped,
for example. The construction corresponds to that of a known PIN photodiode.
It should be noted that the layer
221 with good conductivity protrudes
beyond the two other layers
222,
223 somewhat, in order to create
space for the contact
51. Additional metallization contacts
52,
53,
54,
55 are formed on the outside of the outer semiconductor layer
223. The contacts provide the second contact of the photodiode. On the other
hand, they serve as interconnects for mounting an opto-semiconductor or integrated
circuit, which are fastened on the semiconductor structure
22. If the contacts
52 to
55 are to be isolated from one another, an oxide layer—which
is common in semiconductor technology—can be applied to the bottom semiconductor
layer
223.
The application of an oxide layer on the outer semiconductor layer is also provided
in the following exemplifying embodiments, in any case as long as mutually isolated
interconnects extend on the outer semiconductor layer.
In FIG. 2 another metallization
56 is realized directly on the transparent
carrier plate
21 and stands schematically for additional interconnects on
the carrier plate
2 for conductively contacting additional components that
are fastened to the carrier plate
21.
FIG. 3 represents an exemplifying embodiment in which the optical radiation
element
1 and an integrated circuit
6 are fastened on the semiconductor
structure
22. The integrated circuit
6 is the drive circuit for the
optical radiation element
1, for example. On the semiconductor structure
22 are metallizations
56a,
56b,
57a,
57b for contacting the optical radiation element
1 and the
integrated circuit
6. The optical radiation element
1 is connected
to the metallizations
57a,
57b by flip chip mounting,
so that both contacts point to the carrier
2. The integrated circuit
6,
on the other hand, is represented in a conventionally mounted form (bond wires
7 on the side that is averted from the mounting surface), but the mounting
can also occur as with the opto-semiconductor
1. These contacting techniques
are merely exemplary. The two elements
1,
6 can just as well be joined
to the appertaining contacts
56a,
56b,
57a,
57b on the carrier
2 by conventional methods such as a bonding
technique or flip chip assembly.
FIG. 4 represents an exemplifying embodiment in which the lens is constructed
not as a lens with a spherical surface as in FIGS. 3 and 4, but as a diffractive
optical element
3a, for instance a Fresnel lens. Otherwise, the structure
corresponds to that of FIG. 3, whereby the integrated circuit
6 is not represented
in FIG.
4. The integration of a semiconductor structure
22 into the
carrier plate
21 of the carrier for opto-electronic elements is also suitable
for realizing a receiving device. In this case, the photodiode formed by the semiconductor
structure
22 represents the photodiode of an optical receiver. The thickness
of the semiconductor structure
22 is so realized that the structure substantially
completely absorbs the light striking the carrier plate
21. This is achieved
by selecting the thickness of the semiconductor structure
22 accordingly.
The structure represented in FIG. 4 can also represent the optical receiver.
For example, light that is emitted from the butt of a non-illustrated optical fiber
is focused by the Fresnel lens
3a onto the photodiode that is formed
by the semiconductor structure
22. The resulting photocurrent is amplified
by an electrical preamplifier
8, which is fastened to the carrier
2
and conductively connected to the metallizations
57a,
57b
on the surface of the semiconductor structure, and fed to non-illustrated modules downstream.
Lastly, FIG. 5 represents an exemplifying embodiment wherein the semiconductor
structure
22 forms a plurality of individually structured monitor diodes
9 which are configured in an array, which are schematically represented
in FIG.
5. An array of light-emitting semiconductor elements, particularly
VCSEL lasers which are realized in a transmitting module
11, is allocated
to the monitor diodes
9. Each monitor diode
9 is receives the light
of a transmitting diode
111, as is represented by two exemplary optical
paths
4a,
4b. Each laser
111 of the laser array
11 can thus be monitored individually.
Schematically represented metallization contacts
57a,
57b serve for contacting the laser array
11 with interconnects
that are realized on the surface of the semiconductor structure
22.
In order to produce a plurality of photodiodes
9 in an array, a solid
semiconductor
structure is first deposited on the carrier plate
21. The semiconductor
structure is then isolated into individual regions by sawing, etching or the like,
which regions are provided with separate metallizations and separately contacted.
Alternatively, several semiconductor structures can be separately deposited next
to one another on the carrier plate and separately structured.
The thickness of the carrier
2 equals 200 μm to 300 μm. The
lateral spacing of the individual lasers is on the same order of magnitude.
It should be noted that the semiconductor structure can also be formed only on
subregions of the carrier plate
21. Of course, several such subregions can
also be provided on the carrier plate
21, with each subregion forming one
or more photodiodes.
*
