CN114512896A - Semiconductor light source and preparation method - Google Patents
Semiconductor light source and preparation method Download PDFInfo
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 69
- 238000002360 preparation method Methods 0.000 title abstract description 7
- 239000000758 substrate Substances 0.000 claims abstract description 51
- 238000004519 manufacturing process Methods 0.000 claims abstract description 34
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S2304/00—Special growth methods for semiconductor lasers
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- Semiconductor Lasers (AREA)
Abstract
The embodiment of the invention discloses a semiconductor light source and a preparation method thereof, wherein the preparation method of the semiconductor light source comprises the following steps: forming an epitaxial layer comprising an active region and a passive region which are sequentially divided along a light transmission direction on a first surface of a substrate; manufacturing a single waveguide in the active region; and manufacturing a plurality of waveguides in the passive region, wherein the emergent end of the single waveguide is connected with the incident end of the plurality of waveguides. According to the method, the epitaxial layer is arranged in the light transmission direction and is divided into the active region and the passive region, then the single waveguide structure is arranged in the active region, the multi-waveguide structure is arranged in the passive region, and the emergent end of the single waveguide structure is connected with the incident end of the multi-waveguide structure, so that light beams are gradually changed into the multi-waveguide structure from the single waveguide structure, an enlarged near-field mode spot is obtained, the output of a side-emitting chip at a small divergence angle is realized, and the high light coupling efficiency is obtained.
Description
Technical Field
The embodiment of the invention relates to the field of photoelectricity, in particular to a semiconductor light source and a preparation method thereof.
Background
With the development of optical communication technology, people put higher demands on semiconductor light sources of equipment. Among them, the waveguide type edge emitting chip in the semiconductor light source is often used for high-speed and long-distance transmission due to its good single-mode characteristics. In practical application, the edge emitting chip needs to be packaged, and light beams are coupled into the optical fibers to perform light guide transmission.
At present, most edge-emitting chips enter the optical fiber in an edge-coupling mode, and the degree of edge-coupling efficiency is determined by the divergence angle of the chip. In order to achieve higher coupling efficiency of edge coupling, near-field mode spot needs to be expanded, so as to reduce the divergence angle of the chip, and common implementation schemes include widening of an exit waveguide, narrowing of the exit waveguide, and introduction of an exit window structure.
However, the two schemes of widening and narrowing of the outgoing waveguide have limited range of practical adjustment in specific application; the scheme of introducing the emergent window structure needs to etch the quantum well structure at the emergent side, and then a passive indium phosphide material grows, so that the structure easily causes high-order mode lasing, the length needs to be finely controlled, and the realization process is complex.
Disclosure of Invention
The embodiment of the invention mainly aims to provide a semiconductor light source and a preparation method thereof, aiming at realizing that an edge-emitting chip outputs at a small divergence angle so as to obtain higher optical coupling efficiency.
To achieve the above object, an embodiment of the present invention provides a semiconductor light source, including: the epitaxial layer comprises an active region and a passive region which are sequentially divided along a light transmission direction, wherein: the active region is provided with a single waveguide; the passive region is provided with a plurality of waveguides; and the emergent end of the single waveguide is connected with the incident end of the multiple waveguides.
In order to achieve the above object, an embodiment of the present invention further provides a method for manufacturing a semiconductor light source, the method including forming an epitaxial layer including an active region and a passive region sequentially divided along a light transmission direction on a first surface of a substrate; manufacturing a single waveguide in the active region; and manufacturing a plurality of waveguides in the passive region, wherein the emergent end of the single waveguide is connected with the incident end of the plurality of waveguides.
According to the semiconductor light source and the preparation method provided by the embodiment of the invention, the epitaxial layer is arranged on the semiconductor light source along the light transmission direction, the epitaxial layer is divided into the active region and the passive region along the light transmission direction, the single waveguide structure is arranged on the active region, the multi-waveguide structure is arranged on the passive region, the emergent end of the single waveguide structure is connected with the incident end of the multi-waveguide structure, light beams are transmitted to the multi-waveguide structure from the single waveguide structure to be output, so that the enlarged near-field mode spot is obtained, the small divergence angle output is achieved, and the higher light coupling efficiency is obtained.
Drawings
FIG. 1 is a schematic cross-sectional view of a prior art electroabsorption modulated laser;
fig. 2 is a schematic cross-sectional structure diagram of a conventional directly modulated semiconductor laser;
FIG. 3 is a schematic structural diagram of a semiconductor light source according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a semiconductor light source according to another embodiment of the present invention;
FIG. 5A is a lateral cross-sectional view of a semiconductor light source in accordance with one embodiment of the present invention;
FIG. 5B is a lateral cross-sectional view of a semiconductor light source in accordance with another embodiment of the present invention;
FIG. 6A is a schematic diagram of a near-field pattern of a semiconductor light source according to an embodiment of the present invention;
FIG. 6B is a schematic diagram of a near-field pattern of a semiconductor light source according to an embodiment of the present invention;
FIG. 7A is a far field schematic of a semiconductor light source according to an embodiment of the present invention;
FIG. 7B is a far field schematic of a semiconductor light source according to one embodiment of the present invention;
FIG. 8 is a graph illustrating the divergence angle of a semiconductor light source and a conventional chip according to an embodiment of the present invention;
FIG. 9 is a flow chart of a method of fabricating a semiconductor light source according to an embodiment of the invention;
FIGS. 10A to 10H are schematic process views illustrating a method for fabricating a semiconductor light source according to an embodiment of the invention;
fig. 11A to 11G are schematic process views illustrating a method for manufacturing a semiconductor light source according to another embodiment of the invention.
Reference numerals:
the optical waveguide device includes a substrate 100, a single waveguide 300, a laser 500, an electrical isolation portion 600, a modulator 700, an active region 210, an inactive region 220, a dual waveguide 310, a triple waveguide 320, a first quantum well layer 510, a grating layer 520, a first waveguide layer 530, a second waveguide layer 610, a second quantum well layer 710, a third waveguide layer 720, a fourth waveguide layer 230, a fifth waveguide layer 240, a hard mask 211, a dielectric layer 212, a first insulating layer 213, a second P electrode 215, a first P electrode 216, an antireflection film 217, a high-reflection film 218, an N electrode 219, and a second insulating layer 231.
Detailed Description
It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
In the following description, suffixes such as "module", "part", or "unit" used to denote elements are used only for facilitating the explanation of the present invention, and have no peculiar meaning in itself. Thus, "module", "component" or "unit" may be used mixedly.
It should be understood that in the description of the embodiments of the present invention, a plurality (or a plurality) means two or more, more than, less than, more than, etc. are understood as excluding the number, and more than, less than, etc. are understood as including the number. If the description of "first", "second", etc. is used for the purpose of distinguishing technical features, it is not intended to indicate or imply relative importance or to implicitly indicate the number of indicated technical features or to implicitly indicate the precedence of the indicated technical features.
In the description of the present invention, unless otherwise explicitly defined, terms such as arrangement, installation, connection and the like should be broadly construed, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the detailed contents of the technical solutions.
Those of ordinary skill in the art will appreciate that the connections described in the embodiments of the present invention include direct connections and indirect connections through intermediate components.
In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. The embodiments of the present invention will be further explained with reference to the drawings.
For ease of understanding, the related art semiconductor light source structure will be first described. Fig. 1 is a schematic cross-sectional structure diagram of a conventional electro-absorption modulated laser. The electro-absorption modulated laser shown in fig. 1 comprises a laser 500, an electrical isolator 600 and a modulator 700, and the laser 500 and the modulator 700 are respectively provided with single waveguide structures 300a and 300b to guide and transmit light beams. Fig. 2 is a schematic cross-sectional structure diagram of a conventional directly modulated semiconductor laser. The directly modulated semiconductor laser shown in fig. 2 is a semiconductor laser 500 employing a vertical cavity surface, and the vertical cavity surface semiconductor laser 500 is provided with a single waveguide structure 300c for guiding and transmitting a light beam. As shown in fig. 1 and 2, a semiconductor light source generally includes only an active region 210, and guided transmission of a light beam is achieved by a single waveguide structure of the active region 210.
Fig. 3 illustrates a semiconductor light source provided by an embodiment of the present invention. As shown in fig. 3, the semiconductor light source includes a substrate 100 and an epitaxial layer disposed on a first surface of the substrate 100. The epitaxial layer includes an active region 210 and a passive region 220 sequentially divided along a light transmission direction, wherein the active region 210 is an active region that can implement gain amplification or modulation of a light beam, and the passive region 220 is an inactive region. In the embodiment of the present invention, the active region 210 is provided with a single waveguide, the passive region 220 is provided with multiple waveguides, and the exit end of the single waveguide is connected to the entrance ends of the multiple waveguides. The semiconductor light source is divided into an active region 210 and a passive region 220 along the light transmission direction, and light beams are output from a single waveguide guided mode of the active region 210 to multiple waveguides of the passive region 220, so that the near-field mode spot of the light beams can be enlarged, the output with a small divergence angle is realized, and high light coupling efficiency is obtained.
It should be understood that a single waveguide of embodiments of the present invention may be connected to multiple waveguides by a mode converter to enable a transitional connection between the single waveguide and the multiple waveguides by the mode converter.
Illustratively, the mode converter may include a rectangular waveguide, a wedge waveguide, and a curved waveguide. In a specific implementation, the line widths of the rectangular waveguide and the wedge waveguide may be set to 1 μm to 3 μm, and the lengths may be set to 1 μm to 50 μm; the length of the curved waveguide may be set to 3 μm to 50 μm. Of course, the mode converter may also include only one of a rectangular waveguide, a wedge waveguide, a curved waveguide, or any two; or, a waveguide with a similar shape is used to replace any one of the rectangular waveguide, the wedge waveguide, and the curved waveguide, and the embodiment of the present invention does not impose too much limitation on the specific implementation form of the mode converter.
The substrate 100 of the embodiment of the invention may be a structure made of an n-type indium phosphide material, and the thickness of the indium phosphide substrate 100 may be 350 μm.
The epitaxial layer of embodiments of the present invention may have a thickness of 5cm to 11 cm.
The active region 210 of the epitaxial layer of an embodiment of the present invention includes a laser 500. Illustratively, as shown in fig. 3, the laser 500 includes a first quantum well layer 510, a grating layer 520, and a first waveguide layer 530 sequentially disposed along an epitaxial growth direction, and the single waveguide includes a first single waveguide disposed on the first waveguide layer 530.
As shown in fig. 3, the active region 210 of the epitaxial layer of the embodiment of the present invention may further include: the electric isolation part 600 and the modulator 700, and the laser 500, the electric isolation part 600 and the modulator 700 are sequentially arranged along the optical transmission direction, and the three parts form an electric absorption modulation laser. In a specific implementation, light emitted from the laser 500 is waveguide-modulated by the electro-absorption modulator 700 and then output, and the electrical isolation unit 600 is used to separate the laser 500 and the modulator 700. The quantum well structures of the laser 500 and the modulator 700 are different, for example, the number of quantum well pairs of the laser 500 is 8, and the number of quantum well pairs of the modulator 700 is 11.
Illustratively, the electrical isolation section 600 shown in fig. 3 may include a second waveguide layer 610, the second waveguide layer 610 being located at the active region 210. Optionally, a second insulating layer 231 may be further disposed on the second waveguide layer 610.
Illustratively, the modulator 700 shown in fig. 3 may include a second quantum well layer 710 and a third waveguide layer 720 sequentially disposed along an epitaxial growth direction. In a specific implementation, the laser 500, the electrical isolation portion 600, and the modulator 700 are sequentially disposed in an epitaxial layer along the optical transmission direction, and the light beam passes through the waveguide layers of the laser 500 and the electrical isolation portion 600 and then is transmitted to the third waveguide layer 720.
It is understood that a lower confinement layer may be disposed between the substrate 100 and the first and second quantum well layers 510 and 710, and a dielectric layer 212 may be disposed over the first and third waveguide layers 530 and 720, respectively.
Illustratively, the single waveguide shown in fig. 3 further includes a second single waveguide disposed on the second waveguide layer 610 and a third single waveguide disposed on the third waveguide layer 720, and the optical beam is guided and transmitted through the first single waveguide, the second single waveguide and the third single waveguide.
As shown in fig. 3, the inactive region 220 of the epitaxial layer of the embodiment of the present invention includes a fourth waveguide layer 230, and a plurality of waveguides are disposed in the fourth waveguide layer 230. In a specific implementation, the line width of the multi-waveguide structure may be set to 0.2 μm to 1 μm, and the distance between the waveguides may be set to 0.1 μm to 1 μm.
Illustratively, the first and second quantum well layers 510 and 710 according to the embodiment of the invention may be made of ingaasp or ingaas aluminum material, the strain amount may be set to 1.2% to 1.5%, and the quantum well pair number may be set to 8 to 12.
Illustratively, as shown in fig. 3, a first P-electrode 216 is further formed on the first waveguide layer 530, where the first P-electrode is a P-electrode of the laser 500; a second P-electrode 215 is also formed on the third waveguide layer 720, where the second P-electrode 215 is the P-electrode of the modulator 700; the second surface of the substrate 100 is provided with an N electrode 219; the light-emitting side of the semiconductor light source is coated with an antireflection film 217, and the backlight side is coated with a high-reflection film 218.
According to the scheme provided by the embodiment of the invention, the epitaxial layer of the semiconductor light source is divided into the active region 210 and the passive region 220 along the light transmission direction, the single waveguide structure is arranged in the active region 210, the multi-waveguide structure is arranged in the passive region, the emergent end of the single waveguide structure is connected with the incident end of the multi-waveguide structure, so that light beams are transmitted to the multi-waveguide structure from the single waveguide structure to be output, the enlarged near-field mode spot is obtained, the small divergence angle output is achieved, and the high light coupling efficiency is obtained. Furthermore, by providing multiple waveguide structures of different sizes and spacings, higher coupling efficiency into the optical fiber can be achieved.
As shown in fig. 4, fig. 4 illustrates a semiconductor light source provided by another embodiment of the present invention, which includes a substrate 100 and an epitaxial layer disposed on a first surface of the substrate 100. The epitaxial layer comprises an active region 210 and an inactive region 220 which are sequentially divided along the light transmission direction, wherein the active region 210 is provided with a single waveguide; the passive region 220 is provided with multiple waveguides; the exit end of the single waveguide is connected with the incident end of the multiple waveguides. The semiconductor light source is divided into an active region 210 and a passive region 220 along a light transmission direction, wherein the active region 210 is an active region which can gain amplify or modulate a light beam, and the passive region 220 is an inactive region. The light beam is output from the single waveguide guided mode of the active region 210 to the multi-waveguide of the passive region 220, and after passing through the multi-waveguide, the light beam obtains an enlarged near-field mode spot, and can be output at a small divergence angle, so that high optical coupling efficiency is obtained.
It should be understood that a single waveguide of embodiments of the present invention may be connected to multiple waveguides by a mode converter to enable a transitional connection between the single waveguide and the multiple waveguides by the mode converter.
Illustratively, the mode converter may include a rectangular waveguide, a wedge waveguide, and a curved waveguide. In a specific implementation, the line widths of the rectangular waveguide and the wedge waveguide may be set to 1 μm to 3 μm, and the lengths may be set to 1 μm to 50 μm; the length of the curved waveguide may be set to 3 μm to 50 μm. Of course, the mode converter may include only any one or any two of a rectangular waveguide, a wedge waveguide, and a curved waveguide; or, any one of the rectangular waveguide, the wedge waveguide and the curved waveguide may be replaced by a waveguide with a similar shape, and the specific arrangement form of the mode converter is not limited in the embodiment of the present invention.
Illustratively, the epitaxial layers of the semiconductor light source include a laser 500. As shown in fig. 4, the laser 500 may specifically include: the first quantum well layer 510, the grating layer 520 and the first waveguide layer 530 are sequentially arranged along the epitaxial growth direction, the first quantum well layer 510, the grating layer 520 and the first waveguide layer 530 are located in the active region 210, and the single waveguide comprises a first single waveguide arranged on the first waveguide layer 530.
As shown in fig. 4, in one possible implementation, the epitaxial layer may further include a fifth waveguide layer 240, and the fifth waveguide layer 240 is disposed on the first quantum well layer 510 near the substrate 100, so that the laser 500 with the vertical-type dual-waveguide structure is obtained. Illustratively, the fifth waveguide layer 240 shown in fig. 4 extends from the active region 210 to the inactive region 220, and the multiple waveguides are disposed at portions of the fifth waveguide layer 240 located in the inactive region 220. In a specific implementation, the line width of the multi-waveguide structure may be set to 0.2 μm to 1 μm, and the distance between the waveguides may be set to 0.1 μm to 1 μm. The fifth waveguide layer 240 may be further provided with a first insulating layer 213 on a portion of the inactive region 210.
Optionally, the single waveguide further includes a fourth single waveguide disposed on the fifth waveguide layer 240, that is, the single waveguide is disposed on a portion of the fifth waveguide layer 240 located in the active region 210.
In the embodiment shown in fig. 4, in a specific implementation, light beams are generated in the first quantum well layer 510, guided through the first waveguide layer 530, and enter the multiple waveguides of the fifth waveguide layer 240 in the passive region 220.
Fig. 5A is a lateral cross-sectional view of a semiconductor light source according to an embodiment of the present invention, and as shown in fig. 5A, the multiple waveguides of the passive region according to an embodiment of the present invention may be three waveguides 320, and the single waveguide 300 of the active region 210 is transited to the three waveguides 320 of the passive region 220 through a mode converter. Fig. 5B is a lateral cross-sectional view of another semiconductor light source according to an embodiment of the present invention, and as shown in fig. 5B, the multiple waveguides according to an embodiment of the present invention may be a dual waveguide 310. Of course, the multi-waveguide structure in the embodiment of the present invention may also adopt a multi-waveguide with a larger number of waveguides, and the embodiment does not limit the specific form of the multi-waveguide.
Fig. 6A is a schematic diagram of a near-field mode spot of a semiconductor light source having a passive region using three waveguides according to an embodiment of the present invention, fig. 7A is a schematic diagram of a far-field of a semiconductor light source having a passive region using three waveguides according to an embodiment of the present invention, and fig. 8 is a schematic diagram of a divergence angle curve of a semiconductor light source and a conventional chip according to an embodiment of the present invention. As shown in fig. 6A, 7A, and 8, after the light beam is emitted through the three-waveguide of the passive region, an enlarged near-field mode spot is obtained, and output with a small divergence angle can be realized, thereby improving the optical coupling efficiency.
Fig. 6B is a schematic diagram of a near-field mode spot of a semiconductor light source having a passive region using a dual waveguide according to an embodiment of the present invention, fig. 7B is a schematic diagram of a far-field mode spot of a semiconductor light source having a passive region using a dual waveguide according to an embodiment of the present invention, and fig. 8 is a schematic diagram of a divergence angle curve of a semiconductor light source and a conventional chip according to an embodiment of the present invention. As shown in fig. 6B, 7B, and 8, after the light beam is emitted through the two-wave outgoing of the passive region, an enlarged near-field mode spot is obtained, and output with a small divergence angle can be realized, thereby improving the optical coupling efficiency.
The embodiment also provides a method for manufacturing a semiconductor light source, as shown in fig. 9, the method includes the following steps:
step S100, an epitaxial layer including an active region 210 and a passive region 220 sequentially divided in a light transmission direction is formed on a first surface of the substrate 100.
In the embodiment of the present invention, an epitaxial layer is formed on the surface of the substrate 100 of the semiconductor light source, and the epitaxial layer includes an active region 210 and a passive region 220 which are sequentially divided along the light transmission direction. The active region 210 is a multi-quantum well region of the chip and is an energized region, and the intrinsic absorption of the waveguide is relatively large, so as to realize gain amplification and/or modulation of the optical signal; passive region 220 is a bulk material and is an unpowered region with small intrinsic absorption by the waveguide.
Illustratively, the step S100 of forming an epitaxial layer on the first surface of the substrate 100, which includes the active region 210 and the passive region 220 sequentially divided along the light transmission direction, may be specifically implemented by: epitaxially growing an active layer on the first surface of the substrate 100 to obtain an active region 210 of the epitaxial layer; and removing a part of the active layer, and epitaxially growing a passive layer on the exposed surface after the active layer is removed to obtain a passive region 220 of the epitaxial layer.
Step S200, manufacturing a single waveguide in an active region 210;
step S300, a plurality of waveguides are manufactured in the passive region 220, and the emergent end of the single waveguide is connected with the incident end of the plurality of waveguides.
It should be understood that the multi-waveguide is a triple waveguide or a double waveguide, and the exit end of the single waveguide is connected to the entrance end of the multi-waveguide. A mode converter can be arranged between the single waveguide and the multiple waveguides, and the single waveguide is converted into the multiple waveguides.
For example, the waveguide may be fabricated by contact exposure, vacuum exposure, projection exposure or electron beam exposure, which is not limited by the embodiment. For example, the epitaxial growth of the semiconductor light source may use metal organic vapor deposition, selective area epitaxy or molecular beam epitaxy, which is not limited by the embodiments of the present invention.
It should be understood that, in the method, through steps S100, S200, and S300, an epitaxial layer disposed along a light transmission direction on a semiconductor light source is divided into an active region 210 and a passive region 220, and then a single waveguide structure is disposed in the active region 210, a multi-waveguide structure is disposed in the passive region 220, and an exit end of the single waveguide structure is connected to an entrance end of the multi-waveguide structure, so that a light beam is buffered from the single waveguide structure to the multi-waveguide structure, an enlarged near-field mode spot is obtained, and thus, a small divergence angle output is achieved, and a high light coupling efficiency is obtained. In addition, the coupling efficiency of the light beams entering the optical fiber can be adjusted according to the sizes and the intervals of different multi-waveguide structures.
The following provides a specific exemplary description of a method for manufacturing a semiconductor light source according to an embodiment of the present invention with reference to specific examples.
When the method for manufacturing a semiconductor light source according to the embodiment of the present invention is used for manufacturing a semiconductor light source as shown in fig. 3, the following steps may be specifically performed.
As shown in fig. 10A, a first quantum well layer 510, a grating layer 520, and a first waveguide layer 530 are epitaxially grown in sequence on a first surface of a substrate 100, so as to obtain a laser 500; and epitaxially growing a second quantum well layer 710 and a third waveguide layer 720 in that order on the first surface of the substrate 100, resulting in the modulator 700. In this way, an epitaxial growth of an active layer on the first surface of the substrate 100 is achieved, resulting in an active region 210 of the epitaxial layer, where the active layer comprises the laser 500 and the modulator 700.
As shown in fig. 10B, a portion between the laser 500 and the modulator 700 is removed to expose a first surface of the substrate 100, so as to form an electrical isolation 600 between the laser 500 and the modulator 700, wherein the electrical isolation 600 is used for isolating electrodes of the laser 500 and the modulator 700.
As shown in fig. 10B, a portion of the second quantum well layer 710 and the third waveguide layer 720 is removed to expose the first surface of the substrate 100 to define the inactive region 220.
In a specific implementation, a hard mask 211 may be disposed on the laser 500 and the modulator 700, the hard mask 211 may be a silicon dioxide or silicon nitride material, and the hard mask 211 is provided with a pattern of the electrical isolation 600 and the inactive region 220; etching is then performed according to the pattern on the hard mask 211 resulting in the electrical isolation 600 and the passive regions 220. The etching method may adopt a combination of a dry method and a wet method, the dry method etches the corrosion barrier layer (i.e. the first surface of the substrate 100) under the quantum well, and then the etching end face is rinsed by using an etching solution, the etched bottom face is aligned, and the ion damage of the interface is removed.
As shown in fig. 10C, a fourth waveguide layer 230 is epitaxially grown on the first surface of the substrate 100, resulting in an inactive region 220 of the epitaxial layer. In this way, a portion of the active layer is removed, and the surface exposed after the active layer is removed is epitaxially grown to obtain the passive region 220 of the epitaxial layer.
As shown in fig. 10C, a second waveguide layer 610 is epitaxially grown on the first surface of the substrate 100, resulting in the electrical isolation portion 600. The second waveguide layer 610 belongs to the active layer, and the electrical isolation section 600, the laser 500 and the modulator 700 together form the active region 210. To this end, forming an epitaxial layer including an active region 210 and an inactive region 220 sequentially divided in a light transmission direction on the first surface of the substrate 100 is completed.
It is understood that the fourth waveguide layer 230 and the second waveguide layer 610 may be a low composition low index of refraction insulating indium gallium arsenide phosphide (InGaAsP) material.
As shown in fig. 10D, the hard mask 211 on the laser 500 and modulator 700 is removed.
As shown in fig. 10E, a first single waveguide is formed in the first waveguide layer 530; fabricating a second single waveguide in the second waveguide layer 610; fabricating a third single waveguide in the third waveguide layer 720; multiple waveguides are fabricated in the fourth waveguide layer 230. The waveguides of the active region 210 and the passive region 220 can be manufactured in one step, and the problem of deflection of the axes of the waveguides does not exist, so that the light-emitting axial direction does not deflect, the modal stability is increased, the packaging cost and efficiency are reduced, and the projection type exposure or the electron beam exposure can be specifically adopted. Thus, a single waveguide 300 is fabricated in the laser 500, the modulator 700 and the electrical isolation 600, and multiple waveguides are fabricated in the passive region 220, where the multiple waveguides may be three waveguides 320 or two waveguides 310. In addition, a mode converter can be arranged between the single waveguide 300 and the multiple waveguides, and transition connection from the single waveguide 300 to the multiple waveguides is realized.
As shown in fig. 10F, a dielectric layer 212 is disposed on the laser 500 and the modulator 700, where the dielectric layer 212 may be silicon dioxide or silicon nitride material, and includes a P-electrode hollow pattern, which can be used as an electrode manufacturing template and a protection layer for the electrode contact surface of the laser 500 and the modulator 700.
As shown in fig. 10G, a second insulating layer 231 is grown on the second waveguide layer 610 of the electrically isolated region, and a first insulating layer 213 is grown on the fourth waveguide layer 230 of the inactive region, where the second insulating layer 231 and the first insulating layer 213 correspond to cladding layers of the second waveguide layer 610 and the fourth waveguide layer 230, and may be specifically an insulating indium phosphide (inp) material having a refractive index consistent with that of the substrate 100.
As shown in fig. 10H, a first P electrode 216 and a second P electrode 215 are formed in the area corresponding to the hollow pattern of the dielectric layer 212, and an N electrode 219 is formed on the second surface of the substrate 100. It will be appreciated that the first P-electrode 216 is located on the laser 500 and the second P-electrode 215 is located on the modulator 700, with the two P-electrodes being separated by an electrical separator 600. The P electrode 219 and the N electrode 219 may be formed by magnetron sputtering or evaporation sputtering. In addition, after the first P-electrode 216 and the second P-electrode 215 are formed, the substrate 100 may be thinned and polished to 80 μm to 120 μm, and then the N-electrode 219 is disposed on the second surface of the substrate 100.
As shown in fig. 10H, this example is further coated with an anti-reflection film 217 on the light-emitting side and a high-reflection film 218 on the backlight side. The reflection index of the reflection reducing film 217 may be less than 0.1%, and the reflection index of the high reflection film 218 may be 85% to 95%.
This example obtains a semiconductor light source including a high power laser 500, an electrical isolator 600, and an electro-absorption modulator 700 through the manufacturing process shown in fig. 10A to 10H, where a passive multi-waveguide is disposed on the light exit side of the semiconductor light source to obtain an enlarged near-field mode spot, thereby achieving a small divergence angle output and a high optical coupling efficiency.
When the method for manufacturing a semiconductor light source according to the embodiment of the present invention is used for manufacturing a semiconductor light source as shown in fig. 4, the following steps may be specifically performed.
As shown in fig. 11A, epitaxially growing a fifth waveguide layer 240, a first quantum well layer 510, a grating layer 520 and a first waveguide layer 530 on the first surface of the substrate 100 to obtain an active region 210 of the epitaxial layer; the fifth waveguide layer 240 may be made of a low-composition low-refractive-index insulating indium gallium arsenic phosphide (ingaasp) material. In this way, an active layer is epitaxially grown on the first surface of the substrate 100, and an active region 210 of the epitaxial layer is obtained.
As shown in fig. 11B, a hard mask 211 is disposed on the first waveguide layer 530, the hard mask 211 may be a silicon dioxide or silicon nitride material, and the hard mask 211 is disposed with a pattern of the inactive region 220; and then etching is performed according to the pattern on the hard mask 211 to obtain the area where the epitaxial layer passive region 220 needs to be manufactured. The etching method may adopt a combination of a dry method and a wet method, dry etching is performed on the etch stop layer (i.e., the surface of the fifth waveguide layer 240) under the quantum well, and a portion of the first quantum well layer 510, the grating layer 520, and the first waveguide layer 530 is removed to expose the fifth waveguide layer 240, thereby obtaining the passive region 220 of the epitaxial layer. Thus, a part of the active layer is removed, the active layer is epitaxially grown on the exposed surface after the active layer is removed, the passive region 220 of the epitaxial layer is obtained, the etching end face is rinsed by using etching solution, the etching bottom face is aligned, and ion damage of the interface is removed.
As shown in fig. 11C, the hard mask 211 is removed.
As shown in fig. 11D, a first single waveguide 300 is formed on the first waveguide layer 530; after removing a portion of the first quantum well layer 510, the grating layer 520, and the first waveguide layer 530, the exposed portion of the fifth waveguide layer 240 is used to fabricate a multi-waveguide; the waveguides of the active region 210 and the passive region 220 can be manufactured in one step, and the problem of deflection of the axes of the waveguides does not exist, so that the light-emitting axial direction does not deflect, the modal stability is increased, the packaging cost and efficiency are reduced, and the projection type exposure or the electron beam exposure can be specifically adopted. The multiple waveguides can be three waveguides or two waveguides. In addition, a mode converter can be disposed between the active region 210 and the passive region 220 to realize transition connection of a single waveguide to multiple waveguides.
As shown in fig. 11E, a dielectric layer 212 is disposed over the first waveguide layer 530. The dielectric layer 212 may be silicon dioxide or silicon nitride material, and includes a P-electrode hollow pattern, which can be used as an electrode manufacturing template and a protection layer of the electrode contact surface of the laser 500.
As shown in fig. 11F, a first insulating layer 213 is formed on the exposed region of fifth waveguide layer 240, and first insulating layer 213 may be specifically an insulating indium phosphide (inp) material having a refractive index identical to that of substrate 100.
As shown in fig. 11G, a first P electrode 216 is formed on the dielectric layer 212, and an N electrode 219 is disposed on the second surface of the substrate 100. In a specific implementation, after the first P electrode 216 is fabricated, the substrate 100 may be thinned and polished to 80 μm to 120 μm, and then the N electrode 219 is disposed on the second surface of the substrate 100.
As shown in FIG. 11G, an antireflection film 217 is coated on the light exit side and a high reflection film 218 is coated on the backlight side. The reflection index of the reflection reducing film 217 may be less than 0.1%, and the reflection index of the high reflection film 218 may be 85% to 95%.
In this example, through the manufacturing process shown in fig. 11A to 11G, a semiconductor light source including a vertical dual-waveguide laser 500 is obtained, where a passive multi-waveguide is disposed on a light exit side of the semiconductor light source, and an enlarged near-field mode spot is obtained, so that a small divergence angle output is achieved, and a high optical coupling efficiency is obtained.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
It is further to be understood that while operations are depicted in the drawings in a particular order, this is not to be understood as requiring that such operations be performed in the particular order shown or in serial order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, parallel processing may be advantageous.
The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, and are not to be construed as limiting the scope of the invention. Any modifications, equivalents and improvements which may occur to those skilled in the art without departing from the scope and spirit of the present invention are intended to be within the scope of the claims.
Claims (14)
1. A semiconductor light source comprising a substrate and an epitaxial layer disposed on a first surface of the substrate, the epitaxial layer comprising an active region and a passive region sequentially divided along a light transmission direction, wherein:
the active region is provided with a single waveguide;
the passive region is provided with a plurality of waveguides;
and the emergent end of the single waveguide is connected with the incident end of the multiple waveguides.
2. The semiconductor light source of claim 1, wherein the single waveguide is connected to the multiple waveguides by a mode converter.
3. The semiconductor light source of claim 2, wherein the mode converter comprises any one or combination of rectangular waveguides, wedge waveguides, and curved waveguides.
4. The semiconductor light source of claim 1, wherein the epitaxial layer comprises a laser comprising a first quantum well layer, a grating layer, and a first waveguide layer disposed in sequence along an epitaxial growth direction, the first quantum well layer, the grating layer, and the first waveguide layer being located in the active region, the single waveguide comprising a first single waveguide disposed at the first waveguide layer.
5. The semiconductor light source of claim 4, wherein the epitaxial layer further comprises an electrical isolator and a modulator, the laser, the electrical isolator and the modulator being arranged in sequence along a light transmission direction;
the electrical isolation section comprises a second waveguide layer, the second waveguide layer being located in the active region;
the modulator comprises a second quantum well layer and a third waveguide layer which are sequentially arranged along the epitaxial growth direction, and the second quantum well layer and the third waveguide layer are positioned in the active region;
the single waveguide further includes a second single waveguide disposed on the second waveguide layer and a third single waveguide disposed on the third waveguide layer.
6. The semiconductor light source of claim 4 wherein the epitaxial layer further comprises a fifth waveguide layer disposed on a side of the first quantum well layer proximate the substrate.
7. The semiconductor light source of claim 6, wherein the fifth waveguide layer extends from the active region to the inactive region, and the multiple waveguide is disposed at a portion of the fifth waveguide layer at the inactive region.
8. A semiconductor light source as claimed in claim 1 or 4, characterized in that the epitaxial layer comprises a fourth waveguide layer, which is located in the passive region, the multiple waveguides being arranged in the fourth waveguide layer.
9. A method for manufacturing a semiconductor light source, comprising:
forming an epitaxial layer comprising an active region and a passive region which are sequentially divided along a light transmission direction on a first surface of a substrate;
manufacturing a single waveguide in the active region;
and manufacturing a plurality of waveguides in the passive region, wherein the emergent end of the single waveguide is connected with the incident end of the plurality of waveguides.
10. The method according to claim 9, wherein the forming an epitaxial layer including an active region and a passive region sequentially divided in a light transmission direction on the first surface of the substrate comprises:
epitaxially growing an active layer on the first surface of the substrate to obtain an active region of the epitaxial layer;
and removing a part of the active layer, and epitaxially growing a passive layer on the exposed surface after the active layer is removed to obtain a passive region of the epitaxial layer.
11. The method of manufacturing of claim 10, wherein the active region of the epitaxial layer comprises a laser; the epitaxially growing an active layer on the first surface of the substrate to obtain an active region of the epitaxial layer includes:
sequentially epitaxially growing a first quantum well layer, a grating layer and a first waveguide layer on the first surface of the substrate to obtain the laser;
the manufacturing of the single waveguide in the active region comprises the following steps:
and manufacturing a first single waveguide on the first waveguide layer.
12. The method of manufacturing according to claim 11, wherein the active region of the epitaxial layer further comprises an electrical isolation and a modulator; the epitaxially growing an active layer on the first surface of the substrate to obtain an active region of the epitaxial layer, further comprising:
sequentially epitaxially growing a second quantum well layer and a third waveguide layer on the first surface of the substrate to obtain the modulator;
removing a part between the laser and the modulator to expose the first surface of the substrate, and epitaxially growing a second waveguide layer on the first surface of the substrate to obtain the electrical isolation part;
the manufacturing of the single waveguide in the active region further comprises:
manufacturing a second single waveguide on the second waveguide layer;
and manufacturing a third single waveguide on the third waveguide layer.
13. The method according to claim 12, wherein the removing a portion of the active layer and the epitaxially growing a passive layer on the exposed surface after removing the active layer to obtain the passive region of the epitaxial layer comprises:
removing a portion of the second quantum well layer and the third waveguide layer to expose the first surface of the substrate;
epitaxially growing a fourth waveguide layer on the first surface of the substrate to obtain a passive region of the epitaxial layer;
the method for manufacturing the multi-waveguide in the passive region comprises the following steps:
and manufacturing a plurality of waveguides on the fourth waveguide layer.
14. The method of claim 10, wherein the epitaxially growing an active layer on the first surface of the substrate to obtain an active region of the epitaxial layer comprises:
epitaxially growing a fifth waveguide layer, a first quantum well layer, a grating layer and a first waveguide layer on the first surface of the substrate to obtain an active region of the epitaxial layer;
removing a part of the active layer, and epitaxially growing a passive layer on the exposed surface after removing the active layer to obtain a passive region of the epitaxial layer, wherein the passive region comprises:
removing parts of the first quantum well layer, the grating layer and the first waveguide layer to expose the fifth waveguide layer, so as to obtain a passive region of the epitaxial layer;
the manufacturing of the single waveguide in the active region comprises the following steps:
manufacturing a first single waveguide on the first waveguide layer;
the method for manufacturing the multi-waveguide in the passive region comprises the following steps:
and after removing parts of the first quantum well layer, the grating layer and the first waveguide layer, manufacturing the multi-waveguide by the exposed part of the fifth waveguide layer.
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| US4371966A (en) * | 1980-11-06 | 1983-02-01 | Xerox Corporation | Heterostructure lasers with combination active strip and passive waveguide strip |
| CN1464603A (en) * | 2002-06-21 | 2003-12-31 | 中国科学院半导体研究所 | Multi-quantum well waveguide butt coupling method |
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