CN115296142A - Laser and manufacturing method thereof - Google Patents
Laser and manufacturing method thereof Download PDFInfo
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- CN115296142A CN115296142A CN202210949078.2A CN202210949078A CN115296142A CN 115296142 A CN115296142 A CN 115296142A CN 202210949078 A CN202210949078 A CN 202210949078A CN 115296142 A CN115296142 A CN 115296142A
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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
- H01S5/2004—Confining in the direction perpendicular to the layer structure
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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
Abstract
The application discloses laser instrument and preparation method thereof relates to the field of semiconductor photoelectric devices, and the laser instrument includes: the laser device module comprises a substrate and a laser device module arranged on the substrate; the laser device module comprises a first waveguide boss, a first boss and a semi-insulating current blocking layer, wherein the first waveguide boss is arranged on the substrate and comprises a grating, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss. The laser instrument in this application includes substrate and laser instrument module, and the laser instrument module is including range upon range of first waveguide boss and first boss, and first waveguide boss both sides and second boss both sides are equipped with semi-insulating electric current and block the layer, and the layer is blocked for semi-insulating in this application promptly the electric current, need not to set up "binary channels recess", makes the parasitic capacitance of laser instrument lower to make the laser instrument have enough high frequency working property.
Description
Technical Field
The present application relates to the field of semiconductor photoelectric devices, and in particular, to a laser and a method for fabricating the same.
Background
A buried-heterostructure (BH) is a typical waveguide structure in an optoelectronic device such as a Laser Diode (LD), an electro-absorption modulated laser (EML), and the like. The BH structure has a current blocking layer generated by reverse-biasing the blocking layers with P-type and N-type InP. This results in a relatively large parasitic capacitance and hence poor high frequency performance of the device. Especially above 25Gbps, performance of the device design is nearly impossible to achieve. Currently, to solve this problem, a "dual channel groove" is formed on both sides of the waveguide. Taking EML as an example, the "two-channel groove" bottom reaches the substrate. However, the current is blocked by the P-type/N-type InP current blocking layers around the Multiple Quantum Well (MQW) EA-MQW in the electro-absorption (EA) region of the EML and the multiple quantum well LD-MQW waveguide region in the LD region, so that the parasitic capacitance is high, resulting in poor high-frequency performance of the device at 25Gbps or more.
Therefore, how to solve the above technical problems should be a great concern to those skilled in the art.
Disclosure of Invention
The application aims to provide a laser and a manufacturing method thereof so as to improve the high-frequency performance of the laser.
In order to solve the above technical problem, the present application provides a laser, including:
the laser device module comprises a substrate and a laser device module arranged on the substrate;
the laser device module comprises a first waveguide boss, a first boss and a semi-insulating current blocking layer, wherein the first waveguide boss is arranged on the substrate and comprises a grating, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss.
Optionally, the semi-insulating current blocking layer comprises at least two semi-insulating layers.
Optionally, when the semi-insulating current blocking layer includes two semi-insulating layers, an upper surface of the first semi-insulating layer at the bottom is flush with an upper surface of the first waveguide boss, and the second semi-insulating layer at the top is flush with an upper surface of the first boss.
Optionally, the method further includes:
the electroabsorption module is arranged on the substrate and integrated with the laser device module, and comprises a second waveguide boss without gratings, a second boss arranged on the second waveguide boss and a semi-insulating current blocking layer, wherein the semi-insulating current blocking layer is arranged on two sides of the second waveguide boss and two sides of the second boss.
Optionally, the method further includes:
and the semi-insulating window is arranged on the end face of the electric absorption module and shields the multiple quantum wells in the second waveguide boss, the top of the semi-insulating window extends to the second cladding layer in the second boss, the bottom of the semi-insulating window extends to the first cladding layer in the second waveguide boss, and the semi-insulating window is connected with the first semi-insulating layer and grows simultaneously.
Optionally, when the semi-insulating current blocking layer includes two semi-insulating layers, the electrode isolation region between the electroabsorption module and the laser device module includes a second semi-insulating layer extending to the inside of the laser, and the bottom of the second semi-insulating layer and the top of the first semi-insulating layer are located on the same surface.
The application also provides a laser manufacturing method, which comprises the following steps:
obtaining a substrate;
preparing a laser device module on the substrate, wherein the laser device module comprises a first waveguide boss which is arranged on the substrate and contains a grating, a first boss which is arranged on the first waveguide boss, and a semi-insulating current blocking layer, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss.
Optionally, the method further includes:
preparing an electric absorption module integrated with the laser device module on the substrate, wherein the electric absorption module comprises a second waveguide boss without a grating, a second boss and a semi-insulating current blocking layer, the second waveguide boss is arranged on the substrate, the second boss is arranged on the second waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the second waveguide boss and two sides of the second boss.
Optionally, when the semi-insulating current blocking layer includes two semi-insulating layers, the preparing the laser device module and the electroabsorption module on the substrate includes:
epitaxially growing a first structural layer containing a grating embedded layer on the substrate;
selectively etching the first structural layer, and selectively epitaxially growing a third structural layer without a grating embedded layer in an etching area, wherein the third structural layer is flush with the upper surface of the first structural layer;
forming a first patterned mask on the upper surfaces of the first structural layer and the third structural layer;
etching the first structural layer and the third structural layer under the action of the first graphical mask to correspondingly form the first waveguide boss and the second waveguide boss;
epitaxially growing first semi-insulating layers on two sides of the first waveguide boss and two sides of the second waveguide boss;
removing the first graphical mask and epitaxially growing a second structural layer;
forming a second patterned mask on the second structural layer;
etching the second structure layer under the action of the second patterned mask to form a first boss on the first waveguide boss and a second boss on the second waveguide boss, wherein the etching is stopped until the first semi-insulating layer is etched;
epitaxially growing second semi-insulating layers on two sides of the first boss and two sides of the second boss;
and removing the second patterned mask.
Optionally, a gap is left between the first patterned mask and the end face of the electroabsorption module;
correspondingly, epitaxially growing a first semi-insulating layer on both sides of the first waveguide mesa and both sides of the second waveguide mesa includes:
and epitaxially growing first semi-insulating layers on two sides of the first waveguide boss and two sides of the second waveguide boss, forming a semi-insulating window in an etching region corresponding to the gap, wherein the top of the semi-insulating window extends to the second cladding layer in the second boss, the bottom of the semi-insulating window extends to the first cladding layer in the second waveguide boss, and the semi-insulating window shields multiple quantum wells in the second waveguide boss.
Optionally, an electrode isolation gap exists between the laser device module and the electric absorption module through the second patterned mask;
correspondingly, etching the second structure layer under the action of the second patterned mask to form a first boss on the first waveguide boss and a second boss on the second waveguide boss comprises:
etching the second structural layer under the action of the second patterned mask to form the first boss, the second boss and a groove between the laser device module and the electric absorption module, wherein the bottom of the groove and the top of the first semi-insulating layer are positioned on the same surface;
correspondingly, epitaxially growing second semi-insulating layers on both sides of the first boss and both sides of the second boss includes:
and epitaxially growing the second semi-insulating layers on two sides of the first boss and two sides of the second boss, and epitaxially growing the second semi-insulating layers in the grooves at the same time.
The application provides a laser, includes: the laser device module comprises a substrate and a laser device module arranged on the substrate; the laser device module comprises a first waveguide boss, a first boss and a semi-insulating current blocking layer, wherein the first waveguide boss is arranged on the substrate and comprises a grating, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss.
It is thus clear that laser instrument in this application includes substrate and laser instrument module, and the laser instrument module is including range upon range of first waveguide boss and first boss, and the both sides of first waveguide boss and the both sides of first boss are equipped with semi-insulating electric current and block the layer, and the layer is blocked for semi-insulating in this application promptly, need not to set up "binary channels recess", alright make the parasitic capacitance of laser instrument lower to make the laser instrument have enough high frequency working property, can exceed 25 Gbps's performance.
In addition, the application also provides a laser manufacturing method with the advantages.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions of the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.
FIG. 1 is a schematic diagram of an EML in the prior art;
FIG. 2 is a schematic cross-sectional view of the EML of FIG. 1 at BB';
FIG. 3 is a schematic cross-sectional view of the EML of FIG. 1 at AA';
FIG. 4 is a top view of the EML of FIG. 1;
fig. 5 is a schematic cross-sectional view of a laser according to an embodiment of the present disclosure;
FIG. 6 is a top view of an EML provided by an embodiment of the present application;
fig. 7 is a schematic structural diagram of an EML according to an embodiment of the present disclosure;
FIG. 8 is a schematic cross-sectional view of the EML of FIG. 7 at BB';
FIG. 9 is a schematic cross-sectional view of the EML of FIG. 7 at AA';
FIG. 10 is a schematic cross-sectional view of the EML of FIG. 7 at CC';
fig. 11 is a flowchart of a method for fabricating a laser according to an embodiment of the present disclosure;
FIG. 12 is a flow chart of another method for fabricating a laser according to an embodiment of the present disclosure;
fig. 13 is a flowchart illustrating a method for manufacturing a laser device module and an electro-absorption module according to an embodiment of the present disclosure;
fig. 14 to 23 are flow charts of processes for manufacturing a laser device module and an electro-absorption module according to an embodiment of the present disclosure;
FIG. 24 is a schematic view of another first patterned mask used in the present application during the fabrication of a laser;
FIG. 25 is a schematic view of another second patterned mask used in the process of fabricating a laser according to the present application;
FIG. 26 is a schematic diagram illustrating the etching of a groove corresponding to an electrode isolation region during the laser fabrication process according to the present application;
FIG. 27 is a schematic cross-sectional view of an EML of the present application at CC' when the electrode isolation region includes a second semi-insulating layer;
in the figure: 1'. N-type InP substrate, 2'. N-type InP cladding layer, 3'. EA-MQW,4'. LD-MQW,5'. P-type InGaAs contact layer, 6'. P-type InP cladding layer, 7'. Double-channel groove, 8'. N-type InP current blocking layer, 9'. P-type InP current blocking layer, 10'. P-type electrode, 11'. N-type electrode, 12'. Electrode isolation region, 13'. SiO 2 The semiconductor device comprises an isolation layer, 14', a grating, 1, a substrate, 2, a first cladding layer, 3, a multiple quantum well, 4, a spacing layer, 5, a grating, 6, a second cladding layer, 7, a contact layer, 8, a semi-insulating current blocking layer, 9, a first electrode, 10, a second electrode, 11, an electrode isolation region, 12, a semi-insulating window, 13, an isolation layer, 14, a cladding layer, 15, a mask layer, 16, a first patterned mask, 17, a second patterned mask, 18, a groove, 19, a grating embedding layer, 81, a first semi-insulating layer, 82, a second semi-insulating layer, 111, a gap, 31.EA-MQW and 32.LD-MQW.
Detailed Description
In order that those skilled in the art will better understand the disclosure, the following detailed description is given with reference to the accompanying drawings. It should be apparent that the described embodiments are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
As described in the background section, in order to improve the high-frequency performance of the laser, at present, two "dual-channel grooves" are formed on two sides of the laser waveguide, taking an EML as an example, as shown in fig. 1 to 4, the EML may be divided into an EA region and an LD region, an N-type InP cladding layer 2', MQW, a P-type InP cladding layer 6', a P-type InGaAs contact layer 5', a P-type electrode 10', and an N-type electrode 11' are sequentially grown on the upper surface of an N-type InP substrate 1', wherein the MQW includes an EA-MQW3' located in the EA region and an LD-MQW4' located in the LD region, an electrode isolation region 12' is located between the P-type electrode 10' located in the EA region and the P-type electrode 10' located in the LD region, and an SiO is located between the P-type InGaAs contact layer 5' and the P-type electrode 10' 2 An isolation layer 13'. The LD region has a grating 14'. The bottom of the double-channel groove 7 reaches the N-type InP substrate 1', the EA-MQW3' and the LD-MQW4' are blocked by the P-type InP current blocking layer 9' and the N-type InP current blocking layer 8', and due to the existence of the P-type InP current blocking layer 9' and the N-type InP current blocking layer 8', the parasitic capacitance is high, so that the high-frequency performance of the device is poor above 25 Gbps.
In view of the above, the present application provides a laser, please refer to fig. 5, which includes:
the laser device comprises a substrate 1 and a laser device module arranged on the substrate 1;
the laser device module comprises a first waveguide boss containing a grating, a first boss and a semi-insulating current blocking layer 8, wherein the first waveguide boss is arranged on the substrate 1, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer 8 is arranged on two sides of the first waveguide boss and two sides of the first boss.
The semi-insulating current blocking layers 8 are specifically located on both sides of the protrusion in the first waveguide boss and on both sides of the protrusion in the first boss.
It should be noted that the laser further comprises a first electrode 9 on the lower surface of the substrate 1, and a second electrode on the lower surface of the laser moduleA second electrode 10 on the upper surface, and an isolation layer 13 between the second electrode 10 and the semi-insulating current blocking layer 8. The material of the isolation layer 13 may be SiO 2 . Wherein the laser module is located on the upper surface of the substrate 1. The upper and lower surfaces, etc. are referred to herein as being oriented or positional based on the orientation or positional relationship shown in the drawings, merely for convenience in describing the invention, and are not intended to limit the components so referred to having this particular orientation.
The first waveguide boss comprises a first cladding layer 2, a multi-quantum well 3, a spacing layer 4, a grating 5 and a covering layer which are laminated in the direction far away from the substrate 1, and the first boss comprises a second cladding layer 6 and a contact layer 7 which are laminated in the direction far away from the substrate 1. Wherein, the width of the multiple quantum well 3 can be 1.5 to 2 μm. The cladding layer is the same material as the second cladding layer 6.
The substrate 1 may be an N-type InP substrate, the first cladding layer 2 may be an N-type InP cladding layer, the spacer layer 4 may be a P-type InP spacer layer 4, the second cladding layer 6 may be a P-type InP cladding layer, the contact layer 7 may be a P-type InGaAs contact layer, the cladding layer may be a P-type InP cladding layer, the first electrode 9 may be an N-type electrode, and the second electrode may be a P-type electrode.
The semi-insulating current blocking layer 8 is on both sides of the first waveguide boss and on both sides of the first boss along the waveguide axis. Note that, in the present application, the specific structure of the semi-insulating current blocking layer 8 is not limited. For example, the semi-insulating current blocking layer 8 may have a single-layer structure, extending from the bottom of the first waveguide mesa at both sides of the bump to the top of the bump in the first mesa, as shown in fig. 5; or, the semi-insulating current blocking layer 8 is a multi-layer structure, the semi-insulating current blocking layer 8 includes at least two semi-insulating layers, such as two semi-insulating layers, three semi-insulating layers, four semi-insulating layers, and the like, when the number of layers of the semi-insulating layers exceeds three, the semi-insulating layers continue to be sequentially stacked, and the structure between the semi-insulating layers is set according to the prior art.
When the semi-insulating current blocking layer 8 comprises two semi-insulating layers, the upper surface of the first semi-insulating layer at the bottom is flush with the upper surface of the first waveguide boss, and the second semi-insulating layer at the top is flush with the upper surface of the first boss. The material of the semi-insulating current blocking layer 8 is InP doped with Fe.
When the semi-insulating current blocking layer 8 is of a single-layer structure, a thicker semi-insulating current blocking layer 8 needs to be grown at one time, the thickness of the semi-insulating current blocking layer 8 needs to be 4 μm, and a first waveguide boss and a first boss which are about 4um high are formed by an etching process. Wherein the width of MQW is 1.5-2 μm, so that the single mode condition of laser can be satisfied. It is more difficult for the first waveguide mesa and the first mesa of relatively high height to maintain the width of the MQW, and, in the epitaxial growth, abnormal epitaxial growth often occurs on the top surface of semi-insulating current blocking layer 8, forming abnormal surface S', as shown in fig. 5. In the actual process, the optimal growth condition needs to be found to have a normal surface, and the manufacturing process condition is harsh. In order to simplify the manufacturing process of the laser, preferably, the semi-insulating current blocking layer 8 includes at least two semi-insulating layers, each semi-insulating layer is grown separately, the height of each semi-insulating layer can be 2 μm, the growth is easy, and the width of the MQW is also easy to maintain.
It should be noted that the type of laser is not limited in the present application, and a laser having a BH structure is within the scope of the present application. For example, when the Laser is a DML (direct Modulated Laser), the Laser only includes the substrate 1 and the Laser device module disposed thereon, and the cross-sectional schematic diagram is shown in fig. 5; when the laser is an EML, an electro-absorption module is further included, and the specific structure is described below.
Laser instrument in this application includes substrate 1 and laser instrument module, the laser instrument module is including range upon range of first waveguide boss and first boss, the both sides of first waveguide boss and the both sides of first boss are equipped with semi-insulating electric current and block layer 8, the electric current blocks the layer for semi-insulating in this application promptly, need not to set up "binary channels recess", alright make the parasitic capacitance of laser instrument lower to make the laser instrument have enough high frequency working property, can exceed 25 Gbps's performance.
On the basis of the above embodiments, in an embodiment of the present application, referring to fig. 6 to 10, the laser further includes:
the electroabsorption module is arranged on the substrate 1 and integrated with the laser device module, and comprises a second waveguide boss without a grating, a second boss arranged on the second waveguide boss and a semi-insulating current blocking layer 8, wherein the second waveguide boss and the semi-insulating current blocking layer 8 are arranged on the substrate 1, and the semi-insulating current blocking layer 8 is arranged on two sides of the second waveguide boss and two sides of the second boss.
The semi-insulating current blocking layers 8 in the electro-absorption module are specifically positioned on two sides of the middle bulge in the second waveguide boss and two sides of the middle bulge in the second boss, and are distributed along the axis of the waveguide.
Referring to fig. 8, the semi-insulating current blocking layer 8 of fig. 8 is illustrated as including two semi-insulating layers, and hereinafter referred to as a first semi-insulating layer 81 and a second semi-insulating layer 82 in order of growth of the semi-insulating layers for convenience of description. The second waveguide boss comprises a first cladding layer 2, an EA-multiple quantum well 31 and a cladding layer which are laminated in the direction far away from the substrate 1, the second boss comprises a second cladding layer 6 and a contact layer 7 which are laminated in the direction far away from the substrate 1, the height of the second waveguide boss is equal to that of the first waveguide boss, and the height of the second boss is equal to that of the first boss. The laser device module and the electric absorption module both comprise multiple quantum wells, and for the convenience of distinguishing, the multiple quantum wells in the laser device module are called LD-MQW32, and the multiple quantum wells in the electric absorption module are called EA-MQW31, as shown in FIG. 9.
The upper surface of the electroabsorption module is provided with a second electrode 10, the lower surface of the substrate 1 is provided with a first electrode 9, and the first electrode 9 extends to the region corresponding to the electroabsorption module, it should be noted that an electrode isolation region 11 exists between the second electrode 10 on the upper surface of the electroabsorption module and the second electrode 10 on the upper surface of the laser device module, as shown in fig. 6.
In this embodiment, the semi-insulating current blocking layer 8 in the laser device module and the electro-absorption module may be a single-layer structure, and extends from the bottom of the first waveguide boss and the bottom of the second waveguide boss to the top of the first boss and the top of the second boss; alternatively, the semi-insulating current blocking layer 8 has a multi-layer structure, and the semi-insulating current blocking layer 8 includes at least two semi-insulating layers, such as two semi-insulating layers, three semi-insulating layers, four semi-insulating layers, and the like. When the semi-insulating current blocking layer 8 comprises two semi-insulating layers, referring to fig. 8, the upper surface of the first semi-insulating layer 81 at the bottom is flush with the upper surfaces of the first waveguide mesa and the second waveguide mesa, and the second semi-insulating layer 82 at the top is flush with the upper surfaces of the first mesa and the second mesa.
Alternatively, as an implementation, the electrode isolation region 11 may be a gap similar to that shown in fig. 3 and extending from the upper surface of the second electrode 10 to the lower surface of the contact layer 7. However, this is not a specific limitation in the present application. In other embodiments of the present application, referring to fig. 9 and 10, when the semi-insulating current blocking layer comprises two semi-insulating layers, the electrode isolation region 11 between the electroabsorption module and the laser device module comprises a second semi-insulating layer 82 extending into the laser, and the bottom of the second semi-insulating layer 82 is located on the same surface as the top of the first semi-insulating layer 81. At this time, the electrode isolation region 11 further includes a gap 111 located above the second semi-insulating layer 82. The top of the second semi-insulating layer 82 may extend to the upper surface of the contact layer 7, or below the upper surface of the contact layer 7, or slightly above the upper surface of the contact layer 7, as long as the laser device module and the second electrode 10 of the electro-absorption module can be isolated. The material of the second semi-insulating layer 82 is Fe-doped InP.
Preferably, the electrode isolation region 11 includes a second semi-insulating layer 82 that extends into the laser interior. When the electrode isolation region 11 is a gap like that shown in fig. 3, there is not enough high resistance between the electric absorption module and the laser device module, but the performance of the electric absorption module and the laser device module may be unstable, and the yield may be poor. When the electrode isolation region 11 includes the second semi-insulating layer 82 extending to the inside of the laser, the contact layer 7 and the second cladding layer 6 in the region where the electrode isolation region 11 is located are removed and a semi-insulating material is grown, and a sufficiently high isolation resistance can be obtained, so that the functions of the electro-absorption module and the laser device module can be stably operated. The width of the second semi-insulating layer 82 may be between 10 μm and 50 μm, depending on the required isolation resistance.
The laser in this embodiment is an EML, and in order to reduce the reflectivity, an AR (anti-reflective) coating may be disposed on the front surface (end surface) of the EML to prevent light reflection. When the process thickness and composition of the AR coating film need to be controlled in order to achieve low reflectivity below 0.1%.
Preferably, in one embodiment of the present application, the laser may further include: and a semi-insulating window 12 arranged on the end face of the electro-absorption module and used for shielding a multi-quantum well (EA-MQW 31) in the second waveguide boss, wherein the top of the semi-insulating window extends to the second cladding layer 6 in the second boss, and the bottom of the semi-insulating window extends to the first cladding layer 2 in the second waveguide boss, and as shown in fig. 7 and 9, the reflectivity of the end face AR coating can be further reduced. Wherein, the material of the semi-insulating window is InP doped with Fe, and the width can be 5-10 μm.
The present application further provides a method for manufacturing a laser, please refer to fig. 11, which includes:
step S101: a substrate is obtained.
Step S102: preparing a laser device module on the substrate, wherein the laser device module comprises a first waveguide boss containing a grating, a first boss and a semi-insulating current blocking layer, the first waveguide boss is arranged on the substrate, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss.
The laser in this embodiment is a DML device, and when the semi-insulating current group fault includes two semi-insulating layers, the manufacturing process of the laser device module at this time includes:
a1: a first structural layer containing a grating embedding layer is epitaxially grown on a substrate.
b1: the grating embedded layer over the MQW of the first structural layer forms a grating.
c1: a cladding layer is epitaxially grown again over the grating.
d1: a first patterned mask is formed over the first structural layer.
e1: and etching the first structure layer under the action of the first patterned mask to correspondingly form a first waveguide boss. Wherein etching is stopped until the substrate of the first structural layer is not reached.
f1: and epitaxially growing a first semi-insulating layer on two sides of the first waveguide boss.
g1: and removing the first patterned mask and epitaxially growing a second structural layer.
h1: and forming a second patterned mask on the second structural layer.
i1: and etching the second structural layer under the action of the second graphical mask to form a first boss positioned on the first waveguide boss. Wherein, the etching is stopped until the first semi-insulating layer is etched.
j1: and epitaxially growing second semi-insulating layers on two sides of the second boss.
k1: removing the second patterned mask;
l1: electrodes are prepared on the upper and lower surfaces of the structure.
The first waveguide boss comprises a first cladding layer, a multi-quantum well, a spacing layer, a grating and a covering layer which are stacked in the direction far away from the substrate, and the first boss comprises a second cladding layer and a contact layer which are stacked in the direction far away from the substrate.
In the present application, the specific structure of the semi-insulating current blocking layer is not limited. For example, the semi-insulating current blocking layer may have a single-layer structure that is grown once and extends from the bottom of the two sides of the protrusion in the first waveguide boss to the top of the protrusion in the first waveguide boss, or may have a multi-layer structure that includes at least two semi-insulating layers that are independently epitaxially grown at least twice, such as two semi-insulating layers, three semi-insulating layers, four semi-insulating layers, and the like. When the semi-insulating current blocking layer comprises two semi-insulating layers, the upper surface of the first semi-insulating layer at the bottom is flush with the upper surface of the first waveguide boss, and the second semi-insulating layer at the top is flush with the upper surface of the first boss.
It should be noted that, after the laser device module is manufactured, the method further includes: forming an isolation layer on the upper surface of the semi-insulating current blocking layer, and forming a second electrode on the upper surface of the isolation layer; the substrate is thinned to a thickness of 90 to 100 μm, and a first electrode is formed on the lower surface of the substrate.
The specific process of fabricating the laser device module is described below together with the process of fabricating the electro-absorption module, and refer to the following embodiments.
Laser instrument in this application includes substrate and laser instrument module, and the laser instrument module is including range upon range of first waveguide boss and first boss, and the both sides of first waveguide boss and the both sides of first boss are equipped with semi-insulating electric current and block the layer, and the layer is blocked for semi-insulating in this application promptly, need not to set up "binary channels recess", alright make the parasitic capacitance of laser instrument lower to make the laser instrument have enough high frequency working property, can exceed 25 Gbps's performance.
Referring to fig. 12, on the basis of the foregoing embodiment, the present application further provides a method for manufacturing a laser, including:
step S201: a substrate is obtained.
Step S202: preparing the laser device module and an electric absorption module integrated with the laser device module on the substrate, wherein the laser device module comprises a first waveguide boss which is arranged on the substrate and contains a grating, a first boss which is arranged on the first waveguide boss and a semi-insulating current blocking layer; the electroabsorption module comprises a second waveguide boss without a grating, a second boss and a semi-insulating current blocking layer, wherein the second waveguide boss is arranged on the substrate, the second boss is arranged on the second waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and the second waveguide boss and on two sides of the first boss and the second boss.
When the semi-insulating current blocking layer has a single-layer structure grown at a single time, the step S202 includes:
a2: epitaxially growing a first structural layer containing a grating embedded layer on a substrate;
b2: and selectively etching the first structural layer, and selectively and epitaxially growing a third structural layer without the grating embedded layer in the etching area. And the third structural layer is flush with the upper surface of the first structural layer.
c2: the grating embedded layer above the LD-MQW of the first structural layer forms a grating.
d2: and epitaxially growing a second structural layer again above the grating.
e2: and forming a second patterned mask on the second structural layer.
f2: and etching the second structural layer under the action of the second patterned mask to form a first boss positioned on the first waveguide boss and a second boss positioned on the second waveguide boss.
g2: and epitaxially growing semi-insulating current blocking layers on two sides of the first waveguide boss, the second waveguide boss, the first boss and the second boss.
h2: and removing the second patterned mask.
i2: electrodes are prepared on the upper and lower surfaces of the structure.
Taking the example that the semi-insulating current blocking layer includes two semi-insulating layers as an example, referring to fig. 13, the process for preparing the laser device module and the electric absorption module includes:
step 301: and epitaxially growing a first structural layer containing a grating embedded layer on the substrate.
Referring to fig. 14, a first cladding layer 2, an LD-MQW32, a spacer layer 4, a grating embedded layer 19, and a cladding layer 14 are epitaxially grown on the upper surface of a substrate 1 in this order.
Step S302: and selectively etching the first structural layer, and selectively and epitaxially growing a third structural layer without a grating embedded layer in an etching area, wherein the third structural layer is flush with the upper surface of the first structural layer.
Referring to fig. 15 (a) and 15 (b), a mask layer 15 is deposited on the upper surface of the first structural layer, and the first structural layer is etched under the action of the mask layer 15 to form an electro-absorption module. Mask layer 15 may be SiO 2 And (5) masking the layer.
Referring to FIG. 16, EA-MQW31 and capping layer 14 are epitaxially grown in sequence in the etched region.
After step S302 and before step S303, the following steps are performed: the grating embedding layer 19 over the LD-MQW of the first structural layer forms a grating, and then a second cladding layer is epitaxially grown again over the grating.
Step S303: forming a first patterned mask on the upper surfaces of the first structural layer and the third structural layer.
Referring to FIG. 17, the width of the first patterned mask 16 may be 4 μm to 5 μm, and the first patterned mask 16 may be SiO 2 And (5) masking the layer.
Step S304: and etching the first structural layer and the third structural layer under the action of the first graphical mask to correspondingly form the first waveguide boss and the second waveguide boss.
Referring to fig. 18 (a) for a schematic cross-sectional view of an area where the laser device module is located after etching, referring to fig. 18 (b) for a schematic cross-sectional view of an area where the electro-absorption module is located, the etching depth may be 2 μm, and the width D1 of the first protrusion and the third protrusion may be between 1.5 μm and 2 μm. The first waveguide boss includes a first cladding layer 2, an LD-MQW32, a spacer layer, a grating 5, a cladding layer, which are laminated in a direction away from the substrate 1, and the second waveguide boss includes a first cladding layer 2, an EA-MQW31, a cladding layer, which are laminated in a direction away from the substrate 1.
Step S305: and epitaxially growing a first semi-insulating layer on two sides of the first waveguide boss and two sides of the second waveguide boss.
Referring to fig. 19, the upper surface of the epitaxially grown first semi-insulating layer 81 is flush with the upper surfaces of the first waveguide boss and the second waveguide boss.
Step S306: and removing the first patterned mask and epitaxially growing a second structural layer.
Referring to fig. 20, the second structural layer includes the epitaxially grown second cladding layer 6 and contact layer 7.
Step S307: and forming a second graphical mask on the second structural layer.
The width D2 of the second patterned mask 17 may be between 5 μm and 10 μm, and the second patterned mask 17 may be SiO 2 And (5) masking the layer. Fig. 21 is a schematic cross-sectional view of the region where the electro-absorption module is located in this step.
An electrode isolation gap exists between the laser device module and the electro-absorption module, which is described below.
Step S308: and etching the second structure layer under the action of the second patterned mask to form a first boss positioned on the first waveguide boss and a second boss positioned on the second waveguide boss, wherein the etching is stopped until the first semi-insulating layer is etched.
Fig. 22 (a) is a schematic cross-sectional view of an area where the laser device module is located after etching, and fig. 22 (b) is a schematic cross-sectional view of an area where the electro-absorption module is located, where the first boss includes the second cladding layer 6 and the contact layer 7 stacked in a direction away from the substrate, and the second boss includes the second cladding layer 6 and the contact layer 7 stacked in a direction away from the substrate.
Step S309: and forming second semi-insulating layers on two sides of the first boss and two sides of the second boss.
Referring to fig. 23 (a) for a cross-sectional view of an area where the laser device module is located after etching, referring to fig. 23 (b) for a cross-sectional view of an area where the electro-absorption module is located, an upper surface of the first semi-insulating layer 81 is flush with an upper surface of the second patterned mask 17.
Step S310: and removing the second patterned mask.
When the semi-insulating current blocking layer has a single-layer structure, in step S305, the first semi-insulating layer with a required height is directly grown at one time as a semi-insulating current group layer when the first semi-insulating layer is grown, and the height of the semi-insulating current group layer is the sum of the heights of the two semi-insulating layers; when the semi-insulating current blocking layer comprises three or more semi-insulating layers, the semi-insulating current blocking layer is continuously grown in an overlapping mode. When the semi-insulating current blocking layer includes at least two semi-insulating layers, laser fabrication is easier and the width of the MQW is also easier to maintain.
On the basis of the above embodiments, in an embodiment of the present application, when a first patterned mask is formed on the upper surfaces of the first structural layer and the third structural layer, a gap is left between the first patterned mask and the end surface of the electroabsorption module;
correspondingly, epitaxially growing a first semi-insulating layer on both sides of the first waveguide mesa and both sides of the second waveguide mesa includes:
and epitaxially growing first semi-insulating layers on two sides of the first waveguide boss and two sides of the second waveguide boss, forming a semi-insulating window in an etching region corresponding to the gap, wherein the top of the semi-insulating window extends to the second cladding layer in the second boss, the bottom of the semi-insulating window extends to the first cladding layer in the second waveguide boss, and the semi-insulating window shields the multiple quantum wells in the second waveguide boss.
When a gap is left between the first patterned mask and the end face of the electric absorption module, as shown in fig. 24, the length L1 of the gap may be 5 μm to 10 μm, and when etching is performed under the action of the first patterned mask 16, the corresponding region below the gap is etched, and the etching bottom extends to the first cladding layer in the second boss.
Making a semi-insulating window in the laser in this embodiment can reduce the reflectivity of the end AR coating.
On the basis of the above embodiment, in an embodiment of the present application, the second patterned mask has an electrode isolation gap between the laser device module and the electro-absorption module;
correspondingly, etching the second structure layer under the action of the second patterned mask to form a first boss on the first waveguide boss and a second boss on the second waveguide boss comprises:
etching the second structure layer under the action of the second patterned mask to form the first boss, the second boss and a groove between the laser device module and the electric absorption module, wherein the bottom of the groove and the top of the first semi-insulating layer are positioned on the same surface;
correspondingly, epitaxially growing second semi-insulating layers on both sides of the first boss and both sides of the second boss includes:
and epitaxially growing the second semi-insulating layers on two sides of the first boss and two sides of the second boss, and epitaxially growing the second semi-insulating layers in the grooves at the same time.
When the second patterned mask 17 has an electrode isolation gap between the laser device module and the electro-absorption module, as shown in fig. 25, the length L2 of the electrode isolation gap may be 10 μm to 50 μm; when etched under the second patterned mask 17, a recess 18 is formed below corresponding to the electrode isolation gap, as shown in fig. 26. A schematic cross-sectional view of the electrode isolation region between the laser device module and the electroabsorption module after epitaxial growth of the second semi-insulating layer 82 is shown in fig. 27.
When epitaxially growing the second semi-insulating layer 82 by depositing semi-insulating material in the recess 18, the top of the second semi-insulating layer 82 may extend to the upper surface of the contact layer 7, or slightly below the upper surface of the contact layer 7, or slightly above the upper surface of the contact layer 7, as long as the laser device module and the second electrode 10 of the electro-absorption module can be isolated.
In this embodiment, when the electrode isolation region is the second semi-insulating layer extending to the inside of the laser, the contact layer and the second cladding layer in the region where the electrode isolation region is located are removed, and a semi-insulating material is grown, so that a sufficiently high isolation resistance can be obtained, and the functions of the electric absorption module and the laser device module can stably operate.
The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The laser and the manufacturing method thereof provided by the present application are described in detail above. The principles and embodiments of the present application are described herein using specific examples, which are only used to help understand the method and its core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.
Claims (11)
1. A laser, comprising:
the laser device module comprises a substrate and a laser device module arranged on the substrate;
the laser device module comprises a first waveguide boss, a first boss and a semi-insulating current blocking layer, wherein the first waveguide boss is arranged on the substrate and comprises a grating, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss.
2. The laser of claim 1, wherein the semi-insulating current blocking layer comprises at least two semi-insulating layers.
3. The laser of claim 2, wherein when the semi-insulating current blocking layer comprises two semi-insulating layers, an upper surface of a first semi-insulating layer at the bottom is flush with an upper surface of the first waveguide mesa and a second semi-insulating layer at the top is flush with the upper surface of the first mesa.
4. The laser of any of claims 1 to 3, further comprising:
the electroabsorption module is arranged on the substrate and integrated with the laser device module, and comprises a second waveguide boss without gratings, a second boss arranged on the second waveguide boss and a semi-insulating current blocking layer, wherein the semi-insulating current blocking layer is arranged on two sides of the second waveguide boss and two sides of the second boss.
5. The laser of claim 4, further comprising:
and the semi-insulating window is arranged on the end face of the electric absorption module and shields the multiple quantum wells in the second waveguide boss, the top of the semi-insulating window extends to the second cladding layer in the second boss, the bottom of the semi-insulating window extends to the first cladding layer in the second waveguide boss, and the semi-insulating window is connected with the first semi-insulating layer and grows simultaneously.
6. The laser of claim 4, wherein when the semi-insulating current blocking layer comprises two semi-insulating layers, the electrode isolation region between the electroabsorption module and the laser device module comprises a second semi-insulating layer extending into the laser, the bottom of the second semi-insulating layer being on the same surface as the top of the first semi-insulating layer.
7. A method of fabricating a laser, comprising:
obtaining a substrate;
preparing a laser device module on the substrate, wherein the laser device module comprises a first waveguide boss containing a grating, a first boss and a semi-insulating current blocking layer, the first waveguide boss is arranged on the substrate, the first boss is arranged on the first waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the first waveguide boss and two sides of the first boss.
8. The method of fabricating a laser of claim 7, further comprising:
preparing an electric absorption module integrated with the laser device module on the substrate, wherein the electric absorption module comprises a second waveguide boss without a grating, a second boss and a semi-insulating current blocking layer, the second waveguide boss is arranged on the substrate, the second boss is arranged on the second waveguide boss, and the semi-insulating current blocking layer is arranged on two sides of the second waveguide boss and two sides of the second boss.
9. The method of claim 8, wherein when the semi-insulating current blocking layer comprises two semi-insulating layers, fabricating the laser device module and the electroabsorption module on the substrate comprises:
epitaxially growing a first structural layer containing a grating embedded layer on the substrate;
selectively etching the first structural layer, and selectively epitaxially growing a third structural layer without a grating embedded layer in an etching area, wherein the third structural layer is flush with the upper surface of the first structural layer;
forming a first patterned mask on the upper surfaces of the first structural layer and the third structural layer;
etching the first structural layer and the third structural layer under the action of the first graphical mask to correspondingly form the first waveguide boss and the second waveguide boss;
epitaxially growing first semi-insulating layers on two sides of the first waveguide boss and two sides of the second waveguide boss;
removing the first graphical mask and epitaxially growing a second structural layer;
forming a second patterned mask on the second structural layer;
etching the second structure layer under the action of the second patterned mask to form a first boss on the first waveguide boss and a second boss on the second waveguide boss, wherein the etching is stopped until the first semi-insulating layer is etched;
epitaxially growing second semi-insulating layers on two sides of the first boss and two sides of the second boss;
and removing the second patterned mask.
10. The method of claim 9, wherein a gap is left between the first patterned mask and the end surface of the electro-absorption module;
correspondingly, epitaxially growing a first semi-insulating layer on both sides of the first waveguide mesa and both sides of the second waveguide mesa includes:
and epitaxially growing first semi-insulating layers on two sides of the first waveguide boss and two sides of the second waveguide boss, forming a semi-insulating window in an etching area corresponding to the gap, wherein the top of the semi-insulating window extends to the second cladding layer in the second boss, the bottom of the semi-insulating window extends to the first cladding layer in the second waveguide boss, and the semi-insulating window shields multiple quantum wells in the second waveguide boss.
11. The method of claim 9, wherein the second patterned mask has an electrode isolation gap between the laser device module and the electroabsorption module;
correspondingly, etching the second structure layer under the action of the second patterned mask to form a first boss on the first waveguide boss and a second boss on the second waveguide boss comprises:
etching the second structural layer under the action of the second patterned mask to form the first boss, the second boss and a groove between the laser device module and the electric absorption module, wherein the bottom of the groove and the top of the first semi-insulating layer are positioned on the same surface;
correspondingly, epitaxially growing second semi-insulating layers on two sides of the first boss and two sides of the second boss comprises:
and epitaxially growing the second semi-insulating layers on two sides of the first boss and two sides of the second boss, and epitaxially growing the second semi-insulating layers in the groove at the same time.
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| US5978402A (en) * | 1996-12-11 | 1999-11-02 | Mitsubishi Denki Kabushiki Kaisha | Semiconductor laser device |
| CN103378544A (en) * | 2012-04-16 | 2013-10-30 | 三菱电机株式会社 | Modulator integrated laser device |
| CN111164475A (en) * | 2017-10-03 | 2020-05-15 | 三菱电机株式会社 | Semiconductor optical integrated element |
| CN112042069A (en) * | 2018-04-27 | 2020-12-04 | 住友电工光电子器件创新株式会社 | Optical semiconductor element and method for manufacturing the same, and optical integrated semiconductor element and method for manufacturing the same |
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- 2022-08-09 CN CN202210949078.2A patent/CN115296142A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5978402A (en) * | 1996-12-11 | 1999-11-02 | Mitsubishi Denki Kabushiki Kaisha | Semiconductor laser device |
| CN103378544A (en) * | 2012-04-16 | 2013-10-30 | 三菱电机株式会社 | Modulator integrated laser device |
| CN111164475A (en) * | 2017-10-03 | 2020-05-15 | 三菱电机株式会社 | Semiconductor optical integrated element |
| CN112042069A (en) * | 2018-04-27 | 2020-12-04 | 住友电工光电子器件创新株式会社 | Optical semiconductor element and method for manufacturing the same, and optical integrated semiconductor element and method for manufacturing the same |
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