High-speed multi-junction cascade vertical cavity surface emitting laser structure and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor lasers. The number of quantum wells of the strained quantum well active region structure is limited by strain accumulation, the total thickness needs to be smaller than the critical thickness, implementation is achieved by increasing the number of the quantum wells, but the excessive number of the quantum wells can cause increase of threshold current; according to the high-speed multi-junction cascaded wafer fusion type vertical cavity surface emitting laser and the preparation method thereof, the active regions are connected in series in the same resonant cavity by using the tunnel junctions, so that the threshold carrier density is effectively reduced, the differential gain of the laser is improved, the threshold current is reduced, and the performance of the laser is improved. And the output power and the small signal modulation bandwidth of the laser are remarkably improved while the resistance and the absorption loss are not multiplied.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor laser, more particularly, to a high-speed multi-junction vertical cavity surface emitting laser structure and a preparation method thereof. BACKGROUND

[0002] The materials for preparing the VCSEL can be divided into two parts, one is the active region material system, and the other is the DBR material system. When the active region of the long-wavelength 1300 nm VCSEL is prepared, the commonly used active region materials include InGaAsP / InP, AlGaInAs / InP, GalnNAs / GaAs, etc. The 1.3 μm VCSEL that is currently studied more is grown on a GaAs substrate to form a GaAs / AIGaAs DBR and a GalnNAs / GaAs active region. However, for the GalnNAs / GaAs VCSEL, it is difficult to grow GalnAs, which leads to the fact that the emission wavelength is generally less than 1.3 μm. For the InP-based long-wavelength VCSEL, the lattice-matched DBR material generally adopts InGaAsP / InP and AlGalnAs / InP, but the thermal conductivity of the quaternary material is low, and the difference in refractive index is small, so that a large number of DBR pairs (> 30 pairs) are needed to obtain high reflectivity, which brings difficulties to the growth of the material. At the same time, the thick DBR layer has high resistance and thermal resistance, which leads to the fact that the device cannot work continuously and stably at room temperature. Therefore, in the production of the 1.3 μm VCSEL, the wafer fusion technology is adopted to directly bond the high-quality GaAs-based DBR and the InP-based active region to produce the long-wavelength VCSEL, which can obtain better performance. However, in the communication aspect, due to the influence of the optical cavity length and the topological structure of the short-cavity VCSEL with the minimum mode volume, the small signal modulation bandwidth of the wafer fusion 1.3 μm VCSEL device still lags behind the conventional structure device.

[0003] The differential gain of the active region is a key problem affecting the further improvement of the output power and the small signal modulation bandwidth of the 1.3 μm wafer fusion type vertical cavity surface emitting laser. The strained quantum well is often used as a method to improve the differential gain of the quantum well laser, but the number of quantum wells in the strained quantum well active region structure is limited by strain accumulation, and the total thickness needs to be less than the critical thickness. The differential gain can be significantly enhanced by reducing the threshold carrier density of each quantum well. In theory, it can be achieved by increasing the number of quantum wells, but too many quantum wells will increase the threshold current. The multi-junction cascade VCSEL can reduce the threshold carrier density while increasing the total number of quantum wells in the active region. In the multi-junction cascade VCSEL, the carriers can be recombined under the action of the tunnel junction after passing through the active region, effectively reducing the threshold current, improving the differential gain and enhancing the small signal modulation bandwidth. Therefore, designing a multi-junction cascade active region structure for wafer fusion type vertical cavity surface emitting laser is of great significance to further enhance the small signal modulation bandwidth. SUMMARY

[0004] In view of the problems existing in the prior art, the purpose of the present application is to provide a high-speed multi-junction cascade wafer fusion type vertical cavity surface emitting laser and a preparation method thereof. In view of the problems of the 1.3 μm wafer fusion type vertical cavity surface emitting laser, such as the limitation of the differential gain of the active region by the number of quantum wells and the low small signal modulation bandwidth, the present application uses a tunnel junction to connect the active regions in series in the same resonant cavity, effectively reduces the threshold carrier density, improves the differential gain of the laser, and reduces the threshold current. Without doubling the resistance and absorption loss, the output power and small signal modulation bandwidth of the laser are significantly improved.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: A high-speed multi-junction cascade wafer fusion type vertical cavity surface emitting laser uses a tunnel junction to connect the quantum well active regions in series in the same resonant cavity, comprising an n-GaAs substrate grown on a crystal surface, and an n-GaAs buffer layer, a bot-distributed Bragg reflector layer, a multi-junction cascade active region, a p-In 0.52 Al 0.48 As buried tunnel junction layer, n-InP buried tunnel junction layer, InP spacer layer, top-distributed Bragg reflector layer and GaAs cap layer grown in the growth direction. The multi-junction cascade active region comprises three cascaded active region structures, and a quantum well active region layer is arranged between the two InP spacer layers in the active region structure. 0.52 Al 0.48 The p-In

[0006] Further, the quantum well active region layers in the active region structure include six layers of In 0.44 Ga 0.326 Al 0.234 As barrier layers and five layers of In 0.68 Ga 0.175 Al 0.145 As quantum wells, In 0.44 Ga 0.326 Al 0.234 As barrier layers and In 0.68 Ga 0.175 Al 0.145 As quantum wells are spaced apart, In 0.44 Ga 0.326 Al 0.234 As barrier layers are 8.4 nm thick, In 0.68 Ga 0.175 Al 0.145 As quantum well layers are each 4.4 nm thick.

[0007] Further, the InP spacer layers bonded to the bot-distributed Bragg reflector in the active region structure are 163 nm thick, are of n-type 2 x 10 18 cm -3 -6, and the InP spacer layers bonded to the top-distributed Bragg reflector are 308 nm thick, are of n-type 2 x 10 18 cm -3 -6, and the remaining InP spacer layers are 251 nm thick and are un-doped.

[0008] Further, the p-In 0.52 Al 0.48 As tunnel junction layer is 10 nm thick and is doped at a concentration of 1 x 10 20 cm -3 -7, and the n-InP tunnel junction layer is 20 nm thick and is doped at a concentration of 5 x 10 19 cm -3 -8.

[0009] Further, the bot-distributed Bragg reflector is n-type doped and includes 35 pairs of n-GaAs high refractive index layers and n-Al 0.9 Ga 0.1 As low refractive index layers, with the n-Al 0.9 Ga 0.1 As low refractive index layer at the beginning, and the top-distributed Bragg reflector layer is n-type doped and includes 23 pairs of n-GaAs high refractive index layers and n-Al 0.9 Ga 0.1 As low refractive index layers, with the n-GaAs high refractive index layer at the beginning.

[0010] The application discloses a preparation method of a wafer fusion type vertical cavity surface emitting laser of a high-speed multi-junction cascade, and relates to the technical field of lasers. Step 1. Cleaning the surface of the n-GaAs substrate: hydrogen is introduced, the reaction chamber temperature is 700-740 DEG C, and the cleaning lasts for 5-15 minutes, so that the particle contaminants on the surface of the substrate are cleaned and surface oxygen atoms are removed; Step 2. Growth of the n-GaAs buffer layer: the temperature is reduced to 650-680 DEG C, the trimethylgallium flow rate is 90 sccm, the arsine flow rate is 440 sccm, the silane flow rate is 50-100 sccm, the growth thickness is 500 nm, and the n-type doping concentration is 2x10 18 cm -3 ; Step 3. Growth of the bot-distributed Bragg reflector: the growth temperature is 650-680 DEG C, and one growth cycle sequence is as follows: the n-Al 0.9 Ga 0.1 As low-refractive-index layer with a growth thickness of 107.3 nm, the n-GaAs high-refractive-index layer with a growth thickness of 92.7 nm, and the n-type doping concentration is 2x10 18 cm -3 , and the cycle growth is 35 cycles; Step 4. Growth of the active region structure: the InP spacer layer is grown on the InP substrate, the thickness is 163 nm, and the n-type doping concentration is 2x10 18 cm -3 ; The quantum well active region layer is grown on the InP spacer layer, six layers of In 0.44 Ga 0.326 Al 0.234 As barrier layers and five layers of In 0.68 Ga 0.175 Al 0.145 As quantum well layers are grown in sequence; The InP spacer layer is grown on the quantum well active region layer, the thickness is 251 nm, and the doping concentration is 1x10 20 cm -3 ; Step 5. Growth of the p-In 0.52 Al 0.48 As tunnel junction layer, the thickness is 10 nm, and the doping concentration is 1x10 20 cm -3 ; n-InP tunnel junction layer growth: the thickness is 20 nm, and the n-type doping concentration is 5x10 19 cm -3 ; Step 6. Active region structure growth: InP spacer layer is grown on n-InP tunnel junction layer, quantum well active region layer is grown on InP spacer layer, InP spacer layer is grown on quantum well active region layer, both InP spacer layers are grown with a thickness of 251 nm, and the rest of the conditions are the same as those in step 4 for growing InP spacer layer on quantum well active region layer; Step 7. Repeat step 5; Step 8. Repeat step 6; Step 9. p-In 0.52 Al 0.48 As buried tunnel junction layer growth: thickness of 10 nm, doping concentration of 1×10 20 cm -3 ; Step 10. n-InP buried tunnel junction layer growth: thickness of 20 nm, n-type doping concentration of 5×10 19 cm -3 ; Step 11. InP spacer layer growth: thickness of 308 nm, and the rest of the growth conditions are the same as those in step 6 for growing InP spacer layer; Step 12. top-distributed Bragg reflector growth: growth temperature is 680 ℃ to control Zn source doping amount, DEZn flow rate is 5 sccm when growing GaAs high refractive index layer, DEZn source flow rate is 50 sccm when growing Al 0.9 Ga 0.1 As low refractive index layer, one growth cycle sequence: growing n-GaAs high refractive index layer with a thickness of 92.7 nm, growing n-Al 0.9 Ga 0.1 As low refractive index layer with a thickness of 107.3 nm, n-type doping concentration of 2×10 18 cm -3 , and the cycle is repeated for 23 times; Step 13. p-GaAs cap layer growth: temperature is reduced to 550-650 ℃, trimethylgallium flow rate is 90 sccm, arsine flow rate is 440 sccm, carbon tetrabromide flow rate is 10-25 sccm, thickness is 5 nm, p-type doping concentration is greater than 1×10 19 cm -3 ; Step 14. Etch stop layer is grown on n-GaAs substrate, active region and DBR are bonded together by using direct bonding technology, bonding interface is InP / GaAs, then InP substrate on one side is thinned, InP substrate and the corresponding etch stop layer are removed by chemical etching method, top-distributed Bragg reflector is bonded with the active region and bot-distributed Bragg reflector which have been bonded together by using direct bonding technology, bonding interface is InP / GaAs, and the second bonding is completed.

[0011] In summary, the invention has the following beneficial effects: This invention addresses the issues of high threshold carrier density and low differential gain in the active region of lasers, while reducing the threshold current. Without significantly increasing resistance and absorption loss, it substantially improves the output power and small-signal modulation bandwidth of a wafer-fused vertical-cavity surface-emitting laser (VCSEL). Under room-temperature continuous-wave conditions, the triple-junction VCSEL achieves a 3 dB modulation bandwidth of 16.8 GHz, representing an approximately 19.1% improvement over the -3 dB bandwidth of a single-junction VCSEL. Furthermore, with an injection current of 10 mA, the triple-junction VCSEL achieves an output power of 11.2 mW, a 180% increase compared to the single-junction VCSEL. This invention significantly enhances the output power of lasers. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the active region vertical cavity surface-emitting laser of the multi-junction cascaded quantum well of the present invention; Figure 2 This is a schematic diagram of the multi-junction cascaded active region structure of the present invention; Figure 3 This is a schematic diagram of the energy band structure of the multi-junction cascaded active region of the present invention; Figure 4 PI curves of single-junction, two-junction cascaded, and three-junction cascaded vertical-cavity surface-emitting lasers under continuous-state conditions at room temperature; Figure 5 The small-signal modulation response of single-junction and three-junction cascaded vertical-cavity surface-emitting lasers under continuous-state conditions at room temperature is given. Detailed Implementation

[0013] The present invention will now be described in further detail with reference to the accompanying drawings.

[0014] It should be noted that, for ease of description, the descriptions of direction in the following text are consistent with the directions in the accompanying drawings, but they do not limit the structure of the present invention.

[0015] like Figures 1-4 As shown, this invention discloses a high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser (VCSEL). It utilizes tunnel junctions to connect quantum well active regions in series within the same resonant cavity. The system includes an n-GaAs substrate grown on a crystal surface, and sequentially grown along the growth direction an n-GaAs buffer layer, a bot-distributed Bragg mirror, a multi-junction cascaded active region, and a p-In... 0.52 Al 0.48The structure consists of an As buried tunnel junction layer, an n-InP buried tunnel junction layer, an InP space layer, a top-distributed Bragg mirror layer, and a GaAs capping layer. An n-GaAs buffer layer is grown on an n-GaAs substrate, and a top-distributed Bragg mirror layer is grown on the n-GaAs buffer layer. A multi-junction cascaded active region is bonded to the top-distributed Bragg mirror layer. p-In... 0.52 Al 0.48 As buried tunnel layers grow on multi-layered cascaded active regions, and n-InP buried tunnel layers grow on p-In 0.52 Al 0.48 An InP space layer grows on an n-InP buried tunneling layer. A top-distributed Bragg mirror layer is then bonded to a multi-junction cascaded active region that has already undergone primary bonding. A GaAs cap layer grows on the top-distributed Bragg mirror layer. The multi-junction cascaded active region comprises three cascaded active region structures. A quantum well active region layer is located between two InP space layers in each active region structure. Adjacent active region structures are connected by p-InP space layers. 0.52 Al 0.48 The As tunneling layer and the n-InP tunneling layer are connected. The quantum well active region layer in the active region structure includes six In layers. 0.44 Ga 0.326 Al 0.234 As barrier layer and five In layers 0.68 Ga 0.175 Al 0.145 As a quantum well, In 0.44 Ga 0.326 Al 0.234 As barrier layer and In 0.68 Ga 0.175 Al 0.145 As quantum well spacing distribution, each In layer 0.68 Ga 0.175 Al 0.145 Both sides of the As quantum well layer are In 0.44 Ga 0.326 Al 0.234 As a barrier layer, all In 0.68 Ga 0.175 Al 0.145 As quantum wells all consist of two layers of In 0.44 Ga 0.326 Al 0.234 As a barrier layer surrounds, In 0.44 Ga 0.326 Al 0.234 The thickness of the As barrier layer is 8.4 nm, and the In layer is... 0.68 Ga 0.175 Al 0.145 The thickness of the As quantum well layer is 4.4 nm.

[0016] The InP space layer bonded to the bot-distributed Bragg mirror in the active region structure has a thickness of 163 nm and a doping concentration of 2 × 10⁻⁶ for n-type. 18 cm -3 The InP space layer bonded to the top-distributed Bragg mirror has a thickness of 308 nm and a doping type and concentration of n-type 2×10⁻⁶. 18 cm -3 The remaining InP space layer is 251 nm thick and undoped.

[0017] p-In 0.52 Al 0.48 The thickness of the As tunneling layer is 10 nm, and the doping concentration is 1×10⁻⁶. 20 cm -3 The n-InP tunnel junction layer has a thickness of 20 nm and a doping concentration of 5 × 10⁻⁶. 19 cm -3 .

[0018] The bot-distributed Bragg mirror is n-type doped, comprising 35 pairs of n-GaAs high-refractive-index layers and n-Al. 0.9 Ga 0.1 As a low-refractive-index layer, with n-Al as the starting point. 0.9 Ga 0.1 As low refractive index layer; the top-distributed Bragg mirror layer is n-type doped, including 23 pairs of n-GaAs high refractive index layers and n-Al 0.9 Ga 0.1 The As low-refractive-index layer is started by an n-GaAs high-refractive-index layer.

[0019] This invention also discloses a method for fabricating a high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser, used to fabricate the aforementioned high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser, specifically including the following steps: Step 1. Clean the n-GaAs substrate surface: Introduce hydrogen gas and keep the reaction chamber temperature at 700-740℃ for 5-15 minutes to clean off particulate contaminants and remove surface oxygen atoms from the substrate surface. Step 2. n-GaAs buffer layer growth: Temperature reduced to 650–680 °C, trimethylgallium flux of 90 sccm, arsenane flux of 440 sccm, silane flux of 50–100 sccm, growth thickness of 500 nm, n-type doping concentration of 2 × 10⁻⁶ 18 cm -3 ; Step 3. Bot - Distribution Bragg reflector growth: Growth temperature is 650~680 ℃, one growth cycle sequence: grow n-Al with a thickness of 107.3 nm. 0.9 Ga 0.1 A low-refractive-index As layer was formed, and a 92.7 nm thick n-GaAs high-refractive-index layer was grown with an n-type doping concentration of 2 × 10⁻⁶. 18 cm -3 It grows in 35 cycles; Step 4. Active region structure growth: An InP space layer with a thickness of 163 nm and an n-type doping concentration of 2 × 10⁻⁶ nm is grown on an InP substrate. 18 cm -3 ; A quantum well active region layer is grown on the InP space layer, with six layers of In... 0.44 Ga 0.326 Al 0.234 As barrier layer and five layers In 0.68 Ga 0.175 Al 0.145 As quantum well spacing growth; An InP space layer with a thickness of 251 nm was grown in the active region of the quantum well, with a doping concentration of 2 × 10⁻⁶. 18 cm -3 ; Step 5. p-In 0.52 Al 0.48 As tunnel junctions are grown with a thickness of 10 nm and a doping concentration of 1×10⁻⁶. 20 cm -3 ; n-InP tunnel junction growth: thickness 20 nm, n-type doping concentration 5 × 10⁻⁶ 19 cm -3 ; Step 6. Active region structure growth: Grow an InP space layer in the n-InP tunnel junction layer, grow a quantum well active region layer on the InP space layer, and grow an InP space layer on the quantum well active region layer. The thickness of the two InP space layers is 251 nm. The other conditions are the same as in Step 4 for growing an InP space layer in the quantum well active region layer. Step 7. Repeat step 5; Step 8. Repeat step 6; Step 9. p-In 0.52 Al 0.48 As buried tunnel layer growth: thickness 10 nm, doping concentration 1×10⁻⁶ 20 cm -3 ; Step 10. Growth of n-InP buried tunnel junction: thickness 20 nm, n-type doping concentration 5 × 10⁻⁶19 cm -3 ; Step 11. InP space layer growth: The thickness is 308 nm, and the remaining growth conditions are the same as those in Step 6 for InP space layer growth. Step 12. Top-distributed Bragg mirror growth: The growth temperature is 680 ℃ to control the Zn source doping amount. The DEZn flux is 5 sccm during the growth of the GaAs high refractive index layer. Al growth... 0.9 Ga 0.1 When the As low-refractive-index layer is grown, the DEZn source flux is 50 sccm. One growth cycle sequence is: growing a 92.7 nm thick n-GaAs high-refractive-index layer, then growing a 107.3 nm thick n-Al layer. 0.9 Ga 0.1 As a low-refractive-index layer, the n-type doping concentration is 2 × 10⁻⁶ 18 cm -3 It grows in 23 cycles.

[0020] Step 13. p-GaAs capping layer growth: Temperature reduced to 550~650 ℃, trimethylgallium flux of 90 sccm, arsenane flux of 440 sccm, carbon tetrabromide flux of 10~25 sccm, growth thickness of 5 nm, p-type doping concentration greater than 1×10 19 cm -3 .

[0021] Step 14. Grow an etching stop layer on the n-GaAs substrate so that the GaAs substrate can be etched away after subsequent bonding processes. Use direct bonding technology to bond the active region to the DBR together. The bonding interface is InP / GaAs. Then, thin one side of the InP substrate to 50-60μm. Then, use chemical etching to remove the InP substrate and the corresponding etching stop layer. Use direct bonding technology to bond the top-distributed Bragg mirror to the already bonded active region and the bottom-distributed Bragg mirror together. The bonding interface is InP / GaAs. This completes the second bonding process.

[0022] Figure 3 This diagram illustrates the band structure of the active region in a multi-junction cascaded vertical-cavity surface-emitting laser (VCSEL). An injected electron undergoes radiative recombination to generate a photon, which then transitions from the conduction band to the valence band. When the tunnel junction reverses direction, the recombinated electron tunnels under the influence of an electric field to the conduction band of the next active region, where it undergoes further radiative recombination. When an electron passes through the tunnel junction into multiple active regions, it can be recombinated multiple times to generate multiple photons.

[0023] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser, characterized in that: The active regions of a quantum well are connected in series within the same resonant cavity using tunnel junctions. This includes an n-GaAs substrate grown on a crystal plane, and sequentially grown n-GaAs buffer layers, a bot-distributed Bragg mirror layer, a multi-junction cascaded active region, and a p-In... 0.52 Al 0.48 The layers consist of an As buried tunnel layer, an n-InP buried tunnel layer, an InP space layer, a top-distributed Bragg reflector layer, and a GaAs cap layer, among which: The multi-junction cascaded active region comprises three cascaded active region structures. A quantum well active region layer is disposed between two InP space layers in the active region structure, and adjacent active region structures are connected by p-In 0.52 Al 0.48 The As tunnel layer and the n-InP tunnel layer are connected.

2. The high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser according to claim 1, characterized in that: The quantum well active region layer in the active region structure includes six layers of In. 0.44 Ga 0.326 Al 0.234 As barrier layer and five In layers 0.68 Ga 0.175 Al 0.145 As a quantum well, In 0.44 Ga 0.326 Al 0.234 As barrier layer and In 0.68 Ga 0.175 Al 0.145 As quantum well spacing distribution, In 0.44 Ga 0.326 Al 0.234 The thickness of the As barrier layer is 8.4 nm, and the In layer is... 0.68 Ga 0.175 Al 0.145 The thickness of the As quantum well layers is 4.4 nm.

3. The high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser according to claim 2, characterized in that: The InP space layer bonded to the bot-distributed Bragg mirror in the active region structure has a thickness of 163 nm and a doping type and concentration of n-type 2×10⁻⁶. 18 cm -3 The InP space layer bonded to the top-distributed Bragg mirror has a thickness of 308 nm and a doping type and concentration of n-type 2×10⁻⁶. 18 cm -3 The remaining InP space layer is 251 nm thick and undoped.

4. The high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser according to claim 1, characterized in that: The p-In 0.52 Al 0.48 The thickness of the As tunneling layer is 10 nm, and the doping concentration is 1×10⁻⁶. 20 cm -3 The n-InP tunnel junction layer has a thickness of 20 nm and a doping concentration of 5 × 10⁻⁶. 19 cm -3 .

5. The high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser according to claim 1, characterized in that: The bot-distributed Bragg mirror is n-type doped, comprising 35 pairs of n-GaAs high-refractive-index layers and n-Al. 0.9 Ga 0.1 As a low-refractive-index layer, with n-Al as the starting point. 0.9 Ga 0.1 As low refractive index layer; the top-distributed Bragg mirror layer is n-type doped, including 23 pairs of n-GaAs high refractive index layers and n-Al 0.9 Ga 0.1 The As low-refractive-index layer is started by an n-GaAs high-refractive-index layer.

6. A method for fabricating a high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser, used to fabricate the high-speed multi-junction cascaded wafer-fused vertical-cavity surface-emitting laser as described in any one of claims 1 to 5, characterized in that: Specifically, the following steps are included: Step 1. Clean the n-GaAs substrate surface: Introduce hydrogen gas and keep the reaction chamber temperature at 700-740℃ for 5-15 minutes to clean off particulate contaminants and remove surface oxygen atoms from the substrate surface. Step 2. n-GaAs buffer layer growth: Temperature reduced to 650–680 °C, trimethylgallium flux of 90 sccm, arsenane flux of 440 sccm, silane flux of 50–100 sccm, growth thickness of 500 nm, n-type doping concentration of 2 × 10⁻⁶ 18 cm -3 ; Step 3. Bot-distributed Bragg reflector growth: Growth temperature is 650~680 ℃, one growth cycle sequence: growing n-Al with a thickness of 107.3 nm. 0.9 Ga 0.1 A low-refractive-index As layer was formed, and a 92.7 nm thick n-GaAs high-refractive-index layer was grown with an n-type doping concentration of 2 × 10⁻⁶. 18 cm -3 It grows in 35 cycles; Step 4. Active region structure growth: An InP space layer with a thickness of 163 nm and an n-type doping concentration of 2 × 10⁻⁶ nm is grown on an InP substrate. 18 cm -3 ; A quantum well active region layer is grown on the InP space layer, with six layers of In... 0.44 Ga 0.326 Al 0.234 As barrier layer and five layers In 0.68 Ga 0.175 Al 0.145 As quantum well spacing growth; An InP space layer with a thickness of 251 nm and a doping concentration of 2 × 10⁻⁶ was grown in the active region of the quantum well. 18 cm -3 ; Step 5. p-In 0.52 Al 0.48 As tunnel junctions are grown with a thickness of 10 nm and a doping concentration of 1×10⁻⁶. 20 cm -3 ; n-InP tunnel junction growth: thickness 20 nm, n-type doping concentration 5 × 10⁻⁶ 19 cm -3 ; Step 6. Active region structure growth: Grow an InP space layer in the n-InP tunnel junction layer, grow a quantum well active region layer on the InP space layer, and grow an InP space layer on the quantum well active region layer. The thickness of the two InP space layers is 251 nm. The other conditions are the same as in Step 4 for growing an InP space layer in the quantum well active region layer. Step 7. Repeat step 5; Step 8. Repeat step 6; Step 9. p-In 0.52 Al 0.48 As buried tunnel layer growth: thickness 10 nm, doping concentration 1×10⁻⁶ 20 cm -3 ; Step 10. Growth of n-InP buried tunnel junction: thickness 20 nm, n-type doping concentration 5 × 10⁻⁶ 19 cm -3 ; Step 11. InP space layer growth: The thickness is 308 nm, and the remaining growth conditions are the same as those in Step 6 for InP space layer growth. Step 12. Top-distributed Bragg mirror growth: The growth temperature is 680 ℃ to control the Zn source doping amount. The DEZn flux is 5 sccm during the growth of the GaAs high refractive index layer. Al growth... 0.9 Ga 0.1 When growing the low-refractive-index As layer, the DEZn source flux is 50 sccm. One growth cycle sequence is: growing a 92.7 nm thick n-GaAs high-refractive-index layer, followed by a 107.3 nm thick n-Al layer. 0.9 Ga 0.1 As a low-refractive-index layer, the n-type doping concentration is 2 × 10⁻⁶ 18 cm -3 It grows in 23 cycles; Step 13. p-GaAs capping layer growth: Temperature reduced to 550~650 ℃, trimethylgallium flux of 90 sccm, arsenane flux of 440 sccm, carbon tetrabromide flux of 10~25 sccm, growth thickness of 5 nm, p-type doping concentration greater than 1×10 19 cm -3 ; Step 14. Grow an etching stop layer on the n-GaAs substrate. Use direct bonding technology to bond the active region to the DBR. The bonding interface is InP / GaAs. Then, thin one side of the InP substrate. Then, use chemical etching to remove the InP substrate and the corresponding etching stop layer. Use direct bonding technology to bond the top-distributed Bragg mirror to the already bonded active region and the bottom-distributed Bragg mirror. The bonding interface is InP / GaAs. This completes the second bonding.

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