An O-band silicon-based III-V quantum dot narrow linewidth laser and its preparation method

Abstract

The present invention relates to the field of semiconductor laser technology, and more specifically to an O-band silicon-based III-V quantum dot narrow-linewidth laser and a method for preparing the same. The O-band silicon-based III-V quantum dot narrow-linewidth laser comprises a silicon substrate layer, on which are sequentially stacked a buffer layer, a lower waveguide layer, a lower confinement layer, a quantum dot active layer, an upper confinement layer, an upper waveguide layer, an ohmic contact layer, and an electrode layer; the upper waveguide layer and the ohmic contact layer form a ridge waveguide and a grating on at least one side of the ridge waveguide; and the quantum dot active layer comprises an InAs quantum dot layer / InGaAs barrier layer. The O-band silicon-based III-V quantum dot narrow-linewidth laser of the present invention has the advantages of narrow linewidth, high reflection tolerance, high temperature stability, and low threshold current density.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor lasers, and in particular to an O-band silicon-based III-V quantum dot narrow-linewidth laser and a preparation method thereof. Background Art

[0002] Currently, semiconductor lasers are developing rapidly towards narrow linewidth and integration. By optimizing the laser chip structure design, monolithic integrated narrow linewidth laser output can be obtained. At the same time, combined with its advantages of small size, light weight, high conversion efficiency, and wide spectral range, narrow linewidth lasers have a wide range of applications in coherent optical communications, atomic clock pumping and other fields.

[0003] Currently, directly growing quantum dots on silicon substrates facilitates silicon photonics integration. By introducing surface sidewall gratings on both sides of the ridge waveguide of an O-band (1260-1360 nm) quantum dot laser, it is possible to achieve quantum dot lasers with narrow linewidth and excellent temperature stability, expanding their applications in optoelectronics fields such as coherent optical communications. Furthermore, backward-propagating light generated in the laser optical path for various reasons can generate noise after returning to the laser, affecting the laser's operating stability. Therefore, an optical isolator is required between the semiconductor laser source and the transmission system to mitigate the negative effects of reflected light on the source's stability. However, isolators typically require an external coupling chip, which occupies a large chip volume. Furthermore, the magneto-optical materials typically used in isolators are incompatible with the laser material. To address these issues, III-V quantum dot lasers offer a very small linewidth broadening factor, 20 times smaller than traditional quantum well lasers. They also effectively reduce the negative effects of reflected light on the source's power stability and offer excellent reflection tolerance, eliminating the need for optical isolators and significantly reducing the cost and size of the laser chip. However, it is currently extremely challenging to prepare high-performance O-band silicon-based III-V quantum dot narrow-linewidth lasers that can be monolithically integrated. Summary of the Invention

[0004] The purpose of the present invention is to provide an O-band silicon-based III-V quantum dot narrow-linewidth laser to solve the problem in the prior art that it is difficult to prepare a high-performance O-band silicon-based III-V quantum dot narrow-linewidth laser that can be monolithically integrated.

[0005] In order to solve the above problems, the present invention proposes an O-band silicon-based III-V quantum dot narrow linewidth laser, the technical solution adopted is:

[0006] An O-band silicon-based III-V quantum dot narrow-linewidth laser comprises a silicon substrate layer, on which a buffer layer, a lower waveguide layer, a lower confinement layer, a quantum dot active layer, an upper confinement layer, an upper waveguide layer, an ohmic contact layer, and an electrode layer are sequentially stacked; the upper waveguide layer and the ohmic contact layer form a ridge waveguide and a grating on at least one side of the ridge waveguide; the quantum dot active layer comprises an InAs quantum dot layer / InGaAs barrier layer.

[0007] Furthermore, the buffer layer comprises an AlAs nucleation layer, a GaAs buffer layer and an AlGaAs dislocation filtering layer in order from bottom to top, and the thickness of the GaAs buffer layer is 0.2-2 μm.

[0008] Furthermore, the number of periods of the InAs quantum dot layer / InGaAs barrier layer is 2-15; and the thickness of the InGaAs barrier layer is 2-20 nm.

[0009] Furthermore, the width of the ridge waveguide is 1.5-3 μm, the width of the single-sided grating is 0.5-3 μm, the grating is a first-order grating or a high-order grating, the period of the first-order grating is 180-250 nm, and the duty cycle is 0.35-0.75.

[0010] Furthermore, the lower waveguide layer is an n-type AlGaAs waveguide layer with a thickness of 30-800 nm; the lower confinement layer is an n-type AlGaAs confinement layer with a thickness of 50-300 nm; the upper confinement layer is a p-type AlGaAs confinement layer with a thickness of 3-50 nm; the upper waveguide layer is a p-type AlGaAs waveguide layer with a thickness of 200-3000 nm; and the ohmic contact layer is a p-type GaAs ohmic contact layer with a thickness of 5-50 nm.

[0011] Furthermore, the silicon substrate layer is a Si (001) substrate or an SOI substrate.

[0012] Furthermore, the ridge waveguide is a strip-shaped body located in the middle, and both sides of the ridge waveguide have symmetrical gratings extending along the length direction of the strip-shaped body, and the height of the gratings is consistent with the thickness of the upper waveguide layer.

[0013] Furthermore, both sides of the gratings on both sides away from the ridge waveguide and between adjacent gratings are filled with benzocyclobutene material to form a filling layer, and the thickness of the filling layer is consistent with the thickness of the upper waveguide layer.

[0014] Furthermore, a SiO2 passivation layer is deposited between the grating and the filling layer and the electrode layer, and a metal contact window is opened on the SiO2 passivation layer. The width of the metal contact window is the same as the width of the ohmic contact layer, and the ohmic contact layer is exposed to complete the ohmic contact with the electrode layer.

[0015] Beneficial Effects: This invention is an improved invention. By epitaxially growing a buffer layer, a lower waveguide layer, a lower confinement layer, an InAs quantum dot layer / InGaAs barrier layer, an upper confinement layer, an upper waveguide layer, and an ohmic contact layer on a silicon substrate layer, the invention achieves epitaxial growth of III-V quantum dots. In the structural design of the O-band silicon-based III-V quantum dot narrow-linewidth laser, the upper waveguide layer and the ohmic contact layer are formed onto the ridge waveguide and the grating on at least one side of the ridge waveguide. This achieves a high-performance, monolithically integrated O-band silicon-based quantum dot narrow-linewidth laser, providing an ideal on-chip narrow-linewidth light source for future large-scale silicon photonic integrated systems. The O-band silicon-based III-V quantum dot narrow-linewidth laser of the present invention has the advantages of narrow linewidth, high reflection tolerance, high temperature stability, and low threshold current density, providing an ideal on-chip light source for future on-chip interconnect systems.

[0016] The buffer layer includes an AlAs nucleation layer, a GaAs buffer layer and an AlGaAs dislocation filtering layer from bottom to top. The thickness of the GaAs buffer layer is 0.2-2 μm. The above structural layers effectively prevent dislocations caused by lattice mismatch from being transferred to the quantum dot gain region, ensuring that high-density and high-quality III-V quantum dots can be epitaxially grown.

[0017] The number of periods of the InAs quantum dot layer / InGaAs barrier layer is 2-15, which comprises a combination of multiple quantum dot layers and barrier layers. The thickness of the InGaAs barrier layer is 2-20 nm, which improves the gain bandwidth and quantum efficiency of the laser and reduces the threshold current.

[0018] The width of the ridge waveguide is 1.5-3 μm, the width of the single-sided grating is 0.5-3 μm, the grating is a first-order grating or a high-order grating, the period of the first-order grating is 180-250 nm, and the duty cycle is 0.35-0.75, ensuring that the performance of the waveguide and the processing effect of the optical signal are optimal.

[0019] The lower waveguide layer is an n-type AlGaAs waveguide layer with a thickness of 30-800nm; the lower confinement layer is an n-type AlGaAs confinement layer with a thickness of 50-300nm; the upper confinement layer is a p-type AlGaAs confinement layer with a thickness of 3-50nm; the upper waveguide layer is a p-type AlGaAs waveguide layer with a thickness of 200-3000nm; and the ohmic contact layer is a p-type GaAs ohmic contact layer with a thickness of 5-50nm. In this structure, both the waveguide and confinement layers are made of AlGaAs material. The lower waveguide and confinement layers are both n-type (i.e., with a high electron concentration), while the upper confinement layer is p-type (i.e., with a high hole concentration). This structure optimizes the laser, thereby improving its efficiency and stability.

[0020] The ridge waveguide is a strip-shaped main body located in the middle. There are symmetrical gratings extending along the length of the strip body on both sides of the ridge waveguide. The height of the grating is consistent with the thickness of the upper waveguide layer, which can effectively improve the feedback effect of the grating and further improve the filtering effect of the order Bragg grating on the ridge waveguide.

[0021] The two sides of the gratings on both sides away from the ridge waveguide and between adjacent gratings are filled with benzocyclobutene material to form a filling layer. The thickness of the filling layer is consistent with the thickness of the upper waveguide layer, which is used to optimize the performance of the optical waveguide and improve the efficiency and stability of the optical waveguide.

[0022] A SiO2 passivation layer is deposited between the grating and the filling layer and the electrode layer. A metal contact window is provided on the SiO2 passivation layer. The width of the metal contact window is the same as that of the ohmic contact layer, and the ohmic contact layer is exposed to complete the ohmic contact with the electrode layer. It is used to protect the structure below the SiO2 passivation layer from the influence of the external environment, and it can also prevent the intrusion of moisture and other impurities, thereby maintaining the long-term stability and reliability of the laser. At the same time, conductive metal connections are formed on the passivation layer. These metal connections can be used to further connect to external circuits to realize the input and output of current, thereby controlling the operation of the laser. This design not only ensures the electrical connection of the laser, but also ensures the high performance and reliability of the laser.

[0023] The present invention also proposes a method for preparing an O-band silicon-based III-V quantum dot narrow-linewidth laser, the technical solution adopted is:

[0024] A method for preparing an O-band silicon-based III-V quantum dot narrow-linewidth laser comprises the following steps:

[0025] S1, epitaxially growing a buffer layer, a lower waveguide layer, a lower confinement layer, an InAs quantum dot layer / InGaAs barrier layer, an upper confinement layer, an upper waveguide layer and an ohmic contact layer on a silicon substrate layer in sequence;

[0026] S2, using a photolithography method to form a ridge waveguide and gratings on both sides of the ridge waveguide from the upper waveguide layer and the ohmic contact layer;

[0027] S3, filling benzocyclobutene material on both sides of the gratings away from the ridge waveguide and between adjacent gratings to form a filling layer with the same thickness as the upper waveguide layer;

[0028] S4, depositing a SiO2 passivation layer on the grating and the filling layer, and opening a metal contact window on the SiO2 passivation layer with a width equal to that of the ohmic contact layer, wherein the ohmic contact layer is disposed in the metal contact window;

[0029] S5, preparing an electrode layer on the SiO2 passivation layer and the ohmic contact layer by electron beam evaporation or magnetron sputtering to obtain the O-band silicon-based III-V quantum dot narrow linewidth laser.

[0030] Beneficial Effects: This method for preparing an O-band silicon-based III-V quantum dot narrow-linewidth laser epitaxially grows a buffer layer, a lower waveguide layer, a lower confinement layer, an InAs quantum dot layer / InGaAs barrier layer, an upper confinement layer, an upper waveguide layer, and an ohmic contact layer on a silicon substrate layer to achieve epitaxial growth of III-V quantum dots. In the structural design of the O-band silicon-based III-V quantum dot narrow-linewidth laser, the upper waveguide layer and the ohmic contact layer form a ridge waveguide, and gratings are etched on both sides of the ridge waveguide. This achieves the preparation of a high-performance, monolithically integrated O-band silicon-based quantum dot narrow-linewidth laser, providing an ideal on-chip narrow-linewidth light source for future large-scale silicon photonic integrated systems. The O-band silicon-based III-V quantum dot narrow-linewidth laser prepared by the present invention has the advantages of narrow linewidth, high reflection tolerance, high temperature stability, and low threshold current density, providing an ideal on-chip light source for future on-chip interconnect systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of the laser in Example 1 of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention;

[0032] Figure 2 1. This is a top view schematic diagram of the ridge waveguide and grating in Example 1 of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention;

[0033] In the figure, 1. Si (001) substrate layer, 2. n-type buffer layer, 3. n-type AlGaAs waveguide layer, 4. n-type AlGaAs confinement layer, 5. InAs quantum dot layer / InGaAs barrier layer, 6. p-type AlGaAs confinement layer, 7. p-type AlGaAs waveguide layer, 8. p-type GaAs ohmic contact layer, 9. AlGaAs grating layer, 10. SiO2 passivation layer, 11. Metal contact layer, 12. Filling layer. DETAILED DESCRIPTION

[0034] As cited in the background art, it is extremely challenging to prepare a high-performance, monolithically integrated O-band silicon-based III-V quantum dot narrow-linewidth laser in the prior art. Therefore, the present invention provides an O-band silicon-based III-V quantum dot narrow-linewidth laser, comprising a silicon substrate layer for growing quantum dots on the silicon substrate layer; a buffer layer, a lower waveguide layer, a lower confinement layer, a quantum dot active layer, an upper confinement layer, an upper waveguide layer, and an ohmic contact layer sequentially stacked on the silicon substrate layer, wherein the buffer layer is used to effectively prevent dislocations caused by lattice mismatch from being transmitted to the quantum dot gain region, ensuring that high-density, high-quality III-V quantum dots can be epitaxially grown; the upper waveguide layer and the ohmic contact layer form a ridge waveguide and a grating on at least one side of the ridge waveguide, which plays a role in filtering and narrowing the linewidth; the quantum dot active layer includes an InAs quantum dot layer / InGaAs barrier layer, which is used to improve the optoelectronic performance of the laser, reduce the linewidth, and reduce emission. The O-band silicon-based III-V quantum dot narrow-linewidth laser prepared by the present invention has the advantages of narrow linewidth, high reflection tolerance, high temperature stability, and low threshold current density, providing an ideal on-chip light source for future on-chip interconnection systems.

[0035] Specific embodiment 1 of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention:

[0036] In this embodiment, Figure 1 、 Figure 2 As shown, an O-band silicon-based III-V quantum dot narrow linewidth laser comprises a silicon substrate layer, on which a buffer layer, a lower waveguide layer, a lower confinement layer, a quantum dot active layer, an upper confinement layer, an upper waveguide layer, an ohmic contact layer and an electrode layer are sequentially stacked, wherein the upper waveguide layer and the ohmic contact layer form a ridge waveguide and a grating on one side of the ridge waveguide; wherein the silicon substrate layer is a Si (001) substrate layer 1; the electrode layer is a metal contact layer 11; the quantum dot active layer is an InAs quantum dot layer / InGaAs barrier layer 5, the period number is 2-15, the thickness of the InGaAs barrier layer is 2-20 nm, and the wavelength is O-band (1260-1360 nm).

[0037] Specifically, the lower waveguide layer is grown on the upper surface of the buffer layer. The lower waveguide layer is an n-type waveguide layer. The n-type waveguide layer is Al x GaAs 1-x , where 0<x<1, the thickness of the n-type AlGaAs waveguide layer 3 is 30-800nm, and Si is used as a dopant with a doping concentration ≥0.5×10 18 cm -2 The lower confinement layer is grown on the upper surface of the n-type AlGaAs waveguide layer 3, the lower confinement layer is the n-type confinement layer, the n-type confinement layer is Al x GaAs 1-xWherein, 0<x<1, the thickness of the n-type AlGaAs confinement layer 4 is 50-300nm, Si is used as a dopant, and the doping concentration is ≥0.3×10 18 cm -2 The upper confinement layer is grown on the upper surface of the InAs quantum dot layer / InGaAs barrier layer 5, and the upper confinement layer is a p-type confinement layer, and the p-type confinement layer is Al x GaAs 1-x , where 0<x<1, the thickness of the p-type AlGaAs confinement layer 6 is 3-50nm, and Mg is used as a dopant with a doping concentration ≥1×10 18 cm -2 The upper waveguide layer is grown on the upper surface of the p-type AlGaAs confinement layer 6, the upper waveguide layer is a p-type waveguide layer, and the p-type waveguide layer is Al x Ga 1-x As, where 0<x<1, the p-type AlGaAs waveguide layer 7 has a thickness of 200-3000 nm, and Mg is used as a dopant with a doping concentration ≥0.5×10 18 cm -2 The ohmic contact layer is grown on the upper surface of the p-type AlGaAs waveguide layer 7. The ohmic contact layer is a p-type ohmic contact layer. The p-type ohmic contact layer is a p-type GaAs ohmic contact layer 8. The thickness of the p-type GaAs ohmic contact layer 8 is 5-50 nm. Mg is used as a dopant with a doping concentration of ≥3×10 19 cm -2 .

[0038] In order to effectively improve the feedback effect of the grating and further improve the filtering effect of the high-order Bragg grating on the ridge waveguide, in this embodiment, Figure 1 and Figure 2 As shown, the ridge waveguide and the gratings on both sides of the ridge waveguide are etched from a p-type AlGaAs waveguide layer 7 and a p-type GaAs ohmic contact layer 8; the ridge waveguide is a strip-shaped body located in the middle, and symmetrical gratings extending along the length of the strip-shaped body are arranged on both sides of the ridge waveguide, forming an AlGaAs grating layer 9. The AlGaAs grating layer 9 is processed so that the height of the grating is consistent with the thickness of the upper waveguide layer, that is, the thickness of the AlGaAs grating layer 9 is consistent with the thickness of the p-type AlGaAs waveguide layer 7. Among them, the width of the ridge waveguide is 1.5-3μm, the width of the single-sided grating is 0.5-3μm, the grating is a first-order grating, the period of the first-order grating is 180-250nm, and the duty cycle is 0.35-0.75; or a high-order grating can be used, that is, the grating can use a third-order grating (the grating period is 3 times the period of the first-order grating); the grating can also use a fifth-order grating (the grating period is 5 times the period of the first-order grating).

[0039] In other embodiments, the silicon substrate layer may be an SOI substrate layer.

[0040] In other embodiments, the ridge waveguide is a strip-shaped body located in the middle, and a grating extending along the length direction of the strip-shaped body is provided on the left side of the ridge waveguide, constituting an AlGaAs grating layer 9; in other embodiments, the ridge waveguide is a strip-shaped body located in the middle, and a grating extending along the length direction of the strip-shaped body is provided on the right side of the ridge waveguide, constituting an AlGaAs grating layer 9.

[0041] In other embodiments, the lower waveguide layer is a p-type waveguide layer, and the p-type waveguide layer is Al x Ga 1-x As, where 0<x<1, the thickness of the p-type AlGaAs waveguide layer is 200-3000nm, and Mg is used as a dopant with a doping concentration ≥0.5×10 18 cm -2 ; The lower limiting layer is a p-type limiting layer, and the p-type limiting layer is Al x GaAs 1-x , where 0<x<1, the thickness of the p-type AlGaAs confinement layer is 3-50nm, and Mg is used as a dopant with a doping concentration ≥1×10 18 cm -2 ; The upper limiting layer is an n-type limiting layer, and the n-type limiting layer is Al x GaAs 1-x , where 0<x<1, the thickness of the n-type AlGaAs confinement layer is 2-4nm, the thickness is 50-300nm, Si is used as a dopant, and the doping concentration is ≥0.3×10 18 cm -2 ; The upper waveguide layer is an n-type waveguide layer, and the n-type waveguide layer is Al x GaAs 1-x , where 0<x<1, the thickness of the n-type AlGaAs waveguide layer is 30-800nm, and Si is used as a dopant with a doping concentration ≥0.5×10 18 cm -2 .

[0042] Specific embodiment 2 of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention:

[0043] Based on the technical concept of the present invention described above, or based on the specific embodiment of the present invention described above, another embodiment is provided below.

[0044] In this embodiment, the buffer layer is an n-type buffer layer 2, which includes an AlAs nucleation layer, a GaAs buffer layer, and an AlGaAs dislocation filter layer from bottom to top, wherein the thickness of the GaAs buffer layer is 0.2-2 μm. The specific implementation process is: epitaxially growing an n-type buffer layer 2 on a Si (001) substrate layer 1, wherein the n-type buffer layer 2 includes a GaAs buffer layer, and epitaxially growing the GaAs buffer layer specifically includes: first, growing an AlAs nucleation layer with a thickness of 3-12 nm on the Si (001) substrate layer 1, then growing a GaAs layer with a thickness of 0.2-2 μm as a buffer layer, and subsequently growing multiple AlGaAs layers as dislocation filter layers. In this application, structural layers such as a nucleation layer and a dislocation filter layer are introduced into the growth of the buffer layer to prevent dislocations caused by lattice mismatch from being transferred to the quantum dot gain region, thereby ensuring that high-density and high-quality III-V quantum dots can be epitaxially grown.

[0045] Specific embodiment 3 of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention:

[0046] Based on the technical concept of the present invention described above, or based on the specific embodiment of the present invention described above, another embodiment is provided below.

[0047] In this embodiment, a filling layer 12 is formed by filling the gratings on both sides away from the ridge waveguide and between adjacent gratings with a benzocyclobutene material. The lower surface of the filling layer 12 contacts the upper surface of the p-type AlGaAs confinement layer 6, so that the thickness of the filling layer 12 is consistent with the thickness of the upper waveguide layer, i.e., the p-type AlGaAs waveguide layer 7. This is used to optimize the performance of the optical waveguide and improve the efficiency and stability of the optical waveguide.

[0048] A SiO2 passivation layer 10 is deposited between the upper contact surface of the grating and filling layer 12 on both sides of the ridge waveguide and the lower contact surface of the metal contact layer 11. A metal contact window is provided on the SiO2 passivation layer 10. The width of the metal contact window is the same as the width of the p-type GaAs ohmic contact layer 8. The p-type GaAs ohmic contact layer 8 is arranged in the metal contact window so that the p-type GaAs ohmic contact layer 8 is exposed, thereby completing the contact between the metal contact layer 11 and the p-type GaAs ohmic contact layer 8. The above structure is used to protect the structure below the SiO2 passivation layer 10 from the influence of the external environment, and also prevents the intrusion of moisture and other impurities, thereby maintaining the long-term stability and reliability of the laser. At the same time, conductive metal connections are formed on the passivation layer. These metal connections can be used to further connect to external circuits to realize the input and output of current, thereby controlling the operation of the laser. This design not only ensures the electrical connection of the laser, but also ensures the high performance and reliability of the laser.

[0049] Specific Example 1 of the preparation method of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention:

[0050] The method for preparing an O-band silicon-based III-V quantum dot narrow linewidth laser comprises the following steps:

[0051] First, a buffer layer, a lower waveguide layer, a lower confinement layer, an InAs quantum dot layer / InGaAs barrier layer, an upper confinement layer, an upper waveguide layer and an ohmic contact layer are epitaxially grown in sequence on a silicon substrate layer;

[0052] Specifically, a buffer layer is first epitaxially grown on a silicon substrate layer, that is, an n-type buffer layer 2 is epitaxially grown on a Si (001) substrate layer 1, wherein the n-type buffer layer 2 includes a GaAs buffer layer. The epitaxial growth of the GaAs buffer layer specifically includes: first, growing a 3-12 nm AlAs nucleation layer on the Si (001) substrate layer 1, then growing a GaAs layer with a thickness of 0.2-2 μm as a buffer layer, and subsequently growing multiple AlGaAs layers as dislocation filter layers. Then, an n-type AlGaAs waveguide layer, an n-type AlGaAs confinement layer, an InAs quantum dot layer / InGaAs barrier layer, a p-type AlGaAs confinement layer, a p-type AlGaAs waveguide layer, and a p-type GaAs ohmic contact layer are sequentially grown on the AlGaAs layer; wherein the number of periods of the InAs quantum dot layer / InGaAs barrier layer is 2-15, the thickness of the InGaAs barrier layer is 2-20 nm, and the wavelength is in the O band (1260-1360 nm).

[0053] Specifically, the lower waveguide layer is an n-type waveguide layer, and the n-type waveguide layer is Al x GaAs 1-x , where 0<x<1, the thickness of the n-type AlGaAs waveguide layer 3 is 30-800nm, and Si is used as a dopant with a doping concentration ≥0.5×10 18 cm -2 The lower confinement layer is grown on the upper surface of the n-type AlGaAs waveguide layer 3, the lower confinement layer is the n-type confinement layer, the n-type confinement layer is Al x GaAs 1-x Wherein, 0<x<1, the thickness of the n-type AlGaAs confinement layer 4 is 50-300nm, Si is used as a dopant, and the doping concentration is ≥0.3×10 18 cm -2 The upper confinement layer is grown on the upper surface of the InAs quantum dot layer / InGaAs barrier layer 5, and the upper confinement layer is a p-type confinement layer, and the p-type confinement layer is Al x GaAs 1-x , where 0<x<1, the thickness of the p-type AlGaAs confinement layer 6 is 3-50nm, and Mg is used as a dopant with a doping concentration ≥1×10 18 cm-2 The upper waveguide layer is grown on the upper surface of the p-type AlGaAs confinement layer 6, the upper waveguide layer is a p-type waveguide layer, and the p-type waveguide layer is Al x Ga 1-x As, where 0<x<1, the p-type AlGaAs waveguide layer 7 has a thickness of 200-3000 nm, and Mg is used as a dopant with a doping concentration ≥0.5×10 18 cm -2 The ohmic contact layer is grown on the upper surface of the p-type AlGaAs waveguide layer 7. The ohmic contact layer is a p-type ohmic contact layer. The p-type ohmic contact layer is a p-type GaAs ohmic contact layer 8. The thickness of the p-type GaAs ohmic contact layer 8 is 5-50 nm. Mg is used as a dopant with a doping concentration of ≥3×10 19 cm -2 .

[0054] Secondly, the upper waveguide layer and the ohmic contact layer are formed into a ridge waveguide by photolithography and etching, and gratings are etched on both sides of the ridge waveguide;

[0055] Specifically, a p-type AlGaAs waveguide layer 7 and a p-type GaAs ohmic contact layer 8 are photolithographically etched to form a ridge waveguide and gratings on both sides of the ridge waveguide. The ridge waveguide is a centrally located strip-shaped body, with symmetrical gratings extending along the length of the strip on either side of the ridge waveguide, forming an AlGaAs grating layer 9. The AlGaAs grating layer 9 is processed so that the height of the gratings is consistent with the thickness of the upper waveguide layer, that is, the thickness of the AlGaAs grating layer 9 is consistent with the thickness of the p-type AlGaAs waveguide layer 7. The ridge waveguide has a width of 1.5-3 μm, the width of the single-sided grating is 0.5-3 μm, and the grating is a first-order grating with a period of 180-250 nm and a duty cycle of 0.35-0.75. Alternatively, a higher-order grating can be used.

[0056] Next, filling benzocyclobutene material on both sides of the gratings away from the ridge waveguide and between adjacent gratings to form a filling layer with the same thickness as the upper waveguide layer;

[0057] Specifically, benzocyclobutene (BCB) material is filled on both sides of the gratings away from the ridge waveguide and between adjacent gratings to form a filling layer 12 with the same thickness as the upper waveguide layer. The lower surface of the filling layer 12 contacts the upper surface of the p-type AlGaAs confinement layer 6, so that the thickness of the filling layer 12 is consistent with the thickness of the upper waveguide layer, that is, the p-type AlGaAs waveguide layer 7.

[0058] Then, a SiO2 passivation layer is deposited on the grating and the filling layer, and a metal contact window with a width equal to that of the ohmic contact layer is opened on the SiO2 passivation layer, and the ohmic contact layer is arranged in the metal contact window;

[0059] Specifically, a SiO2 passivation layer 10 is deposited on the grating and filling layer on both sides of the ridge waveguide, and a metal contact window is opened on the SiO2 passivation layer 10. The width of the metal contact window is the same as the width of the p-type GaAs ohmic contact layer 8, and the p-type GaAs ohmic contact layer 8 is arranged in the metal contact window, so that the p-type GaAs ohmic contact layer 8 is exposed, thereby completing the contact between the p-type GaAs ohmic contact layer 8 and the metal contact layer 11.

[0060] Finally, an electrode layer is prepared on the SiO2 passivation layer and the ohmic contact layer by electron beam evaporation or magnetron sputtering to obtain the O-band silicon-based III-V quantum dot narrow linewidth laser.

[0061] Specifically, a metal contact layer 11 is prepared on the SiO2 passivation layer 10 and the p-type GaAs ohmic contact layer 8 by electron beam evaporation or magnetron sputtering, and ohmic contact is achieved by high temperature annealing, wherein the high temperature annealing temperature is 300-500°C and the time is 2-10 min.

[0062] Through the above description of the specific embodiment of the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention, it can be seen that the O-band silicon-based III-V quantum dot narrow linewidth laser of the present invention includes a silicon substrate layer for growing quantum dots on the silicon substrate layer; a buffer layer, a lower waveguide layer, a lower confinement layer, an InAs quantum dot layer / InGaAs barrier layer, an upper confinement layer, an upper waveguide layer and an ohmic contact layer are sequentially stacked on the silicon substrate layer, wherein the buffer layer is used to effectively prevent dislocations caused by lattice mismatch from being transferred to the quantum dot gain region, ensuring that high-density and high-quality III-V quantum dots can be epitaxially grown; the upper waveguide layer and the ohmic contact layer form a ridge waveguide and a grating on at least one side of the ridge waveguide, which play a role in filtering and narrowing the linewidth; the quantum dot active layer includes an InAs quantum dot layer / InGaAs barrier layer, which is used to improve the optoelectronic performance of the laser, reduce the linewidth, and reduce reflection. The O-band silicon-based III-V quantum dot narrow-linewidth laser of the present invention has the advantages of narrow linewidth, high reflection tolerance, high temperature stability, and low threshold current density, providing an ideal on-chip light source for future on-chip interconnection systems.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be based on the claims. Any equivalent structural changes made using the contents of the description and drawings of the present invention shall be included in the scope of protection of the present invention.

Claims

1. An O-band silicon-based III-V quantum dot narrow-linewidth laser, characterized in that: The invention comprises a silicon substrate layer, on which a buffer layer, a lower waveguide layer, a lower confinement layer, a quantum dot active layer, an upper confinement layer, an upper waveguide layer, an ohmic contact layer and an electrode layer are sequentially stacked; the upper waveguide layer and the ohmic contact layer are etched into a ridge waveguide and a grating on at least one side of the ridge waveguide; the quantum dot active layer comprises an InAs quantum dot layer / InGaAs barrier layer; the buffer layer comprises an AlAs nucleation layer, a GaAs buffer layer and an AlGaAs dislocation filter layer from bottom to top, and the thickness of the GaAs buffer layer is 0.2-2 μm; the width of the ridge waveguide is 1.5-3 μm, and the grating on one side is 1.5-3 μm. The width of the grating is 0.5-3 μm, the grating is a first-order grating or a high-order grating, the period of the first-order grating is 180-250 nm, and the duty cycle is 0.35-0.75; the ridge waveguide is a strip-shaped body located in the middle, and the two sides of the ridge waveguide have symmetrical gratings extending along the length direction of the strip-shaped body, and the height of the grating is consistent with the thickness of the upper waveguide layer; the thickness of the InGaAs barrier layer is 2-20 nm; the AlGaAs dislocation filter layer is a plurality of AlGaAs layers; the lower confinement layer is an n-type AlGaAs confinement layer with a thickness of 50-300 nm, and Si is used as a dopant with a doping concentration of ≥0.3×10 18 cm -2 The upper confinement layer is a P-type AlGaAs confinement layer with a thickness of 3-50 nm, and Mg is used as a dopant with a doping concentration of ≥1×10 18 cm -2 The two sides of the gratings on both sides away from the ridge waveguide and between adjacent gratings are filled with benzocyclobutene material to form a filling layer, and the thickness of the filling layer is consistent with the thickness of the upper waveguide layer; a SiO2 passivation layer is deposited between the gratings, the filling layer and the electrode layer, and a metal contact window is opened on the SiO2 passivation layer. The width of the metal contact window is the same as the width of the ohmic contact layer, and the ohmic contact layer is exposed to complete the ohmic contact with the electrode layer.

2. The O-band silicon-based III-V quantum dot narrow linewidth laser according to claim 1, characterized in that: The number of periods of the InAs quantum dot layer / InGaAs barrier layer is 2-15.

3. The O-band silicon-based III-V quantum dot narrow linewidth laser according to claim 1, characterized in that: The lower waveguide layer is an n-type AlGaAs waveguide layer with a thickness of 30-800 nm; the upper waveguide layer is a p-type AlGaAs waveguide layer with a thickness of 200-3000 nm; and the ohmic contact layer is a p-type GaAs ohmic contact layer with a thickness of 5-50 nm.

4. The O-band silicon-based III-V quantum dot narrow linewidth laser according to claim 1, characterized in that: The silicon substrate layer is a Si (001) substrate or an SOI substrate.

5. A method for preparing an O-band silicon-based III-V quantum dot narrow linewidth laser, characterized in that: For the preparation of the O-band silicon-based III-V quantum dot narrow linewidth laser as claimed in any one of claims 1 to 4, The following steps are involved: S1, epitaxially growing a buffer layer, a lower waveguide layer, a lower confinement layer, an InAs quantum dot layer / InGaAs barrier layer, an upper confinement layer, an upper waveguide layer and an ohmic contact layer on a silicon substrate layer in sequence; S2, using a photolithography method to form a ridge waveguide from the upper waveguide layer and the ohmic contact layer, and etching gratings on both sides of the ridge waveguide; S3, filling benzocyclobutene material on both sides of the gratings away from the ridge waveguide and between adjacent gratings to form a filling layer with the same thickness as the upper waveguide layer; S4, depositing a SiO2 passivation layer on the grating and the filling layer, and opening a metal contact window on the SiO2 passivation layer with a width equal to that of the ohmic contact layer, wherein the ohmic contact layer is disposed in the metal contact window; S5, preparing an electrode layer on the SiO2 passivation layer and the ohmic contact layer by electron beam evaporation or magnetron sputtering to obtain the O-band silicon-based III-V quantum dot narrow linewidth laser.

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