A high-speed wide-spectrum response photoelectric detector, an epitaxial structure and a preparation method thereof

Abstract

The application provides a high-speed wide-spectrum response photoelectric detector, an epitaxial structure and a preparation method thereof, and relates to the field of photoelectric chip manufacturing and processing. x Ga y As buffer layer, an In x1 Ga y1 As buffer layer, an N-In x2 Ga y2 As contact layer, an In x2 Ga y2 As intrinsic layer, an InGaAsP transition layer and a P-In x2 Ga y2 As contact layer; x+y=1, x1+y1=1 and x2+y2=1. The chip containing the epitaxial structure has a response wavelength covering 850nm-1650nm, is fast in response speed and wide in response wavelength.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of photoelectric chip manufacturing and processing, in particular to a high-speed wide-spectrum response photoelectric detector, an epitaxial structure and a preparation method thereof. BACKGROUND

[0002] With the advent of the AI era, the optical fiber communication industry has ushered in tremendous development. Optical fiber communication mainly has three application scenarios, namely, access network, telecommunication network and data center. Among them, the access network is mainly single-mode application, and the rate is developing from 10GPON to 50G PON; the telecommunication network is also moving towards 6G after the 5G wave in 2020, which is also mainly single-mode application; and the data center is developing towards 800G or even 1.6T rate driven by the AI era, which is divided into short-distance transmission and medium-long-distance transmission. The short-distance transmission is mainly multi-mode application, accounting for more than 70%, and the medium-long-distance transmission is mainly single-mode application. The working principle of optical fiber communication is to convert electrical signals into optical signals by a transmitter, transmit the optical signals of a specific wavelength through an optical fiber, and convert the optical signals into electrical signals by a receiver to complete signal transmission.

[0003] An optical module is a core device in an optical fiber communication system, which completes photoelectric conversion function and is mainly composed of a transmitting optical chip (laser) and a detecting optical chip (detector). According to different application scenarios, the optical module is divided into a multi-mode module (850nm VCSEL chip) for short-distance transmission and a single-mode module (1270-1577nm DFB / EML chip) for medium-long-distance transmission. For instruments and apparatuses for testing optical modules, it is necessary to test the wavelengths covered by multi-mode modules and single-mode modules at the same time, and the working core is to use a photoelectric detector to perform photoelectric conversion.

[0004] At present, the common photoelectric detectors on the market mainly detect GaAs epitaxial structures with a wavelength of 850nm, Si epitaxial structures with a wavelength of 400nm-1100nm and InGaAs epitaxial structures with a wavelength of 960nm-1650nm. The wavelength range of the spectral response is narrow, and the detection rate is low, which cannot meet the testing needs of high-speed optical modules. SUMMARY

[0005] The present application aims to provide an epitaxial structure of a high-speed wide-spectrum response photoelectric detector, which can realize response wavelength coverage of 850nm-1650nm, is compatible with single-mode and multi-mode applications, and can be applied to high-end instruments and apparatuses, such as high-speed oscilloscopes for testing optical module eye diagrams, after being packaged into a device.

[0006] Another object of the present application is to provide a preparation method of an epitaxial structure of a high-speed wide-spectrum response photodetector, which adopts a MBE molecular beam epitaxy method to precisely control the content of each component in each layer of alloy and reduce lattice defects generated in the growth process of the epitaxial structure due to different In contents.

[0007] A third object of the present application is to provide a high-speed wide-spectrum response photodetector, which has a chip bandwidth of up to 30GHz and can perform single-wave 100Gbps rate data transmission.

[0008] The present application solves the technical problem by adopting the following technical solutions.

[0009] In one aspect, the present application provides an epitaxial structure of a high-speed wide-spectrum response photodetector, which comprises, in sequence, an InP buffer layer, an In x Ga y As buffer layer, an In x1 Ga y1 As buffer layer, an N-In x2 Ga y2 As contact layer, an In x2 Ga y2 As intrinsic layer, an InGaAsP transition layer, and a P-In x2 Ga y2 As contact layer; x+y=1, x1+y1=1, and x2+y2=1.

[0010] The N-In x2 Ga y2 As contact layer is N-type doped, and the P-In x2 Ga y2 As contact layer is P-type doped, and the two layers are used to prepare P / N electrodes of the photodetector to collect electron and hole generated current.

[0011] The In x2 Ga y2 As intrinsic layer is the core layer of the entire photodetector, which is not doped to form a high-resistance depletion layer, receives light, and performs photoelectric conversion.

[0012] In some embodiments of the present application, the value of x is 0.53-0.55, the value of x1 is 0.55-0.6, and the value of x2 is 0.6-0.61.

[0013] In some embodiments of the present application, the In x2 Ga y2 As intrinsic layer has a response wavelength of 850nm-1650nm.

[0014] In some embodiments of the present application, the thickness of the InP buffer layer is 2um; In x Ga y The thickness of the InP buffer layer is 1um; In x1 Ga y1 The thickness of the InP buffer layer is 1um; N-In x2 Ga y2 The thickness of the InP buffer layer is 0.5um; In x2 Ga y2 The thickness of the InP buffer layer is 1um; InGaAsP transition layer is 0.5um; In x2 Ga y2 The thickness of the InP buffer layer is 0.2um.

[0015] In some embodiments of the present application, the thickness of the substrate is 350um.

[0016] In some embodiments of the present application, the material of the substrate is iron-containing InP alloy.

[0017] In another aspect, the embodiments of the present application provide a preparation method of an epitaxial structure of a high-speed wide-spectrum response photodetector, comprising the following steps:

[0018] S1, preparing a substrate;

[0019] S2, based on the MBE molecular beam epitaxy method, depositing elements on the substrate according to the element ratio of each layer of material to form an epitaxial structure.

[0020] A high-speed wide-spectrum response photodetector, which contains the above-mentioned epitaxial structure in the chip.

[0021] Compared with the prior art, the embodiments of the present application have at least the following advantages or beneficial effects:

[0022] The epitaxial structure of the high-speed wide-spectrum response photodetector provided by the present application covers a response wavelength of 850nm-1650nm, has a fast response speed, and has a wide response wavelength.

[0023] The photodetector based on the epitaxial structure has a chip bandwidth of up to 30GHz, and can perform single-wave 100Gbps rate data transmission. The detector chip can cover a response wavelength of 850nm-1650nm, is compatible with single-mode and multi-mode applications, and after packaging, can be applied to high-end instruments and meters, such as a high-speed oscilloscope for testing the eye diagram of an optical module, and a vector network analyzer for testing transmission characteristics as an optical base, testing the transmission performance of an 850nm VCSEL or a DFB laser of 1270nm-1577nm. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A cross-sectional schematic diagram of a traditional InGaAs / InP epitaxial structure;

[0026] Figure 2 This is a cross-sectional schematic diagram of the InGaAs / InP epitaxial structure of Embodiment 1 of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of a chip containing the epitaxial structure of Embodiment 1. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0030] Traditional InGaAs / InP epitaxial structures, such as Figure 1 As shown, the main structure is P(p-In) 0.53 Ga 0.47 As)-I (Intrinsic-In) 0.53 Ga 0.47 As)-N(n-In 0.53 Ga 0.47 As) structure. The material of this structure is In. 0.53 Ga 0.47 The As layer is chosen because its lattice is perfectly matched to the InP substrate, resulting in minimal defects during epitaxial growth and allowing for high-quality epitaxial layers. However, the response wavelength of this epitaxial structure (PD) is limited to a minimum of 960 nm. Improving the PD's response rate can be achieved by reducing the PD's optical window to decrease chip capacitance and by reducing the thickness of the I-region to shorten carrier transit time.

[0031] The high-speed, broadband response photodetector provided by this invention employs an InGaAs / InP material system. The composition of the epitaxial structure is modulated to increase the In content and the bandgap of the InGaAs material, thereby achieving a response wavelength coverage of 850nm-1650nm. To obtain a high-quality, high-In-content epitaxial structure, MBE (molecular beam epitaxy) is used to grow the epitaxial structure on a substrate. An InGaAs bandgap gradient buffer layer is added to the substrate to reduce the generation of defects during the epitaxial process.

[0032] For traditional epitaxial structures, InP exhibits strong absorption of short-wavelength light. Therefore, by removing the InP Cap layer, the overall chip thickness is reduced, thereby increasing the responsivity at the short wavelength of 850nm. Finally, the responsivity is further improved by optimizing the antireflection coating of the optical window and adding a high-reflectivity coating on the back of the chip. The high-speed, broadband response photodetector epitaxial structure provided by this invention is as follows: Figure 2 As shown.

[0033] Specifically, embodiments of the present invention provide an epitaxial structure for a high-speed, wide-spectrum-response photodetector. This epitaxial structure includes an InP buffer layer and an In... sequentially grown on a substrate. x Ga y As buffer layer, In x1 Ga y1 As buffer layer, N-In x2 Ga y2 As contact layer, In x2 Ga y2 As intrinsic layer, InGaAsP transition layer and P-In x2 Ga y2 As contact layer; x+y=1, x1+y1=1, x2+y2=1.

[0034] In some embodiments of the present invention, in the above-described epitaxial structure, the value of x is 0.53~0.55, the value of x1 is 0.55~0.6, and the value of x2 is 0.6~0.61, wherein, in the In x2 Ga y2 In the intrinsic layer As, x2=0.6, y2=0.4.

[0035] In some embodiments of the present invention, the In x2 Ga y2 The response wavelength of the intrinsic As layer is 850nm-1650nm.

[0036] In some embodiments of the present invention, the thickness of the InP buffer layer is 2 μm; In x Gay As buffer layer is 1um;‌In x1 Ga y1 As buffer layer is 1um;‌N-In x2 Ga y2 As contact layer is 0.5um;‌In x2 Ga y2 As intrinsic layer is 1um;‌InGaAsP transition layer is 0.5um;‌P-In x2 Ga y2 As contact layer is 0.2um.

[0037] In some embodiments of the present application, the InGaAs intrinsic layer has a thickness of 1um.

[0038] In some embodiments of the present application, the substrate has a thickness of 350um.

[0039] In some embodiments of the present application, the substrate is made of iron-containing InP alloy.

[0040] In another aspect, the embodiments of the present application provide a method for preparing an epitaxial structure of a high-speed wide-spectrum response photodetector, comprising the following steps:

[0041] S1, preparing a substrate;

[0042] S2, based on MBE molecular beam epitaxy method, depositing elements on the substrate according to the component ratio of each layer to form an epitaxial structure.

[0043] A high-speed wide-spectrum response photodetector, which contains the above-mentioned epitaxial structure in the chip. The features and performance of the present application are further described in detail in combination with the embodiments.

[0044] Embodiment 1

[0045] The epitaxial structure of the present embodiment is prepared according to the element ratio and preparation method of each layer as follows:

[0046] ‌InP buffer layer,‌In x Ga y As buffer layer,‌In x1 Ga y1 As buffer layer,‌N-In x2 Ga y2 As contact layer,‌In x2 Ga y2 As intrinsic layer,‌InGaAsP transition layer and‌P-In x2 Ga y2As contact layer; wherein, x=0.54, y=0.46, x1=0.56, y1=0.44, x2=0.6, y2=0.4.

[0047] S1, preparing a substrate;

[0048] S2, based on MBE molecular beam epitaxy method, element deposition is performed on the substrate according to the component ratio of each layer to form an epitaxial structure.

[0049] Embodiment 2

[0050] The epitaxial structure of the embodiment is prepared according to the element ratio and preparation method of each layer as follows:

[0051] ‌InP buffer layer, ‌In x Ga y As buffer layer, ‌In x1 Ga y1 As buffer layer, ‌N-In x2 Ga y2 As contact layer, ‌In x2 Ga y2 As intrinsic layer, ‌InGaAsP transition layer and ‌P-In x2 Ga y2 As contact layer; wherein, x=0.55, y=0.45, x1=0.58, y1=0.42, x2=0.6, y2=0.4.

[0052] S1, preparing a substrate;

[0053] S2, based on MBE molecular beam epitaxy method, element deposition is performed on the substrate according to the component ratio of each layer to form an epitaxial structure.

[0054] Embodiment 3

[0055] The epitaxial structure of the embodiment is prepared according to the element ratio and preparation method of each layer as follows:

[0056] ‌InP buffer layer, ‌In x Ga y As buffer layer, ‌In x1 Ga y1 As buffer layer, ‌N-In x2 Ga y2 As contact layer, ‌In x2 Ga y2 As intrinsic layer, ‌InGaAsP transition layer and ‌P-In x2 Ga y2 As contact layer; wherein, x=0.55, y=0.45, x1=0.59, y1=0.41, x2=0.61, y2=0.39.

[0057] S1, Prepare the substrate;

[0058] S2, based on MBE molecular beam epitaxy, elemental deposition is performed on the substrate according to the composition ratio of each layer to form an epitaxial structure.

[0059] Comparative Example 1

[0060] like Figure 1 As shown, a conventional epitaxial structure was fabricated. The structure includes: an InP Cap layer with a thickness of 0.5 μm; a P-InGaAs Contact layer with a thickness of 0.2 μm; an InGaAsP Transition layer with a thickness of 0.5 μm; an InGaAs Intrinsic Layer with a thickness of 1 μm; an N-InGaAs Contact Layer with a thickness of 0.5 μm; an InP Buffer Layer with a thickness of 3 μm; and a substrate (InP(Fe)-Sub, containing iron) with a thickness of 350 μm.

[0061] Experimental Example

[0062] The epitaxial structures of Examples 1-3 and Comparative Example 1 were fabricated into detector chips through processes such as photolithography, cleaning, and thin film deposition. Figure 3 As shown in Table 1, its bandwidth and response wavelength range were tested.

[0063] Table 1

[0064]

[0065] The method for testing bandwidth is as follows: a vector network analyzer is used, and the device is tested after it is packaged.

[0066] Response wavelength: Broadband light source test, light is given to the PD optical window, and the magnitude of the current generated by the PD can be used to calculate the responsivity value.

[0067] exist Figure 2 In the middle, P-In x2 Ga y2 As contact layer (P-In) x2 Ga y2 As Contact Layer), with a thickness of 0.2 μm; InGaAsP Transition Layer, with a thickness of 0.5 μm; In x2 Gay2 As intrinsic layer (In) x2 Ga y2 As an Intrinsic Layer), its thickness is 1 μm; N-In x2 Ga y2 As contact layer (N-In) x2 Ga y2 As a contact layer, its thickness is 0.5 μm; In x1 Ga y1 As buffer layer (In) x1 Ga y1 As a buffer layer), its thickness is 1µm; In x Ga y As buffer layer (In) x Ga y As Buffer Layer), with a thickness of 1um; InP Buffer Layer, with a thickness of 2um; Substrate (InP(Fe)-Sub, containing iron), with a thickness of 350um.

[0068] In summary, the embodiments of the present invention provide a high-speed, wide-spectrum response photodetector with a response wavelength covering 850nm-1650nm, characterized by fast response speed and wide response wavelength.

[0069] Based on this epitaxial structure, the photodetector chip has a bandwidth of up to 30 GHz, enabling data transmission at a single-wavelength rate of 100 Gbps. This detector chip can achieve a response wavelength coverage of 850 nm to 1650 nm, is compatible with both single-mode and multi-mode applications, and, when packaged into a device, can be used in high-end instrumentation, such as high-speed oscilloscopes for testing the eye diagrams of optical modules, and as a vector network analyzer used as an optical base to test the transmission characteristics of 850 nm VCSELs or 1270 nm to 1577 nm DFB lasers.

[0070] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. An epitaxial structure of a high-rate wide-spectrum response photodetector, characterized in that, comprises an InP buffer layer, an In x Ga y As buffer layer, an In x1 Ga y1 As buffer layer, an N-In x2 Ga y2 As contact layer, an In x2 Ga y2 As intrinsic layer, an InGaAsP transition layer and a P-In x2 Ga y2 As contact layer; x+y=1, x1+y1=1, x2+y2=1; the value of x is 0.53~0.55, the value of x1 is 0.55~0.6, the value of x2 is 0.6~0.

61.

2. The epitaxial structure for high-rate, broad-spectrum response photodetectors of claim 1, wherein, The In x2 Ga y2 The response wavelength of the As intrinsic layer is 850-1650 nm.

3. The epitaxial structure for high-speed, wide-spectrum response photodetectors of claim 1, wherein The thickness of the InP buffer layer is 2um; In x Ga y The thickness of the GaAs buffer layer is 1um; In x1 Ga y1 The thickness of the GaAs buffer layer is 1um; N-In x2 Ga y2 The thickness of the GaAs contact layer is 0.5um; In x2 Ga y2 The thickness of the InGaAs intrinsic layer is 1um; InGaAsP transition layer is 0.5um; P-In x2 Ga y2 The thickness of the GaAs contact layer is 0.2um.

4. The epitaxial structure for high-speed, wide-spectrum response photodetectors of claim 1, wherein The thickness of the substrate is 350um.

5. The epitaxial structure for high-speed, wide-spectrum response photodetectors of claim 1, wherein The material of the substrate is InP alloy containing iron.

6. A method of fabricating an epitaxial structure of a high-speed, wide-spectrum response photodetector as claimed in any one of claims 1-5, characterized in that, The method comprises the following steps: S1, preparing a substrate; S2, depositing elements on the substrate according to the component ratio of each layer based on the MBE molecular beam epitaxy method to form an epitaxial structure.

7. A high-rate, wide-spectrum response photodetector, characterized in that, The epitaxial structure according to any one of claims 1-5.

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