Lateral incidence type backlight monitoring detector and manufacturing method thereof

Abstract

The invention provides a side incidence type backlight monitoring detector and a manufacturing method thereof, and relates to the technical field of semiconductor detectors. The side incidence type backlight monitoring detector comprises a substrate; the buffer layer, the absorption layer, the top layer, the contact layer and the insulation layer are sequentially stacked on the surface of the substrate; the trapezoidal etching groove is arranged between the insulating layer and the substrate and comprises a side wall, and the side wall is configured to be a light reflecting surface and is used for reflecting a laser beam incident from the side surface of the substrate; and the diffusion region is arranged between the contact layer and the absorption layer and is used for receiving the laser beam. According to the side incidence type backlight monitoring detector provided by the invention, the positions and the sizes of the diffusion region and the light reflecting surface can be obtained by photoetching the top layer of the epitaxial structure at the same time, so that the position and the size of the diffusion region can be accurately controlled, a high-difficulty alignment technology is avoided, and the tolerance is relatively large.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor detectors, and in particular, to a side-incident backlight monitoring detector and a manufacturing method thereof. Background Art

[0002] In an optical transmission component (TOSA) or an optical emission module used in an optical communication system, in order to monitor or control the optical power output from the fiber in front of a laser, a pin-type photodetector (pin-PD) is generally installed on the optical path behind the laser. The side-incident PD can detect the incident light parallel to the installation surface. Since such a PD can be easily installed on a PLC in a flip-chip manner like an edge-emitting LD, the assembly cost is reduced.

[0003] Currently, side-incident detector chips mainly achieve the reflection of side-incident light by etching a V-groove or a curved reflecting surface on the substrate surface. Therefore, it is necessary to perform photolithography on the epitaxial layer to form a diffusion region, and also perform backside photolithography on the thinned substrate surface to form a reflecting surface. At the same time, it is necessary to accurately align the reflecting surface with the diffusion region. The process difficulty of double-sided photolithography and alignment is very high. Summary of the Invention

[0004] In view of the above problems, the present invention provides a side-incident backlight monitoring detector and a manufacturing method thereof.

[0005] According to an aspect of an embodiment of the present invention, there is provided a side-incident backlight monitoring detector, including: a substrate; a buffer layer, an absorption layer, a top layer, a contact layer, and an insulating layer sequentially stacked on the surface of the substrate; a trapezoidal etching groove provided between the insulating layer and the substrate, including side walls, wherein the side walls are configured as light reflecting surfaces for reflecting a laser beam incident from the side of the substrate; and a diffusion region provided between the contact layer and the absorption layer for receiving the laser beam.

[0006] According to an embodiment of the present invention, the side-incident backlight monitoring detector further includes: an electrode window provided at one end of the diffusion region away from the trapezoidal etching groove; a metal layer provided on the insulating layer and connected to the electrode window; a P-type contact electrode provided on the insulating layer and connected to the metal layer; and an N-type contact electrode provided at one end of the substrate away from the P-type contact electrode.

[0007] According to an embodiment of the present invention, the side-incident backlight monitoring detector further includes: an antireflection film provided on the same side of the P-type contact electrode to the N-type contact electrode and close to the diffusion region for the incident laser beam; the material of the antireflection film is Al2O3, and the thickness of the antireflection film is 100 nm to 200 nm.

[0008] According to an embodiment of the present invention, the material of the substrate includes Fe-doped semi-insulating InP material, and the thickness of the substrate is 100 μm to 200 μm.

[0009] According to an embodiment of the present invention, the material of the buffer layer includes N-type InP material, wherein the doping concentration of the N-type InP material is N = 1 - 5E18, and the thickness of the N-type InP material is 400 nm to 500 nm.

[0010] According to an embodiment of the present invention, the material of the absorption layer includes InGaAs material, wherein the doping concentration of the InGaAs material is N = 1E14 - 5E14, and the thickness of the InGaAs material is 2500 nm to 3000 nm.

[0011] According to an embodiment of the present invention, the material of the top layer includes N-InP material, wherein the doping concentration of the N-InP material is N = 3E16, and the thickness of the N-InP material is 200 nm to 300 nm.

[0012] According to an embodiment of the present invention, the material of the contact layer includes InGaAs material, wherein the doping concentration of the InGaAs material is N = 3E16, and the thickness of the InGaAs material is 30 nm to 80 nm.

[0013] According to an embodiment of the present invention, the material of the insulating layer includes silicon nitride or silicon dioxide, and the thickness of the insulating layer is 150 nm to 250 nm.

[0014] On the other hand, according to an embodiment of the present invention, a method for manufacturing a side-incident backlight monitoring detector is provided, including: growing a buffer layer, an absorption layer, and a contact layer on a substrate from bottom to top in sequence; growing an insulating layer on the contact layer by plasma-enhanced chemical vapor deposition; etching the insulating layer and obtaining a diffusion region by using a Zn diffusion technique; etching a trapezoidal etching groove between the insulating layer and the substrate by photolithography and wet etching methods to form a light reflection surface, wherein the light reflection surface can reflect a laser beam incident from the side of the substrate to the diffusion region through the light reflection surface.

[0015] The side-incident backlight monitoring detector and the manufacturing method thereof provided by the present invention have at least the following beneficial effects:

[0016] (1) For the side-incident backlight monitoring detector provided by the present invention, since the position and size of the diffusion region and the light reflection surface can be simultaneously obtained by photolithography from the top layer of the epitaxial structure, the position and size of the diffusion region can be accurately controlled, avoiding the use of high-difficulty alignment techniques and having a large tolerance.

[0017] (2) For the method for manufacturing a side-incident backlight monitoring detector provided by the present invention, the diffusion region and the light reflection surface can be etched on the epitaxial layer simultaneously, the steps are simple and easy to operate, and the technical problem of double-sided photolithography of the substrate after thinning is avoided. Description of the Drawings

[0018] Through the following description of the embodiments of the present invention with reference to the accompanying drawings, the above content and other objects, features and advantages of the present invention will become clearer. In the drawings:

[0019] Figure 1 Schematically shows a cross-sectional view of the side-incident backlight monitoring detector structure according to an embodiment of the present invention parallel to the epitaxial growth direction;

[0020] Figure 2 Schematically shows a top view of the side-incident backlight monitoring detector structure according to an embodiment of the present invention.

[0021]

Reference Signs

[0022] 1 - Substrate; 2 - Buffer layer; 3 - Absorbing layer; 4 - Top layer; 5 - Contact layer; 6 - Insulating layer; 7 - Diffusion region; 8 - P-type contact electrode; 9 - N-type contact electrode; 10 - Antireflection film; 11 - Trapezoidal etching groove; 12 - Metal layer; 13 - Electrode window. Detailed Embodiments

[0023] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further details the present invention in conjunction with specific embodiments and with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. The terms used herein are merely for the purpose of describing specific embodiments and are not intended to limit the present invention. The terms "include", "comprise", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0024] In the present invention, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection or can communicate with each other; it can be a direct connection, or indirectly connected through an intermediate medium, and can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the subsystems or components referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0026] Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted. Moreover, the shapes, sizes, and positional relationships of the components in the drawings do not reflect the actual sizes, proportions, and actual positional relationships.

[0027] Similarly, in order to streamline the present invention and help understand one or more of the various aspects of the invention, in the above description of the exemplary embodiments of the present invention, the various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. The description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0028] In addition, the terms "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Therefore, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0029] In the case of using expressions similar to "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand such expressions (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0030] In the technical solution of the present invention, the processing of the data involved (such as including but not limited to user personal information), such as collection, storage, use, processing, transmission, provision, disclosure, and application, etc., all comply with the provisions of relevant laws and regulations, take necessary confidentiality measures, and do not violate public order and good customs.

[0031] Figure 1 Schematically shown is a cross-sectional view of a side-incident backlight monitoring detector structure according to an embodiment of the present invention parallel to the epitaxial growth direction.

[0032] As Figure 1 shown, the side-incident backlight monitoring detector of this embodiment includes: an epitaxial structure, and the epitaxial structure includes:

[0033] Substrate 1.

[0034] From Figure 1 the direction shown, a buffer layer 2, an absorption layer 3, a top layer 4, a contact layer 5, and an insulating layer 6 are sequentially stacked on the surface of substrate 1.

[0035] A trapezoidal etching groove 11 is provided between the insulating layer 6 and the substrate 1. The trapezoidal etching groove 11 includes side walls, and among them, the side walls are configured as light reflection surfaces for reflecting a laser beam incident from the side of the substrate 1.

[0036] A diffusion region 7 is provided between the contact layer 4 and the absorption layer 3 for receiving the laser beam.

[0037] For the side-incident backlight monitoring detector provided by the present invention, since the positions and sizes of the diffusion region 7 and the light reflection surface can be simultaneously obtained by lithography from the top layer of the epitaxial structure, the positions and sizes of the diffusion region 7 can be precisely controlled, avoiding the use of high-difficulty alignment techniques and having a relatively large tolerance.

[0038] As a preferred embodiment, the material of the substrate 1 can be, for example, Fe-doped semi-insulating InP material, and the thickness of the substrate 1 is 100 μm to 200 μm, specifically, for example, 120 μm.

[0039] As a preferred embodiment, the material of the buffer layer 2 includes N-type InP material, where the doping concentration of the N-type InP material is N = 1 - 5E18, and the thickness of the N-type InP material is 400 nm to 500 nm.

[0040] As a preferred embodiment, the material of the absorption layer 3 includes InGaAs material, where the doping concentration of the InGaAs material is N = 1E14 - 5E14, and the thickness of the InGaAs material is 2500 nm to 3000 nm.

[0041] As a preferred embodiment, the material of the top layer 4 includes N-InP material, where the doping concentration of the N-InP material is N = 3E16, and the thickness of the N-InP material is 200 nm to 300 nm.

[0042] As a preferred embodiment, the material of the contact layer 5 includes InGaAs material, wherein the doping concentration of the InGaAs material is N = 3E16, and the thickness of the InGaAs material is 30 nm to 80 nm.

[0043] As a preferred embodiment, the material of the insulating layer 6 includes silicon nitride or silicon dioxide, the thickness of the insulating layer is 150 nm to 250 nm, and specifically, for example, it can be 200 nm.

[0044] As a preferred embodiment, the side wall of the trapezoidal etching groove 11 forms an angle of 40° to 60° with the surface of the epitaxial structure, and the trapezoidal etching groove 11 etches from the epitaxial structure to the substrate 1, and the depth can be, for example, 60 μm.

[0045] Based on the above embodiments, the side-incident backlight monitoring detector of this embodiment further includes: an electrode window 13, a metal layer 12, a P-type contact electrode 8, and an N-type contact electrode 9.

[0046] From Figure 1 As shown in the direction, the electrode window 13 is provided at one end of the diffusion region 7 away from the trapezoidal etching groove 11, and the electrode window 13 is formed by etching a part of the insulating layer 6 on the diffusion region 7, and the diameter can be, for example, 20 μm to 30 μm.

[0047] The metal layer 12 is provided on the insulating layer 6 and is connected to the electrode window 13.

[0048] The P-type contact electrode 8 is provided on the insulating layer 6 and is connected to the metal layer 12.

[0049] In this embodiment, a metal layer 12 is evaporated on the insulating layer 6, and the remaining metal layer 12 is peeled off to obtain the P-type contact electrode 8. The P-type contact electrode 8 is connected to the diffusion region 7 through the electrode window 13. The material of the metal layer 12 can be, for example, TiPtAu, the diameter of the P-type contact electrode 8 is 90 μm to 100 μm, and the thickness is 200 nm to 300 nm.

[0050] The N-type contact electrode 9 is provided at one end of the substrate 1 away from the P-type contact electrode 8.

[0051] In this embodiment, after the substrate 1 is thinned and polished, a layer of metal layer 12 is evaporated on the surface of the substrate 1 to form the N-type contact electrode 9. The material of the metal layer 12 can be, for example, Au / GeNi, and the thickness is 200 nm to 300 nm.

[0052] Based on the above embodiments, the side-incident backlight monitoring detector of this embodiment further includes: an antireflection film 10.

[0053] The antireflection film 10 is provided at the same side position from the P-type contact electrode 8 to the N-type contact electrode 9 and is close to the diffusion region 7 for incident laser beams.

[0054] As a preferred embodiment, the material of the antireflection film 10 is Al2O3, and the thickness of the antireflection film 10 is 100 nm to 200 nm.

[0055] Figure 2 The top view of the side-incident backlight monitoring detector structure according to an embodiment of the present invention is schematically shown.

[0056] As Figure 2 shown, as a preferred embodiment, the shape of the corrosion window of the trapezoidal corrosion groove 11 on the surface of the epitaxial structure is rectangular, the length thereof can be, for example, 120 μm, and the width thereof is 60 μm to 100 μm.

[0057] As a preferred embodiment, when viewed from the Figure 1 direction shown, the diffusion region 7 is disposed at the left end of the trapezoidal corrosion groove 11, doped with Zn, the diameter thereof is greater than 120 μm, the diffusion depth is 1 μm to 1.6 μm, and the diffusion reaches the absorption layer 3. In this embodiment, the inclination angle of the position of the diffusion region 7 with respect to the side wall of the trapezoidal corrosion groove 11 is set with the depth.

[0058] As a preferred embodiment, for the side-incident backlight monitoring detector according to an embodiment of the present invention, the thickness of the chip can be, for example, 120 μm, the length can be, for example, 300 μm, and the width can be, for example, 350 μm.

[0059] According to another aspect of the embodiment of the present invention, a method for manufacturing a side-incident backlight monitoring detector is further provided, including:

[0060] Growing a buffer layer, an absorption layer, a top layer, and a contact layer on the substrate from bottom to top.

[0061] In this embodiment, using MOCVD or MBE technology on an Fe-doped semi-insulating InP substrate, by metalorganic chemical vapor deposition, a buffer layer, an absorption layer, a top layer, and a contact layer are grown on the substrate from bottom to top in sequence.

[0062] Growing an insulating layer on the contact layer by plasma enhanced chemical vapor deposition (PECVD).

[0063] Etching the insulating layer and obtaining a diffusion region by using Zn diffusion technology.

[0064] Etching away the silicon oxide on the surface of the insulating layer.

[0065] Using PECVD to grow silicon oxide, and etching a trapezoidal corrosion groove between the insulating layer and the substrate by photolithography and wet etching methods to form a light reflecting surface, and the light reflecting surface can make the laser beam incident from the side of the substrate and be reflected to the diffusion region through the light reflecting surface.

[0066] Etching away the silicon oxide on the surface of the insulating layer again.

[0067] PECVD is used again to grow silicon oxide, and electrode windows and electrode patterns are etched through photolithography.

[0068] A metal layer is evaporated on the chip surface, and the metal layer outside the electrode windows and electrode patterns is stripped to form P-type contact electrodes.

[0069] After the substrate is thinned and polished, a metal layer is evaporated on the substrate surface to form N-type contact electrodes.

[0070] The chip is cleaved to form a natural cleavage plane on the side of the chip, and an antireflection film is deposited on the side of the incident light.

[0071] The method for preparing a side-incident backlight monitoring detector provided by the present invention can simultaneously etch a diffusion region and a light reflection surface on the epitaxial layer. The steps are simple and easy to operate, avoiding the technical problem of double-sided photolithography of the substrate after thinning.

[0072] The flowcharts and block diagrams in the accompanying drawings illustrate the system architectures, functions, and operations that the systems and methods according to various embodiments of the present invention may implement. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the above-mentioned module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the accompanying drawings. For example, two consecutive blocks shown may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and the combination of blocks in the block diagram or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or operations, or can be implemented by a combination of dedicated hardware and computer instructions.

[0073] Those skilled in the art can understand that the features described in the various embodiments of the present invention can be combined in various ways and / or combinations, even if such combinations or combinations are not explicitly described in the present invention. In particular, without departing from the spirit and teachings of the present invention, the features described in the various embodiments of the present invention can be combined and / or combined in various ways. All such combinations and / or combinations fall within the scope of the present invention.

[0074] The embodiments of the present invention have been described above. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present invention. Although the embodiments have been described separately above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Without departing from the scope of the present invention, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present invention.

Claims

1. A side-incident backlight monitoring detector, characterized in that, Comprising: A substrate; A buffer layer, an absorption layer, a top layer, a contact layer, and an insulating layer sequentially stacked on the surface of the substrate; A trapezoidal etching groove provided between the insulating layer and the substrate, including side walls, wherein the side walls are configured as light reflection surfaces for reflecting a laser beam incident from the side of the substrate; A diffusion region provided between the contact layer and the absorption layer for receiving the laser beam.

2. The side-incident backlight monitoring detector according to claim 1, characterized in that Further comprising: An electrode window provided at one end of the diffusion region away from the trapezoidal etching groove; A metal layer provided on the insulating layer and connected to the electrode window; A P-type contact electrode provided on the insulating layer and connected to the metal layer; An N-type contact electrode provided at one end of the substrate away from the P-type contact electrode.

3. The side-incident backlight monitoring detector according to claim 2, wherein Further comprising: An antireflection film provided on the same side of the P-type contact electrode to the N-type contact electrode and close to the diffusion region for incident of the laser beam; the material of the antireflection film is Al2O3, and the thickness of the antireflection film is 100 nm to 200 nm.

4. The side-incident backlight monitoring detector according to claim 1, characterized in that, The material of the substrate includes Fe-doped semi-insulating InP material, and the thickness of the substrate is 100 μm to 200 μm.

5. The side-incident backlight monitoring detector according to claim 1, characterized in that, The material of the buffer layer includes N-type InP material, wherein the doping concentration of the N-type InP material is N = 1 - 5E18, and the thickness of the N-type InP material is 400 nm to 500 nm.

6. The side-incident backlight monitoring detector according to claim 1, wherein The material of the absorption layer includes InGaAs material, wherein the doping concentration of the InGaAs material is N = 1E14 - 5E14, and the thickness of the InGaAs material is 2500 nm to 3000 nm.

7. The side-incident backlight monitoring detector according to claim 1, characterized in that, The material of the top layer includes N-InP material, wherein the doping concentration of the N-InP material is N = 3E16, and the thickness of the N-InP material is 200 nm to 300 nm.

8. The side-incident backlight monitoring detector according to claim 1, characterized in that The material of the contact layer includes InGaAs material, wherein the doping concentration of the InGaAs material is N = 3E16, and the thickness of the InGaAs material is 30 nm to 80 nm.

9. The side-incident backlight monitoring detector according to claim 1, characterized in that, The material of the insulating layer includes silicon nitride or silicon dioxide, and the thickness of the insulating layer is 150 nm to 250 nm.

10. A method for preparing a side-incident backlight monitoring detector, characterized in that, Comprising: Growing a buffer layer, an absorption layer, a top layer, and a contact layer on the substrate in sequence from bottom to top; Growing an insulating layer on the contact layer by plasma enhanced chemical vapor deposition; Etching the insulating layer and obtaining a diffusion region by using Zn diffusion technology; Etching a trapezoidal etching groove between the insulating layer and the substrate by photolithography and wet etching methods to form a light reflection surface, wherein the light reflection surface can make the laser beam incident from the side of the substrate be reflected to the diffusion region through the light reflection surface.

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