Semiconductor structure with low ohmic contact resistivity and semiconductor intermediate structure thereof
By introducing an InP protective layer and optimizing the contact surface in semiconductor lasers, the problem of high ohmic contact resistivity was solved, achieving the effects of reducing contact resistivity and improving production consistency.
Patent Information
- Application Number
- CN202423296052.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-30
AI Technical Summary
In the prior art, semiconductor lasers have high ohmic contact resistivity, which leads to increased energy loss, localized heating and poor stability. Furthermore, surface contamination and oxide residues in the contact layer during the production process affect contact quality.
An InP protective layer is used to protect the contact layer, forming a ridge waveguide layer for the semiconductor laser. During the production process, the silicon dioxide insulating layer on top of the ridge waveguide layer is removed by wet etching to optimize the contact surface characteristics and reduce the ohmic contact resistivity.
It effectively reduces ohmic contact resistivity, improves the performance stability of semiconductor lasers and the consistency of the production process, and increases yield.
Smart Images
Figure CN223612844U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a laser technology field especially relates to a semiconductor structure of low ohmic contact resistivity and semiconductor intermediate structure thereof. BACKGROUND
[0002] The semiconductor laser is an important device as a transmitting end in optical communication, and its performance directly affects the quality of optical communication signal transmission. The ohmic contact resistivity refers to the resistance characteristic of the contact between the metal electrode and the semiconductor material in the semiconductor device. As an important index of the semiconductor laser, the ohmic contact resistivity affects the contact resistance, power consumption, bandwidth and stability of the device. The known influencing factors of the ohmic contact resistivity include the selection of contact material, doping concentration, surface treatment and process, and annealing treatment, etc. Higher ohmic contact resistivity will increase the energy loss during current flow, thereby increasing the power consumption, and will also cause local heating, affecting the stability and life of the device.
[0003] In order to reduce the ohmic contact resistivity of the semiconductor laser, the doping concentration of the P-type contact layer can be increased, different metal materials can be selected, and the annealing temperature can be optimized, etc. In the preparation process of the traditional structure, the contact layer as the outermost layer needs to be directly contacted with photoresist, silicon oxide and ion bombardment of reactive ion etching multiple times, which will introduce organic reactants, inorganic substances and injected ions on the surface, thereby affecting the ohmic contact resistivity. The poor contact between the metal and the semiconductor may be caused by the existence of surface impurities or oxides, thereby increasing the contact resistance. In addition, due to the difference in electronic structure of different materials, complete matching may not be achieved, resulting in an undesirable ohmic contact.
[0004] Therefore, it is necessary to provide a semiconductor structure with low ohmic contact resistivity, which not only can achieve the purpose of reducing the ohmic contact resistivity, but also can improve the consistency and product yield in the production process. Utility model content
[0005] Therefore, it is necessary to provide a semiconductor structure with low ohmic contact resistivity, which not only can achieve the purpose of reducing the ohmic contact resistivity, but also can improve the consistency and product yield in the production process.
[0006] To achieve the above technical purpose, the utility model adopts the following technical scheme:
[0007] The utility model provides a kind of semiconductor structure of low ohmic contact resistivity, including substrate, substrate is sequentially laminated and made with: lower limit layer, multiple quantum layer, upper limit layer and cover layer;Further include the contact layer and InP protective layer made on the cover layer and sequentially laminated setting;In the state of having InP protective layer, the cover layer, contact layer and InP protective layer are used to form the ridge waveguide layer of semiconductor laser.
[0008] The utility model discloses a kind of semiconductor intermediate structure of low ohmic contact resistivity, including the semiconductor structure described in above technical solution, the cover layer, contact layer and InP protective layer of the semiconductor structure form the ridge waveguide layer of semiconductor laser;The top surface and side portion enclosing surface of the ridge waveguide layer and the surface of upper limit layer are all made with silicon dioxide insulating layer, and the silicon dioxide insulating layer of the top of ridge waveguide layer is etched.
[0009] Further, the substrate is N-type InP or GaAs substrate.
[0010] Further, the lower limit layer is made of InGaAsP or InGaAlAs material.
[0011] Further, the thickness of the multiple quantum layer is 50nm-100nm;Wherein, the thickness of each quantum well is 4nm-5nm.
[0012] Further, the upper limit layer is made of high bandgap material.
[0013] Further, the thickness of the cover layer is 200nm-300nm.
[0014] Further, the length of the ridge top is 500 μm-2000 μm.
[0015] Further, the silicon dioxide insulating layer on the top of ridge waveguide layer is etched off.
[0016] Compared with prior art, the utility model has the beneficial effects that by adding InP protective layer in semiconductor structure, in the state of having InP protective layer, the cover layer, contact layer and InP protective layer are used to form the ridge waveguide layer of semiconductor laser, not only can effectively protect contact layer, avoid its damage or pollution, but also can reduce the ohmic contact resistance of metal electrode and semiconductor contact area by optimizing contact surface characteristics, so as to realize the purpose of reducing ohmic contact resistivity, which has important significance for improving the performance of semiconductor laser or other optoelectronic devices.In addition, the semiconductor structure can also improve the consistency and yield of semiconductor laser in production process, and ensure stable product quality. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 A structure schematic view of one embodiment of the semiconductor structure with low ohmic contact resistivity provided by the utility model;
[0018] Figure 2 A structure schematic view of one embodiment of the semiconductor intermediate structure with low ohmic contact resistivity provided by the utility model;
[0019] Figure 3 A structure schematic view of the semiconductor laser made by the semiconductor intermediate structure provided by the utility model;
[0020] In the figure: 11-substrate, 12-lower limiting layer, 13-multiquantum layer, 14-upper limiting layer, 15-cover layer, 16-contact layer, 17-InP protective layer, 18-silicon dioxide insulation layer, 19-P type gold electrode, 20-N type electrode. DETAILED DESCRIPTION
[0021] The preferred embodiments of the utility model will be described in detail below with reference to the drawings, wherein the drawings form a part of the present application and are used together with the embodiments of the utility model to explain the principles of the utility model, and are not used to limit the scope of the utility model.
[0022] In the description of the present application, the meaning of "a plurality of" is two or more than two, unless otherwise explicitly and specifically limited.
[0023] In this paper, the "embodiment" means that the specific features, structures or characteristics described in combination with the embodiment can be contained in at least one embodiment of the utility model. The phrase appears at various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment to other embodiments. The skilled person explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.
[0024] Embodiment 1
[0025] The utility model provides a kind of semiconductor structure with low ohmic contact resistivity, please refer to Figure 1 , including substrate 11, the substrate 11 is sequentially laminated and is made with: lower limiting layer 12, multiquantum layer 13, upper limiting layer 14 and cover layer 15;It further includes the contact layer 16 and InP protective layer 17 made on the cover layer and sequentially laminated;In the state of having InP protective layer 17, the cover layer 15, contact layer 16 and InP protective layer 17 are used to form the ridge-shaped waveguide layer of semiconductor laser.
[0026] This invention provides a semiconductor structure with low ohmic contact resistivity. With the InP protective layer 17, it effectively protects the contact layer, preventing damage or contamination. When fabricating a semiconductor laser based on this structure, the ohmic contact resistance between the metal electrode and the semiconductor contact area can be reduced by optimizing the contact surface characteristics, thereby achieving a lower ohmic contact resistivity. This is significant for improving the performance of semiconductor lasers or other optoelectronic devices. Furthermore, this semiconductor structure can improve the consistency and yield rate during the semiconductor laser manufacturing process, ensuring stable product quality.
[0027] Example 2
[0028] This utility model provides a semiconductor intermediate structure with low ohmic contact resistivity, including the semiconductor structure described in Embodiment 1, such as... Figure 2 As shown, the capping layer 15, contact layer 16, and InP protective layer 17 of the semiconductor structure form a ridge waveguide layer of the semiconductor laser; a silicon dioxide insulating layer 18 is formed on the top surface and side enclosure of the ridge waveguide layer and the surface of the upper confinement layer 14, and the silicon dioxide insulating layer on the top of the ridge waveguide layer is etched.
[0029] In the above structure, the InP protective layer 17 effectively protects the contact layer 16. The surface of the ridge waveguide layer includes a top surface and enclosing sidewall surfaces. By removing the silicon dioxide insulating layer 18 from the top surface of the ridge waveguide, a fresh contact layer surface can be provided to contact the P-type metal layer during the subsequent fabrication of a laser based on this semiconductor intermediate structure, thereby achieving a lower ohmic contact resistivity. The other parts of the ridge waveguide layer still retain the silicon dioxide insulating layer 18, which can electrically isolate the structure, help reduce current leakage, ensure that the current can be accurately conducted along the active region of the laser, and improve efficiency.
[0030] The semiconductor intermediate structure with low ohmic contact resistivity provided by this invention can not only reduce the ohmic contact resistivity, but also improve product consistency and yield during the production process.
[0031] In a preferred embodiment, the substrate 11 is an N-type InP or GaAs substrate. The substrate laser serves as the base for the entire structure, providing support. N-type InP or GaAs substrates possess excellent crystal quality and electronic properties, making them preferred materials for manufacturing semiconductor lasers.
[0032] In a preferred embodiment, the lower confinement layer 12 is made of InGaAsP or InGaAlAs material. The lower confinement layer can control the injection of charge carriers in the quantum well, thereby confining the charge carriers and preventing them from diffusing too quickly.
[0033] As a preferred embodiment, the thickness of the multiple quantum layer 13 is 50nm-100nm; wherein the thickness of each quantum well is 4nm-5nm. The multiple quantum well layer is the core region of the laser, and the laser gain region is formed by multiple thin quantum well layers.
[0034] As a preferred embodiment, the upper confinement layer 14 is made of high bandgap material. The upper confinement layer is used to control the longitudinal mode of the laser, and to ensure that the laser mainly propagates along the waveguide direction. This layer prevents the carrier from diffusing laterally by a large bandgap.
[0035] As a preferred embodiment, the thickness of the cap layer 15 is 200nm-300nm. The cap layer can be InP or other conductive materials (such as InGaAs), which ensures that the current can be effectively injected.
[0036] The waveguide size directly affects the mode characteristics and beam quality of the laser, and needs to be optimized during fabrication to ensure high current injection efficiency and good optical mode. As a preferred embodiment, the length of the ridge top is in the range of 500μm-2000μm.
[0037] Embodiment 3
[0038] As shown in Figure 3 , Figure 3 The structure of the semiconductor laser fabricated on the low-ohmic contact resistivity semiconductor intermediate structure described in embodiments 1 and 2 is shown. The preparation method of the laser is as follows:
[0039] First, as shown in Figure 1 , the lower confinement layer 12, the multiple quantum layer 13, the upper confinement layer 14, the cap layer 15, the contact layer 16, and the InP protective layer 17 are sequentially grown on an N-type InP substrate 11, i.e. the growth of all materials of the semiconductor laser is completed;
[0040] Secondly, the ridge waveguide of the semiconductor laser is prepared by lithography, etching and wet etching process, and the silicon dioxide insulating layer 18 above the ridge waveguide is etched off, only the silicon dioxide insulating layer 18 outside the ridge waveguide is reserved, and the pattern of the P-face electrode with adhesive stripping is lithographed;
[0041] Finally, the InP protective layer 17 on the surface of the ridge waveguide is removed by wet etching in a certain hydrochloric acid solution, then the P-type gold electrode 19 is grown, and the back alloy N-type electrode 20 is prepared by thinning, and the whole chip preparation is completed.
[0042] By growing a layer of InP protective layer outside the P-type contact layer, and removing the protective layer by wet etching before growing the P-type gold electrode, the purpose of reducing the ohmic contact resistivity of the device is achieved. In the traditional structure, the contact layer as the outermost layer needs to be directly contacted with photoresist, silicon oxide and ion bombardment of reactive ion etching multiple times during device preparation, which will introduce organic reactants, inorganic substances and implanted ions on its surface, thereby affecting its ohmic contact resistivity. Therefore, in the process of manufacturing the laser, a layer of InP protective layer is grown outside the P-type contact layer, and the protective layer is removed by wet etching before growing the P-type gold electrode, so as to achieve the purpose of reducing the ohmic contact resistivity of the device.
[0043] The structure of the finished laser produced is as shown in Figure 3 , comprising a substrate 11, which is sequentially laminated with a lower limiting layer 12, a multi-quantum layer 13, an upper limiting layer 14 and a cover layer 15;
[0044] The middle of the cover layer 15 is a convex ridge shape, and the top of the ridge shape is provided with a contact layer 16; the contact layer 16 at the top of the ridge shape is directly contacted with a P-type gold electrode 19; the surface of the other part of the ridge shape is provided with a silicon dioxide insulating layer 18; and the bottom of the substrate 11 is provided with an N-type electrode 20.
[0045] As a preferred embodiment, the contact layer 16 is a heavily doped P-type gold electrode 19. The heavily doped P-type gold electrode can significantly reduce the ohmic contact resistance between the metal and the semiconductor. The semiconductor material with high P-type doping concentration has high carrier concentration, so that the conduction of electrons is more smooth when the metal and the semiconductor are in contact, thereby reducing the contact resistance. At the same time, the stability, reliability and heat management capability of the laser are also enhanced, which can better cope with complex working environments such as high power and high frequency.
[0046] The total length of the laser refers to the length of the entire resonant cavity of the semiconductor laser, i.e. the length of the ridge waveguide. The total length of the resonant cavity is a key design parameter, which affects the output characteristics and stability of the laser. As a preferred embodiment, the total length of the laser is 200-5mm.
[0047] As a preferred embodiment, the thickness of the P-type gold electrode 19 is 100-500nm. The P-type gold electrode is formed by metal deposition technology, and sufficient conductivity needs to be ensured during production, while not interfering with other functions of the laser.
[0048] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A semiconductor structure with low specific contact resistance, comprising a substrate, on which are sequentially stacked: a lower confinement layer, a multi-quantum layer, an upper confinement layer and a cap layer; characterized in that, Further comprising a contact layer and an InP protective layer which are made on the cover layer and are sequentially stacked; the cover layer, the contact layer and the InP protective layer are used to form a ridge waveguide layer of a semiconductor laser in the state of having the InP protective layer.
2. A semiconductor intermediate structure of low specific contact resistance, characterized in that The semiconductor structure of claim 1, wherein the cover layer, the contact layer and the InP protective layer of the semiconductor structure form a ridge waveguide layer of a semiconductor laser; the top surface and the side surface of the ridge waveguide layer and the surface of the upper confining layer are all made of a silicon dioxide insulating layer, and the silicon dioxide insulating layer on the top of the ridge waveguide layer is etched.
3. The low ohmic contact resistivity semiconductor interposer of claim 2, wherein, The substrate is an N-type InP or GaAs substrate.
4. The low ohmic contact resistivity semiconductor interlayer structure according to claim 2, wherein The lower confining layer is made of InGaAsP or InGaAlAs material.
5. The low ohmic contact resistivity semiconductor interposer of claim 2, wherein, The thickness of the multi-quantum layer is 50-100 nm; wherein the thickness of each quantum well is 4-5 nm.
6. The low ohmic contact resistivity semiconductor interposer of claim 2, wherein, The upper and lower confining layers are made of high bandgap material.
7. The low ohmic contact resistivity semiconductor interposer of claim 2, wherein, The thickness of the cover layer is 200-300 nm.
8. The low ohmic contact resistivity semiconductor interposer of claim 2, wherein, The length of the ridge top ranges from 500 μm to 2000 μm.
9. The low specific contact resistance semiconductor interstructure of claim 2, wherein, The silicon dioxide insulating layer on the top of the ridge waveguide layer is etched away completely.