An electro-optical phase shifter, an optical chip, an optical chip manufacturing method and a laser radar

Abstract

This application provides an electro-optic phase shifter, an optical chip, a method for fabricating the optical chip, and a lidar, including a ridge waveguide and two edge regions. The ridge waveguide extends along a first direction, and the two edge regions are respectively disposed on both sides of the ridge waveguide along a second direction. The first direction and the second direction are perpendicular. The edge regions include an electrode connection portion and a clearance portion arranged sequentially along the first direction. The thickness of the electrode connection portion is greater than the thickness of the clearance portion, and the electrode connection portion is used to connect a metal electrode.

Description

Technical Field

[0001] This application belongs to the field of chip manufacturing technology, and more specifically, relates to an electro-optic phase shifter, an optical chip, a method for manufacturing an optical chip, and a lidar. Background Technology

[0002] Electro-optic phase shifters are a crucial component of silicon-based optical phased arrays, which are the core of all-solid-state lidar. To meet the ranging requirements of lidar, the number of optical phased arrays in lidar systems ranges from thousands to tens of thousands. The number of electro-optic phase shifters is on the same order of magnitude as the number of optical phased arrays. If it is necessary to reduce the size of the optical phased array, options include reducing the spacing between the electro-optic phase shifters or decreasing the size of the electro-optic phase shifters themselves.

[0003] In existing technologies, to reduce the size of electro-optic phase shifters and thus the volume of optical phased arrays, the approach is to reduce the spacing between the ridge waveguides on the semiconductor layer of the phase shifter and the positive and negative electrodes. However, since the positive and negative electrodes on the semiconductor layer of the electro-optic phase shifter are heavily doped regions with a high carrier concentration, the light absorption loss of the carriers is very high. Even if the size of the electro-optic phase shifter can be reduced, it still has very high optical loss. Summary of the Invention

[0004] The purpose of this application is to provide an electro-optic phase shifter, an optical chip, a method for manufacturing the optical chip, and a lidar, which can not only reduce the size of the phase shifter but also reduce optical loss.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] An electro-optic phase shifter is provided, comprising a ridge waveguide and two edge regions, wherein the ridge waveguide extends along a first direction, and the two edge regions are respectively disposed on both sides of the ridge waveguide along a second direction, wherein the first direction and the second direction are perpendicular to each other.

[0007] The edge region includes an electrode connection portion and a clearance portion arranged sequentially along the first direction. The thickness of the electrode connection portion is greater than the thickness of the clearance portion. The electrode connection portion is used to connect a metal electrode.

[0008] In some embodiments, the ridge waveguide includes an inner ridge region and two outer ridge regions respectively disposed on both sides of the inner ridge region along the second direction, and the two edge regions are respectively disposed on both sides of the two outer ridge regions along the second direction;

[0009] The thickness of the inner ridge region is greater than that of the outer ridge region, the thickness of the electrode connection portion is the same as that of the inner ridge region, and the thickness of the clearance portion is less than that of the inner ridge region.

[0010] In some embodiments, the thickness of the avoidance portion is equal to the thickness of the outer ridge region.

[0011] In some embodiments, the extension dimension of the electrode connection portion along the first direction is smaller than the extension dimension of the clearance portion along the first direction.

[0012] In some embodiments, the extension dimension of the electrode connection portion along the first direction accounts for less than or equal to 30% of the extension dimension of the edge region along the first direction.

[0013] In some embodiments, the extension dimension of the electrode connection portion along the first direction is greater than or equal to 0.9 μm.

[0014] In some embodiments, the edge region includes two clearance portions respectively disposed on both sides of the electrode connection portion along the first direction.

[0015] In some embodiments, the thickness dimensions of the two clearance portions are the same or different.

[0016] The beneficial effects of the electro-optic phase shifter provided in this application are as follows:

[0017] Compared with the prior art, the electro-optic phase shifter provided in this application includes an electrode connection portion and a clearance portion arranged sequentially along a first direction in the edge region. The thickness of the electrode connection portion is greater than the thickness of the clearance portion, and the electrode connection portion is used to connect to the metal electrode. In other words, the ridge waveguide achieves electrical connection with the metal electrode only through a small portion of the material in the edge region (electrode connection portion).

[0018] Compared to existing solutions where the overall thickness of the edge region and the ridge waveguide are the same, the electro-optic phase shifter provided in this application thins a portion of the edge region along the thickness direction, retaining only a small portion of the original thickness so that it can be connected to the metal electrode. Removing a portion of the material from the edge region in the thickness direction reduces optical loss caused by the heavily doped region. Furthermore, by reducing the optical loss caused by the heavily doped region, the size of the phase shifter can be reduced by decreasing the dimensions of the ridge waveguide along the second direction.

[0019] Another object of this application is to provide an optical chip, which includes the electro-optic phase shifter as described above.

[0020] The optical chip application provided in this application includes the electro-optic phase shifter provided in this application. Since the electro-optic phase shifter provided in this application has low optical loss, the size of the electro-optic phase shifter can be reduced. Therefore, it can not only reduce the optical loss of the optical chip, but also reduce the chip size and reduce the chip manufacturing cost.

[0021] Another object of this application is to provide a lidar comprising the optical chip as described above or the electro-optical phase shifter as described above.

[0022] The lidar application provided in this application uses the electro-optic phase shifter or optical chip provided in this application. Since the electro-optic phase shifter and optical chip provided in this application have low optical loss, the size of the electro-optic phase shifter and optical chip can be reduced. Therefore, not only can the internal loss of the lidar be reduced, but the space occupied by the chip in the lidar is also reduced, which is conducive to reducing the overall volume of the lidar and reducing the manufacturing cost of a single chip, thereby reducing the manufacturing cost of the lidar.

[0023] Another object of this application is a method for fabricating an optical chip, comprising:

[0024] Provide substrate;

[0025] A semiconductor device layer is formed on the substrate;

[0026] The semiconductor device layer includes an electro-optic phase shifter, which includes a ridge waveguide and two edge regions. The ridge waveguide extends along a first direction, and the two edge regions are respectively disposed on both sides of the ridge waveguide along a second direction. The first direction and the second direction are perpendicular. The edge regions include an electrode connection portion and a clearance portion arranged sequentially along the first direction. The thickness of the electrode connection portion is greater than the thickness of the clearance portion. The electrode connection portion is used to connect a metal electrode.

[0027] The beneficial effects of the optical chip fabrication method provided in this application are as follows:

[0028] Compared with the prior art, the optical chip fabrication method provided in this application removes a portion of the material with thickness on the edge region to form a clearance portion, thereby retaining the original thickness of the material on the edge region to form an electrode connection portion.

[0029] Compared to existing methods where the overall thickness of the edge region and the thickness of the ridge waveguide are the same, the optical chip fabrication method provided in this application retains only a small portion of the original thickness in the edge region, allowing it to be connected to metal electrodes. By removing a portion of the material in the edge region along the thickness direction, the optical loss caused by the heavily doped region can be reduced. Furthermore, with the reduction in optical loss caused by the heavily doped region, the size of the phase shifter can be reduced by shrinking the dimensions of the ridge waveguide along the second direction. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a front view of an existing electro-optic phase shifter;

[0032] Figure 2 for Figure 1 A sectional view along the A′-A′ direction;

[0033] Figure 3 A front view of the electro-optic phase shifter provided in an embodiment of this application;

[0034] Figure 4 for Figure 3 A cross-sectional view along the AA direction;

[0035] Figure 5 for Figure 3 Cross-sectional view along the BB direction;

[0036] Figure 6 A cross-sectional view of the position of the electro-optic phase shifter at the electrode connection portion provided in the embodiment of this application;

[0037] Figure 7 A flowchart illustrating a method for fabricating an optical chip according to an embodiment of this application.

[0038] The following are the labeling elements in the figure:

[0039] 101. Substrate layer; 102. Insulating layer;

[0040] 1031. Ridge waveguide; 1032. Edge region;

[0041] 1031a, Internal spine region; 1031b, External spine region;

[0042] 1032a, Electrode connection part; 1032b, Clearance part;

[0043] 201. Metal electrode. Detailed Implementation

[0044] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0045] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0046] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0047] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0048] The present application will now describe an electro-optic phase shifter, an optical chip, a method for manufacturing the optical chip, and a lidar provided in the embodiments of this application.

[0049] Please see Figures 3 to 5 As shown, the electro-optic phase shifter provided in this application embodiment includes a ridge waveguide 1031 and two edge regions 1032. The ridge waveguide 1031 extends along a first direction, and the two edge regions 1032 are respectively disposed on both sides of the ridge waveguide 1031 along a second direction.

[0050] The edge region 1032 includes an electrode connection portion 1032a and a clearance portion 1032b arranged sequentially along a first direction. The thickness of the electrode connection portion 1032a is greater than the thickness of the ridge waveguide 1031. That is, the thickness of the clearance portion 1032b is greater than zero and less than the thickness of the electrode connection portion 1032a. The first direction, the second direction, and the thickness are all perpendicular to each other.

[0051] In some embodiments, the ridge waveguide 1031 is part of the semiconductor layer in a semiconductor-on-insulator substrate, and the substrate may be a silicon-on-insulator (SOI) substrate. Generally, the substrate includes a substrate layer 101, an insulating layer 102 disposed on the substrate layer 101, and a semiconductor layer disposed on the insulating layer 102. Those skilled in the art should understand that the bottom sides of the electrode connection portion 1032a and the clearance portion 1032b are flush, that is, the bottom sides of the semiconductor layer. The difference in thickness between the electrode connection portion 1032a and the clearance portion 1032b is that the top side of the electrode connection portion 1032a is higher than the top side of the clearance portion 1032b.

[0052] In some embodiments, the first direction can be the length direction of the substrate, and the second direction can be the width direction of the substrate, wherein the length extension dimension of the substrate is greater than the width dimension. In other embodiments, the first direction can be the width direction of the substrate, and the second direction can be the length direction of the substrate, wherein the length extension dimension of the substrate is greater than the width dimension. The thickness dimension refers to the dimension along the thickness direction, which refers to the stacking direction of the substrate layer, insulating layer, and semiconductor layer.

[0053] The electro-optic phase shifter provided in this application embodiment includes an edge region 1032 comprising an electrode connection portion 1032a and a clearance portion 1032b arranged sequentially along a first direction. The thickness of the electrode connection portion 1032a is greater than the thickness of the clearance portion 1032b. The electrode connection portion 1032a can be used as a metal electrode located above a semiconductor layer.

[0054] Compared to existing ones, such as Figure 1 and Figure 2 The electrode portion 13 shown is designed to have the same overall thickness as the maximum thickness of the ridge waveguide. The electro-optic phase shifter provided in this application thins a portion of the edge region 1032 along the thickness direction, retaining only a small portion of the original material in the edge region 1032, allowing it to connect to the metal electrode. By removing a portion of the material from the edge region in the thickness direction, optical loss caused by the heavily doped region can be reduced. Furthermore, based on the reduced optical loss caused by the heavily doped region, the size of the phase shifter can be reduced by shrinking the dimension of the ridge waveguide along the second direction.

[0055] The electrode connection portion 1032a is used to electrically connect to the metal electrode 201, thereby achieving the purpose of applying a modulation signal to the two edge regions 1032 to change the carrier concentration. In other words, while meeting the requirement of electrically connecting the metal electrode 201, the dimension of the electrode connection portion 1032a along the first direction can be as small as possible. The clearance portion 1032b, as a part whose optical loss can be reduced through thinning, can have its dimension along the first direction as large as possible to achieve optimal reduction of optical loss.

[0056] in, Figure 1 and Figure 2 The diagram shows two electrode sections 13 distributed on both sides of two plate sections 12 in a conventional phase shifter. The two plate sections 12 are distributed on both sides of a central section 11, and the overall thickness of the electrode sections 13 is the same as the maximum thickness of the central section.

[0057] In some embodiments, the ridge waveguide 1031 includes an inner ridge region 1031a and two outer ridge regions 1031b respectively disposed on both sides of the inner ridge region 1031a along a second direction, and two edge regions 1032 respectively disposed on both sides of the two outer ridge regions 1031b along the second direction. The thickness of the inner ridge region 1031a is greater than the thickness of the outer ridge regions 1031b, the thickness of the electrode connection portion 1032a is the same as the thickness of the inner ridge region 1031a, and the thickness of the clearance portion 1032b is less than the thickness of the inner ridge region 1031a.

[0058] Reference Figure 6 As shown, in an exemplary embodiment, an edge region 1032 can be heavily doped into a P-type semiconductor, and an outer ridge region 1031b located on the same side as the edge region 1032 can be lightly doped into a corresponding P-type semiconductor. The portion of the inner ridge region 1031a adjacent to the outer ridge region 1031b can also be lightly doped into the same P-type semiconductor. Similarly, another edge region 1032 can be heavily doped into an N-type semiconductor, and another outer ridge region 1031b located on the same side as the other edge region 1032 can be lightly doped into a corresponding N-type semiconductor. The portion of the inner ridge region 1031a adjacent to the other outer ridge region 1031b can also be lightly doped into the same N-type semiconductor. Thus, an edge region 1032, an outer ridge region 1031b, an inner ridge region 1031a, another outer ridge region 1031b, and another edge region 1032 form a PN junction. By applying a modulation signal to the two edge regions 1032, the carrier concentration in the two edge regions 1032, the two outer ridge regions 1031b, and the inner ridge region 1031a can be changed, thereby changing the refractive index of the ridge waveguide 1031 and thus achieving modulation of light.

[0059] In some specific embodiments, the thickness of the avoidance portion 1032b is equal to the thickness of the outer ridge region 1031b, or the thickness of the avoidance portion 1032b is greater than the thickness of the outer ridge region 1031b, or the thickness of the avoidance portion 1032b is less than the thickness of the outer ridge region 1031b.

[0060] In some embodiments, the edge region includes two clearance portions respectively disposed on both sides of the electrode connection portion along the first direction, and the edge region occupies one cycle in the entire phase shifter, with the two clearance portions having the same or different thickness dimensions.

[0061] An electro-optic phase shifter may include n cycles arranged sequentially along a first direction, each cycle including a ridge waveguide (e.g., ...) along the first direction. Figure 5 (as shown) and mountain-shaped waveguides (such as) Figure 4 As shown, the two sides of the mountain-shaped waveguide are two electrode connection parts 1032a, which are positive electrode connection parts and negative electrode connection parts, respectively. The positive electrode in the metal electrode connects all n positive electrode connection parts, and the negative electrode in the metal electrode connects all n negative electrode connection parts. In this embodiment, by reducing the proportion of the length of the mountain-shaped waveguide to each cycle, the transmission loss of the electro-optic phase shifter can be reduced and the phase shifting efficiency can be improved.

[0062] In some embodiments, the extension dimension of the electrode connection portion 1032a along the first direction is smaller than the extension dimension of the clearance portion 1032b along the first direction. In some specific embodiments, the proportion of the extension dimension of the electrode connection portion 1032a along the first direction in the extension dimension of the edge region 1032 along the first direction is less than or equal to 30%. In some specific embodiments, the proportion of the extension dimension of the electrode connection portion 1032a along the first direction in the edge region 1032 can be 0-10%. Correspondingly, the proportion of the extension dimension of the clearance portion 1032b along the first direction in the extension dimension of the edge region 1032 along the first direction can reach 90% or more. This ratio applies to one cycle of the phase shifter, and also to multiple cycles of the phase shifter.

[0063] In some embodiments, the extension dimension of the electrode connection portion 1032a along the first direction is greater than or equal to 0.9 μm. When the extension dimension of the electrode connection portion 1032a along the first direction is equal to 0.9 μm, the requirement for electrically connecting the metal electrode 201 can be met. Based on this, the dimension of the electrode connection portion 1032a along the first direction can be as small as possible.

[0064] In some embodiments, the thickness of the clearance portion 1032b is uniformly distributed in the first direction. Uniform distribution means that the thickness of the clearance portion 1032b remains constant. In some embodiments, the thickness of the clearance portion 1032b can be varied in the first direction. For example, in the direction from the clearance portion 1032b to the electrode connection portion 1032a, the thickness of the clearance portion 1032b can gradually increase, or it can increase at equal intervals in a stepped manner, or it can undulate like a sine wave. Of course, the thickness of the clearance portion 1032b can be uniformly distributed or non-uniformly distributed.

[0065] In some embodiments, the thickness of the clearance portion 1032b in the two edge regions is the same or different. In some embodiments, the two edge regions 1032 are symmetrically arranged on both sides of the ridge waveguide 1031 along a second direction.

[0066] Another objective of this application embodiment is to provide an optical chip, which includes the electro-optic phase shifter as described above. The optical chip provided in this application embodiment uses the electro-optic phase shifter provided in this application. Since the electro-optic phase shifter provided in this application embodiment has low optical loss, the size of the electro-optic phase shifter can be reduced. Therefore, it can not only reduce the optical loss of the optical chip, but also reduce the chip size and manufacturing cost.

[0067] Another objective of this application embodiment is to provide a lidar, which includes the optical chip or the electro-optic phase shifter as described above. The lidar provided in this application embodiment utilizes the electro-optic phase shifter or optical chip provided in this application embodiment. Because the electro-optic phase shifter and optical chip provided in this application embodiment have low optical loss, their size can be reduced. Therefore, not only can the internal loss of the lidar be reduced, but the space occupied by the chip in the lidar is also reduced, which is beneficial for reducing the overall size of the lidar and lowering the manufacturing cost of a single chip, thereby reducing the manufacturing cost of the lidar.

[0068] Reference Figure 7 As shown, another objective of this application embodiment is a method for fabricating an optical chip, the method comprising:

[0069] 1001. Provide a substrate; specifically, the substrate may be an SOI substrate.

[0070] 1002. Forming a semiconductor device layer on a substrate;

[0071] The semiconductor device layer includes an electro-optic phase shifter, which includes a ridge waveguide and two edge regions. The ridge waveguide extends along a first direction, and the two edge regions are respectively disposed on both sides of the ridge waveguide along a second direction. The first direction and the second direction are perpendicular. The edge regions include an electrode connection portion and a clearance portion arranged sequentially along the first direction. The thickness of the electrode connection portion is greater than the thickness of the clearance portion. The electrode connection portion is used to connect a metal electrode.

[0072] The optical chip fabrication method provided in this application removes a portion of the material with a certain thickness from the edge region to form a clearance portion, thereby leaving the material with the original thickness in the edge region to form an electrode connection portion.

[0073] Compared to existing methods where the overall thickness of the edge region and the thickness of the ridge waveguide are the same, the optical chip fabrication method provided in this application retains only a small portion of the original thickness in the edge region, allowing it to be connected to metal electrodes. By removing a portion of the material in the edge region along the thickness direction, the optical loss caused by the heavily doped region can be reduced. Furthermore, based on the reduced optical loss caused by the heavily doped region, the size of the phase shifter can be reduced by shrinking the dimensions of the ridge waveguide along the second direction.

[0074] The aforementioned ridge waveguide, electrode connection portion, and clearance portion can be formed by etching. Etching includes, but is not limited to, wet etching and dry etching, depending on the etching rate along different crystal orientations in the etching solution. Wet etching can be divided into isotropic etching and anisotropic etching. Dry etching employs physical methods (e.g., sputtering, ion etching) or chemical methods (e.g., reactive ion etching).

[0075] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An electro-optic phase shifter, characterized in that: It includes a ridge waveguide and two edge regions, the ridge waveguide extending along a first direction, and the two edge regions respectively disposed on both sides of the ridge waveguide along a second direction, wherein the first direction and the second direction are perpendicular to each other; The edge region includes an electrode connection portion and a clearance portion arranged sequentially along the first direction. The thickness of the electrode connection portion is greater than the thickness of the clearance portion. The electrode connection portion is used to connect a metal electrode.

2. The electro-optic phase shifter as described in claim 1, characterized in that: The ridge waveguide includes an inner ridge region and two outer ridge regions respectively disposed on both sides of the inner ridge region along the second direction, and the two edge regions are respectively disposed on both sides of the two outer ridge regions along the second direction; The thickness of the inner ridge region is greater than that of the outer ridge region, the thickness of the electrode connection portion is the same as that of the inner ridge region, and the thickness of the clearance portion is less than that of the inner ridge region.

3. The electro-optic phase shifter as described in claim 2, characterized in that: The thickness of the avoidance portion is equal to the thickness of the outer ridge region.

4. The electro-optic phase shifter as described in claim 1, characterized in that: The extension dimension of the electrode connection portion along the first direction is smaller than the extension dimension of the clearance portion along the first direction.

5. The electro-optic phase shifter as described in claim 4, characterized in that: The proportion of the extension dimension of the electrode connection portion along the first direction in the extension dimension of the edge region along the first direction is less than or equal to 30%.

6. The electro-optic phase shifter as described in claim 4, characterized in that: The extension dimension of the electrode connection portion along the first direction is greater than or equal to 0.9 μm.

7. The electro-optic phase shifter as described in any one of claims 1-6, characterized in that: The edge region includes two clearance portions respectively disposed on both sides of the electrode connection portion along the first direction.

8. The electro-optic phase shifter as described in claim 7, characterized in that: The thickness dimensions of the two clearance portions may be the same or different.

9. An optical chip, characterized in that: The optical chip includes an electro-optic phase shifter as described in any one of claims 1-8.

10. A lidar, characterized in that: The lidar includes an electro-optic phase shifter as described in any one of claims 1-8; Alternatively, the lidar may include the optical chip as described in claim 9.

11. A method for fabricating an optical chip, characterized in that, include: Provide substrate; A semiconductor device layer is formed on the substrate; The semiconductor device layer includes an electro-optic phase shifter, which includes a ridge waveguide and two edge regions. The ridge waveguide extends along a first direction, and the two edge regions are respectively disposed on both sides of the ridge waveguide along a second direction. The first direction and the second direction are perpendicular. The edge regions include an electrode connection portion and a clearance portion arranged sequentially along the first direction. The thickness of the electrode connection portion is greater than the thickness of the clearance portion. The electrode connection portion is used to connect a metal electrode.

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