Thermo-optical phase shifter and preparation method thereof

Abstract

The invention relates to a thermo-optical phase shifter and a preparation method thereof. A thermo-optical phase shifter includes: a substrate; the waveguide is arranged on the substrate; the first doped region and the second doped region are respectively arranged on two sides of the waveguide and are connected with the waveguide; the first metal interconnection structure is arranged to enable the first doped region and the second doped region which are connected through the first metal interconnection structure to form a plurality of parallel structures; and a second metal interconnection structure disposed to connect the plurality of parallel structures that are not adjacent in series.

Description

Technical Field

[0001] The present disclosure relates to the field of integrated optics, and more particularly, to a thermo-optical phase shifter and a method for preparing the same. Background Art

[0002] Optical communications and photonics applications play a vital role in modern information technology. Efficient optical devices are essential for achieving high-speed, high-bandwidth, and low-loss data transmission and processing. In integrated optics, the thermo-optic effect has been widely used to modulate optical signals. This effect modulates the phase of the optical signal by introducing a heat source into the waveguide to change the waveguide's refractive index. A Mach-Zehnder interferometer (MZI) composed of thermo-optical phase shifters is called a thermo-optic modulator. They can be used to modulate optical signals in optical communication systems, including data transmission and optical networks.

[0003] Thermo-optic phase shifters, which utilize the thermo-optic effect to modulate the phase of optical signals, are crucial for achieving high-speed, high-bandwidth, and low-loss data transmission and processing. Currently, thermo-optic phase shifters are widely used in fields such as optical communication systems, optical sensors, biomedical imaging, and lidar. Despite their widespread application in integrated optics, the speed of these metal resistor-based thermo-optic modulators is limited due to the relatively long transient thermal response time. Therefore, further improvements in thermo-optic modulator efficiency are needed to meet the demands of high-speed electro-optic modulators. Summary of the Invention

[0004] A brief overview of the present disclosure is provided below to provide a basic understanding of some aspects of the present disclosure. However, it should be understood that this overview is not an exhaustive overview of the present disclosure. It is not intended to identify key or important parts of the present disclosure, nor is it intended to limit the scope of the present disclosure. Its purpose is simply to present certain concepts of the present disclosure in a simplified form as a prelude to the more detailed description that will be given later.

[0005] According to a first aspect of the present disclosure, a thermo-optical phase shifter is provided. The thermo-optical phase shifter includes: a substrate; a waveguide disposed on the substrate; a first doped region and a second doped region disposed on either side of the waveguide and connected to the waveguide; a first metal interconnect structure configured such that the first doped region and the second doped region connected via the first metal interconnect structure form a plurality of parallel structures; and a second metal interconnect structure configured to connect the plurality of non-adjacent parallel structures in series.

[0006] In some embodiments, the first doped region is an N-type doped region, and the second doped region is a P-type doped region.

[0007] In some embodiments, the thermo-optical phase shifter further includes a pair of outward-expanded metal contact regions, the pair of outward-expanded metal contact regions including a first outward-expanded metal contact region connected to the first doped region and a second outward-expanded metal contact region connected to the second doped region.

[0008] In some embodiments, the first outwardly expanded metal contact region and the second outwardly expanded metal contact region are symmetrical with respect to the waveguide.

[0009] In some embodiments, the thermo-optical phase shifter includes a plurality of pairs of expanded metal contact regions arranged at regular intervals along the waveguide direction.

[0010] In some embodiments, the first outward-expanded metal contact regions in each outward-expanded metal contact region pair are separated from each other by an insulating material, and the second outward-expanded metal contact regions in each outward-expanded metal contact region pair are separated from each other by an insulating material.

[0011] In some embodiments, the first metal interconnect structure is disposed to directly connect with the corresponding pair of outward-expanded metal contact regions.

[0012] In some embodiments, one end of the parallel structure is electrically coupled to a first electrical port, and the other end of the parallel structure is electrically coupled to a second electrical port different from the first electrical port.

[0013] In some embodiments, the thermo-optical phase shifter further includes: a first insulating layer disposed above the waveguide, wherein a first portion of the first metal interconnect structure is disposed to pass through the first insulating layer to connect to the first doped region and the second doped region, respectively, and a second portion of the first metal interconnect structure is disposed above the first insulating layer to connect to the first portion of the first metal interconnect structure, thereby forming a parallel structure; and a second insulating layer disposed above the first metal interconnect structure, wherein a first portion of the second metal interconnect structure is disposed to pass through the second insulating layer to connect to the first metal interconnect structure, a second portion of the second metal interconnect structure is disposed above the second insulating layer to connect to the first portion of the second metal interconnect structure, and a third portion of the second metal interconnect structure is disposed to extend from the second portion of the second metal interconnect structure to connect non-adjacent parallel structures in series.

[0014] In some embodiments, the thermo-optical phase shifter further includes: a buried oxide layer disposed above the substrate and below the waveguide; and a semiconductor device region disposed between the first doped region and the waveguide and between the second doped region and the waveguide.

[0015] According to a second aspect of the present disclosure, a method for fabricating a thermo-optical phase shifter is provided. The method comprises: providing a substrate; forming a waveguide on the substrate; forming a first doped region and a second doped region on either side of the waveguide, connected to the waveguide; forming a first metal interconnect structure such that the first doped region and the second doped region connected via the first metal interconnect structure form a plurality of parallel structures; and forming a second metal interconnect structure to connect the plurality of non-adjacent parallel structures in series.

[0016] In some embodiments, the first doped region is formed as an N-type doped region, and the second doped region is formed as a P-type doped region.

[0017] In some embodiments, after forming the first doped region and the second doped region, a pair of outward-expanded metal contact regions is formed, such that the pair of outward-expanded metal contact regions includes a first outward-expanded metal contact region connected to the first doped region and a second outward-expanded metal contact region connected to the second doped region.

[0018] In some embodiments, the first outwardly expanded metal contact region and the second outwardly expanded metal contact region are formed symmetrically with respect to the waveguide.

[0019] In some embodiments, forming the outward-expanded metal contact region pairs includes arranging a plurality of outward-expanded metal contact region pairs at regular intervals along the waveguide direction.

[0020] In some embodiments, forming the first metal interconnect structure includes: forming a first insulating layer over the waveguide; etching the first insulating layer until the pair of outward-expanded metal contact regions are exposed to form a plurality of first through-holes aligned with the first outward-expanded metal contact regions and the second outward-expanded metal contact regions, respectively; depositing metal material in the plurality of first through-holes to form a first portion of the first metal interconnect structure, and forming a second portion of the first metal interconnect structure over the first insulating layer to connect the first portion of the first metal interconnect structure, thereby forming the first metal interconnect structure.

[0021] In some embodiments, forming a second metal interconnect structure includes: forming a second insulating layer over the first metal interconnect structure; etching the second insulating layer until the first metal interconnect structure is exposed to form a plurality of second through-holes; depositing metal material in the plurality of second through-holes to form a first portion of the second metal interconnect structure, forming a second portion of the second metal interconnect structure over the second insulating layer to connect the first portion of the second metal interconnect structure, and extending from the second portion of the second metal interconnect structure to form a third portion of the second metal interconnect structure to connect non-adjacent parallel structures in series.

[0022] In some embodiments, the second through-hole may be formed to align with the first through-hole.

[0023] In some embodiments, the method further includes electrically coupling one end of the parallel structure to a first electrical port, and electrically coupling the other end of the parallel structure to a second electrical port different from the first electrical port.

[0024] In some embodiments, the method further includes: forming a buried oxide layer on the substrate immediately after providing the substrate; and forming semiconductor device regions connected to the waveguide on both sides of the waveguide after forming the waveguide and before forming the first doped region and the second doped region.

[0025] The advantage of the embodiments disclosed herein is that the structure employed includes physically connecting the ion implantation region to the central waveguide without using an insulating layer material for filling. Since semiconductor materials have a greater thermal conductivity than insulating layer materials, the thermal conductivity efficiency is greatly improved, thereby reducing the power consumption and response time required to produce the same phase shift for light.

[0026] Another advantage of the embodiments of the present disclosure is that the rectangular outward-expanding metal connection area facilitates the metal perforation process, and through the series-parallel method, the overall resistance is reduced, thereby reducing the overall power consumption of the chip.

[0027] Another advantage of the embodiments of the present disclosure is that the resistive heating region can be formed by using ion implantation in a silicon photonics process simultaneously with the modulator ion implantation step, thereby simplifying the thermal phase shifter process steps.

[0028] It should be appreciated that the advantages described above need not all be realized in one or some specific embodiments, but may be partially dispersed across different embodiments according to the present disclosure. Embodiments according to the present disclosure may have one or some of the advantages described above, or may alternatively or additionally have other advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The foregoing and other features and advantages of the present disclosure will become apparent from the following description of the embodiments of the present disclosure taken in conjunction with the accompanying drawings, which are incorporated herein and form a part of the specification and serve to further explain the principles of the present disclosure and enable those skilled in the art to make and use the present disclosure.

[0030] Figure 1A and Figure 1B Schematically illustrates a top plan view of a thermo-optical phase shifter according to some embodiments of the present disclosure;

[0031] Figure 2 Schematically shows Figure 1A A cross-sectional view of the thermo-optical phase shifter along the AA' direction is shown;

[0032] Figure 3 A flow chart showing a method for preparing a thermo-optical phase shifter according to some embodiments of the present disclosure is shown;

[0033] Figure 4 A flow chart showing a method for preparing a thermo-optical phase shifter according to other embodiments of the present disclosure is shown;

[0034] Figure 5 Schematic diagram showing the process for preparing Figure 4 Cross-sectional views of a device corresponding to corresponding steps of a non-limiting example process of a thermo-optical phase shifter.

[0035] Note that in the embodiments described below, the same reference numerals are sometimes used in common across different drawings to denote the same parts or parts having the same functions, and their repeated descriptions are omitted. In some cases, similar reference numerals and letters are used to denote similar items, so once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0036] For ease of understanding, the positions, sizes, and ranges of various structures shown in the drawings and the like may not represent actual positions, sizes, and ranges, etc. Therefore, the present disclosure is not limited to the positions, sizes, and ranges disclosed in the drawings and the like. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present disclosure.

[0038] The following description of at least one exemplary embodiment is merely illustrative and is not intended to limit the present disclosure, its application, or use. In other words, the structures and methods herein are presented in an exemplary manner to illustrate various embodiments of the structures and methods of the present disclosure. However, those skilled in the art will appreciate that these are merely exemplary of the disclosure that may be implemented, and are not exhaustive. Furthermore, the drawings are not necessarily drawn to scale, and some features may be exaggerated to illustrate details of specific components.

[0039] In addition, technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0040] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0041] A thermo-optical phase shifter is a device that uses the thermo-optic effect to modulate the phase of an optical signal. Generally speaking, a thermo-optical phase shifter is implemented by forming a heat source near a waveguide (e.g., above, below, or on both sides of the waveguide) to provide heat to the waveguide. This heat source is usually a metal resistor. When an external power source coupled to the metal resistor serving as the heat source is turned on, the heat source will generate heat due to the Joule effect. At least a portion of this heat will be conducted to the waveguide through the layer structure that may exist between the waveguide and the heat source, causing the temperature of at least a portion of the waveguide to increase, thereby changing the refractive index of the waveguide and, in turn, changing the phase of the optical signal transmitted by the waveguide. At the same time, in order to reduce heat loss, a thermal insulation groove will be provided near the waveguide or the substrate near the waveguide will be hollowed out to utilize the low thermal conductivity of air to concentrate the heat near the waveguide. However, due to the relatively long transient response time of metal resistors and the fact that the heat source and waveguide cannot be in direct contact but are separated by one or more layers, the amount of heat transferred from the heat source to the waveguide is small and the transfer rate is also low. Furthermore, the low thermal conductivity of air results in a slow optical signal modulation speed and a low phase shift ratio in this type of thermo-optical phase shifter. Furthermore, due to the aforementioned heat transfer principle, the power consumption of this thermo-optical phase shifter is also high. Therefore, a thermo-optical phase shifter with an improved structure is desired to provide high-efficiency optical signal modulation and reduce power consumption.

[0042] To address the aforementioned issues, the present disclosure provides a thermo-optical phase shifter. This device incorporates first and second doped regions on either side of a waveguide as heat sources. This allows the heat sources to be physically connected to the central waveguide of the thermo-optical phase shifter without any insulating material intervening. This improves the efficiency with which heat generated by the heat sources is transferred to the central waveguide, thereby increasing the optical signal modulation speed and phase shift rate of the thermo-optical phase shifter. Furthermore, the thermo-optical phase shifter provided by the present disclosure further incorporates a first metal interconnect structure to connect the first and second doped regions to form multiple parallel structures, and a second metal interconnect structure to connect multiple non-adjacent parallel structures in series. This hybrid three-dimensional structure, formed by the first and second metal interconnect structures, reduces the overall resistance of the first and second doped regions, thereby reducing the overall power consumption of the thermo-optical phase shifter.

[0043] The following describes thermo-optical phase shifters according to some embodiments of the present disclosure in detail, with reference to the accompanying drawings. It will be appreciated that actual thermo-optical phase shifters may include additional components, which are not shown in the drawings and will not be discussed herein to avoid obscuring the key points of the present disclosure. Furthermore, for the sake of brevity, only one of the similar or identical components is labeled in the figures.

[0044] Now refer to Figure 1A 、 1B and Figure 2, it should be understood that Figure 1A and Figure 1B The top view of the same embodiment is shown. For the sake of clarity of the reference numerals, it will be referred to as FIG1 in the following description. As shown in the figure, FIG1 schematically shows a top plan view of a thermo-optical phase shifter according to some embodiments of the present disclosure. Figure 2 The cross-sectional view of the thermo-optical phase shifter shown in FIG1 along the AA' direction is schematically shown. Figure 2 As shown, the thermo-optical phase shifter 100 may include a substrate 118 and a waveguide 102 disposed on the substrate 118. Although the waveguide shown in FIG1 is a single linear waveguide, those skilled in the art will appreciate that the waveguide in the thermo-optical phase shifter of the present disclosure may also be multiple linear waveguides, one or more curved waveguides, or one or more ring waveguides, and adjacent waveguides may share a single heat source or each may be provided with multiple heat sources.

[0045] The thermo-optical phase shifter 100 may further include: a first doped region 1061 and a second doped region 1062, respectively disposed on either side of the waveguide 102 and connected to the waveguide 102. In one non-limiting embodiment, the first doped region 1061 is an N-type doped region, and the second doped region 1062 is a P-type doped region. Of course, in other embodiments, the first doped region 1061 may be a P-type doped region, and the second doped region 1062 may be an N-type doped region, or the first doped region 1061 and the second doped region 1062 may be a mixed N-type and P-type doped region. It is understood that those skilled in the art may further configure the specific composition of the first and second doped regions based on actual circumstances.

[0046] Additionally, the thermo-optical phase shifter 100 may further include a first metal interconnect structure 110 and a second metal interconnect structure 112. The first metal interconnect structure 110 is configured such that the first doped regions 1061 and the second doped regions 1062 connected via the first metal interconnect structure 110 form a plurality of parallel structures, and the second metal interconnect structure 112 is configured to connect the plurality of non-adjacent parallel structures in series. Because the first doped regions 1061 and the second doped regions 1062 are located on opposite sides of the waveguide 102, in the absence of the first metal interconnect structure 110, powering the first doped regions 1061 and the second doped regions 1062 requires providing power input / output (I / O) ports electrically coupled to the first doped regions 1061 and the second doped regions 1062, respectively. This is disadvantageous for compact thermo-optical phase shifters with limited space. Therefore, by introducing the first metal interconnect structure 110 to form a parallel structure between the first doped region 1061 and the second doped region 1062 on either side of the waveguide 102, only one power I / O port is required for the parallel structure, enabling the parallel connection of the first and second doped regions while minimizing space usage. Furthermore, since the thermo-optical phase shifter contains multiple parallel structures, the introduction of the second metal interconnect structure 112 allows multiple non-adjacent parallel structures to be connected in series, thereby requiring only a pair of power I / O ports and thus conserving available device space.

[0047] Specifically, in some embodiments, as shown in FIG. 1 and FIG. Figure 2 As shown, the thermo-optical phase shifter 100 may further include a first insulating layer 122 disposed on the waveguide 102, wherein the first portion S1 of the first metal interconnect structure 110 is disposed to pass through the first insulating layer 122 to be connected to the first doped region 1061 and the second doped region 1062, respectively, and the second portion S2 of the first metal interconnect structure 110 is disposed on the first insulating layer 122 to be connected to the first portion S1 of the first metal interconnect structure 110, thereby forming a parallel structure. Additionally, the thermo-optical phase shifter 100 may further include a second insulating layer 124 disposed on the first metal interconnect structure 110, wherein a first portion S1' of the second metal interconnect structure 112 is disposed to pass through the second insulating layer 122 to connect to the first metal interconnect structure 110, a second portion S2' of the metal interconnect structure 112 is disposed on the second insulating layer 124 to connect to the first portion S1' of the second metal interconnect structure 112, and a third portion S3' of the second metal interconnect structure 112 is disposed to extend from the second portion S2' of the second metal interconnect structure 112 to connect non-adjacent parallel structures in series. It is understood that Figure 1BThe third portion S3' of the second metal interconnect structure shown is merely schematic and does not represent a substantial limitation. In some embodiments, the length and shape of S3' may vary, such as being curved or in other combined shapes for device wiring needs or for connecting multiple first metal interconnect structures 110 connected to the same potential.

[0048] Furthermore, in some embodiments, one end of the parallel structure is electrically coupled to the first electrical port 114, and the other end of the parallel structure is electrically coupled to a second electrical port 116 different from the first electrical port 114. It should be understood that the second metal interconnect structure 112 may include a plurality of metal structures that are not electrically connected to each other, such as metal structures that are not physically connected or that form insulating portions with each other, thereby being connected to the first electrical port and the second electrical port 116, respectively. For example, as shown in FIG. 1 and FIG. Figure 2 As shown, since second metal interconnect 112 is connected to first metal interconnect 110, and first metal interconnect 110 is connected to first doped region 1061 and second doped region 1062, one end of second metal interconnect 1121, which is equivalent to one end of the parallel structure, can be electrically coupled to first electrical port 114, and one end of second metal interconnect 1124, which is equivalent to the other end of the parallel structure, can be electrically coupled to second electrical port 116. First electrical port 114 can be grounded, and second electrical port 116 can be connected to a power source, or first electrical port 114 can be connected to a negative electrode, and second electrical port 116 can be connected to a positive electrode. It is understood that this is merely exemplary and non-limiting, and those skilled in the art can arbitrarily set the power source type coupled to first electrical port 114 and second electrical port 116 and / or the potential formed, as long as the potential difference between first electrical port 114 and second electrical port 116 meets the requirements.

[0049] Continuing to refer to Figures 1 and Figure 2From left to right, the first metal interconnect structure 110 includes first metal interconnect structures 1101, 1102, 1103, and 1104, and the second metal interconnect structure 112 includes second metal interconnect structures 1121, 1122, 1123, and 1124. The aforementioned parallel structures can be considered to be a portion of the first doped region 1061 and a portion of the second doped region 1062 connected to the first portion S1 of the first metal interconnect structure 110. Therefore, from left to right, the thermo-optical phase shifter 100 includes a first parallel structure, a second parallel structure, a third parallel structure, and a fourth parallel structure. Because the second metal interconnect structure 112 is configured to connect non-adjacent parallel structures in series, the second metal interconnect structure 1121 and the second metal interconnect structure 1123 in FIG. 1 connect the first and third parallel structures in series via their respective interconnected third portions S3', and the second metal interconnect structure 1122 and the second metal interconnect structure 1124 connect the second and fourth parallel structures in series via their respective interconnected third portions S3'. It is understood that this is only exemplary and not restrictive. Those skilled in the art will understand that the second metal interconnect structure 112 can not only connect in series two parallel structures separated by one parallel structure, but also connect in series two or more parallel structures separated by multiple parallel structures, depending on the structure and performance of the thermo-optical phase shifter desired in the actual preparation process. However, in order to avoid overly complex structures and wiring, the following are selected: Figure 2 The series-parallel hybrid stereoscopic structure of the thermo-optical phase shifters shown is advantageous.

[0050] As shown in Figure 1 and Figure 2 In the structure of the thermo-optical phase shifter shown in FIG, due to the series-parallel hybrid three-dimensional structure formed by the first metal interconnect structure 110 and the second metal interconnect structure 112, the resistance segment formed by the first doped region 1061 and the second doped region 1062 is divided into M sub-resistance segments with the same resistance value (M is a positive integer, and M shown in FIG. 1 is at least 3). Assuming that the total resistance value of the resistance segment is R, the resistance value of each sub-resistance segment is Then the sub-resistance segments are connected in parallel, so that the current value in each sub-resistance segment is reduced to half of the original current value I, that is, Since the voltage remains unchanged, the power consumption of each sub-resistance segment is The power consumption of the entire thermo-optical phase shifter That is to say, compared with the power consumption of the common thermo-optical phase shifter which does not use the series-parallel hybrid structure, the power consumption of the thermo-optical phase shifter disclosed in the present invention can be reduced to that of the common thermo-optical phase shifter. It should be understood that in some embodiments, since the power supply ports that need to be insulated and the corresponding doping areas / metal contact areas are connected through different metal interconnect structures distributed above the two insulating layers, complex wiring on the same plane is avoided, so that the above-mentioned series-parallel mixed three-dimensional structure can also simplify the wiring difficulty and optimize the device space.

[0051] In some embodiments, as shown in FIG. Figure 2 As shown, the thermo-optical phase shifter 100 may further include a buried oxide layer 120 disposed on the substrate 118 and below the waveguide 102, and a semiconductor device region 104 disposed between the first doped region 1061 and the waveguide 102 and between the second doped region 1062 and the waveguide 102. Figure 2 It can be clearly understood that, as previously described, the first doped region 1061 and the second doped region 1062, serving as heat sources, are physically connected to the waveguide 102 via the semiconductor device region 104. Since the semiconductor device region 104, which is spaced between the first doped region 1061 and the second doped region 1062, has a higher thermal conductivity than the insulating material, the efficiency of heat transfer from the heat source to the waveguide is improved, avoiding the need for an insulating region with lower thermal conductivity between the heat source and the waveguide, thereby reducing heat loss.

[0052] Additionally, in order to be compatible with the standard metal through-hole process in the semiconductor manufacturing process, in some embodiments, as shown in FIG. Figure 2 As shown, the thermo-optical phase shifter 100 may further include expanded metal contact regions 1081 and 1082, wherein the first expanded metal contact region 1081 is connected to the first doped region 1061, and the second expanded metal contact region 1082 is connected to the second doped region 1062. The first expanded metal contact region 1081 and the second expanded metal contact region 1082 are symmetrical with respect to the waveguide 102. For simplicity, the first expanded metal contact region 1081 and the second expanded metal contact region 1082 are collectively referred to as the expanded metal contact region pair 108 below. In particular, the first expanded metal contact region 1081 and the second expanded metal base region 1082 can each be formed as an independent rectangle. Furthermore, the thermo-optical phase shifter 100 may include a plurality of pairs of outwardly expanded metal contact regions 108 arranged at regular intervals along the waveguide 102. These pairs of outwardly expanded metal contact regions 108 are spaced apart from each other and arranged outside the corresponding doped regions relative to the waveguide 102, thereby corresponding to the S1 portions of the plurality of first metal interconnect structures 110 connected to the corresponding heat sources, and connected to the power supply I / O port via the second metal interconnect structure 112. Specifically, the first outwardly expanded metal contact regions 1081 in each pair of outwardly expanded metal contact regions 108 are separated by an insulating material (e.g., Figure 2The first insulating layer 122 and / or the second insulating layer 124 (shown) are separated from each other; similarly, the corresponding second outward-expanded metal contact regions 1082 are also separated from each other by insulating material. For example, the thermo-optical phase shifter 100 shown in FIG1 includes four pairs of outward-expanded metal contact regions 108 (the first insulating layer 122 and the second insulating layer 124 are not shown) to correspond to four first metal interconnect structures 110 and four second metal interconnect structures 112. It will be understood that this is merely exemplary and non-limiting, and those skilled in the art can appropriately configure the shape and number of the outward-expanded metal contact region pairs 108 based on actual needs.

[0053] Furthermore, in some embodiments, the first metal interconnect structure 110 is configured to be directly connected to the corresponding pair of outward-expanded metal contact regions 108. Specifically, referring to FIG. 1 and FIG. Figure 2 When the thermo-optical phase shifter 100 includes the pair of expanded metal contact regions 108, the first metal interconnect 110 is directly connected to the corresponding pair of expanded metal contact regions 108, while the second metal interconnect 112 is connected to the first metal interconnect 110. Furthermore, the first and second expanded metal contact regions 1081 and 1082 of the pair of expanded metal contact regions 108 are connected to the first and second doped regions 1061 and 1062, respectively. This connects the first and second metal interconnects 110 and 112 to the first and second doped regions 1061 and 1062. Conversely, when the thermo-optical phase shifter 100 does not include the pair of expanded metal contact regions 108, the first metal interconnect 110 is directly connected to the first and second doped regions 1061 and 1062, thereby connecting the first and second metal interconnects 110 and 112 to the first and second doped regions 1061 and 1062. Considering the operational difficulty of the manufacturing process and the electrical conduction / heat generation efficiency of the heating circuit, it is advantageous to further provide an outward-expanded metal contact region pair 108 in the thermo-optical phase shifter 100 .

[0054] In another aspect, the present disclosure provides a method for preparing a thermo-optical phase shifter. Figure 3 As shown, the method 200 for fabricating a thermo-optical phase shifter may include: providing a substrate at step S202; forming a waveguide on the substrate at step S204; forming a first doped region and a second doped region connected to the waveguide on both sides of the waveguide at step S206; forming a first metal interconnect structure at step S208, such that the first doped region and the second doped region connected via the first metal interconnect structure form a plurality of parallel structures; and forming a second metal interconnect structure at step S210, connecting the plurality of non-adjacent parallel structures in series.

[0055] In some embodiments, at step S206 , the first doping region may be formed as an N-type doping region, and the second doping region may be formed as a P-type doping region.

[0056] In some embodiments, as Figure 4 As shown, the step of forming the waveguide in method 200 may further include forming a buried oxide layer on the substrate (i.e., step S203), and forming the waveguide on the buried oxide layer (i.e., step S204'). Additionally, semiconductor device regions connected to the waveguide are formed on both sides of the waveguide (i.e., step S205), i.e., the semiconductor regions are formed between the waveguide and the two doped regions on either side. Additionally, method 200 may further include forming a pair of outwardly expanded metal contact regions on the first doped region and the second doped region on a side away from the waveguide, such that the pair of outwardly expanded metal contact regions includes a first outwardly expanded metal contact region connected to the first doped region and a second outwardly expanded metal contact region connected to the second doped region (i.e., step S207).

[0057] Furthermore, the first outwardly expanded metal contact region and the second outwardly expanded metal contact region are symmetrical with respect to the waveguide. The "symmetrical" relationship here includes that the first outwardly expanded metal contact region and the second outwardly expanded metal contact region have a symmetrical relationship with respect to the centerline of the waveguide (i.e., the distance is equal), and / or the cross-sectional shape and area distributed on both sides of the waveguide are the same, wherein the centerline of the waveguide is as follows: Figure 1B The centerline x shown in FIG is parallel to the waveguide extension direction. It should be understood that the two outward-expanded metal contact areas can be asymmetrical, but when the two outward-expanded metal contact areas are at equal distances from the waveguide and have the same cross-sectional shape and area, the heating effect on both sides of the waveguide is symmetrical, which helps to reduce possible uneven heating problems and avoid affecting device performance and service life.

[0058] In some embodiments, at step S207 , forming the outward-expanded metal contact region pairs includes arranging a plurality of outward-expanded metal contact region pairs at regular intervals along the waveguide direction.

[0059] In some embodiments, at step S208, forming the first metal interconnect structure includes: forming a first insulating layer over the waveguide; etching the first insulating layer until the pair of outward-expanded metal contact regions are exposed to form a plurality of first through-holes aligned with the first outward-expanded metal contact regions and the second outward-expanded metal contact regions, respectively; depositing a metal material in the plurality of first through-holes to form a first portion of the first metal interconnect structure, and forming a second portion of the first metal interconnect structure over the first insulating layer to connect the first portion of the first metal interconnect structure, thereby forming the first metal interconnect structure.

[0060] In some embodiments, at step S210, forming the second metal interconnect structure includes: forming a second insulating layer over the first metal interconnect structure; etching the second insulating layer until the first metal interconnect structure is exposed to form a plurality of second vias; depositing metal material in the plurality of second vias to form a first portion of the second metal interconnect structure, forming a second portion of the second metal interconnect structure over the second insulating layer to connect the first portion of the second metal interconnect structure, and extending from the second portion of the second metal interconnect structure to form a third portion of the second metal interconnect structure to connect non-adjacent parallel structures in series. Optionally, in some embodiments, the second vias can be further formed to align with the first vias, in other words, so that the first via, the second via, and the corresponding first / second expanded metal contact regions are aligned.

[0061] In some embodiments, the method 200 further includes electrically coupling one end of the parallel structure to a first electrical port, and electrically coupling the other end of the parallel structure to a second electrical port different from the first electrical port.

[0062] The embodiment of the method 200 may be similar to the various embodiments of the aforementioned thermo-optical phase shifter, and will not be described in detail here.

[0063] The following combination Figure 5 (including (a) to (i)) describes the method for preparing FIG. 1 and FIG. Figure 2 The non-limiting example process of the thermo-optical phase shifter is shown. In this article, for example, the corresponding film layer can be formed by various suitable deposition methods (including but not limited to atomic layer deposition, chemical vapor deposition, physical vapor deposition, plasma-enhanced chemical vapor deposition, low-pressure chemical vapor deposition, etc.), and can be etched by any suitable etching method (including but not limited to dry etching or wet etching, etc.), which will not be described in detail here.

[0064] Figure 5 Schematic diagram showing the process for preparing Figure 4 Cross-sectional views of the device corresponding to corresponding steps of a non-limiting example process of a thermo-optical phase shifter. Figure 5 As shown in (a), a substrate 118 is provided, wherein the material of substrate 118 includes, but is not limited to, thin-film lithium niobate, single crystal silicon, polycrystalline silicon, gallium arsenide, sapphire, quartz, silicon carbide, silicon on insulator (SOI), etc. Subsequently, a buried oxide layer 120 is formed on substrate 118, and waveguide 102 is formed on buried oxide layer 120 through multiple etching steps. Specifically, the overall waveguide region width can be, for example, between 5 μm and 12 μm, and the central waveguide width can be, for example, between 100 nm and 500 nm.

[0065] Furthermore, semiconductor device regions 104 connected to the waveguide 102 are formed on both sides of the waveguide 102. Figure 5 As shown in (b), ion implantation regions (in some examples, the cross-sectional distance between the ion implantation regions and the central waveguide is not less than 0.8 μm) are retained on both sides of the semiconductor device region 104 to form a first doped region 1061 and a second doped region 1062 using an ion implantation process. The width of the first doped region 1061 and the second doped region 1062 can be, for example, between 4 μm and 5 μm.

[0066] Further, if Figure 5 As shown in Figure (c), multiple pairs of outward-expanded metal contact regions 108 are formed outside the first doped region 1061 and the second doped region 1062, spaced apart by a fixed length along the direction of the waveguide 102. The first outward-expanded metal contact region 1081 of each outward-expanded metal contact region pair 108 is connected to the first doped region 1061, and the second outward-expanded metal contact region 1082 is connected to the second doped region 1062. The fixed length between the outward-expanded metal contact region pairs 108 depends on the specific structure and requirements of the thermo-optical phase shifter. Furthermore, the first outward-expanded metal contact region 1081 and the second outward-expanded metal contact region 1082 in each outward-expanded metal contact region pair 108 are symmetrical with respect to the waveguide 102. Furthermore, the widths of the first outward-expanded metal contact region 1081 and the second outward-expanded metal contact region 1082 can be, for example, between 5 μm and 10 μm.

[0067] Further, if Figure 5 As shown in (d), a first insulating layer 122 is formed on the waveguide 102. The material thereof may include but is not limited to silicon nitride, silicon oxide, etc. The thickness of the first insulating layer 122 may be, for example, between 50 nm and 2 μm. Figure 5 As shown in (e), the first insulating layer 122 is etched until the pair of outward-expanded metal contact regions 108 are exposed to form a plurality of first through holes 126 aligned with the first outward-expanded metal contact region 1081 and the second outward-expanded metal contact region 1082. Figure 5 As shown in (f), a metal material is deposited and etched in the plurality of first through holes 126 to form a first portion S1 of the first metal interconnection structure 110, and a metal material is deposited and etched on the first insulating layer 122 to form a second portion S2 connected to the first portion S1 of the first metal interconnection structure 110, thereby forming a first metal interconnection structure 110 (including but not limited to titanium, gold, platinum, etc.).

[0068] Further, if Figure 5 As shown in (g), a second insulating layer 124 is formed on the first metal interconnection structure 110. Figure 5As shown in (h), the second insulating layer 124 is etched until the first metal interconnect structure 110 is exposed to form a plurality of second through holes 128. Optionally, in some embodiments, the second through holes 128 can also be formed to align with the first through holes 126, so that when power is supplied to the first doped region 1061 and the second doped region 1062, the current transmission path is shortened, thereby improving the optical signal modulation speed of the thermo-optical phase shifter. Then, as shown in FIG. Figure 5 As shown in (i), metal material is deposited and etched in the plurality of second through-holes 128 to form a first portion S1' of the second metal interconnect structure 112, metal material is deposited and etched on the second insulating layer 124 to form a second portion S2' connecting the first portion S1' of the second metal interconnect structure 112, and metal material is deposited and etched on the second insulating layer 124 to form a third portion S3' extending from the second portion S2' of the second metal interconnect structure 112 to connect non-adjacent parallel structures in series, thereby forming the second metal interconnect structure 112.

[0069] Additionally, if Figure 5 As shown in (i), the first electrical port 114 is electrically coupled to one end of the second metal interconnect structure 112, and a section of the second electrical port 116 is electrically coupled to one end of another second metal interconnect structure 112, thereby realizing power supply from the first and second electrical ports to the first and second doped regions.

[0070] The words "left," "right," "front," "back," "top," "bottom," "up," "down," "high," "low," and the like, if any, in the specification and claims, are used for descriptive purposes and are not necessarily intended to describe invariant relative positions. It should be understood that the words so used are interchangeable under appropriate circumstances such that the embodiments of the present disclosure described herein, for example, are capable of operation in orientations other than those illustrated or otherwise described herein. For example, features previously described as "above" other features could be described as "below" the other features when the apparatus in the accompanying drawings is turned over. The apparatus can also be otherwise oriented (rotated 90 degrees or in other orientations) and relative spatial relationships will be interpreted accordingly.

[0071] In the specification and claims, when an element is referred to as being "on," "attached," "connected," "coupled," or "in contact with," etc., another element, the element may be directly on, directly attached, directly connected, directly coupled, or directly in contact with the other element, or one or more intervening elements may be present. In contrast, when an element is referred to as being "directly" "on," "directly attached," "directly connected," "directly coupled," or "in direct contact with" another element, there will be no intervening elements. In the specification and claims, when a feature is arranged "adjacent" to another feature, it may mean that the feature has a portion that overlaps with the adjacent feature or a portion that is located above or below the adjacent feature.

[0072] As used herein, the word "exemplary" means "serving as an example, instance, or illustration," rather than as a "model" to be precisely copied. Any implementation described as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, this disclosure is not to be bound by any expressed or implied theory presented in the technical field, background, summary, or detailed description.

[0073] As used herein, the term "substantially" is intended to encompass any minor variations due to design or manufacturing imperfections, device or component tolerances, environmental influences, and / or other factors. The term "substantially" also allows for deviations from a perfect or ideal condition due to parasitic effects, noise, and other practical considerations that may be present in actual implementations.

[0074] Additionally, terms such as "first," "second," and the like may also be used herein for reference purposes only and are not intended to be limiting. For example, the terms "first," "second," and other numerical terms referring to structures or elements do not imply a sequence or order unless the context clearly indicates otherwise.

[0075] It should also be understood that when the term “include / comprises” is used in this document, it indicates the presence of the specified features, integers, steps, operations, units and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, units and / or components and / or their combinations.

[0076] In this disclosure, the term "provide" is used in a broad sense to cover all ways of obtaining an object, and thus "providing an object" includes but is not limited to "purchasing", "preparing / manufacturing", "arranging / setting up", "installing / assembling", and / or "ordering" an object, etc.

[0077] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0078] Those skilled in the art will appreciate that the boundaries between the above-mentioned operations are merely illustrative. Multiple operations can be combined into a single operation, a single operation can be distributed among additional operations, and operations can be performed at least partially overlapping in time. Moreover, alternative embodiments can include multiple instances of a particular operation, and the order of operations can be changed in various other embodiments. However, other modifications, variations, and replacements are also possible. Aspects and elements of all embodiments disclosed above can be combined in any manner and / or in combination with aspects or elements of other embodiments to provide multiple additional embodiments. Therefore, this specification and the accompanying drawings should be considered illustrative, not restrictive.

[0079] Although some specific embodiments of the present disclosure have been described in detail by way of examples, those skilled in the art will appreciate that the above examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The various embodiments disclosed herein may be combined in any manner without departing from the spirit and scope of the present disclosure. Those skilled in the art will also appreciate that various modifications may be made to the embodiments without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.

Claims

1. A thermo-optical phase shifter, comprising: substrate; a waveguide disposed on the substrate; a first doped region and a second doped region respectively disposed on both sides of the waveguide and connected to the waveguide; a first metal interconnect structure, wherein the first metal interconnect structure is configured such that the first doped regions and the second doped regions connected via the first metal interconnect structure form a plurality of parallel structures; as well as A second metal interconnect structure is configured to connect the plurality of non-adjacent parallel structures in series.

2. The thermo-optical phase shifter according to claim 1, wherein: The first doping region is an N-type doping region, and the second doping region is a P-type doping region.

3. The thermo-optical phase shifter according to claim 1 , further comprising: A pair of outward-expanded metal contact regions includes a first outward-expanded metal contact region connected to the first doped region and a second outward-expanded metal contact region connected to the second doped region.

4. The thermo-optical phase shifter according to claim 3, wherein: The first outwardly expanded metal contact region and the second outwardly expanded metal contact region are symmetrical with respect to the waveguide.

5. The thermo-optical phase shifter according to claim 3, wherein: The thermo-optical phase shifter includes a plurality of pairs of outward-expanded metal contact regions arranged at regular intervals along the waveguide direction.

6. The thermo-optical phase shifter according to claim 5, wherein: The first outward-expanded metal contact regions in each pair of outward-expanded metal contact regions are separated from each other by an insulating material, and the second outward-expanded metal contact regions in each pair of outward-expanded metal contact regions are separated from each other by an insulating material.

7. The thermo-optical phase shifter according to claim 3, wherein: The first metal interconnect structure is configured to be directly connected to the corresponding pair of outward-expanded metal contact regions.

8. The thermo-optical phase shifter according to claim 1, wherein: One end of the parallel structure is electrically coupled to a first electrical port, and the other end of the parallel structure is electrically coupled to a second electrical port different from the first electrical port.

9. The thermo-optical phase shifter according to claim 1 , further comprising: a first insulating layer disposed on the waveguide, wherein a first portion of the first metal interconnect structure is disposed through the first insulating layer to connect to the first doped region and the second doped region, respectively, and a second portion of the first metal interconnect structure is disposed on the first insulating layer to connect to the first portion of the first metal interconnect structure, thereby forming the parallel structure; and A second insulating layer is arranged above the first metal interconnect structure, wherein a first portion of the second metal interconnect structure is arranged to pass through the second insulating layer to be connected to the first metal interconnect structure, a second portion of the second metal interconnect structure is arranged above the second insulating layer to be connected to the first portion of the second metal interconnect structure, and a third portion of the second metal interconnect structure is arranged to extend from the second portion of the second metal interconnect structure to connect non-adjacent parallel structures in series.

10. The thermo-optical phase shifter according to claim 1 , further comprising: a buried oxide layer disposed above the substrate and below the waveguide; as well as A semiconductor device region is disposed between the first doped region and the waveguide and between the second doped region and the waveguide.

11. A method for preparing a thermo-optical phase shifter, comprising: providing a substrate; forming a waveguide on the substrate; forming a first doped region and a second doped region connected to the waveguide on both sides of the waveguide; forming a first metal interconnect structure so that the first doped regions and the second doped regions connected via the first metal interconnect structure form a plurality of parallel structures; as well as A second metal interconnection structure is formed to connect the non-adjacent parallel structures in series.

12. The thermo-optical phase shifter according to claim 11, wherein: The first doping region is formed as an N-type doping region, and the second doping region is formed as a P-type doping region.

13. The method according to claim 11, further comprising: After forming the first doped region and the second doped region, a pair of outward-expanded metal contact regions is formed, such that the pair of outward-expanded metal contact regions includes a first outward-expanded metal contact region connected to the first doped region and a second outward-expanded metal contact region connected to the second doped region.

14. The method according to claim 13, further comprising: The first outwardly expanded metal contact region and the second outwardly expanded metal contact region are formed symmetrically with respect to the waveguide.

15. The method according to claim 13, wherein Forming the outward-expanded metal contact region pairs includes arranging a plurality of the outward-expanded metal contact region pairs at regular intervals along the waveguide direction.

16. The method according to claim 13, wherein: Forming a first metal interconnect structure includes: forming a first insulating layer over the waveguide; Etching the first insulating layer until the pair of outward-expanded metal contact regions are exposed to form a plurality of first through holes aligned with the first outward-expanded metal contact region and the second outward-expanded metal contact region; A metal material is deposited in the plurality of first vias to form a first portion of the first metal interconnect structure, and a second portion of the first metal interconnect structure is formed over the first insulating layer to connect the first portion of the first metal interconnect structure, thereby forming the first metal interconnect structure.

17. The method according to claim 16, wherein Forming a second metal interconnect structure includes: forming a second insulating layer over the first metal interconnect structure; etching the second insulating layer until the first metal interconnect structure is exposed to form a plurality of second through holes; A metal material is deposited in the plurality of second through holes to form a first portion of the second metal interconnect structure, a second portion of the second metal interconnect structure is formed over the second insulating layer to connect the first portion of the second metal interconnect structure, and a third portion of the second metal interconnect structure is formed extending from the second portion of the second metal interconnect structure to connect the non-adjacent parallel structures in series.

18. The method according to claim 17, wherein The second through hole may be formed to be aligned with the first through hole.

19. The method according to claim 11, further comprising: One end of the parallel structure is electrically coupled to a first electrical port, and the other end of the parallel structure is electrically coupled to a second electrical port different from the first electrical port.

20. The method of claim 11, further comprising: After providing the substrate, forming a buried oxide layer on the substrate; as well as After forming the waveguide and before forming the first doping region and the second doping region, semiconductor device regions connected to the waveguide are formed on both sides of the waveguide.

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