Integrated circuit device
By employing a tapered light absorption structure and a PIN photodiode structure in the photodetector, the problems of insufficient photon absorption and limited bandwidth under high photon power are solved, achieving a combination of a wide 3 dB bandwidth and high saturation current, thus improving the performance of the photodetector.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD
- Filing Date
- 2025-03-17
- Publication Date
- 2026-06-09
AI Technical Summary
Existing photodetectors suffer from insufficient photon absorption and limited bandwidth at high photon power, making it difficult to balance a wide 3 dB bandwidth with high saturation current.
A conical light absorption structure is adopted, which has a smaller width at the point where the light intensity is highest and a larger width at a distance. The structure is connected through the conical region and combined with the PIN photodiode structure to optimize the light absorption characteristics of the photodiode.
This achievement combines a wide 3 dB bandwidth and high saturation current in the photodetector at high photon power, thus improving the performance of the photodetector.
Smart Images
Figure CN224343700U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to an integrated circuit device. Background Technology
[0002] Silicon photonics studies and applies photonic systems that use silicon as the optical medium. Therefore, the use of silicon photonics facilitates the construction of highly efficient information processing integrated circuit (IC) devices because they are compatible with complementary metal-oxide-semiconductor (CMOS) technology. These low-cost, high-yield devices can be used in a variety of application areas, including but not limited to microwave photonics, optical sensing, optical communications, telecommunications, and high-performance computing. In these areas, photodetectors are used to detect information provided in photonic signals. Therefore, there is a high demand for high-speed, high-power photodetectors in IC devices, making it a particular focus of research and development. Utility Model Content
[0003] This invention provides an integrated circuit (IC) device. The device includes: an optical waveguide structure on a substrate; and a photodiode structure on the substrate and laterally adjacent to the optical waveguide structure. The photodiode structure includes: a doped structure comprising a first semiconductor material, and a light-absorbing structure comprising a second semiconductor material and contacting the doped structure. The light-absorbing structure is aligned with an optical coupler structure along a direction. The light-absorbing structure includes: a first region adjacent to the optical waveguide structure, the first region having a first width perpendicular to the direction; a second region away from the optical waveguide structure, the second region having a second width perpendicular to the direction, the second width being greater than the first width; and a tapered region connecting the first region and the second region, the tapered region having a first end adjacent to the first region and a second end adjacent to the second region, the first end having a first width perpendicular to the direction, and the second end having a second width perpendicular to the direction.
[0004] This invention relates to an integrated circuit device. The device includes: an optical waveguide structure located above a substrate; and a photodiode structure located above the substrate and laterally adjacent to the optical waveguide structure along a direction from the optical waveguide structure. The photodiode structure includes a light-absorbing structure comprising a near-end region, a tapered region, and a far-end region sequentially arranged along the direction from the optical waveguide structure. The near-end region has a first width laterally perpendicular to the direction; the far-end region has a second width laterally perpendicular to the direction, the second direction being greater than the first direction; and the tapered region has a width that linearly increases from a first end adjacent to the near-end region to a second end adjacent to the far-end region. Attached Figure Description
[0005] The various aspects of this utility model will be best understood from the following detailed description in conjunction with the accompanying drawings. It should be noted that, in accordance with standard practice in this industry, the various features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the various features may be arbitrarily enlarged or reduced.
[0006] Figure 1A This is a schematic plan view of some embodiments of a photodiode structure employing a conical light absorption structure according to the present invention.
[0007] Figure 1B and Figure 1C Qualitative diagrams of light intensity and the number of electron / hole pairs are shown for some embodiments of the photodiode structure according to the present invention.
[0008] Figure 2A This is a plan view of some embodiments of a photodiode structure employing a conical light absorption structure according to the present invention.
[0009] Figures 2B to 2D The illustration depicts, according to the content of this utility model, in Figure 2A Side view of the structure of some embodiments of the photodiode structure at the corresponding position in the middle.
[0010] Figures 3A to 3O Cross-sectional views are shown of some embodiments of an IC device comprising a photodiode structure using a tapered light-absorbing structure at multiple manufacturing stages, according to the present invention.
[0011] Figure 4 The illustration depicts a structure formed according to the content of this utility model. Figures 3A to 3O Methods for some embodiments of a photodiode structure.
[0012] Explanation of reference numerals in the attached figures
[0013] 100: Photodiode Structure
[0014] 101: Input Light
[0015] 102: Light absorption structure
[0016] 104: Area 1
[0017] 106: Conical region
[0018] 108: Second Area
[0019] 110: Optical Coupler Structure
[0020] 120: Doped Structure
[0021] 130: Light Intensity (Pint) Curve
[0022] 132: Number of electron-hole pairs (Neh)
[0023] 202: Substrate
[0024] 204: Oxide layer
[0025] 206, 304: Semiconductor layer
[0026] 212: First n-type region
[0027] 214: Second n-type region
[0028] 216: Silicide layer
[0029] 222: First p-type region
[0030] 224: Second p-type region
[0031] 230: Contact Etching Stop Layer
[0032] 300: IC devices
[0033] 302: First oxide layer
[0034] 306, 307, 309, 320: Trench
[0035] 308: Oxide Materials
[0036] 310: Silicide metal layer
[0037] 324: Conductive contact structure
[0038] 326: Conductive structure
[0039] 328: Interconnect via
[0040] 400: Method
[0041] 402, 404, 406, 408, 410, 412, 414: Actions
[0042] W1: First width
[0043] W2: Second width
[0044] L: Length Detailed Implementation
[0045] This invention provides many different embodiments or examples for implementing various features of the invention. Specific examples of components and arrangements are described below to simplify the scope of the invention. These are, of course, merely examples and are not intended to be limiting. For example, in the following description, the formation of a first feature on or above a second feature may include embodiments where the first and second features are in direct contact, or embodiments where an additional feature is formed between the first and second features, such that the first and second features may not be in direct contact. Furthermore, reference numerals and / or letters may be repeated in various examples of the invention. This repetition is for simplicity and clarity and does not in itself indicate a relationship between the various embodiments and / or configurations discussed.
[0046] In addition, spatial relative terms such as "beneath," "below," "lower," "above," and "upper" may be used in this document to describe the relationship between one component or feature and another component or features as shown in the figure. Besides the orientation depicted in the figure, spatial relative terms are intended to cover different orientations of the device during use or operation. The device may be in other orientations (rotated 90 degrees or other orientations), and the spatial relative descriptors used herein will be interpreted accordingly.
[0047] In some photodetectors (PDs), such as photodiodes, a rectangular structure of semiconductor material (such as germanium (Ge)) can be used as the light absorption component. The principal axis (e.g., length) of this rectangular structure can be aligned with the central axis of an optical coupler (e.g., a structure that converts light from a waveguide to a spot size corresponding to the photodetector), and the secondary axis (e.g., width) of the rectangular structure can transverse the optical coupler. Based on the rectangular structure of the light absorption component, the photodetector can have specific radio frequency (RF) behavior, where higher photocurrents are associated with a narrower 3 dB (e.g., half-power) bandwidth.
[0048] To provide a wider 3 dB bandwidth to facilitate a larger frequency range of operation for the photodetector, the width of the rectangular structure can be reduced to decrease its light absorption capability, particularly at the front end or light receiver, thereby reducing the number of generated electron-hole pairs. This reduction in electron-hole pairs can lead to a lower space charge screening effect, resulting in a wider 3 dB bandwidth for the photodetector. However, reducing the width of the rectangular structure may also reduce the saturation current of the photodetector. Therefore, at high photon power, the light-absorbing component may absorb significantly fewer photons than it receives. Thus, adjusting the width of the rectangular light-absorbing structure necessitates a trade-off between the photodetector's bandwidth (e.g., high speed) and saturation current capability (e.g., high power).
[0049] To address these issues, this invention provides several embodiments of photodetectors employing a tapered light-absorbing structure. In some embodiments, the light absorption may have three regions: a first region with a first width at one end of the light-absorbing structure; a second region with a second width at the opposite end of the light-absorbing structure, wherein the second width is greater than the first width; and a tapered region connecting the first and second regions. By employing a light-absorbing structure with this tapered profile, a reduced amount of absorbed light is associated with the first region, which has the highest received light intensity and a smaller width, thereby supporting a relatively wide 3 dB bandwidth in the first region. A higher saturation current is supported in the second region, which has a lower received light intensity and a larger width, than in the first region. Therefore, in some embodiments, the combined effect of the tapered light-absorbing structure is a relatively wide 3 dB bandwidth and a relatively high saturation current.
[0050] Therefore, some embodiments of IC devices employing photodiodes with tapered light absorption structures can provide high-power, high-speed photodiodes that support enhanced performance for microwave photonics, optical sensing, optical communications, and other applications targeted by silicon photonics platforms.
[0051] Figure 1A This is a schematic plan view of some embodiments of a photodetector (e.g., a photodiode structure 100) employing a tapered light absorption structure 102 according to the present invention. As shown, the photodiode structure 100 receives input light 101 via an adjacent optocoupler structure 110. As shown, the optocoupler structure 110 can serve as a spot size converter from waveguide-related dimensions to dimensions related to the photodiode structure 100. However, in other embodiments, [the following can be used]. Figure 1AOther types of optical coupler structures, besides those specifically shown elsewhere in this document, are used to provide light to the photodiode structure 100.
[0052] The photodiode structure 100 may include a doped structure 120 (e.g., a semiconductor layer including n-type and p-type regions, as described in detail below) and a light-absorbing structure 102. In some embodiments, the light-absorbing structure 102 is typically tapered, having a relatively small width at the input end (e.g., the location where input light 101 is received from the optocoupler structure 110) and a relatively large width at the end opposite to the input end. More specifically, in some embodiments, the light-absorbing structure 102 may have a first region 104 (e.g., a narrow region 104) and a second region 108 (e.g., a wide region 108) located at opposite ends, and a tapered region 106 connecting the first region 104 and the second region 108 along the length of the light-absorbing structure 102. As described above, in some embodiments, this tapered profile of the light-absorbing structure 102 can provide high power and high-speed performance for the corresponding photodiode structure 100, which may be advantageous when used in a silicon photonics platform.
[0053] Figure 1B and Figure 1C Qualitative diagrams of light intensity and the number of electron / hole pairs are shown for some embodiments of the photodiode structure 100 according to the present invention. More specifically, Figure 1B It is along the x-direction (e.g., as Figure 1A As shown, the light intensity (P) along the length L of the direction in which the input light 101 enters the photodiode structure 100 is... int Curve 130. Similarly, Figure 1C It is the number of electron-hole pairs (N) along the length L in the x-direction. eh Curve 132. In Figure 1B and Figure 1C In the middle, the solid line curve is drawn to show the relationship with... Figure 1A The indicator characteristics associated with the light absorption structure 102 are shown by the dashed lines, while the same characteristics are depicted for theoretical rectangular (e.g., non-conical) light absorption structures. Therefore, in Figure 1B In the middle, light intensity P int The curvature of curve 130 can be adjusted so that P int It is relatively low in the lower range of x, relatively high in some intermediate ranges of x, and at the expected level in the high range of x up to length L. Figure 1C N ehThe same adjustment or smoothing curvature is also illustrated in curve 132. Therefore, as described above, the first region 104 of the light-absorbing structure 102, with its smaller width, may result in a reduced amount of light absorbed at and near the input of the light-absorbing structure, thereby contributing to a relatively wide 3 dB bandwidth at the first region 104. In the second region 108, where the received light intensity is lower, the wider second region 108 supports a higher saturation current than the first region 104. Therefore, in some embodiments, the combined effect of the first region 104, the second region 108, and the tapered region 106 intervening therebetween is a wide 3 dB bandwidth and a correspondingly high saturation current.
[0054] Figure 2A This is a plan view of some embodiments of a photodiode structure 100 employing a tapered light absorption structure 102 according to the present invention. In some embodiments, the photodiode structure 100 may be adjacent to and optically coupled to an optocoupler structure 110, which receives input light 101 and provides the light to the input end of the light absorption structure 102 of the photodiode structure 100. In some embodiments, the optocoupler structure 110 may include a first semiconductor material (e.g., silicon (Si)). In some embodiments, the optocoupler structure 110 may be used as a light spot size converter to obtain light from a waveguide (not in...) Figure 2A The first spot size associated with the photodiode structure 100 (as explicitly described herein) is converted to a second spot size associated with the photodiode structure 100. However, other types of optical couplers not described herein may be used to provide light (e.g., in the form of photonic signals) to the photodiode structure 100. In some embodiments, the optical coupler structure 110 and the photodiode structure 100 may be at least partially covered by an oxide layer 204 (e.g., silicon oxide (SiO2)). x (such as silicon dioxide (SiO2) or another oxide material) surround or cover.
[0055] The photodiode structure 100 may include a light-absorbing structure 102 and a doped structure 120. In some embodiments, the doped structure 120 may include a first semiconductor material (e.g., silicon (Si), as may be used in the optocoupler structure 110), and the light-absorbing structure 102 may include a second semiconductor material (e.g., germanium (Ge)). In some embodiments, the photodiode structure 100 may be configured as a positive-intrinsic-negative (PIN) photodiode, wherein the doped structure 120 provides the n-type and p-type semiconductor regions of the PIN photodiode, and the light-absorbing structure 102 provides the intrinsic semiconductor region of the PIN photodiode. However, in other embodiments, other photodetector structures using a tapered light-absorbing structure 102 may be employed.
[0056] As described above, the light absorption structure 102 may include a first region 104, a tapered region 106, and a second region 108, sequentially starting from the optical coupler structure 110. Figure 2A As shown, the first region 104 may have a first constant width W1, and the second region 108 may have a second constant width W2, wherein W2 is greater than W1. Furthermore, the tapered region 106 connecting the first region 104 and the second region 108 may have a first end adjacent to the first region 104, the first end having a width equal to the width W1 of the first region 104. The tapered region 106 may also have a second end opposite to the first end and adjacent to the second region 108, the second end having a width equal to the width W2 of the second region 108. Furthermore, in some embodiments, the width of the tapered region 106 may linearly vary from width W1 to width W2 along the length of the tapered region 106.
[0057] In some embodiments, the widths W1 and W2, the length L, and the length of each of the first region 104, the second region 108, and the tapered region 106 can be selected to provide a desired 3 dB bandwidth and / or saturation current level. Factors that may be considered include, but are not limited to, the desired 3 dB bandwidth and / or saturation current, the semiconductor material used for the light-absorbing structure 102, footprint limitations in the IC device employing the photodiode structure 100, and so on. In some embodiments, such as Figure 2AAs shown, for the total length L of the light-absorbing structure 102, the first region 104 may have a length of approximately 25%-35% of the length L, the tapered region 106 may have a length of approximately 45%-55% of the length L, and the second region 108 may have a length of approximately 15%-25% of the length L. Furthermore, in some embodiments, the length L may be in the range of 10 micrometers (µm) to 20 µm, the length of the first region 104 may be in the range of 3 µm to 6 µm, the length of the tapered region 106 may be in the range of 5 µm to 10 µm, and the length of the second region 108 may be in the range of 2 µm to 4 µm. In some embodiments, the width W1 may be in the range of 0.3 µm to 0.6 µm, and the width W2 may be in the range of 0.5 µm to 1.0 µm.
[0058] The doped structure 120 may include multiple doped (e.g., p-type and n-type) regions of a semiconductor material (e.g., silicon (Si)) aligned along the length of the light-absorbing structure 102 (e.g., parallel to the direction of incident light 101). In some embodiments, these regions may include a first n-type region 212, a first p-type region 222, a second n-type region 214, and a second p-type region 224 formed in a semiconductor layer 206, which may be the same as the forming layer of the optical coupling structure 110. Furthermore, in some embodiments, the doping concentration of the second n-type region 214 and the second p-type region 224 may be higher than that of the first n-type region 212 and the first p-type region 222. Figure 2A As shown in the plan view, each of the first n-type region 212, the first p-type region 222, the second n-type region 214, and the second p-type region 224 can be parallel to the alignment direction of the light absorption structure 102.
[0059] Figures 2B to 2D The illustration depicts, according to the content of this utility model, in Figure 2A Side view of the structure of the photodiode structure 100 at the corresponding position in some embodiments. More specifically, Figure 2B A cross-sectional view of a photodiode structure 100 corresponding to the first region 104 of the light absorption structure 102 is shown. Figure 2C A cross-sectional view of a photodiode structure 100 corresponding to the conical region 106 of the light absorption structure 102 is shown. Figure 2DA cross-sectional view of the photodiode structure 100 corresponding to the second region 108 of the light absorption structure 102 is shown. In some embodiments, the first n-type region 212 and the first p-type region 222 may be laterally contacted and may be U-shaped. Furthermore, in some embodiments, the second n-type region 214 and the second p-type region 224 may be respectively disposed on a portion of the first n-type region 212 and the first p-type region 222, separated from the light absorption structure 102. Furthermore, the total thickness (in words) of each of the light absorption structure 102 (e.g., including the first region 104, the tapered region 106, and the second region 108), the first n-type region 212, the first p-type region 222, the second n-type region 214, and the second p-type region 224 is [not specified in the original text]. Figures 2B to 2D The vertical direction (of the region) can be constant. In other embodiments, other configurations of the first n-type region 212, the first p-type region 222, the second n-type region 214, and the second p-type region 224 are also possible, and are not limited to these configurations. Figures 2A to 2D The configurations shown.
[0060] Furthermore, in some embodiments, such as Figures 2B to 2D As shown, a silicide layer 216 may be formed on each of the second n-type region 214 and the second p-type region 224 to facilitate the second n-type region 214 and the second p-type region 224 with corresponding conductive contact structures (not shown) that may subsequently be formed thereon. Figures 2A to 2D The low contact resistance between (the two sides) is discussed in detail below.
[0061] like Figures 2B to 2D As shown, the light-absorbing structure 102 and the doped structure 120 may be disposed within one or more oxide layers 204 above the substrate 202 (e.g., a silicon (Si) substrate). Furthermore, in some embodiments, a contact etch stop layer 230 may be disposed above the oxide layer 204. In other embodiments, the IC device including the photodiode structure 100 may include other layers and / or structures, details of which will be described below.
[0062] Figures 3A to 3O The illustration shows cross-sectional views of some embodiments of an IC device 300 comprising a photodiode structure 100 using a tapered light absorption structure 102 at various manufacturing stages, according to the present invention. In some embodiments, Figures 3A to 3O This indicates that in the context of the above Figure 2C The manufacturing stage of the photodiode structure 100 is shown in the cross-section at the conical region 106. Although Figures 3A to 3O Described as a series of actions, it should be understood that these actions are not limiting, as the order of actions in each series may be changed in other embodiments, and the disclosed methods are applicable to other structures. In other embodiments, some actions shown and / or described may be omitted in whole or in part.
[0063] For example, Figure 3A The illustration depicts a substrate 202 (e.g., a silicon (Si) substrate) over which a first oxide layer 302 (e.g., a bottom oxide layer or a buried oxide layer) is formed (e.g., deposited). In some embodiments, the first oxide layer 302 may comprise silicon oxide (SiO2). x For example, silicon dioxide (SiO2), or another oxide or dielectric material. Next, Figure 3A A semiconductor layer 304 (e.g., another layer of silicon (Si) or another semiconductor material) is also depicted on top of the first oxide layer 302.
[0064] Figure 3B Trench 306 and trench 307 are illustrated in semiconductor layer 304 (e.g., using photolithography and associated etching). Figure 3B As shown, trench 306 may extend downwards at least to the upper surface of the first oxide layer 302. In some embodiments, trench 307 may extend into a portion of the semiconductor layer 304 without extending into the first oxide layer 302. In some embodiments, when trench 306 is formed, a portion of the semiconductor layer 304 may be connected to... Figure 3B The remaining portion of the semiconductor layer 304 in the cross-sectional view is isolated, and this isolated portion will be used for the photodiode structure 100.
[0065] Figure 3C The illustration shows oxide material 308 formed (e.g., deposited) in trenches 306 and 307 of semiconductor layer 304. In some embodiments, oxide material 308 may include the same material as the first oxide layer 302 (e.g., silicon oxide (SiO2)). x (e.g., silicon dioxide (SiO2), or another oxide or dielectric material). Furthermore, in some embodiments, the deposition of the oxide material 308 can be performed using chemical vapor deposition (CVD) (e.g., high-density plasma (HDP) chemical vapor deposition). Moreover, in some embodiments, the deposition of the oxide material 308 can be followed by a planarization process (e.g., chemical-mechanical planarization (CMP)) to produce a smooth upper surface for the semiconductor layer 304 and the oxide material 308.
[0066] Figure 3D The illustration shows a first n-type region 212 and a first p-type region 222 formed in semiconductor layer 304. In some embodiments, such as Figure 3DAs shown, the first n-type region 212 and the first p-type region 222 are laterally contacted each other in the semiconductor layer 304, located between and parallel to the trenches 306 filled with oxide material 308. Furthermore, in some embodiments, in Figure 3D In the cross-sectional view, the trench 307 filled with oxide material 308, the first n-type region 212 and the first p-type region 222 may be U-shaped.
[0067] Figure 3E The illustration shows a second n-type region 214 formed (e.g., implanted) in a first n-type region 212, and a second p-type region 224 formed (e.g., implanted) in a first p-type region 222. In some embodiments, the second n-type region 214 is formed in the upper region of the first n-type region 212 in the portion laterally adjacent to the oxide material 308, and the second p-type region 224 is formed in the upper region of the first p-type region 222 in the portion laterally adjacent to the oxide material 308. Therefore, in some embodiments, the second n-type region 214 and the second p-type region 224 are aligned parallel to the first n-type region 212 and the first p-type region 222. Furthermore, in some embodiments, the second n-type region 214 may be more heavily doped (e.g., additionally doped) relative to the first n-type region 212, and the second p-type region 224 may be more heavily doped (e.g., additionally doped) relative to the first p-type region 222.
[0068] Figure 3F The diagram illustrates trenches 320 (e.g., for subsequent formation of light-absorbing structures 102) formed along and into the first n-type region 212 and the first p-type region 222 (e.g., by photolithography and associated etching). As described above, Figures 3A to 3O ,in particular Figures 3F to 3O It describes about Figure 2C The cross-sectional view corresponds to the corresponding cross-sectional view of the conical region 106 of the light absorption structure 102. Therefore, in Figure 3F In the cross-sectional view, the width of the groove 320 may be somewhere between the first width W1 and the second width W2. Therefore, in other cross-sectional views, the width of the groove 320 may vary depending on its location along the groove 320. For example, in the portion of the groove 320 associated with the first region 104, the width of the groove 320 may be the first width W1. Correspondingly, in the portion of the groove 320 associated with the second region 108, the width of the groove 320 may be somewhere between the second width W2 and the first width W1.
[0069] Figure 3G The diagram illustrates the formation (e.g., epitaxial growth) of a second semiconductor material (e.g., germanium (Ge)) in trench 320 to fabricate a light-absorbing structure 102. For example... Figure 3GAs shown, the light-absorbing structure 102 can extend above the top surfaces of the first n-type region 212 and the first p-type region 222. In the plan view, the light-absorbing structure 102 can be as described above. Figure 2A As shown, it includes a first region 104, a conical region 106, and a second region 108. (As...) Figure 2A As shown, the first n-type region 212 is in contact with the first side of the light absorption structure 102, and the first p-type region 222 is in contact with the second side of the light absorption structure 102, with the second side and the first side being opposite to each other.
[0070] Figure 3H The illustration shows a second oxide layer 204 formed (e.g., deposited) over the light-absorbing structure 102, the second n-type region 214, the second p-type region 224, and the surrounding structure. In some embodiments, the second oxide layer 204 may comprise the same material as the first oxide layer 302 (e.g., silicon oxide (SiO2)). x (e.g., silicon dioxide (SiO2), or another oxide or dielectric material).
[0071] Figure 3I The diagram illustrates the removal (e.g., by photolithography and associated etching) of the trench 309 located above the second n-type region 214 and the second p-type region 224 in the second oxide layer 204.
[0072] Figure 3J A silicide metal layer 310 is illustrated formed (e.g., deposited) over a second oxide layer 204, a second n-type region 214, and a second p-type region 224. In some embodiments, the silicide metal layer 310 may include nickel (Ni), cobalt (Co), or other metals suitable for silicide processes.
[0073] Figure 3KThe diagram illustrates the formation of a silicide layer 216 (e.g., silicide) using a silicide metal layer 310 on the second n-type region 214 and the second p-type region 224. In some embodiments, the silicide metal layer 310 is heat-treated (e.g., heated at a temperature between 300°C and 500°C) such that the silicide metal layer 310 reacts with the second n-type region 214 and the second p-type region 224, but not with the second oxide layer 204, to form the silicide layer 216 (e.g., forming a first silicide layer on the second n-type region 214 and a second silicide layer on the second p-type region 224). In some embodiments, residues of the silicide metal layer 310 that did not react with the second n-type region 214 and the second p-type region 224 can be washed (e.g., rinsed with a detergent). In some embodiments, the silicide layer 216 helps to provide a low-resistance connection between the second n-type region 214 and the second p-type region 224 and the conductive material subsequently formed thereon, thereby increasing the conductivity of the connection between the second n-type region 214 and the subsequently formed conductive contact structure, and the conductivity of the connection between the second p-type region 224 and another conductive contact structure, as described below.
[0074] Figure 3L The illustration shows the formation (e.g., deposition) of additional oxide material above the silicide layer 216, replacing, for example, Figure 3J The oxide material shown is etched before the deposition of the silicide metal layer 310.
[0075] Figure 3M The illustration shows a contact etch stop layer 230 formed (e.g., deposited) over the second oxide layer 204 (e.g., to prepare for subsequent process operations of the integrated circuit device used in the photodiode structure 100). In some embodiments, the contact etch stop layer 230 may include, but is not limited to, silicon nitride (SiN), silicon carbide (SiC), silicon carbonitride (SiCN), or the like.
[0076] Figure 3N The diagram illustrates the formation (e.g., deposition) of an additional oxide layer 204 (e.g., silicon oxide (SiO2) on the contact etch stop layer 230. x The oxide layer 204, such as silicon dioxide (SiO2), or another oxide or dielectric material, is then used to form (e.g., etch and deposit) a conductive contact structure 324 to contact the silicide layer 216 (e.g., a first silicide layer formed on the second n-type region 214 and a second silicide layer formed on the second p-type region 224), thereby providing electrical connections to the second n-type region 214 and the second p-type region 224 via the conductive contact structure 324. The conductive contact structure 324 may include, but is not limited to, copper (Cu) or another metal, metal alloy, or other conductive material.
[0077] Figure 3O The diagram illustrates the formation (e.g., deposition) of one or more additional oxide layers 204 (e.g., silicon dioxide (SiO2)). x The material used is silicon dioxide (SiO2), or another oxide or dielectric material. A conductive structure 326 is then formed (e.g., etched and deposited) and interconnect vias 328 penetrating one or more additional oxide layers 204 to electrically connect to conductive contact structures 324, thereby providing access from other circuitry within the IC device 300 (not shown). Figure 3O Conductive connections are made between the second n-type region 214 and the second p-type region 224. The conductive structure 326 and the interconnecting via 328 may include, but are not limited to, copper (Cu) or another metal, metal alloy, or other conductive material. Although Figure 3O Two conductive structures 326 and one interconnect via 328 are depicted, but other numbers of conductive structures 326 and interconnect vias 328 may be used in other embodiments.
[0078] Within the IC device 300, as described above, the light absorption structure 102 uses a tapered profile, which promotes high power and high-speed performance of the corresponding photodiode structure 100. Furthermore, as... Figures 3A to 3O The fabrication of the light absorption structure 102 and the associated photodiode structure 100 may not require highly specialized or complex photolithography, etching, deposition or similar IC-related fabrication processes.
[0079] Figure 4 The diagram illustrates some formations such as Figures 3A to 3O The embodiments of method 400 for the illustrated IC device 300 (including photodiode structure 100) are consistent with the present invention. While this method, and other methods illustrated and / or described herein, are shown as a series of actions or events, it should be understood that the present invention is not limited to the shown sequence of actions. Therefore, in some embodiments, these actions may be performed in a different order than shown, and / or may be performed simultaneously. Furthermore, in some embodiments, the shown actions or events may be subdivided into multiple actions or events that may be performed at different times or simultaneously with other actions or sub-actions. In some embodiments, some shown actions or events may be omitted, while others illustrated may be included.
[0080] In action 402, for example, on the substrate (e.g., Figure 3A A first oxide layer (e.g., on the substrate 202) is formed on top of the substrate 202. Figure 3A The first oxide layer 302). In operation 404, a semiconductor layer (e.g., ...) is formed on the first oxide layer. Figure 3A Semiconductor layer 304), the semiconductor layer includes a first semiconductor material. Figure 3ACross-sectional views of some embodiments corresponding to actions 402 and 404 are shown.
[0081] In action 406, a first trench and a second trench parallel to the first trench are formed in the semiconductor layer (e.g., Figure 3B Groove 306). Figure 3B Cross-sectional views of some embodiments corresponding to action 406 are shown.
[0082] In action 408, an oxide material (e.g., Figure 3C The oxide material 308) fills the first trench and the second trench. Figure 3C Cross-sectional views of some embodiments corresponding to action 408 are shown.
[0083] In action 410, a first n-type region (e.g., between the first trench and the second trench and parallel to the first trench and the second trench) is formed in a semiconductor structure. Figure 3D The first n-type region 212) and the first p-type region adjacent to the first n-type region (e.g., Figure 3D The first p-type region 222 in the middle. Figure 3D Cross-sectional views of some embodiments corresponding to action 410 are shown.
[0084] In action 412, a third trench is formed along the first n-type region and the first p-type region. The third trench (e.g.) Figure 3F The trench 320 includes a proximal region (e.g., along the first n-type region and the first p-type region) arranged sequentially. Figure 2A The first region 104 is related), the cone-shaped region (e.g., with Figure 2A (related to the cone-shaped region 106) and the remote region (e.g., related to) Figure 2A The second region 108 is related to this. The proximal region has a first width transverse to the first and second trenches (e.g., Figure 2A The first width W1). The remote region has a second width transverse to the first and second trenches (e.g., Figure 2A The second width (W2) is greater than the first width. The conical region has a width that increases linearly from the first end of the adjacent proximal region to the second end of the adjacent remote region. Figure 3F Cross-sectional views of some embodiments corresponding to action 412 are shown.
[0085] In action 414, the third trench is filled with a second semiconductor material (e.g., a semiconductor material such as germanium (Ge) is used for...). Figure 2A (Light absorption structure 102). Figure 3G Cross-sectional views of some embodiments corresponding to action 414 are shown.
[0086] Some embodiments relate to an integrated circuit (IC) device. The device includes: an optical waveguide structure on a substrate; and a photodiode structure on the substrate and laterally adjacent to the optical waveguide structure. The photodiode structure includes: a doped structure comprising a first semiconductor material, and a light-absorbing structure comprising a second semiconductor material and contacting the doped structure. The light-absorbing structure is aligned with an optocoupler structure in a direction, and includes: a first region adjacent to the optical waveguide structure, the first region having a first width perpendicular to the direction; a second region away from the optical waveguide structure, the second region having a second width perpendicular to the direction, the second width being greater than the first width; and a tapered region connecting the first region and the second region, the tapered region having a first end adjacent to the first region and a second end adjacent to the second region, the first end having a first width perpendicular to the direction, and the second end having a second width perpendicular to the direction.
[0087] Some embodiments relate to an integrated circuit device including an optical waveguide structure located above a substrate; and a photodiode structure located above the substrate and laterally adjacent to the optical waveguide structure. The photodiode structure includes a doped structure comprising a first semiconductor material, and a light-absorbing structure comprising a second semiconductor material and contacting the doped structure. The light-absorbing structure is aligned with the optical waveguide structure along a direction, and includes a first region adjacent to the optical waveguide structure, the first region having a first width perpendicular to the direction; a second region away from the optical waveguide structure, the second region having a second width perpendicular to the direction, the second width being greater than the first width; and a tapered region connecting the first region and the second region, the tapered region having a first end adjacent to the first region and a second end adjacent to the second region, the first end having the first width perpendicular to the direction, and the second end having the second width perpendicular to the direction.
[0088] Some embodiments relate to another integrated circuit device. The device includes: an optical waveguide structure located above a substrate; and a photodiode structure located above the substrate and laterally adjacent to the optical waveguide structure along a direction from the optical waveguide structure. The photodiode structure includes a light-absorbing structure comprising a near-end region, a tapered region, and a far-end region sequentially arranged along the direction from the optical waveguide structure. The near-end region has a first width laterally perpendicular to the direction; the far-end region has a second width laterally perpendicular to the direction, the second direction being greater than the first direction; and the tapered region has a width that linearly increases from a first end adjacent to the near-end region to a second end adjacent to the far-end region.
[0089] It should be understood that in this written description and the following claims, the terms "first," "second," "third," etc., are merely general identifiers used for ease of description to distinguish different components in a figure or series of figures. In themselves, these terms do not imply any temporal order or structural proximity of these components and are not intended to describe corresponding components in different exemplary embodiments and / or embodiments not shown. For example, "first dielectric layer" described with respect to a first figure does not necessarily correspond to "first dielectric layer" described with respect to another figure, nor does it necessarily correspond to "first dielectric layer" in embodiments not shown.
[0090] The above summary of features and embodiments is intended to enable those skilled in the art to better understand aspects of the present invention. Those skilled in the art should understand that they can readily use the present invention as a basis for designing or modifying other processes and structures to achieve the same purpose and / or realize the same advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of the present invention, and that they can make various changes, substitutions, and alterations therein without departing from the spirit and scope of the present invention.
Claims
1. An integrated circuit device, characterized in that, include: An optical coupler structure is located above the substrate; as well as A photodiode structure is located above the substrate and laterally adjacent to the optocoupler structure, the photodiode structure comprising: Doped structures, including a first semiconductor material, and A light-absorbing structure, comprising a second semiconductor material and contacting the doped structure, wherein the light-absorbing structure is aligned with the optical coupler structure along a direction, the light-absorbing structure comprising: A first region, adjacent to the optical coupler structure, has a first width perpendicular to the direction; A second region, located away from the optical coupler structure, has a second width perpendicular to the direction, the second width being greater than the first width; and A conical region connecting the first region to the second region, the conical region having a first end adjacent to the first region and a second end adjacent to the second region, the first end having a first width perpendicular to the direction, and the second end having a second width perpendicular to the direction.
2. The integrated circuit device according to claim 1, characterized in that, The doped structure includes: The first n-type region is aligned parallel to the direction and contacts the first side of the light-absorbing structure; and The first p-type region is aligned parallel to the direction and is in contact with the second side of the light-absorbing structure relative to the first side.
3. The integrated circuit device according to claim 2, characterized in that, The doped structure further includes: The second n-type region is located on a portion of the first n-type region; and The second p-type region is located on a portion of the first p-type region.
4. The integrated circuit device according to claim 3, characterized in that, in: The second n-type region is more heavily doped than the first n-type region; and The second p-type region is more heavily doped than the first p-type region.
5. The integrated circuit device according to claim 3, characterized in that, Including: A first conductive contact structure is disposed above and electrically coupled to the second n-type region; and A second conductive contact structure is disposed above and electrically coupled to the second p-type region.
6. The integrated circuit device according to claim 5, characterized in that, Including: A first silicide layer, connecting the first conductive contact structure to the second n-type region; and The second silicide layer connects the second conductive contact structure to the second p-type region.
7. The integrated circuit device according to claim 1, characterized in that, The first region, the second region, and the conical region of the light-absorbing structure have the same thickness perpendicular to the first width, the second width, and the direction.
8. An integrated circuit device, characterized in that, include: An optical coupler structure is located above the substrate; as well as A photodiode structure is located above the substrate and laterally adjacent to the optical coupler structure along the direction from the optical coupler structure. The photodiode structure includes a light-absorbing structure comprising a near-end region, a tapered region, and a far-end region arranged sequentially along the direction from the optical coupler structure, wherein: The proximal region has a first width that is laterally perpendicular to the direction; The remote region has a second width that is perpendicular to the direction, and the second width is greater than the first width; and The conical region has a width that increases linearly from a first end adjacent to the proximal region to a second end adjacent to the remote region.
9. The integrated circuit device according to claim 8, characterized in that, The photodiode structure further includes a doped structure in contact with the light-absorbing structure and includes a first semiconductor material, wherein the light-absorbing structure includes a second semiconductor material different from the first semiconductor material.
10. The integrated circuit device according to claim 9, characterized in that, The doped structure includes: The first n-type region is aligned parallel to the direction and is in contact with the first side of the light-absorbing structure; The second n-type region is located on a portion of the first n-type region, and the second n-type region is more heavily doped than the first n-type region; A first p-type region, aligned parallel to the direction and in contact with the second side of the light-absorbing structure relative to the first side; and The second p-type region is located on a portion of the first p-type region, and the second p-type region is more heavily doped than the first p-type region.