Optical module

Abstract

The utility model provides an optical module. The waveguide comprises a rib and further comprises a first protrusion and a second protrusion which are located on the opposite sides of the rib respectively. Further, the waveguide is formed by the first semiconductor portion. A light detector is located in the waveguide and includes a PN junction in the rib. A P-type region of the PN junction extends to the first protrusion, and an N-type region of the PN junction extends to the second protrusion. In addition, the first and second bumps house heavily doped P-type and N-type contact regions. The semiconductor region is located on the PN junction. The semiconductor region includes a second semiconductor portion different from the first semiconductor portion. According to the utility model, the second semiconductor part can have a smaller band gap than the first semiconductor part so as to improve the quantum efficiency.

Description

Technical Field

[0001] The embodiment of the utility model relates to an optical module. Background Art

[0002] At high frequencies or high data rates, electrical transmission has reached its limits due to high energy losses over long distances. Therefore, electronic chips that rely on long-distance transmission are turning to optical transmission. Such electronic chips may, for example, include switch chips or system-on-chip (SoC) chips. Such SoC chips may, for example, include application-specific integrated circuit (ASIC) chips, central processing unit (CPU) chips, graphics processing unit (GPU) chips, etc. Utility Model Content

[0003] An embodiment of the utility model provides an optical module, comprising: a waveguide, comprising a rib and further comprising a first protrusion and a second protrusion respectively located at opposite sides of the rib; a light detector, comprising a PN junction located in the rib; and a semiconductor region located on the PN junction, wherein the waveguide comprises a first semiconductor portion, and the semiconductor region comprises a second semiconductor material different from the first semiconductor portion.

[0004] The present invention provides an optical module, comprising: a waveguide arranged around a central region and terminated at the central region; a light detector integrated into the waveguide around the central region; a first pad coupled to an N-type region of the light detector; and a second pad coupled to a P-type region of the light detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] When read in conjunction with the accompanying drawings, the aspects of the present invention are best understood from the following detailed description. It should be noted that, according to standard practice in the industry, various features are not drawn to scale. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0006] Figure 1A-1B Some embodiments of optical modules including light detectors integrated with rib waveguides are shown in cross-sectional and top views, respectively.

[0007] Figure 2A-2B Some top views of various embodiments of optical couplers connected to light detectors are shown.

[0008] Figure 3A-3J Shows Figure 1A Some cross-sectional views of alternative embodiments of optical modules.

[0009] Figure 4 Shows Figure 1A and Figure 1B Cross-sectional view of an optical module of the size of a medium rib waveguide.

[0010] Figure 5 A top view of an array of light detectors is shown.

[0011] Fig. 6A and Figure 6B A top view of an array of light detectors integrated into a photonic circuit is shown.

[0012] Figure 7-Figure 20 A series of cross-sectional views illustrating some embodiments of methods for forming a light detector integrated with a rib waveguide.

[0013] Fig.21 Shows Figure 7-Figure 20 Block diagram of some embodiments of the method. DETAILED DESCRIPTION

[0014] The following utility model content provides many different embodiments or examples for implementing the different features of the provided theme. Specific examples of components and configurations are described below to simplify the utility model content. Of course, these specific examples are only examples and are not intended to be restrictive. For example, in the following description, a first feature is formed above or on a second feature, which may include an embodiment in which the first feature is directly contacted with the second feature, and may also include an embodiment in which an additional feature may be formed between the first feature and the second feature so that the first feature and the second feature may not be in direct contact. In addition, the utility model content may repeat the figure numbers and / or letters in various examples. This repetition is for the purpose of simplicity and clarity, and does not itself specify the relationship between the various embodiments and / or configurations discussed.

[0015] Additionally, for ease of description, spatially relative terms such as "below," "lower," "above," "upper," and the like may be used to describe the relationship of one component or feature to another component or feature as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of a component in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein should be interpreted accordingly.

[0016] The optical module may include a waveguide and a light detector. The waveguide transmits the optical signal to the light detector, and the light detector generates an electrical signal based on the optical signal. Traditionally, some light detectors designed to work with optical circuits and electronic circuits use a flip-chip integration method, in which the optical circuits and electronic circuits are manufactured on separate chips before solder bumps are used to combine the circuits together. However, the flip-chip integration method relies on precise alignment between the joined chips in order to effectively transfer signals between the two chips. Chips used for flip-chip bonding need to have an additional minimum area to support the coupling and separation of a single solder bump. Therefore, it is desirable to adopt a single-chip solution to reduce the area used by the light detector, enhance design flexibility, and reduce the risks associated with misalignment between chips.

[0017] Various embodiments of the present disclosure relate to an optical module including a light detector integrated into a rib waveguide. In some embodiments, the optical module includes a rib waveguide, wherein a portion of the rib waveguide is divided into a P-type region and an N-type region. The P-type region and the N-type region form a PN junction near the center of the rib waveguide. In addition, a bias circuit is coupled to a first protrusion and a second protrusion extending from the P-type region and the N-type region, respectively. The bias circuit reversely biases the PN junction, widening the depletion region near the center of the rib waveguide. Due to the photoelectric effect, photons passing through the rib waveguide may enter the depletion region and generate carriers. The carriers generated in the depletion region are prevented from recombination by the electric field existing across the PN junction, and then the carriers are pulled toward separate protrusions (e.g., the first protrusion and the second protrusion) and enter the bias circuit, generating a measurable current.

[0018] Integrating light detectors into rib waveguides can increase the flexibility of designs using photonic and electronic circuits. For example, devices that use photonic circuits for high-speed and / or long-distance communication between different chips can convert photonic signals into electronic signals without using multiple chips, thereby alleviating or eliminating issues related to chip bonding, alignment, and minimizing space requirements.

[0019] Figure 1A-1B Some embodiments of an optical module including a light detector 101 integrated with a rib waveguide 104 are shown in cross-sectional view 100a and top view 100b, respectively.

[0020] Figure 1A Shows Figure 1B A cross-sectional view along line AA'. Figure 1AA rib waveguide 104 extending on a handle substrate 102 is shown. An insulating layer 106 separates the rib waveguide 104 from the handle substrate 102. The handle substrate 102, the insulating layer 106, and the rib waveguide 104 may include layers of a silicon-on-insulator (SOI) substrate. The rib waveguide 104 is surrounded by a plurality of dielectric layers 108a, 108b, 108c, 108d (108a-108d) and includes a slab 104a. The rib 104b extends from the center of the slab 104a. A first protrusion 104c and a second protrusion 104d extend from the slab 104a on opposite sides of the rib 104b. In some embodiments, the rib 104b may be considered a central rib, while the first protrusion 104c and the second protrusion 104d may be considered a peripheral rib.

[0021] The first doped region 112 extends from the first protrusion 104c to the rib 104b, and the second doped region 114 extends from the second protrusion 104d to the rib 104b. In some embodiments, the first doped region 112 is a P-type region, and the second doped region 114 is an N-type region. In other embodiments, the first doped region 112 is an N-type region, and the second doped region 114 is a P-type region. The first doped region 112 and the second doped region 114 form a PN junction 113 extending through the plate 104a and the rib 104b. In some embodiments, the PN junction 113 is approximately located at the midpoint between the outer side walls of the rib 104b and / or at the center between the first protrusion 104c and the second protrusion 104d.

[0022] The semiconductor region 110 is located on the PN junction 113. In some embodiments, the semiconductor region 110 can be regarded as a semiconductor cap, etc. The rib waveguide 104 includes a first semiconductor material (part), such as single crystal silicon, etc. The semiconductor region 110 includes a second semiconductor material, such as germanium (Ge); or a III-V semiconductor material, such as gallium arsenide (GaAs), indium arsenide (InAs), gallium nitride (GaN), indium phosphide (InP), etc. The second semiconductor material has a higher target radiation absorption coefficient than the first semiconductor material, and may, for example, have a higher electron mobility and / or a different band gap energy relative to the first semiconductor material. In some embodiments, the semiconductor region 110 has no P-type doping and N-type doping, so that the semiconductor region 110 can be considered intrinsic.

[0023] The use of a second semiconductor material (portion) in semiconductor region 110 can increase the quantum efficiency of photodetector 101 in a desired wavelength range. For example, the use of germanium or silicon germanium for semiconductor region 110 can increase the quantum efficiency of near infrared radiation due to the narrow band gap relative to silicon. For the same photon input signal, this increase in quantum efficiency causes the electronic output signal of photodetector 101 to increase proportionally. The increased output signal reduces the effect of noise on the output, which in turn can result in fewer errors and more accurate data transmission between the photonic circuit and the electronic circuit.

[0024] In some embodiments, semiconductor region 110 corresponds to a free carrier concentration modulation peak of photodetector 101. In addition, in some embodiments, the positions of the height center of rib waveguide 104 and the width center of rib waveguide 104 correspond to the peak of the optical electric field during use of photodetector 101. Therefore, since the bottom surface of semiconductor region 110 is elevated relative to the top surface of rib waveguide 104, the carrier modulation peak is higher than the peak of the photodetector field in some embodiments.

[0025] The first heavily doped region 116 is located in the first protrusion 104c. The first heavily doped region 116 has the same doping type as the first doping type region 112, but has a higher doping concentration. The second heavily doped region 118 is located in the second protrusion 104d. The second heavily doped region 118 has the same doping type as the second doping type region 114, but has a higher doping concentration. In some embodiments, the first doping type region 112 and the second doping type region 114 have approximately 2e16 to 9e18 atoms / cm 3 Between 2e15 and 9e17 atoms / cm 3 Between 2e17 and 9e19 atoms / cm 3 In a further embodiment, the first heavily doped region 116 and the second heavily doped region 118 have a doping concentration between about 1e18 and 9e20 atoms / cm 3 Between 1e17 and 9e19 atoms / cm 3 Between 1e19 and 9e21 atoms / cm 3 In some embodiments, the first heavily doped region 116 and the first doping type region 112 overlap in a portion of the plate 104a. The second doping type region 114 and the second heavily doped region 118 may also overlap in a portion of the plate 104a.

[0026] The contact 120 is coupled to the first bump 104c, the second bump 104d, and the semiconductor region 110. The contact 120 connects the first bump 104c, the second bump 104d, and the semiconductor region 110 to the bonding layer 122.

[0027] Figure 1B The wiring layer 122 connects the first protrusion 104c to the first pad 124, the wiring layer 122 connects the second protrusion 104d to the second pad 126, and the wiring layer 122 connects the semiconductor region 110 to the third pad 128. Figure 1B 101. The first pad 124 and the second pad 126 are electrically coupled to a bias circuit 132, and in some embodiments, the third pad 128 is electrically grounded. The bias circuit 132 reverse biases the PN junction 113, thereby increasing the area of ​​the depletion region extending through the PN junction 113. The photon signal 130 is shown traveling through the rib waveguide 104 toward the photodetector 101, where the photon signal 130 generates carriers in the depletion region. The reverse bias of the PN junction 113 further provides an electric field to pull the generated carriers from the rib waveguide 104 toward the electronic circuit (not shown) coupled to the photodetector 101.

[0028] Integrating light detector 101 into a single chip that can house both photonic and electronic circuits increases design flexibility using both photonic and electronic circuits and reduces or eliminates issues associated with chip bonding, alignment, and minimum area requirements for bonding the chips.

[0029] Figure 2A-2B Several top views 200a-200b of various embodiments of optical coupler 202 connected to light detector 101 are shown. Figure 2A In the embodiment, the light detector 101 can be, for example, Figure 1A and Figure 1B As shown. Figure 2B In addition to omitting the semiconductor region 110, the light detector 101 may be, for example, the same Figure 1A and Figure 1B Like in.

[0030] The optical coupler 202 is coupled to the rib waveguide 104 through the strip waveguide 204 and the transition waveguide 206. The optical coupler 202 may be, for example, a grating coupler, an edge coupler, etc. At the transition waveguide 206, the width of the transition waveguide 206 increases from the width of the strip waveguide 204 to the width of the rib 104b of the rib waveguide 104. In addition, the slab 104a transitions from having the width of the strip waveguide 204 to having the width of the rib waveguide 104. One or more additional photonic circuit components (e.g., a power spreader, a Mach-Zehnder modulator (MZM), etc.) may be coupled to the strip waveguide 204 or the rib waveguide 104, for example.

[0031] The PN junction 113 is located at the rib 104b and is formed by the first doped region 112 and the second doped region 114. The first doped region 112 and the second doped region 114 extend from the PN junction 113 and are connected to the first protrusion 104c and the second protrusion 104d, respectively. Further, the first protrusion 104c and the second protrusion 104d accommodate the first heavily doped region 116 and the second heavily doped region 118, respectively. Figure 2A ,and Figure 2B In contrast, the semiconductor region 110 overlaps the rib 104 b and the PN junction 113 .

[0032] Figure 3A-3J Shows Figure 1A Some cross-sectional views 300a-300j of alternative embodiments of optical modules.

[0033] Photons entering the rib waveguide 104 can be represented by an electromagnetic field propagating along the rib waveguide 104. The magnitude of the electromagnetic field is highest near the center of the rib waveguide 104. The square of the magnitude of the electromagnetic field is proportional to the number of photons concentrated at that location. Therefore, the highest concentration of photons in the rib waveguide 104 is at the center of the rib waveguide 104, which is approximately at the center of the width direction of the rib 104b and approximately at the center of the height direction of the rib waveguide 104. Therefore, to improve the carrier generation efficiency (e.g., quantum efficiency), efforts are made to concentrate at the center of the rib waveguide, as described below with respect to Figure 3A-3J described.

[0034] like Figure 3AAs shown in the cross-sectional view 300a of FIG. 1 , the semiconductor region 110 is injected into the rib 104b of the rib waveguide 104. In other words, the second semiconductor material is injected into the rib 104b. Therefore, the semiconductor region 110 includes a first semiconductor material and a second semiconductor material. For example, the first semiconductor material is silicon or includes silicon, and the second semiconductor material is germanium or includes germanium, and the semiconductor region 110 can be silicon germanium or include silicon germanium. However, other suitable materials are also acceptable. In some embodiments, the semiconductor region 110 has a density of approximately 1e18 to 9e25 atoms / cm 3 The doping concentration of the second semiconductor material is between .

[0035] During use of the photodetector 101, an electromagnetic field propagating along the rib waveguide 104 may enter the semiconductor region 110. As described above, the second semiconductor material of the semiconductor region 110 may have a higher absorption coefficient of incident radiation than the first semiconductor material, and thus may improve quantum efficiency. In other words, the second semiconductor material increases the number of carriers generated and converted into photocurrent. Because the semiconductor region 110 is injected into the rib 104b, the semiconductor region 110 overlaps the center of the rib waveguide 104. In addition, because the concentration of photons is highest toward the center of the rib waveguide 104, greater quantum efficiency is achieved.

[0036] In some embodiments, semiconductor region 110 corresponds to a free carrier concentration modulation peak of photodetector 101. Furthermore, in some embodiments, the center of rib waveguide 104 corresponds to a peak of the optical electric field during use of photodetector 101. Therefore, since semiconductor region 110 is at the center of rib waveguide 104, the carrier modulation peak coincides with the peak of the photodetector field in some embodiments.

[0037] like Figure 3B As shown in the cross-sectional view 300b of FIG. 1 , the rib 104b of the rib waveguide 104 is replaced by a semiconductor region 110 deposited above the PN junction 113. The deposited semiconductor region 110 may, for example, provide a greater concentration of the second semiconductor material above the PN junction 113, and a higher concentration than the implanted material in the rib waveguide 104. Therefore, the deposited semiconductor region 110 may further increase the quantum efficiency 104 at a position substantially coincident with the peak of the electromagnetic field in the rib waveguide, thereby further increasing the magnitude of the electrical output signal.

[0038] like Figure 3CAs shown in the cross-sectional view 300c of FIG. 1 , the semiconductor region 110 extends into the plate 104a of the rib waveguide 104 and substantially coincides with the center of the rib waveguide 104. The implanted second semiconductor material coincides with the peak of the electromagnetic field in the rib waveguide 104 at the center of the rib waveguide 104, thereby increasing the efficiency of the light detector 101. In some embodiments, the width Wsr of the semiconductor region 110 is approximately 100-350% of the width Wrb of the rib 104b. However, other suitable percentages are also acceptable.

[0039] like Figure 3D As shown in the cross-sectional view 300d of FIG. 1 , the semiconductor region 110 is deposited directly on the plate 104a, and the polysilicon replacement of the rib 104b is directly above the semiconductor region 110. Figure 1A The semiconductor region 110 in the illustrated embodiment is positioned closer to the center of the rib waveguide 104, providing a more concentrated second semiconductor material of the deposited semiconductor region 110, which can lead to better quantum efficiency. In some embodiments, the width Wsr of the semiconductor region 110 is approximately 100-350% of the width Wrb of the rib 104b. However, other suitable percentages are also acceptable.

[0040] like Figure 3E As shown in the cross-sectional view 300e of FIG. 1 , the semiconductor region 110 is located at the center of the rib 104b between the lower plate 104f and the upper plate 104e. The upper plate 104e extends above the semiconductor region 110 and has a lower surface above the upper surface of the lower plate 104f. The first protrusion 104c extends from the upper plate 104e, and the second protrusion 104d extends from the lower plate 104f. The first protrusion 104c and the second protrusion 104d have upper surfaces flush with each other.

[0041] The first doped region 112 is located in the upper plate 104e and extends to the upper boundary of the semiconductor region 110, and the second doped region 114 is located in the lower plate 104f and extends to the lower boundary of the semiconductor region 110. The first doped region 112, the semiconductor region 110 and the second doped region 114 together form a PIN junction or the like.

[0042] In some embodiments, the fill layer 302 separates the upper plate 104e from the insulating layer 106. In some embodiments, the fill layer 302 is or includes silicon oxide and / or the like. In some embodiments, the upper plate 104e is or includes polysilicon and / or the like, and the lower plate 104f is or includes single crystal silicon and / or the like.

[0043] The semiconductor region 110 is located directly between the first doped region 112 and the second doped region 114 at the center of the rib waveguide 104. The maximum concentration of photons passes through the rib waveguide 104 at the location of the semiconductor region 110, so the increase in the quantum efficiency of the photodetector 101 at this time leads to a greater change in quantum efficiency. The semiconductor region 110 can be implanted or deposited before forming the upper plate 104e.

[0044] like Figure 3F As shown in the cross-sectional view 300f of FIG. 300 , the semiconductor region 110 extends vertically between the first doped region 112 and the second doped region 114. The semiconductor region 110 extends through the center of the rib waveguide 104, which coincides with the peak of the electromagnetic field. When the semiconductor region 110 extends vertically, the depletion region formed at the PIN junction can have a larger cross-sectional area, thereby increasing the amount of charge carriers that can be generated due to the photoelectric effect.

[0045] like Figure 3G As shown in the cross-sectional view 300g of FIG. 1 , the semiconductor region 110 extends laterally between the first doping type region 112 and the second doping type region 114, and overlaps with the first doping type region 112 and the second doping type region 114 in the first type overlapping region 304 and the second type overlapping region 306. This overlap causes the semiconductor region 110 to cover a wider portion of the depletion region, increasing the efficiency of carrier generation over a larger area while still being located in the center of the rib waveguide 104.

[0046] like Figure 3H As shown in the cross-sectional view 300h of FIG. 1 , the semiconductor region 110 has a lower portion extending vertically between the first doping type region 112 and the second doping type region 114 and an upper portion extending horizontally between the first doping type region 112 and the second doping type region 114. This configuration has the semiconductor region 110 extending through the center of the rib waveguide 104 while further increasing the area of ​​the semiconductor region 110 without overlapping with the first doping type region 112 or the second doping type region 114. The increased area of ​​the semiconductor region 110 due to the horizontal extension increases the area of ​​the depletion region.

[0047] like Fig. 3I As shown in the cross-sectional view 300i of FIG. 300 , the second semiconductor region 110b extends below the first semiconductor region 110a and the PN junction 113. The plurality of semiconductor regions 110a and 110b cover the portion of the rib waveguide 104 near the center, while maintaining a direct PN junction 113 between the first doped region 112 and the second doped region 114. The PN junction 113 extends vertically between the first doped region 112 and the second doped region 114, and extends horizontally between the first doped region 112 and the second doped region 114, thereby increasing the area of ​​the depletion region near the center of the rib waveguide 104.

[0048] like Figure 3J As shown in the cross-sectional view 300j of FIG. 1 , the semiconductor region 110 covers the portion of the lower plate 104f extending from the first protrusion 104c to the second protrusion 104d. The first doped region 112 extends into the rib 104b and over the second doped region 114, overlapping the semiconductor region 110 at the first type overlap region 304. The second doped region 114 extends under the rib 104b and overlaps the semiconductor region 110, resulting in a second type overlap region 306. The semiconductor region 110 has an extended width and a larger horizontal spacing between the first doped region 112 and the second doped region 114, which results in a larger depletion region and spans the extended depletion region to increase quantum efficiency.

[0049] Figure 4 Shows Figure 1A and Figure 1B A cross-sectional view 400 of an optical module of a size of a medium rib waveguide.

[0050] In some embodiments, the rib 104b has a first width W1 between about 300 nanometers and 2000 nanometers, between about 200 nanometers and 1500 nanometers, between about 400 nanometers and 2500 nanometers, or in another suitable range. In some embodiments, the first protrusion 104c has a second width W2 between about 120% and 200% of the first width W1. In some embodiments, the second protrusion 104d has a third width W3 between about 120% and 200% of the first width W1. In some embodiments, the first portion of the plate 104a extending between the first protrusion 104c and the rib 104b has a fourth width W4 between about 100% and 200% of the first width W1. In some embodiments, the second portion of the plate 104a extending between the second protrusion 104d and the rib 104b has a fifth width W5 between about 100% and 200% of the first width W1. In some embodiments, the distance D1 between the semiconductor region 110 and the second heavily doped region 118 is approximately between 35% and 99% of the fifth width W5. In some embodiments, the semiconductor region 110 has a sixth width W6 approximately between 100% and 350% of the first width W1.

[0051] In some embodiments, the first heavily doped region 116 has a seventh width W7 between about 150% and 230% of the first width W1. In some embodiments, the first heavily doped region 116 extends through the sidewall of the first protrusion 104c. In some embodiments, the second heavily doped region 118 has an eighth width W8 between about 150% and 230% of the first width W1. In some embodiments, the second heavily doped region 118 extends through the sidewall of the second protrusion 104d. In some embodiments, the first doped type region 112 outside the first heavily doped region 116 has a ninth width W9, which is about 50% to 100% of the combination of the first width W1, the second width W2, and the fourth width W4. In some embodiments, the second doped type region 114 outside the second heavily doped region 118 has a tenth width W10, which is about 50% to 100% of the combination of the first width W1, the second width W2, and the fourth width W4. The first doping type region 112 and the first heavily doped region 116 overlap by about 100 nanometers, 120 nanometers, 150 nanometers, etc. The second doping type region 114 and the second heavily doped region 118 overlap by about 100 nanometers, 120 nanometers, 150 nanometers, etc.

[0052] In some embodiments, the distance from the upper surface of the rib 104b to the bottom surface of the plate 104a has a first height of approximately between 50 nanometers and 1000 nanometers, approximately between 40 nanometers and 800 nanometers, approximately between 60 nanometers and 1200 nanometers, or in another suitable range. In some embodiments, the rib 104b has a second height H2 of approximately between 10% and 90% of the first height H1. In some embodiments, the semiconductor region has a third height H3 of approximately between 1% and 50% of the second height H2. In some embodiments, the plate 104a has a fourth height H4 of approximately between 10% and 90% of the first height H1. In some embodiments, the insulating layer 106 has a fifth height of approximately between 2000 nanometers and 5000 nanometers, approximately between 1800 and 4500 nanometers, approximately between 2200 nanometers and 5500 nanometers, or in another suitable range.

[0053] Figure 5 A top view 500 of an array of light detectors is shown.

[0054] Figure 5A plurality of optical couplers 202a, 202b, 202c, 202d (202a-202d) coupled to an array of light detectors 101a, 101b, 101c, 101d (101a-101d) are shown. The light detectors 101a-101d are coupled to a plurality of first pads 124a, 124b, 124c, 124d (124a-124d), a plurality of second pads 126a, 126b, 126c, 126d (126a-126d), and a plurality of third pads 128a, 128b, 128c, 128d (128a-128d). The array of light detectors 101a-101d receives photon signals and converts the photon signals into electrical signals. The electrical signals are transmitted to the electronic circuit through the plurality of first pads 124a-124d, the plurality of second pads 126a-126d and the plurality of third pads 128a-128d. The light detectors 101a-101d can be, for example, the light detector 101 described in any one or combination of the above embodiments.

[0055] Fig. 6A and Figure 6B A top view 600a, 600b of an array of light detectors integrated into a photonic circuit is shown.

[0056] Fig. 6A A plurality of optical couplers 202a-202d are shown coupled to an array of light detectors 101a-101d surrounding a central region 601. Light detectors 101a-101d include individual first protrusions 104 / 104c, second protrusions 104 / 104d, and semiconductor regions 110a, 110b, 110c, 110d (110a-110d). Light detectors 101a-101d may be, for example, light detectors 101 described in any one or combination of the foregoing embodiments, respectively.

[0057] In some embodiments, rib waveguide 104 extending through the array of photodetectors 101a-101d terminates at central region 601. Photon signals passing through the array of photodetectors 101a-101d, for example, can be absorbed in central region 601. In some embodiments, central region 601 has a semiconductor cap (not shown) configured to absorb remaining photon signals in central region 601.

[0058] Central region 601 may have a polygonal shape (e.g., a diamond, a pentagon, etc.). Photodetectors 101a-101d are evenly spaced around central region 601. In some embodiments, photodetectors 101a-101d are coupled to vertices of the polygonal shape. By coupling an array of photodetectors 101a-101d to central region 601, the area typically used to absorb photon signals output from individual photodetectors in the column array is reduced, increasing the spatial efficiency of the design. Furthermore, embodiments that include one or more additional photodetectors coupled to central region 601 will not (or will minimally) increase the area occupied by the array, thereby increasing the flexibility of the number of photodetectors used and the scalability of the design.

[0059] like Figure 6B As shown, in some embodiments, the individual first bumps 104 / 104 c and the individual second bumps 104 / 104 d are respectively connected to a single first pad 124 and a single second pad 126 . In further embodiments, the individual semiconductor regions 110 a - 110 d are coupled to a single third pad 128 .

[0060] For example, amplitude modulation or frequency modulation may be used to encode information from each photodetector 101a-101d into one or more digital signals. In some embodiments, a clock signal is used to add delay to each output signal from each photodetector 101a-101d so that each photodetector has a different amount of delay. In some embodiments, modulators 602a, 602b, 602c, 602d (602a-602d) change the amplitude and / or frequency of photon signal 130 to be different from each other. The magnitude of photon signal 130 is proportional to the output current of photodetectors 101a-101d because the number of carriers generated is proportional to the number of photons entering the depletion region. Because individual first bumps 104c are coupled to first pads 124 and because individual second bumps 104d are coupled to second pads 126, the electrical signals from the array of photodetectors 101a-101d can be added and / or combined into an output signal.

[0061] In some embodiments, the modulators 602a-602d can be coupled to a fourth pad 604. The electrical signal from the fourth pad 604 can be used to control the modulators 602a-602d. In some embodiments, an attenuator 606 can be coupled to the rib waveguide 104 to further control the magnitude of the photon signal 130. The attenuator 606 can be controlled by a signal received from a fifth pad 608. In some embodiments, the plurality of pads 124, 126, 128, 604, 608 can be coupled to Figure 6B Different than shown.

[0062] Because the individual photodetectors 101a-101d share the same set of pads, space efficiency is improved. Less area is wasted on the pads. In addition, the spacing between photodetectors can be reduced. Thus, each given region can have more than it would otherwise (e.g., with a similar Figure 5 layout) more light detectors.

[0063] refer to Figure 7-Figure 20 A series of cross-sectional views of some embodiments of methods for forming a light detector integrated with a rib waveguide are shown. Figures 7 to 20 It is described with a series of actions, but it should be understood that these actions are not restrictive, because the order of actions can be changed in other embodiments, and the disclosed method is also applicable to other structures. In other embodiments, some of the illustrated and / or described actions can be omitted in whole or in part.

[0064] like Figure 7 As shown in the cross-sectional view 700 of FIG. 1 , an SOI substrate is provided or otherwise formed. The SOI substrate includes a handle substrate 102, an insulating layer 106 covering the handle substrate 102, and a semiconductor layer 702 covering the insulating layer 106. The semiconductor layer 702 is undoped or lightly doped in other ways. The light doping may be, for example, less than about 5e16 atoms / cm 3 or some other suitable value of doping concentration.

[0065] like Figure 8 As shown in the cross-sectional view 800 of FIG. 8 , a first mask layer 802 (eg, photoresist) is deposited over the semiconductor layer 702 and patterned. The patterning may be performed, for example, by photolithography or some other suitable patterning process.

[0066] like Fig. 9 As shown in the cross-sectional view 900 of FIG. 8 , an etching process 902 is performed to etch a first opening 904 in the semiconductor layer 702 according to the first mask layer 802. The etching process may be, for example, plasma dry etching or some other suitable patterning process. The etching process removes the semiconductor layer 702 surrounding the rib waveguide 104 to be formed (see FIG. 1 ). Figure 1A The first mask layer 802 is then removed.

[0067] like Fig.10 As shown in the cross-sectional view 1000 of , the first opening 904 surrounding the semiconductor layer 702 is filled with the first dielectric layer 108a. In some embodiments, the first dielectric layer 108a is formed by depositing a dielectric material over the semiconductor layer 702 and then performing a planarization process (e.g., a chemical mechanical planarization (CMP) process) to remove a portion of the dielectric material over the semiconductor layer 702.

[0068] like Fig.11As shown in the cross-sectional view 1100 of FIG. 1 , a second mask layer 1102 (eg, photoresist) is deposited on the semiconductor layer 702 and patterned. The patterning may be performed, for example, by photolithography or some other suitable patterning process.

[0069] like Fig.12 As shown in the cross-sectional view 1200, an etching process 1202 is performed, and the second mask layer 1102 is formed on the semiconductor layer 702 (see Fig.11 ) to etch the second opening 1204. The etching process may be, for example, plasma dry etching or some other suitable patterning process. The etching process exposes the inner sidewall of the rib waveguide 104. The second mask layer 1102 is then removed.

[0070] like Fig.13 As shown in the cross-sectional view 1300 of FIG. 1 , the rib waveguide 104 is doped to form a first doping type region 112, a second doping type region 114, a first heavily doped region 116, and a second heavily doped region 118. In some embodiments, the semiconductor region 110 (see Figure 3A , 3B , 3D, 3F, 3G, 3H, 3I and 3J) are also formed by doping the rib waveguide 104. The doping of the rib waveguide 104 can be performed by selective ion implantation using a mask at appropriate locations or by some other suitable doping process. The mask can be, for example, a photoresist mask or a hard mask.

[0071] like Fig.14 As shown in the cross-sectional view 1400 of FIG. 14 , the second dielectric layer 108 b is formed on the rib waveguide 104. In some embodiments, the second dielectric layer 108 b is or includes a dielectric material such as silicon oxide (SiO 2 ), etc. In some embodiments, the second dielectric layer is formed using chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), some other suitable deposition process, or a combination of the foregoing.

[0072] like Fig.15 As shown in the cross-sectional view 1500 of FIG. 1 , a third mask layer 1502 (eg, photoresist) is deposited on the second dielectric layer 108 b and patterned. The patterning may be performed, for example, by photolithography or some other suitable patterning process.

[0073] like Fig.16 As shown in the cross-sectional view 1600 of FIG. 1 , an etching process 1602 is performed to etch a third opening 1604 in the second dielectric layer 108 b according to the third mask layer 1502. The etching process may be, for example, plasma dry etching or some other suitable patterning process. The etching process exposes the upper surface of the rib 104 b of the rib-shaped waveguide 104. The second mask layer 1102 is then removed.

[0074] like Fig.17As shown in the cross-sectional view 1700 of FIG. 1700 , in some embodiments, a second semiconductor layer 1702 is deposited over the rib waveguide 104 and the second dielectric layer 108 b. The second semiconductor layer 1702 is or includes a second semiconductor material, such as germanium (Ge), or a III-V semiconductor material, such as gallium arsenide (GaAs), indium arsenide (InAs), gallium nitride (GaN), indium phosphide (InP), etc. The second semiconductor layer 1702 fills the third opening 1604.

[0075] like Fig.18 As shown in the cross-sectional view 1800, the second semiconductor layer 1702 (see FIG. 1 ) above the second dielectric layer 108b is removed. Fig.17 ) portions, leaving the semiconductor region 110 on the rib waveguide 104. In some embodiments, these portions are removed using a planarization process (eg, a CMP process). The semiconductor region 110 is located directly above the rib 104b and the PN junction 113.

[0076] like Fig.19 As shown in the cross-sectional view 1900 of FIG. 1 , a third dielectric layer 108c is formed over the second dielectric layer 108b and the semiconductor region 110. Subsequently, a contact 120 is formed. The contact 120 extends through the third dielectric layer 108c and the second dielectric layer 108b and is coupled to the semiconductor region 110, the first protrusion 104c and the second protrusion 104d. Figure 3B , 3D , 3F, 3G, 3H, 3I and 3J) instead of deposition (see Figure 3A , 3C 3E), the contact 120 is coupled to the semiconductor region 110 implanted in the rib waveguide 104 or is not coupled to the rib waveguide 104 beyond the first protrusion 104c and the second protrusion 104d.

[0077] like Fig. 20 As shown in the cross-sectional view 2000 of FIG. 1 , the bonding layer 122 formed above the contact 120 is the fourth dielectric layer 108d. The bonding layer 122 is coupled to the contact 120 and transmits the electrical signal from the light detector 101 to the first pad 124 and the second pad 126 (see FIG. 1 ). Figure 1B ).

[0078] refer to Fig.21 , Fig.21 Shows Figure 7-Figure 20 Block diagram 2100 of some embodiments of the method.

[0079] At step 2102, the semiconductor layer is patterned to form a first waveguide on the substrate. Fig.11 and Fig.12 .

[0080] At step 2104, the first waveguide is doped to form a first PN junction. Fig.13 .

[0081] At step 2106, a first semiconductor region is formed on the first PN junction using one or both of an implantation process and a deposition process, wherein the semiconductor layer includes a first semiconductor material and the first semiconductor region includes a second semiconductor material different from the first semiconductor material. Figure 16-Figure 18 .

[0082] and Fig.21 The block diagram 2100 is illustrated and described herein as a series of actions or events, and it should be understood that the illustrated order of such actions or events should not be interpreted as limiting. For example, some actions may occur in a different order and / or occur simultaneously with other actions or events other than those shown and / or described herein. In addition, all illustrated actions may not be required to implement one or more aspects or embodiments described herein, and one or more actions described herein may be performed in one or more separate actions and / or stages.

[0083] According to an embodiment of the present disclosure, an optical module includes: a waveguide including a rib and also including a first protrusion and a second protrusion respectively located on opposite sides of the rib; a photodetector including a PN junction located in the rib; and a semiconductor region located on the PN junction, wherein the waveguide includes a first semiconductor material, and the semiconductor region includes a second semiconductor material different from the first semiconductor material.

[0084] In some embodiments, the second semiconductor material has a higher absorption coefficient than the first semiconductor material within a certain wavelength range. In some embodiments, the position of the semiconductor region substantially coincides with the position in the waveguide, and the position is located at the center of the width direction of the waveguide and the center of the height direction of the waveguide. In some embodiments, the semiconductor region is directly above the waveguide and directly contacts the upper surface of the waveguide. In some embodiments, the semiconductor region is injected into the waveguide and includes both the first semiconductor material and the second semiconductor material. In some embodiments, the waveguide includes a flat plate extending below the first protrusion and the second protrusion, and the rib extends directly from the flat plate between the first protrusion and the second protrusion. In some embodiments, the semiconductor region is in the rib of the waveguide and is separated from the flat plate. In some embodiments, the semiconductor region is located in the rib, and the semiconductor region has an inverted T-shaped profile and extends into the flat plate of the waveguide. In some embodiments, a P-type region and an N-type region forming the PN junction are also included, wherein the P-type region and the N-type region have different shapes from the cross-section of the waveguide. In some embodiments, the waveguide includes a first plate extending to the semiconductor region below the first protrusion, and a second plate extending to the semiconductor region below the second protrusion, and wherein an upper surface of the second plate is located below a lower surface of the first plate.

[0085] According to an embodiment of the present disclosure, an optical module includes: a waveguide arranged around a central region and terminated at the central region; a photodetector integrated into the waveguide around the central region; a first pad coupled to an N-type region of the photodetector; and a second pad coupled to a P-type region of the photodetector.

[0086] In some embodiments, the invention further comprises: an amplitude modulator integrated into the waveguide. In some embodiments, the invention further comprises: an attenuator integrated into the waveguide. In some embodiments, the invention further comprises:

[0087] a semiconductor region in the photodetector, wherein the waveguide comprises a first semiconductor material and the semiconductor region comprises a second semiconductor material different from the first semiconductor material; and a third pad coupled to the semiconductor region.

[0088] According to an embodiment of the present disclosure, a method for forming an optical module includes: patterning a semiconductor layer to form a first waveguide on a substrate; doping the first waveguide to form a first PN junction; and forming a first semiconductor region on the first PN junction using one of an injection process or a deposition process, wherein the semiconductor layer includes a first semiconductor material and the first semiconductor region includes a second semiconductor material different from the first semiconductor material.

[0089] In some embodiments, the first semiconductor material comprises silicon, and the second semiconductor material comprises one of germanium or a III-V semiconductor material. In some embodiments, the semiconductor layer is patterned, and further comprises forming a second waveguide and a central polygonal region of the semiconductor layer adjacent to the first waveguide and the second waveguide. In some embodiments, the method further comprises: doping the semiconductor layer to form a second PN junction in the second waveguide; forming a second semiconductor region on the second PN junction using the same method as forming the first semiconductor region; forming a first pad, the first pad being coupled to a first P-type region of the first waveguide and a second P-type region of the second waveguide; and forming a second pad, the second pad being coupled to a first N-type region of the first waveguide and a second N-type region of the second waveguide. In some embodiments, the method further comprises: depositing a dielectric layer to cover the semiconductor layer; and forming contacts through the dielectric layer and extending to the P-type region of the first waveguide, the N-type region of the first waveguide, and the first semiconductor region on the first PN junction, respectively. In some embodiments, the method further comprises: forming a first pad coupled to the P-type region; forming a second pad coupled to the N-type region; and forming a third pad coupled to the first semiconductor region.

[0090] The foregoing summarizes the features of several embodiments so that those of ordinary skill in the art can better understand the aspects of the present invention. Those of ordinary skill in the art should understand that they can easily use the present invention as a basis for designing or modifying other processes and structures for achieving the same purpose and / or achieving the same advantages of the embodiments introduced herein. Those of ordinary skill in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of the present invention, and those of ordinary skill in the art can make various changes, substitutions and modifications herein without departing from the spirit and scope of the present invention.

Claims

1. An optical module, characterized in that: include: a waveguide comprising a rib and further comprising a first protrusion and a second protrusion respectively located on opposite sides of the rib; a light detector including a PN junction located in the rib; as well as A semiconductor region is located on the PN junction, wherein the waveguide includes a first semiconductor portion, and the semiconductor region includes a second semiconductor portion different from the first semiconductor portion.

2. The optical module according to claim 1, characterized in that: The position of the semiconductor region substantially coincides with a position in the waveguide, the position being located at a center in a width direction of the waveguide and a center in a height direction of the waveguide.

3. The optical module according to claim 1, characterized in that: The semiconductor region is located directly above the waveguide and directly contacts an upper surface of the waveguide.

4. The optical module according to claim 1, characterized in that: The semiconductor region is implanted within the waveguide and includes both the first semiconductor portion and the second semiconductor portion.

5. The optical module according to claim 1, characterized in that: The waveguide includes a plate extending below the first protrusion and the second protrusion, and wherein the rib extends directly from the plate between the first protrusion and the second protrusion.

6. The optical module according to claim 5, characterized in that: The semiconductor region is in the rib of the waveguide and is spaced apart from the slab.

7. The optical module according to claim 1, characterized in that: Also included is a P-type region and an N-type region forming the PN junction, wherein the P-type region and the N-type region have different shapes when viewed from the cross section of the waveguide.

8. The optical module according to claim 1, characterized in that: The waveguide includes a first plate extending to the semiconductor region below the first protrusion, and a second plate extending to the semiconductor region below the second protrusion, wherein an upper surface of the second plate is located below a lower surface of the first plate.

9. An optical module, characterized in that: include: a waveguide arranged around the central region and terminating in the central region; a light detector integrated into the waveguide surrounding the central region; A first pad coupled to the N-type region of the light detector; as well as The second pad is coupled to the P-type region of the photodetector.

10. The optical module according to claim 9, characterized in that: Also includes: a semiconductor region in the light detector, wherein the waveguide includes a first semiconductor portion and the semiconductor region includes a second semiconductor portion different from the first semiconductor portion; as well as The third pad is coupled to the semiconductor region.

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