Resonant photodetector and electronic device

Abstract

The invention discloses a resonance type photodetector and electronic equipment. The resonance type photodetector comprises a substrate; a light absorption part, which is arranged on the substrate; the resonant optical waveguide is used for receiving an optical signal input from the outside and coupling the optical signal to each light absorption part; the light absorption part is used for converting the light signal into an electric signal; the upper surface of the resonant optical waveguide is not higher than the upper surface of the light absorption part. By improving the distribution of the detector in the internal light field, the space charge effect can be relieved, and the bandwidth and saturation power of the detector are improved.

Description

Technical Field

[0001] The present application belongs to the field of detector technology, and in particular relates to a resonant optical detector and electronic equipment. Background Art

[0002] At present, with the rapid development of optical communications, silicon-based photonic integrated chips play an important role with their unique advantages. As a bridge connecting the optical domain and the electrical domain, the bandwidth of silicon-based photodetectors is a key indicator that limits the communication capacity of the system. In addition, with the continuous development of silicon-based photonics, the application of silicon-optical integrated systems has extended from the initial digital optical transmission to analog links, and other indicators such as the detector's responsivity, dark current, and saturation power have gradually attracted attention. However, there are many contradictions in these performance indicators in device design, and it is difficult to take them into account at the same time. Therefore, how to optimize silicon-based detectors in a targeted manner and then apply them to different application scenarios is a very important issue. At present, the method for realizing photodetection on a silicon-based integrated platform is mainly to introduce an epitaxial germanium layer compatible with the CMOS process. In order to facilitate large-scale system integration, the optimization scheme of silicon-based germanium detectors (Germanium photodetector; GePD) must take into account process compatibility, which brings difficulties to the optimization design. In coherent optical communication, GePD needs to receive strong local oscillator light to improve OSNR; in analog optical communication, GePD needs to receive optical signals amplified by EDFA and perform linear photoelectric conversion to achieve broadband RF signal amplification. Existing GePDs are limited by electric field shielding effect or space charge effect, and it is difficult to achieve both large bandwidth and high power at the same time. Summary of the invention

[0003] The purpose of the present application is to provide a resonant photodetector and an electronic device, aiming to solve the problem that traditional photodetectors are difficult to achieve both large bandwidth and high power characteristics at the same time.

[0004] A first aspect of an embodiment of the present application provides a resonant photodetector, comprising: a substrate; a light absorbing portion, wherein the light absorbing portion is arranged on the substrate; a resonant optical waveguide, wherein the resonant optical waveguide is used to receive an external optical signal and couple the optical signal to each of the light absorbing portions; the light absorbing portion is used to convert the optical signal into an electrical signal; and the upper surface of the resonant optical waveguide is not higher than the upper surface of the light absorbing portion.

[0005] In one embodiment, the resonant optical waveguide includes a first waveguide portion and a second waveguide portion; the first waveguide portion is used to receive the optical signal input from the outside and transmit the optical signal to the second waveguide portion, and the second waveguide portion is used to couple the optical signal to the light absorbing portion.

[0006] In one embodiment, the second waveguide portion includes two first waveguide regions and two second waveguide regions; the two first waveguide regions are arranged on opposite sides of the light absorbing portion, the two first waveguide regions are used to couple the optical signal to the light absorbing portion, and the two second waveguide regions are used to connect the two first waveguide regions to each other to form a ring waveguide.

[0007] In one embodiment, the resonant photodetector includes a plurality of light absorbing parts, which are arranged on the substrate at intervals along a first horizontal direction; the second waveguide part includes a plurality of first waveguide regions and a plurality of second waveguide regions, which are alternately arranged in sequence along a first horizontal direction; one second waveguide region is connected between two adjacent first waveguide regions, and only one second waveguide region is provided between two adjacent first waveguide regions; the plurality of first waveguide regions are used to couple the optical signal to each of the light absorbing parts, and the plurality of second waveguide regions are used to connect each of the first waveguide regions to each other.

[0008] In one embodiment, the light absorbing portion and the first waveguide region both extend along a second horizontal direction, and the second horizontal direction is perpendicular to the first horizontal direction.

[0009] In one embodiment, the light absorbing portion is made of germanium, and the resonant optical waveguide is made of silicon nitride.

[0010] In one embodiment, the thickness of the light absorbing portion is 600 nm to 700 nm, the distance between the resonant optical waveguide and the substrate is less than 400 nm, and the distance between the first waveguide region and the light absorbing portion is less than 400 nm.

[0011] In one embodiment, the resonant photodetector further includes a voltage bias structure, and the voltage bias structure is used to apply a bias voltage; wherein the voltage bias structure includes a first electrode and a second electrode, the first electrode is arranged on the light absorption part, and the second electrode is arranged on the substrate.

[0012] In one embodiment, the resonant photodetector further includes a thermal adjustment electrode, and the thermal adjustment electrode is used to adjust the device temperature of the resonant photodetector.

[0013] A second aspect of the embodiments of the present application provides an electronic device, comprising the resonant photodetector as described above.

[0014] Compared with the prior art, the embodiments of the present application have the following beneficial effects: by making the upper surface of the resonant optical waveguide not higher than the upper surface of the light absorbing part, the distribution of the light field inside the resonant optical detector is improved, the space charge effect can be alleviated, and the bandwidth and saturation power of the resonant optical detector can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic side view of a resonant photodetector provided in one embodiment of the present application;

[0016] Figure 2 A schematic top view of a resonant light detector provided in one embodiment of the present application;

[0017] Figure 3 Another side view schematic diagram of a resonant light detector provided by an embodiment of the present application;

[0018] Figure 4 Another schematic top view of a resonant photodetector provided by an embodiment of the present application;

[0019] Figure 5 It is another side view schematic diagram of a resonant photodetector provided by an embodiment of the present application;

[0020] Figure 6 A simulation schematic diagram of a resonant light detector provided in one embodiment of the present application;

[0021] Figure 7 Another simulation schematic diagram of a resonant light detector provided by an embodiment of the present application;

[0022] Figure 8 A schematic diagram of an electronic device provided in accordance with an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0026] Figure 1A side view schematic diagram of a resonant photodetector provided in an embodiment of the present application is shown. For ease of description, only the part related to the present embodiment is shown, which is described in detail as follows:

[0027] The resonance type photodetector includes a substrate 100 , a light absorbing portion 200 , and a resonance optical waveguide 300 .

[0028] The light absorbing part 200 is disposed on the substrate 100. The resonant optical waveguide 300 is used to receive an external optical signal and couple the optical signal to each light absorbing part 200. The light absorbing part 200 is used to convert the optical signal into an electrical signal. The upper surface of the resonant optical waveguide 300 is not higher than the upper surface of the light absorbing part 200.

[0029] By making the upper surface of the resonant optical waveguide 300 not higher than the upper surface of the light absorbing part 200 , the distribution of the light field inside the resonant optical detector is improved, the space charge effect can be alleviated, and the bandwidth and saturation power of the resonant optical detector can be increased.

[0030] In one embodiment, the substrate 100 may be a single semiconductor substrate or a compound semiconductor substrate. For example, in some embodiments, the substrate 100 is a silicon (Si) substrate.

[0031] In some embodiments, the light absorbing portion 200 may be prepared by a low pressure chemical vapor deposition (LPCVD) process, and the upper surface of the light absorbing portion 200 is higher than the upper surface of the resonant optical waveguide 300. The thickness of the light absorbing portion 200 prepared by the LPCVD process may reach 600 nm, so that the resonant optical detector can have both high speed and high power characteristics.

[0032] It should be noted that the LPCVD process and the front-end of line (FEOL) process are compatible and can cooperate with each other, that is, the light absorbing part 200 is prepared by the LPCVD process, and the substrate 100, the resonant optical waveguide 300 and other structures are constructed by the front-end process, so as to further reduce the loss of the resonant optical waveguide 300. In some embodiments, the LPCVD process can make the loss of the resonant optical waveguide 300 less than 1.2 dB / cm, and the optical refractive index is fixed at 2.

[0033] In one embodiment, if Figure 1 , Figure 2 As shown, the resonant optical waveguide 300 includes a first waveguide portion 310 and a second waveguide portion 320. The first waveguide portion 310 is used to receive an external optical signal and transmit the optical signal to the second waveguide portion 320, and the second waveguide portion 320 is used to couple the optical signal to the light absorbing portion 200.

[0034] By dividing the resonant optical waveguide 300 into the first waveguide portion 310 and the second waveguide portion 320 , the shape, position and size of the second waveguide portion 320 can be configured more flexibly according to actual needs.

[0035] In one embodiment, if Figure 2 As shown, the resonant photodetector further includes a thermal adjustment electrode 500, which is used to adjust the device temperature of the resonant photodetector. The thermal adjustment electrode can be made of doped silicon or titanium nitride (TiN) metal.

[0036] It should be noted that the temperature of the resonant photodetector can be adjusted by applying a thermal adjustment voltage to the thermal adjustment electrode 500, thereby realizing the absorption wavelength selection of the resonant photodetector. The thermal adjustment electrode 500 can be packaged in the same resonant photodetector with the absorption part 200 and the resonant optical waveguide 300, and the position and size of the thermal adjustment electrode 500 can be set according to the actual situation of the light absorption part 200 and the resonant optical waveguide 300.

[0037] In one embodiment, if Figure 1 , Figure 2 As shown, the second waveguide portion 320 includes two first waveguide regions 321 and two second waveguide regions 322. The two first waveguide regions 321 are disposed on opposite sides of the light absorbing portion 200, the two first waveguide regions 321 are used to couple the optical signal to the light absorbing portion 200, and the two second waveguide regions 322 are used to connect the two first waveguide regions 321 to each other to form a ring waveguide.

[0038] It should be noted that the use of a ring waveguide composed of two first waveguide regions 321 and two second waveguide regions 322 as a light input method can introduce the light field mode evolution process to improve the light field distribution inside the light absorption part 200, thereby reducing the space charge effect and improving the performance of the detector. The light absorption part 200 and the resonant optical waveguide 300 form a micro-ring resonant structure, which can make the resonant optical detector have tunable wavelength sensitivity and achieve efficient wavelength division multiplexing.

[0039] The optical signal transmitted into the second waveguide portion 320 may be circulated in the second waveguide portion 320 and coupled into the light absorbing portion 200 .

[0040] It should be noted that the second waveguide area 322 needs to be bent to form a ring waveguide. Therefore, the bending curvature of the second waveguide area 322 needs to conform to a specific function distribution to achieve the transmission of the optical signal. For example, the bending curvature of the second waveguide area 322 needs to conform to one of the function distributions such as a circular curve, a Bezier curve or an Euler curve. The appropriate function distribution can be selected according to actual needs.

[0041] In one embodiment, if Figure 3 , Figure 4 As shown, the resonant photodetector includes a plurality of light absorbing parts 200, and the plurality of light absorbing parts 200 are arranged on the substrate 100 at intervals along the first horizontal direction. The second waveguide part 320 includes a plurality of first waveguide regions 321 and a plurality of second waveguide regions 322, and the plurality of first waveguide regions 321 and the plurality of light absorbing parts 200 are arranged alternately and spaced in sequence along the first horizontal direction. One second waveguide region 322 is connected between two adjacent first waveguide regions 321, and only one second waveguide region 322 is provided between two adjacent first waveguide regions 321. The plurality of first waveguide regions 321 are used to couple optical signals to each light absorbing part 200, and the plurality of second waveguide regions 322 are used to connect each first waveguide region 321 to each other.

[0042] By providing a plurality of light absorbing parts 200 , the coupling efficiency between the light absorbing parts 200 and the resonant optical waveguide 300 can be improved, thereby improving the working efficiency of the resonant optical detector.

[0043] Exemplarily, in some embodiments, the resonant photodetector includes two light absorbing parts 200, and the second waveguide part 320 includes three first waveguide regions 321 and two second waveguide regions 322. The two light absorbing parts 200 and the three first waveguide regions 321 are sequentially arranged in the order of the first waveguide region 321, the light absorbing part 200, the first waveguide region 321, the light absorbing part 200, and the first waveguide region 321, and the two second waveguide regions 322 are respectively connected to the two first waveguide regions 321, so that the optical signal can be sequentially transmitted between the three first waveguide regions 321.

[0044] In one embodiment, if Figure 3 , Figure 4 As shown, the light absorbing portion 200 and the first waveguide region 321 both extend along a second horizontal direction, and the second horizontal direction is perpendicular to the first horizontal direction.

[0045] It can be understood that each light absorbing portion 200 and each first waveguide region 321 are parallel to each other, so that the optical signal in the first waveguide region 321 can be coupled to the light absorbing portion 200 .

[0046] In one embodiment, the material of the light absorbing portion 200 is germanium (Ge), and the material of the resonant optical waveguide 300 is silicon nitride (SiN).

[0047] Silicon nitride does not exhibit two-photon absorption effects, and supports low-loss optical transmission with high optical power density and large optical bandwidth.

[0048] In one embodiment, the thickness of the light absorbing portion 200 is 600nm-700nm, the spacing between the resonant optical waveguide 300 and the substrate 100 is less than 400nm, and the spacing between the first waveguide region 321 and the light absorbing portion 200 is less than 400nm, preferably 50nm-250nm.

[0049] In some embodiments, the thickness of the light absorbing portion 200 is 650 nm, the spacing between the resonant optical waveguide 300 and the substrate 100 is 100 nm, and the spacing between the first waveguide region 321 and the light absorbing portion 200 is 200 nm.

[0050] By controlling the relative spacing, size, etc. between the light absorbing part 200 and the resonant optical waveguide 300 , the light absorbing part 200 can absorb the optical signal more fully and uniformly.

[0051] In one embodiment, if Figure 5 As shown, the resonant photodetector further includes a voltage bias structure, and the voltage bias structure is used to apply a bias voltage.

[0052] In some embodiments, the voltage bias structure includes a first electrode 410 and a second electrode 420 , the first electrode 410 is disposed on the light absorbing part 200 , and the second electrode 420 is disposed on the substrate 100 .

[0053] It is understood that by applying a bias voltage through the voltage bias structure, the electrical signal generated by the light absorbing part 200 can be obtained. The number of the first electrodes 410 is equal to the number of the light absorbing parts 200.

[0054] In one embodiment, the portion of the light absorbing part 200 in contact with the first electrode 410 is doped with N-type ions, the substrate 100 is a Si material doped with P-type ions, the portion of the substrate 100 in contact with the second electrode 420 is doped with high-concentration P-type ions, and the rest of the substrate 100 may be doped with low-concentration P-type ions. It can be understood that the voltage bias structure in this embodiment adopts a horizontal PIN junction scheme.

[0055] In some embodiments, the voltage bias structure may adopt a vertical PIN junction scheme or a horizontal PIN junction scheme, and the difference between the vertical PIN junction scheme and the horizontal PIN junction scheme is that the direction of the electric field formed by the voltage bias structure of the vertical PIN junction scheme is perpendicular to the substrate 100, and the direction of the electric field formed by the voltage bias structure of the horizontal PIN junction scheme is parallel to the substrate 100. The direction of the electric field in the voltage bias structure can be set according to actual needs by configuring the doping regions of N-type ions and P-type ions and the positions of the first electrode 410 and the second electrode 420.

[0056] Figure 6 Schematic diagram of light field distribution without the resonant optical waveguide 300, Figure 7FIG. 1 is a schematic diagram of light field distribution with a single strip-shaped resonant optical waveguide 300 .

[0057] Figure 6 The light absorbing part 200 in the one-way light signal (light signal from Figure 6 The left side of the light absorbing part 200 is directed toward Figure 6 Under the illumination of the right side of the light absorbing part 200, the optical field intensity of the optical signal of each part of the light absorbing part 200 is high and uneven, resulting in the limitation of the bandwidth and saturation power of the resonant photodetector. Figure 7 The resonant optical waveguide 300 can make the light absorbing part 200 absorb the optical signal more uniformly, alleviate the space charge effect, and improve the bandwidth and saturation power of the resonant optical detector.

[0058] It can be understood that by setting the height of the upper surface of the resonant optical waveguide 300, the light field intensity of the optical signal can be made more uniform in the vertical direction of the light absorbing part 200. By providing the annular resonant optical waveguide 300 and the S-shaped resonant optical waveguide 300 of the above embodiment, the light absorbing part 200 can be coupled with the optical signal multiple times under the premise that the light absorbing part 200 absorbs the optical signal more uniformly, so as to improve the responsivity of the resonant optical detector.

[0059] Figure 8 A schematic diagram of the structure of an electronic device provided by an embodiment of the present application is shown. For the sake of convenience, only the parts related to the present embodiment are shown, which are described in detail as follows:

[0060] The electronic device 10 includes the resonant photodetector 20 according to any one of the above embodiments. For example, the electronic device 10 may be a wireless communication device or a monitoring device.

[0061] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0062] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0063] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A resonant photodetector, characterized in that: include: substrate; a light absorbing portion, the light absorbing portion being disposed on the substrate; a resonant optical waveguide configured to receive an external optical signal and couple the optical signal to each of the light absorbing portions; the light absorbing portions being configured to convert the optical signal into an electrical signal; The upper surface of the resonant optical waveguide is not higher than the upper surface of the light absorbing portion.

2. The resonant photodetector according to claim 1, wherein: The resonant optical waveguide includes a first waveguide portion and a second waveguide portion; The first waveguide portion is used to receive the optical signal input from the outside and transmit the optical signal to the second waveguide portion, and the second waveguide portion is used to couple the optical signal to the light absorbing portion.

3. The resonant photodetector according to claim 2, wherein: The second waveguide portion includes two first waveguide regions and two second waveguide regions; The two first waveguide regions are arranged on opposite sides of the light absorbing portion, and the two first waveguide regions are used to couple the optical signal to the light absorbing portion. The two second waveguide regions are used to connect the two first waveguide regions to form a ring waveguide.

4. The resonant photodetector according to claim 2, wherein: The resonant photodetector includes a plurality of light absorbing portions, and the plurality of light absorbing portions are arranged on the substrate at intervals along a first horizontal direction; The second waveguide portion includes a plurality of first waveguide regions and a plurality of second waveguide regions, wherein the plurality of first waveguide regions and the plurality of light absorbing portions are alternately arranged in sequence along a first horizontal direction; One second waveguide region is connected between two adjacent first waveguide regions, and only one second waveguide region is provided between two adjacent first waveguide regions; The plurality of first waveguide regions are used to couple the optical signal to the respective light absorbing parts, and the plurality of second waveguide regions are used to connect the respective first waveguide regions to each other.

5. The resonant photodetector according to claim 3 or 4, wherein: The light absorbing portion and the first waveguide region both extend along a second horizontal direction, and the second horizontal direction is perpendicular to the first horizontal direction.

6. The resonant photodetector according to any one of claims 1 to 4, wherein: The light absorbing portion is made of germanium, and the resonant optical waveguide is made of silicon nitride.

7. The resonant photodetector according to claim 3 or 4, wherein: The thickness of the light absorbing portion is 600 nm to 700 nm, the distance between the resonant optical waveguide and the substrate is less than 400 nm, and the distance between the first waveguide region and the light absorbing portion is less than 400 nm.

8. The resonant photodetector according to any one of claims 1 to 4, wherein: The resonant photodetector further includes a voltage bias structure, wherein the voltage bias structure is used to apply a bias voltage; The voltage bias structure includes a first electrode and a second electrode, the first electrode is arranged on the light absorption part, and the second electrode is arranged on the substrate.

9. The resonant photodetector according to any one of claims 1 to 4, wherein: The resonant photodetector further includes a thermal adjustment electrode, and the thermal adjustment electrode is used to adjust the device temperature of the resonant photodetector.

10. An electronic device, characterized in that: The method comprises the resonant photodetector according to any one of claims 1 to 9.

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