Broadband photoelectric detector chip with matching function

Abstract

The invention discloses a broadband photoelectric detector chip with a matching function, and belongs to the technical field of broadband semiconductor photoelectric detector chips. A node; the first radio frequency output port is electrically connected with the node; a second radio frequency output port; the cathode of the photodiode is electrically connected with the power supply port, and the anode of the photodiode is electrically connected with the node; the first end of the matched resistor is electrically connected with the node; the first end of the first inductor is electrically connected with the second end of the matching resistor, and the second end of the first inductor is electrically connected with the second radio frequency output port; the broadband photoelectric detector chip with the matching function adopts Layout layout, the matching resistor and the first inductor are symmetrically processed, the matching resistor is evolved into two resistors which are connected in parallel, and the first inductor is evolved into two inductors which are connected in parallel. According to the invention, the bandwidth is expanded, the in-band gain fluctuation and return loss are optimized, the chip-level matching integration level is high, the area is smaller, the consistency is good, and a peripheral matching network is simplified.

Description

Technical Field

[0001] This invention relates to broadband semiconductor photodetector chips, and more specifically to a broadband photodetector chip with built-in matching. Background Technology

[0002] Currently, conventional photodiode (PD) chips only involve active absorption regions, carrier collection regions, and ohmic contacts, and do not include the chip's passive matching network. The matching network is located on the carrier or printed circuit board (PCB). Even chips using back-injection photon flip-chip bonding struggle to overcome the effects introduced by solder, parasitic inductance, and parasitic capacitance. The following are shortcomings of existing technologies: 1) A Chinese invention patent application entitled Matching Circuit, Photodetector and Matching Circuit Determination Method (Application No.: 202410035789.8, Publication No.: CN118089933A) provides a circuit matching method that does not include a matching resistor and the external matching is not inside the chip.

[0003] 2) A Chinese invention patent application (application number: 202311374937.0, publication number: CN117174784A) entitled "A Method for Fabricating an On-Chip Integrated Bias Circuit Photodetector" provides a bias and resistor matching network, but does not provide information on the introduction of broadband inductors, transmission lines, capacitors, and other components. The bandwidth is clearly insufficient.

[0004] 3) A Chinese invention patent application entitled "A T-type Matched Resonance Enhanced Photodetector Receiver Network" (application number: 202211108028.8, publication number: CN115694660A) discloses a narrowband matching network that only improves the gain for matching at specific frequency points, and it is board-level matching rather than chip-internal matching. Summary of the Invention

[0005] The purpose of this invention is to provide a broadband photodetector chip with built-in matching.

[0006] A broadband photodetector chip with built-in matching, comprising: Power supply port; node; The first radio frequency output port is electrically connected to the node; Second RF output port; A photodiode, with its negative terminal electrically connected to the power supply port and its positive terminal electrically connected to the node; A matching resistor, the first end of which is electrically connected to the node; a first inductor having a first end electrically connected to the second end of the matching resistor and a second end electrically connected to the second radio frequency output port; The matching resistor and the first inductor form an internal matching network of the self-matching wideband photodetector chip.

[0007] The internal matching network further comprises: a series inductor connected in series between the anode of the photodiode and the node. The series inductor is symmetrically processed, and the series inductor is evolved into another two inductors in parallel.

[0008] The internal matching network further comprises: a transmission line connected in series between the node and the first radio frequency output port. a capacitor having a first end electrically connected to the first radio frequency output port and a second end electrically connected to the second radio frequency output port.

[0009] The transmission line is a microstrip line.

[0010] A self-matching wideband photodetector chip comprises: a power supply port; a first radio frequency output port; a second radio frequency output port; a photodiode having a cathode electrically connected to the power supply port; a series inductor having a first end electrically connected to the anode of the photodiode and a second end electrically connected to the first radio frequency output port. a matching resistor having a first end electrically connected to the first radio frequency output port and a second end electrically connected to the second radio frequency output port. The matching resistor and the series inductor form an internal matching network of the self-matching wideband photodetector chip.

[0011] The present application has the following beneficial technical effects: Compared with conventional matching, the bandwidth and return loss are greatly improved. The gain fluctuation of 50GHz is improved from 2.5dB to 0.5dB.

[0012] Compared with the matching of the peripheral carrier plate, the self-matching chip of the application greatly reduces the chip area and reduces the patching and alignment process at the package level. The matching size of the peripheral carrier plate is 1500X1000um, and the size of the chip of the application is 400X350um.

[0013] The application creatively moves the peripheral matching network of the detector chip from the carrier plate to the inside of the chip, realizes a single-chip complete function detector chip, simplifies the peripheral circuit, expands the bandwidth, has high integration, good consistency, and is more simple and convenient to use.

[0014] 1) The detector chip not only realizes photoelectric conversion, but also realizes radio frequency impedance matching inside the chip.

[0015] 2) It is a broadband matching, and the theory is to start from DC, and the matching realizes a bandwidth greater than the 3dB bandwidth of the detector chip itself.

[0016] 3) The peripheral circuit is simplified, and only gold wire bonding and eutectic are needed.

[0017] The application directly integrates the matching network inside the chip, not only effectively expands the working bandwidth, but also significantly optimizes the in-band gain fluctuation and return loss indicators. At the same time, the chip-level matching scheme has the advantages of high integration and small area, can greatly simplify the design and deployment of the peripheral matching circuit, and improve the use convenience. Compared with the traditional package-level matching method, the chip-level integrated scheme can significantly improve the performance consistency of the device. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the matching 2 of the application; Figure 2 is a structural schematic diagram of the matching 4 of the application; Figure 3 is a structural schematic diagram of the matching 5 of the application; Figure 4 is a structural schematic diagram of the matching 3 of the application; Figure 5 is a structural schematic diagram of the conventional matching network, i.e. matching 1, involved in the application; Figure 6 is a Layout layout structural schematic diagram of the matching 4 of the application; Figure 7 is a Layout layout structural schematic diagram of the matching 2 of the application; Figure 8 is a Layout layout structural schematic diagram of the matching 5 of the application; Figure 9 is a Layout layout structural schematic diagram of the matching 3 of the application; Figure 10The Layout layout structure schematic diagram matched with the present application 1; Figure 11 The comparison diagram of the gain curve and the output return loss curve of the conventional matching (matching 1) and the gain curve and the output return loss curve of the matching 3 of the present application; Figure 12 The size comparison diagram of the carrier board level matching and the chip level matching; Figure 13 The gain curve diagram of the examples 1-4 and the comparative examples; Figure 14 The output return loss curve diagram of the examples 1-4 and the comparative examples. DETAILED DESCRIPTION

[0019] Example 1, see Figure 1 The wideband photoelectric detector chip with matching of the present application comprises a power supply port P1, a node P, a first radio frequency output port P2, a second radio frequency output port P3, a photoelectric diode PD1, a matching resistor Rm, and a first inductor Lm.

[0020] The first radio frequency output port P2 is electrically connected with the node P. The negative electrode of the photoelectric diode PD1 is electrically connected with the power supply port P1, and the positive electrode of the photoelectric diode PD1 is electrically connected with the node P. The first end of the matching resistor Rm is electrically connected with the node P. The first end of the first inductor Lm is electrically connected with the second end of the matching resistor Rm, and the second end of the first inductor Lm is electrically connected with the second radio frequency output port P3.

[0021] See Figure 7 The wideband photoelectric detector chip with matching of the present embodiment adopts the Layout layout, and the matching resistor Rm and the first inductor Lm are symmetrically processed. The matching resistor Rm evolves into two resistors in parallel, i.e., Rm1 and Rm2, and the first inductor Lm evolves into two inductors in parallel, i.e., Lm1 and Lm2.

[0022] In the present embodiment, the matching resistor Rm and the first inductor Lm constitute the internal matching network of the wideband photoelectric detector chip with matching, which is denoted as matching 2.

[0023] Example 2, see Figure 2 , 6 The difference between the present embodiment and example 1 is that the present embodiment further comprises a series inductor Ls. The series inductor Ls is connected in series between the positive electrode of the photoelectric diode PD1 and the node P. The series inductor Ls is symmetrically processed, and the series inductor Ls evolves into another two inductors in parallel. Except for this, the other parts of the present embodiment are the same as those of example 1.

[0024] The series inductance Ls, the matching resistance Rm and the first inductance Lm jointly constitute an internal matching network of the self-matching wideband photodetector chip in this embodiment, which is denoted as matching 4.

[0025] Referring to Figure 6 , the self-matching wideband photodetector chip in this embodiment adopts a Layout layout, and the first inductance Lm, the matching resistance Rm and the series inductance Ls are symmetrically processed, the first inductance Lm evolves into two inductances in parallel, i.e., Lm1 and Lm2, the matching resistance Rm evolves into two resistances in parallel, i.e., Rm1 and Rm2, and the series inductance Ls evolves into another two inductances in parallel, i.e., Ls1 and Ls2.

[0026] Embodiment 3, referring to Figure 3 The difference between this embodiment and Embodiment 2 is that this embodiment further includes a transmission line TL and a capacitor Cp.

[0027] The transmission line TL is connected in series between the node P and the first radio frequency output port P2. The first end of the capacitor Cp is electrically connected to the first radio frequency output port P2, and the second end of the capacitor Cp is electrically connected to the second radio frequency output port P3. In addition, this embodiment is the same as Embodiment 2.

[0028] The transmission line can be a microstrip line.

[0029] In this embodiment, the transmission line TL and the capacitor Cp jointly constitute an internal matching network of the self-matching wideband photodetector chip with the matching resistance Rm, the first inductance Lm and the series inductance Ls, which is denoted as matching 5.

[0030] Referring to Figure 8 , the self-matching wideband photodetector chip in this embodiment adopts a Layout layout, and the first inductance Lm, the matching resistance Rm and the series inductance Ls are symmetrically processed, the first inductance Lm evolves into two inductances in parallel, i.e., Lm1 and Lm2, the matching resistance Rm evolves into two resistances in parallel, i.e., Rm1 and Rm2, and the series inductance Ls evolves into another two inductances in parallel, i.e., Ls1 and Ls2.

[0031] Embodiment 4, referring to Figure 4 The self-matching wideband photodetector chip of the present application includes a power supply port P1, a first radio frequency output port P2, a second radio frequency output port P3, a photodiode PD1, a matching resistance Rm and a series inductance Ls.

[0032] The negative electrode of the photodiode PD1 is electrically connected with the power supply port P1. The first end of the series inductance Ls is electrically connected with the positive electrode of the photodiode PD1, and the second end of the series inductance Ls is electrically connected with the first radio frequency output port P2. The first end of the matching resistance Rm is electrically connected with the first radio frequency output port P2, and the second end of the matching resistance Rm is electrically connected with the second radio frequency output port P3.

[0033] Referring to Figure 9 , the self-matching wideband photodetector chip of the embodiment adopts Layout layout, and the matching resistance Rm and the series inductance Ls are symmetrically processed. The matching resistance Rm evolves into two resistances in parallel, i.e., Rm1 and Rm2, and the series inductance Ls evolves into another two inductances in parallel, i.e., Ls1 and Ls2.

[0034] In the embodiment, the matching resistance Rm and the series inductance Ls constitute the internal matching network of the self-matching wideband photodetector chip, which is denoted as matching 3.

[0035] In the foregoing embodiments, the matching resistance Rm matches the resistance of the PD chip to the required impedance, which is 50 ohms in the conventional case; however, this is not a necessary choice. It is recommended to select Rm to be slightly greater than 50 ohms to improve the gain under the condition of meeting the output return loss. The series inductance Ls mainly matches the capacitance Cj effect of the PD chip, which can significantly improve the gain at the bandwidth of the PD chip. The function of gain peaking. The first inductance Lm cooperates with the matching resistance Rm to achieve a certain high resistance under high frequency conditions, thereby improving the gain of the chip at high frequencies. Lm and Ls have some similarities in function and need to cooperate to meet the two requirements of impedance matching and gain.

[0036] Comparative Example, Figure 5 The wideband photodetector chip of the conventional matching network includes a power supply port P1, a first radio frequency output port P2, a second radio frequency output port P3, a photodiode PD1, and a matching resistance R19. The negative electrode of the photodiode PD1 is electrically connected with the power supply port P1, and the positive electrode of the photodiode PD1 is electrically connected with the first radio frequency output port P2. The first end of the matching resistance R19 is electrically connected with the first radio frequency output port P2, and the second end of the matching resistance R19 is electrically connected with the second radio frequency output port P3. The conventional matching network is denoted as matching 1.

[0037] Comparing the comparative example with Example 4, the results are specifically shown in Figure 11 From Figure 11 it can be seen that, compared with the conventional matching, there is a great improvement in bandwidth and return loss. The gain fluctuation of 50 GHz is improved from 2.5 dB to 0.5 dB.

[0038] Compared with the matching with the peripheral carrier plate, the self-matching chip area of the present application is greatly reduced, and the patching and alignment process at the package level is reduced. The matching size of the peripheral carrier plate is 1500X1000um, and the size of the chip of the present application is 400X350um. See Figure 12 .

[0039] The gain curves (such as Figure 13 ) and output return loss curves (such as Figure 14 ) of the foregoing embodiments and comparative examples are shown in the following tables.

[0040] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or make equivalent replacements for some technical features, as long as the modifications, equivalent replacements, improvements, etc. are within the spirit and principles of the present application, they should be included in the protection scope of the present application.

Claims

1. A broadband photodetector chip with built-in matching, characterized in that, include: Power supply port; node; The first radio frequency output port is electrically connected to the node; Second RF output port; A photodiode, with its negative terminal electrically connected to the power supply port and its positive terminal electrically connected to the node; A matching resistor, the first end of which is electrically connected to the node; The first inductor has its first end electrically connected to the second end of the matching resistor, and its second end electrically connected to the second RF output port. The matching resistor and the first inductor constitute the internal matching network of the broadband photodetector chip with built-in matching. The broadband photodetector chip with built-in matching adopts a layout, and the matching resistor and the first inductor are both treated symmetrically. The matching resistor is transformed into two resistors connected in parallel, and the first inductor is transformed into two inductors connected in parallel.

2. The broadband photodetector chip with built-in matching according to claim 1, characterized in that, The internal matching network also includes: A series inductor is connected in series between the positive terminal and the node of the photodiode; The series inductors are treated symmetrically, and the series inductors are transformed into two other inductors connected in parallel.

3. The broadband photodetector chip with built-in matching according to claim 2, characterized in that, The internal matching network also includes: A transmission line is connected in series between the node and the first radio frequency output port; A capacitor, the first end of which is electrically connected to the first RF output port, and the second end of which is electrically connected to the second RF output port.

4. The broadband photodetector chip with built-in matching according to claim 3, characterized in that, The transmission line is a microstrip line.

5. A broadband photodetector chip with built-in matching, characterized in that, include: Power supply port; First radio frequency output port; Second RF output port; A photodiode, the negative terminal of which is electrically connected to the power supply port; A series inductor, the first end of which is electrically connected to the positive terminal of the photodiode, and the second end of which is electrically connected to the first RF output port; A matching resistor, the first end of which is electrically connected to the first RF output port, and the second end of which is electrically connected to the second RF output port; Matching resistors and series inductors constitute the internal matching network of the broadband photodetector chip with built-in matching. The broadband photodetector chip with built-in matching adopts a layout, and the matching resistors and series inductors are symmetrically treated. The matching resistors are transformed into two resistors in parallel, and the series inductors are transformed into two other inductors in parallel.

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