Band-pass waveguide structure photoelectric detector and manufacturing method thereof

Abstract

The invention relates to a band-pass type waveguide structure photoelectric detector and a manufacturing method thereof, in the band-pass type waveguide structure photoelectric detector, a ridge waveguide is connected with an optical active absorption region of a photoelectric semiconductor diode, an N electrode is connected with a first grounding wire bonding pad through a first coplanar waveguide, and a P electrode is connected with a signal wire bonding pad through a second coplanar waveguide; the P electrode is further connected with the direct current bias routing bonding pad and one electrode of the capacitor through a stub line, and the other electrode of the capacitor is connected with the second ground wire routing bonding pad through the third coplanar waveguide. The capacitor is connected to the photoelectric semiconductor diode in parallel, bandwidth response is restrained at low frequency, the inductance peak effect is achieved through the coplanar waveguide, and the bandwidth response in a high-frequency band-pass interval is improved through the inductance peak effect; the peak value and the band-pass range of the inductance peak effect are adjusted through the lambda / 4 length of the stub line, and the bandwidth response flatness under the W and F wave band band-pass condition can be met.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a bandpass waveguide structure photoelectric detector and a manufacturing method thereof. Background Art

[0002] With the rapid development of technologies such as AI, cloud computing, and big data, data centers have an increasing demand for high-speed, large-capacity data transmission, which has directly promoted the prosperity of large-capacity fiber-optic communication systems. As the current data transmission capacity grows exponentially, the communication frequency band is becoming increasingly saturated, and 5G millimeter wave technology is an important basic technology in 5G applications. Millimeter wave refers to a special electromagnetic wave with a wavelength of 1 mm to 10 mm and a fluctuation frequency of 30GHz-300GHz. Compared with traditional low-frequency electromagnetic waves, 5G millimeter waves have higher bandwidth and transmission speed, which can achieve faster data transmission and response speed. This makes 5G millimeter waves have broad application prospects in the fields of Internet of Things, intelligent transportation, virtual reality, augmented reality, etc., which can meet the future wireless communication needs for system capacity, transmission rate and differentiated applications.

[0003] The use of optical methods to generate millimeter-wave signals has high frequency, simple structure, and cost savings. It is a key technology for optical radio frequency communication. The key component for generating millimeter-wave signals by optical methods is a high-bandwidth, high-response millimeter-wave photonic mixer module. Millimeter-wave photonic mixer modules are generally W-band and F-band. In order to make the module have better bandwidth flatness within the band range, in addition to high requirements for packaging technology, higher requirements are also placed on high-speed photodetector chips. The bandwidth response curve of traditional high-speed photodetectors drops rapidly at high frequencies and cannot meet the bandwidth response flatness in the W and F band passband conditions. Summary of the invention

[0004] The present invention provides a bandpass waveguide structure photoelectric detector and a manufacturing method thereof to solve at least one of the above technical problems.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a bandpass waveguide structure photoelectric detector, comprising a ridge waveguide, a photoelectric semiconductor diode, a first ground wire bonding pad, a signal wire bonding pad, a DC bias wire bonding pad, a second ground wire bonding pad, a capacitor, a first coplanar waveguide, a second coplanar waveguide, a third coplanar waveguide and a short stub; the ridge waveguide is connected to the light active absorption area of ​​the photoelectric semiconductor diode, the N electrode of the photoelectric semiconductor diode is connected to the first ground wire bonding pad through the first coplanar waveguide, the P electrode of the photoelectric semiconductor diode is connected to the signal wire bonding pad through the second coplanar waveguide, the P electrode of the photoelectric semiconductor diode is also connected to the DC bias wire bonding pad and one electrode of the capacitor through the short stub, and the other electrode of the capacitor is connected to the second ground wire bonding pad through the third coplanar waveguide; the first ground wire bonding pad and the second ground wire bonding pad are grounded together; the length of the short stub is λ / 4, where λ is the wavelength of the millimeter wave.

[0006] Based on the above technical solution, the present invention can also be improved as follows.

[0007] Furthermore, the capacitance value of the capacitor ranges from 1 to 3 pF.

[0008] Furthermore, the lengths of the first coplanar waveguide, the second coplanar waveguide and the third coplanar waveguide are all in the range of 150 to 250 μm.

[0009] Furthermore, the second coplanar waveguide and the stub form an L-shaped structure.

[0010] Furthermore, the ridge waveguide and the photoelectric semiconductor diode form an evanescent waveguide coupling structure.

[0011] Furthermore, the photoelectric semiconductor diode is made by etching an epitaxial layer on a semi-insulating InP substrate; the ridge waveguide, the first ground wire bonding pad, the signal line bonding pad, the DC bias bonding pad, the second ground wire bonding pad, the capacitor, the first coplanar waveguide, the second coplanar waveguide, the third coplanar waveguide and the stub are all integrated on the InP substrate.

[0012] Furthermore, the epitaxial layer includes an InP buffer layer, a waveguide layer, an N contact layer, a drift layer, a cliff layer, an absorption layer, a barrier layer and a P contact layer stacked in sequence from bottom to top.

[0013] Based on the above-mentioned bandpass waveguide structure photoelectric detector, the present invention also provides a method for manufacturing a bandpass waveguide structure photoelectric detector, and the manufacturing method is used to prepare the above-mentioned bandpass waveguide structure photoelectric detector, comprising:

[0014] S1, growing an epitaxial layer on an InP semi-insulating substrate by metal organic vapor deposition or molecular beam epitaxy; wherein the epitaxial layer comprises an InP buffer layer, a waveguide layer, an N contact layer, a drift layer, a cliff layer, an absorption layer, a barrier layer and a P contact layer which are sequentially stacked and grown from bottom to top;

[0015] S2, reserving a first preset pattern area on the P contact layer, and etching away the P contact layer, barrier layer, absorption layer, cliff layer and drift layer outside the first preset pattern area by an ICP process until the N contact layer is exposed to form a P-type mesa;

[0016] S3, reserving a second preset graphic region including the first preset graphic region on the exposed N-contact layer, and etching away the N-contact layer outside the second preset graphic region by an ICP process until the waveguide layer is exposed, so as to form an N-type mesa;

[0017] S4, reserving a third preset pattern area including the second preset pattern area on the exposed waveguide layer, and etching away the waveguide layer and the InP buffer layer outside the third preset pattern area by an ICP process until the InP semi-insulating substrate is exposed to form a ridge waveguide table;

[0018] S5, depositing SiO2 or SiN with a thickness of 800 to 1000 nm as a passivation layer on the P-type mesa, the N-type mesa, the ridge waveguide mesa and the exposed InP semi-insulating substrate by a PECVD method, and opening holes in the passivation layers of the N-type mesa and the P-type mesa;

[0019] S6, making a P electrode on the passivation layer of the P-type table and filling the opening to connect the P contact layer; making an N electrode on the passivation layer of the N-type table and filling the opening to connect the N contact layer; making a first ground wire bonding pad, a signal wire bonding pad, a DC bias wire bonding pad, a second ground wire bonding pad, a capacitor, a first coplanar waveguide, a second coplanar waveguide, a third coplanar waveguide and a short stub on the passivation layer of the InP semi-insulating substrate; wherein the N electrode is connected to the first ground wire bonding pad through the first coplanar waveguide, the P electrode is connected to the signal wire bonding pad through the second coplanar waveguide, the P electrode is also connected to the DC bias wire bonding pad and one electrode of the capacitor through the short stub, and the other electrode of the capacitor is connected to the second ground wire bonding pad through the third coplanar waveguide.

[0020] Based on the above technical solution, the present invention can also be improved as follows.

[0021] Further, the S6 is specifically:

[0022] By electron beam evaporation or magnetron sputtering, an N electrode is fabricated on the passivation layer of the N-type mesa, and the N electrode is extended to the passivation layer of the InP semi-insulating substrate to form a first coplanar waveguide and a first ground wire bonding pad connected to the first coplanar waveguide, a third coplanar waveguide and a second ground wire bonding pad connected to the third coplanar waveguide; wherein when the N electrode is fabricated on the passivation layer of the N-type mesa, the N electrode fills an opening to connect to the N contact layer;

[0023] Selecting a preset area on the third coplanar waveguide as a capacitor lower electrode, using a PECVD method to deposit SiO2 with a thickness of 200 to 300 nm on the capacitor lower electrode as a capacitor insulating layer, and extending it to the passivation layer of the InP semi-insulating substrate to form a preset insulating layer area;

[0024] A DC bias wire bonding pad is manufactured on the preset insulating layer region by electron beam evaporation or magnetron sputtering, and is extended onto the capacitor insulating layer to form a capacitor upper electrode, and is extended onto the passivation layer of the InP semi-insulating substrate to form a short stub, and is extended onto the passivation layer of the P-type table to form a P electrode, and is extended onto the passivation layer of the InP semi-insulating substrate to form a second coplanar waveguide and a signal line bonding pad connected to the second coplanar waveguide; wherein, when the P electrode is formed on the passivation layer of the P-type table, the P electrode fills an opening to connect the P contact layer.

[0025] Further, the S6 is specifically:

[0026] By electron beam evaporation or magnetron sputtering, an N electrode is fabricated on the passivation layer of the N-type mesa, and a capacitor lower electrode and a DC bias wire bonding pad connected to the capacitor lower electrode are fabricated on the passivation layer of the InP semi-insulating substrate; wherein when the N electrode is fabricated on the passivation layer of the N-type mesa, the N electrode fills an opening to connect to the N contact layer;

[0027] Depositing SiO2 with a thickness of 200 to 300 nm as a capacitor insulating layer on the capacitor lower electrode by a PECVD method, and opening a hole in the capacitor insulating layer so that the bottom of the hole is the capacitor lower electrode;

[0028] A first coplanar waveguide connected to the N electrode and a first ground wire bonding pad connected to the first coplanar waveguide are manufactured on the passivation layer of an InP semi-insulating substrate by electron beam evaporation or magnetron sputtering, an upper capacitor electrode is manufactured on the capacitor insulating layer, a third coplanar waveguide connected to the upper capacitor electrode and a second ground wire bonding pad connected to the third coplanar waveguide are manufactured on the passivation layer of the InP semi-insulating substrate, a P electrode is manufactured on the passivation layer of the P-type table, a second coplanar waveguide connected to the P electrode and a signal wire bonding pad connected to the second coplanar waveguide are manufactured on the passivation layer of the InP semi-insulating substrate, a short stub connected to the P electrode is manufactured on the passivation layer of the InP semi-insulating substrate, and the short stub fills an opening on the capacitor insulating layer to connect to the lower capacitor electrode; wherein, when the P electrode is formed on the passivation layer of the P-type table, the P electrode fills the opening to connect to the P contact layer.

[0029] The beneficial effects of the present invention are as follows: a bandpass waveguide structure photodetector and a manufacturing method thereof of the present invention connects a DC-isolating capacitor in parallel to a photoelectric semiconductor diode, which is equivalent to increasing the junction capacitance of the photoelectric semiconductor diode, thereby suppressing the bandwidth response at low frequency; however, increasing the junction capacitance of the photoelectric semiconductor diode will increase the resistance and capacitance parameters of the photodetector, and the increase in the resistance and capacitance parameters of the photodetector will cause the bandwidth of the photodetector to decrease. In order to increase the bandwidth of the photodetector, the present invention realizes an inductance peak effect through a coplanar waveguide to compensate for the capacitance effect of the photodetector, so as to improve the bandwidth response of the photodetector in the high-frequency bandpass interval, thereby satisfying the bandwidth response flatness under the W and F band bandpass conditions; In addition, the short stub in the present invention can realize the bandpass interval adjustment and the isolation function of the millimeter wave signal and the DC signal. The length of the short stub is 1 / 4 of the millimeter wave wavelength. According to the microwave impedance theory, the λ / 4 length means that the load impedance is infinite in a physical sense, so that the signal transmitted to the short stub is completely reflected, so that the millimeter wave signal is completely transmitted from the coplanar waveguide to the signal line bonding pad, and will not be transmitted to the DC bias bonding pad through the short stub, thereby realizing the isolation of the millimeter wave signal from the DC signal; at the same time, the millimeter wave wavelength and the length of the short stub are in a multiple relationship, so changing the length of the short stub also changes the wavelength of the reflected millimeter wave, that is, changes the frequency point of the peak value of the reflected signal, and also adjusts the bandpass interval accordingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of a bandpass waveguide structure photoelectric detector of the present invention;

[0031] Figure 2 A schematic three-dimensional diagram of the chip structure of a bandpass waveguide structure photoelectric detector of the present invention;

[0032] Figure 3 It is a schematic plan view of the chip structure of a bandpass waveguide structure photoelectric detector of the present invention;

[0033] Figure 4 It is the frequency response curve of common photodetector;

[0034] Figure 5 A frequency response curve diagram of a bandpass waveguide structure photoelectric detector of the present invention;

[0035] Figure 6 It is a flow chart of a method for manufacturing a bandpass waveguide structure photoelectric detector of the present invention;

[0036] Figure 7 It is a manufacturing flow chart of S2 to S5 in a manufacturing method of a bandpass waveguide structure photoelectric detector of the present invention;

[0037] Figure 8 A manufacturing flow chart of S6 in a manufacturing method of a bandpass waveguide structure photoelectric detector of the present invention;

[0038] Fig. 9 This is another production flow chart of S6 in the production method of a bandpass waveguide structure photodetector of the present invention.

[0039] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0040] 1. Ridge waveguide; 2. Optoelectronic semiconductor diode; 3. First ground wire bonding pad; 4. Signal wire bonding pad; 5. DC bias wire bonding pad; 6. Second ground wire bonding pad; 7. Capacitor; 8. First coplanar waveguide; 9. Second coplanar waveguide; 10. Third coplanar waveguide; 11. Short stub; 12. Semi-insulating InP substrate. DETAILED DESCRIPTION

[0041] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0042] like Figure 1As shown, a bandpass waveguide structure photoelectric detector includes a ridge waveguide 1, a photoelectric semiconductor diode 2, a first ground wire bonding pad 3, a signal wire bonding pad 4, a DC bias wire bonding pad 5, a second ground wire bonding pad 6, a capacitor 7, a first coplanar waveguide 8, a second coplanar waveguide 9, a third coplanar waveguide 10 and a short stub 11; the ridge waveguide 1 is connected to the light active absorption region of the photoelectric semiconductor diode 2, and the N electrode of the photoelectric semiconductor diode 2 is connected to the first ground wire bonding pad 3 through the first coplanar waveguide 8, The P electrode of the photoelectric semiconductor diode 2 is connected to the signal line bonding pad 4 through the second coplanar waveguide 9, and the P electrode of the photoelectric semiconductor diode 2 is also connected to the DC bias bonding pad 5 and one electrode of the capacitor 7 through the short stub 11, and the other electrode of the capacitor 7 is connected to the second ground wire bonding pad 6 through the third coplanar waveguide 10; the first ground wire bonding pad 3 and the second ground wire bonding pad 6 share a common ground; the length of the short stub 11 is λ / 4, where λ is the wavelength of the millimeter wave.

[0043] Among them, since the first ground wire bonding pad 3 and the second ground wire bonding pad 6 share a common ground, the two ends of the capacitor 7 are actually connected to the N electrode and the P electrode of the photoelectric semiconductor diode 2, that is, the capacitor 7 is connected in parallel with the photoelectric semiconductor diode 2.

[0044] In some embodiments: the capacitance range of the capacitor 7 is 1 to 3 pF. The length range of the first coplanar waveguide 8, the second coplanar waveguide 9 and the third coplanar waveguide 10 are all 150 to 250 μm. Preferably, the length of the coplanar waveguide (including the first coplanar waveguide 8, the second coplanar waveguide 9 and the third coplanar waveguide 10) is selected to be around 200 μm. The second coplanar waveguide 9 and the stub 11 form an L-shaped structure. The ridge waveguide 1 and the photoelectric semiconductor diode 2 form an evanescent waveguide coupling structure. The incident light of the evanescent waveguide coupling structure is incident from the edge rather than from the vertical plane. The waveguide transmits the optical signal and is evanescently coupled to the optical active absorption area of ​​the photodetector. The waveguide structure photodetector has the characteristics of high responsiveness and large response bandwidth.

[0045] In some embodiments: Figure 2 and Figure 3As shown, the photoelectric semiconductor diode 2 is made by etching the epitaxial layer on the semi-insulating InP substrate 12; the ridge waveguide 1, the first ground wire bonding pad 3, the signal wire bonding pad 4, the DC bias bonding pad 5, the second ground wire bonding pad 6, the capacitor 7, the first coplanar waveguide 8, the second coplanar waveguide 9, the third coplanar waveguide 10 and the stub 11 are all integrated on the InP substrate; wherein the epitaxial layer includes an InP buffer layer, a waveguide layer, an N contact layer, a drift layer, a cliff layer, an absorption layer, a barrier layer and a P contact layer stacked in sequence from bottom to top. The I nP buffer layer is used to grow the buffer of the epitaxial structure and reduce the unevenness, stress and other defects of the epitaxial structure; the waveguide layer is used to form a ridge waveguide; the N contact layer serves as the N region of the photoelectric semiconductor diode; the drift layer is used to collect the internal carriers of the photoelectric semiconductor diode; the cliff layer is used to establish a built-in electric field to convert the diffusion motion of the carriers into drifting motion, which has a faster movement speed and a faster response speed; the absorption layer is used to absorb photons and convert them into electrons; the blocking layer is used to block the movement of holes; and the P contact layer serves as the P region of the photoelectric semiconductor diode.

[0046] The present invention provides a bandpass waveguide structure photoelectric detector for converting an optical mixing signal into a millimeter wave signal, the purpose of which is to convert the optical mixing signal into a millimeter wave signal and match the packaging of a millimeter wave photonic mixer module; by connecting a capacitor in parallel to a photoelectric semiconductor diode, the bandwidth response is suppressed at a low frequency, and an inductance peak effect is achieved through a coplanar waveguide, and the inductance peak effect improves the bandwidth response in a high-frequency bandpass interval; the peak value and the bandpass range of the inductance peak effect are adjusted by the λ / 4 length of a short stub.

[0047] Specifically, the present invention increases the junction capacitance of the photoelectric semiconductor diode by connecting a DC-isolating capacitor in parallel to the photoelectric semiconductor diode, thereby suppressing the bandwidth response at low frequencies. However, increasing the junction capacitance of the photoelectric semiconductor diode will increase the resistance and capacitance parameters of the photodetector, and the increase in the resistance and capacitance parameters of the photodetector will cause the bandwidth of the photodetector to decrease. Since the photodetector is a capacitive device, by matching a suitable inductor, the capacitance effect of the photodetector can be compensated at a specific frequency, thereby increasing the bandwidth of the device. Therefore, the present invention forms a coplanar waveguide as an external load inductor during the manufacturing process of the photodetector electrode, and offsets the influence of the parasitic parameters of the photodetector on the frequency response through the inductance value, thereby improving the bandwidth response in the high-frequency bandpass interval. Therefore, in order to improve the bandwidth response of the photodetector in the high-frequency bandpass interval, the present invention realizes the inductance peak effect through the coplanar waveguide to compensate for the capacitance effect of the photodetector, so as to improve the bandwidth response of the photodetector in the high-frequency bandpass interval, so as to meet the bandwidth response flatness in the W and F band pass conditions. In addition, the short stub in the present invention can realize the bandpass interval adjustment and the isolation function of the millimeter wave signal and the DC signal. The length of the short stub is 1 / 4 of the millimeter wave wavelength. According to the microwave impedance theory, the λ / 4 length means that the load impedance is infinite in the physical sense, so that the signal transmitted to the short stub is completely reflected, so that the millimeter wave signal is completely transmitted from the coplanar waveguide to the signal line bonding pad, and will not be transmitted to the DC bias bonding pad (the DC bias bonding pad provides a DC bias for the photoelectric detector) through the short stub, thereby realizing the isolation of the millimeter wave signal from the DC signal; at the same time, the millimeter wave wavelength and the length of the short stub are in a multiple relationship, so changing the length of the short stub also changes the wavelength of the reflected millimeter wave, that is, changes the frequency point of the peak value of the reflected signal, and also adjusts the bandpass interval accordingly.

[0048] Figure 4 The frequency response curve of an ordinary photodetector reflects the bandwidth response characteristics of an ordinary photodetector. The bandwidth of an ordinary photodetector is mainly affected by the carrier transport time and the RC parameter. When the carrier transport time is constant, the larger the RC parameter, the smaller the bandwidth, and the smaller the RC parameter, the larger the bandwidth. At the same time, the bandwidth of an ordinary photodetector is also affected by the peak resonance effect of the inductor. Under the appropriate inductance, the bandwidth has a peak effect at a specific frequency. The junction capacitance of an ordinary photodetector is only less than 50fF, and the series resistance is less than 20Ω, which can ensure that the RC parameter bandwidth is above 80GHz.

[0049] After the present invention connects a 1-3pF capacitor in parallel to the photoelectric semiconductor diode, the RC parameter becomes larger, resulting in a decrease in low-frequency bandwidth response, but the inductance peak effect is achieved through a short stub and a coplanar waveguide of a certain length (about 200um). Figure 5It is a frequency response curve diagram of a bandpass waveguide structure photoelectric detector of the present invention, which reflects the bandwidth response characteristics of the bandpass waveguide structure photoelectric detector of the present invention; Figure 5 In the specific range of 75GHz to 110GHz (W band), a peak effect is presented, and it is suppressed at low frequencies (5 to 60GHz). This ensures a relatively flat bandwidth response within the range of 75GHz to 110GHz, with a flatness of less than 3dB, thus achieving a specific bandpass output characteristic.

[0050] Millimeter wave testing and transmission generally use metal rectangular waveguides for transmission. Rectangular waveguides have low loss and wide bandwidth, and have better performance and cost advantages than traditional coaxial connectors when the frequency exceeds 100GHz. According to the band classification standard of metal rectangular waveguides, the millimeter wave frequency band mainly includes W bandpass band: 75~110GHz; F bandpass band: 90~140GHz; D bandpass band: 110~170GHz and other different bandpass bands. Metal coaxial connectors generally cover the entire band from low frequency to high frequency, such as 0~100GHz, but the insertion loss of coaxial connectors above 100GHz is about 2~3dB; while the insertion loss of bandpass metal waveguides in the 100GHz frequency band is about 0.5dB, with less loss, which is more suitable for millimeter wave testing and transmission.

[0051] Based on the above-mentioned bandpass waveguide structure photoelectric detector, the present invention also provides a method for manufacturing the bandpass waveguide structure photoelectric detector.

[0052] like Figure 6 As shown, a method for manufacturing a bandpass waveguide structure photoelectric detector is used to prepare the bandpass waveguide structure photoelectric detector as described above, comprising:

[0053] S1, growing an epitaxial layer on an InP semi-insulating substrate by metal organic vapor deposition or molecular beam epitaxy; wherein the epitaxial layer comprises an InP buffer layer, a waveguide layer, an N contact layer, a drift layer, a cliff layer, an absorption layer, a barrier layer and a P contact layer which are sequentially stacked and grown from bottom to top;

[0054] S2, reserving a first preset pattern area on the P contact layer, and etching away the P contact layer, barrier layer, absorption layer, cliff layer and drift layer outside the first preset pattern area by an ICP process until the N contact layer is exposed to form a P-type mesa;

[0055] S3, reserving a second preset graphic region including the first preset graphic region on the exposed N-contact layer, and etching away the N-contact layer outside the second preset graphic region by an ICP process until the waveguide layer is exposed, so as to form an N-type mesa;

[0056] S4, reserving a third preset pattern area including the second preset pattern area on the exposed waveguide layer, and etching away the waveguide layer and the InP buffer layer outside the third preset pattern area by an ICP process until the InP semi-insulating substrate is exposed to form a ridge waveguide table;

[0057] S5, depositing SiO2 or SiN with a thickness of 800 to 1000 nm as a passivation layer on the P-type mesa, the N-type mesa, the ridge waveguide mesa and the exposed InP semi-insulating substrate by a PECVD method, and opening holes in the passivation layers of the N-type mesa and the P-type mesa (the passivation layer can protect the side walls of the P-type mesa and the N-type mesa from leakage);

[0058] S6, making a P electrode on the passivation layer of the P-type table and filling the opening to connect the P contact layer; making an N electrode on the passivation layer of the N-type table and filling the opening to connect the N contact layer; making a first ground wire bonding pad, a signal wire bonding pad, a DC bias wire bonding pad, a second ground wire bonding pad, a capacitor, a first coplanar waveguide, a second coplanar waveguide, a third coplanar waveguide and a short stub on the passivation layer of the InP semi-insulating substrate; wherein the N electrode is connected to the first ground wire bonding pad through the first coplanar waveguide, the P electrode is connected to the signal wire bonding pad through the second coplanar waveguide, the P electrode is also connected to the DC bias wire bonding pad and one electrode of the capacitor through the short stub, and the other electrode of the capacitor is connected to the second ground wire bonding pad through the third coplanar waveguide.

[0059] Figure 7 It is a schematic diagram of the manufacturing steps S2 to S5 in the manufacturing method of a bandpass waveguide structure photodetector of the present invention; along the direction of the arrow from left to right, the P-type mesa, N-type mesa, ridge waveguide mesa and passivation opening are manufactured in sequence.

[0060] In some embodiments, Figure 8 As shown, the S6 is specifically:

[0061] S61 a, using electron beam evaporation or magnetron sputtering to form an N electrode on the passivation layer of the N-type mesa (the N electrode uses vapor deposition or electron beam evaporation of AuGe / Ni / Au), and extending it to the passivation layer of the InP semi-insulating substrate to form a first coplanar waveguide and a first ground wire bonding pad connected to the first coplanar waveguide, a third coplanar waveguide and a second ground wire bonding pad connected to the third coplanar waveguide; wherein, when the N electrode is formed on the passivation layer of the N-type mesa, the N electrode fills an opening to connect to the N contact layer;

[0062] S62a, selecting a preset area on the third coplanar waveguide as a capacitor lower electrode, using a PECVD method to deposit SiO2 with a thickness of 200 to 300 nm on the capacitor lower electrode as a capacitor insulating layer, and extending it to the passivation layer of the InP semi-insulating substrate to form a preset insulating layer area;

[0063] S63a, using electron beam evaporation or magnetron sputtering to make a DC bias wire bonding pad on the preset insulating layer area, and extending it to the capacitor insulating layer to form a capacitor upper electrode, and extending it to the passivation layer of the I nP semi-insulating substrate to form a short line, and extending it to the passivation layer of the P-type table to form a P electrode, and extending it to the passivation layer of the I nP semi-insulating substrate to form a second coplanar waveguide and a signal line bonding pad connected to the second coplanar waveguide; wherein, when the P electrode is formed on the passivation layer of the P-type table, the P electrode fills the opening to connect to the P contact layer.

[0064] exist Figure 8 In the method, the lower electrode of the capacitor is connected to the first ground wire bonding pad and the second ground wire bonding pad, and the upper electrode of the capacitor is connected to the short stub and the DC bias bonding pad.

[0065] In other embodiments, Fig. 9 As shown, the S6 is specifically:

[0066] S61 b, using electron beam evaporation or magnetron sputtering to form an N electrode on the passivation layer of the N-type mesa, and to form a capacitor lower electrode and a DC bias wire bonding pad connected to the capacitor lower electrode on the passivation layer of the InP semi-insulating substrate; wherein when the N electrode is formed on the passivation layer of the N-type mesa, the N electrode fills an opening to connect to the N contact layer;

[0067] S62b, using a PECVD method to deposit SiO2 with a thickness of 200 to 300 nm on the capacitor lower electrode as a capacitor insulating layer, and opening a hole in the capacitor insulating layer so that the bottom of the hole is the capacitor lower electrode;

[0068] S63b, using electron beam evaporation or magnetron sputtering to manufacture a first coplanar waveguide connected to the N electrode and a first ground wire bonding pad connected to the first coplanar waveguide on the passivation layer of the InP semi-insulating substrate, manufacture a capacitor upper electrode on the capacitor insulating layer, manufacture a third coplanar waveguide connected to the capacitor upper electrode and a second ground wire bonding pad connected to the third coplanar waveguide on the passivation layer of the InP semi-insulating substrate, manufacture a P electrode on the passivation layer of the P-type table, manufacture a second coplanar waveguide connected to the P electrode and a signal wire bonding pad connected to the second coplanar waveguide on the passivation layer of the InP semi-insulating substrate, manufacture a short stub connected to the P electrode on the passivation layer of the InP semi-insulating substrate, and the short stub fills the opening on the capacitor insulating layer to connect to the capacitor lower electrode; wherein, when the P electrode is formed on the passivation layer of the P-type table, the P electrode fills the opening to connect to the P contact layer.

[0069] exist Fig. 9 In the method, the lower electrode of the capacitor is connected to the short stub and the DC bias bonding pad, and the upper electrode of the capacitor is connected to the first grounding wire bonding pad and the second grounding wire bonding pad.

[0070] The invention discloses a method for manufacturing a bandpass waveguide structure photoelectric detector. The method comprises the following steps: using metal organic vapor deposition or molecular beam epitaxy to grow an epitaxial layer on a semi-insulating substrate, using an ICP process to obtain a P-type table, and obtaining an N-type table and a ridge waveguide table according to the above method. PECVD is used to deposit SiO2 or SiN with a thickness of 800 to 1000 nm as a passivation layer, electron beam evaporation or magnetron sputtering is used to manufacture N table metal (to form an N electrode) and a capacitor bottom electrode, using PECVD to deposit SiO2 with a thickness of 200 to 300 nm as a capacitor insulating layer, electron beam evaporation or magnetron sputtering is used to manufacture P table metal (to form a P electrode), and a stripping process is used to complete the metal manufacturing.

[0071] The bandpass waveguide structure photoelectric detector made by the manufacturing method of the present invention converts the optical mixing signal into a millimeter wave signal and matches the packaging of the millimeter wave photon mixer module; by connecting a capacitor in parallel to the photoelectric semiconductor diode, the bandwidth response is suppressed at a low frequency, and the inductance peak effect is realized through the coplanar waveguide, and the inductance peak effect improves the bandwidth response in the high-frequency bandpass interval; the peak value and the bandpass range of the inductance peak effect are adjusted by the λ / 4 length of the short line, so that the bandwidth response flatness in the W and F band bandpass conditions can be met.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A bandpass waveguide structure photoelectric detector, characterized in that: It includes a ridge waveguide, a photoelectric semiconductor diode, a first ground wire bonding pad, a signal wire bonding pad, a DC bias wire bonding pad, a second ground wire bonding pad, a capacitor, a first coplanar waveguide, a second coplanar waveguide, a third coplanar waveguide and a short stub; the ridge waveguide is connected to the light active absorption area of ​​the photoelectric semiconductor diode, the N electrode of the photoelectric semiconductor diode is connected to the first ground wire bonding pad through the first coplanar waveguide, the P electrode of the photoelectric semiconductor diode is connected to the signal wire bonding pad through the second coplanar waveguide, the P electrode of the photoelectric semiconductor diode is also connected to the DC bias wire bonding pad and one electrode of the capacitor through the short stub, and the other electrode of the capacitor is connected to the second ground wire bonding pad through the third coplanar waveguide; the first ground wire bonding pad and the second ground wire bonding pad share a common ground; the length of the short stub is λ / 4, where λ is the wavelength of the millimeter wave.

2. The bandpass waveguide structure photodetector according to claim 1, characterized in that: The capacitance value of the capacitor ranges from 1 to 3 pF.

3. The bandpass waveguide structure photodetector according to claim 1, characterized in that: The lengths of the first coplanar waveguide, the second coplanar waveguide and the third coplanar waveguide are all in the range of 150 to 250 μm.

4. The bandpass waveguide structure photodetector according to claim 1, characterized in that: The second coplanar waveguide and the short stub form an L-shaped structure.

5. The bandpass waveguide structure photodetector according to claim 1, characterized in that: The ridge waveguide and the photoelectric semiconductor diode form an evanescent waveguide coupling structure.

6. The bandpass waveguide structure photodetector according to claim 1, characterized in that: The photoelectric semiconductor diode is made by etching an epitaxial layer on a semi-insulating InP substrate; the ridge waveguide, the first ground wire bonding pad, the signal line bonding pad, the DC bias bonding pad, the second ground wire bonding pad, the capacitor, the first coplanar waveguide, the second coplanar waveguide, the third coplanar waveguide and the short stub are all integrated on the InP substrate.

7. The bandpass waveguide structure photodetector according to claim 6, characterized in that: The epitaxial layer includes an InP buffer layer, a waveguide layer, an N contact layer, a drift layer, a cliff layer, an absorption layer, a barrier layer and a P contact layer which are sequentially stacked from bottom to top.

8. A method for manufacturing a bandpass waveguide structure photodetector, characterized in that: Used to prepare the bandpass waveguide structure photoelectric detector according to any one of claims 1 to 7, comprising: S1, growing an epitaxial layer on an InP semi-insulating substrate by metal organic vapor deposition or molecular beam epitaxy; wherein the epitaxial layer comprises an InP buffer layer, a waveguide layer, an N contact layer, a drift layer, a cliff layer, an absorption layer, a barrier layer and a P contact layer which are stacked and grown in sequence from bottom to top; S2, reserving a first preset pattern area on the P contact layer, and etching away the P contact layer, barrier layer, absorption layer, cliff layer and drift layer outside the first preset pattern area by an ICP process until the N contact layer is exposed to form a P-type mesa; S3, reserving a second preset graphic region including the first preset graphic region on the exposed N-contact layer, and etching away the N-contact layer outside the second preset graphic region by an ICP process until the waveguide layer is exposed, so as to form an N-type mesa; S4, reserving a third preset graphic region including the second preset graphic region on the exposed waveguide layer, and etching the waveguide layer and the InP buffer layer outside the third preset graphic region by an ICP process until the InP semi-insulating substrate is exposed to form a ridge waveguide table; S5, depositing SiO2 or SiN with a thickness of 800 to 1000 nm as a passivation layer on the P-type mesa, the N-type mesa, the ridge waveguide mesa and the exposed InP semi-insulating substrate by a PECVD method, and opening holes in the passivation layers of the N-type mesa and the P-type mesa; S6, making a P electrode on the passivation layer of the P-type table and filling the opening to connect the P contact layer; making an N electrode on the passivation layer of the N-type table and filling the opening to connect the N contact layer; making a first ground wire bonding pad, a signal wire bonding pad, a DC bias bonding pad, a second ground wire bonding pad, a capacitor, a first coplanar waveguide, a second coplanar waveguide, a third coplanar waveguide and a short stub on the passivation layer of the InP semi-insulating substrate; wherein the N electrode is connected to the first ground wire bonding pad through the first coplanar waveguide, the P electrode is connected to the signal wire bonding pad through the second coplanar waveguide, the P electrode is also connected to the DC bias bonding pad and one electrode of the capacitor through the short stub, and the other electrode of the capacitor is connected to the second ground wire bonding pad through the third coplanar waveguide.

9. The method for manufacturing a bandpass waveguide structure photodetector according to claim 8, characterized in that: The S6 is specifically: By electron beam evaporation or magnetron sputtering, an N electrode is fabricated on the passivation layer of the N-type mesa, and the N electrode is extended to the passivation layer of the InP semi-insulating substrate to form a first coplanar waveguide and a first ground wire bonding pad connected to the first coplanar waveguide, a third coplanar waveguide and a second ground wire bonding pad connected to the third coplanar waveguide; wherein when the N electrode is fabricated on the passivation layer of the N-type mesa, the N electrode fills an opening to connect to the N contact layer; Selecting a preset area on the third coplanar waveguide as a capacitor lower electrode, using a PECVD method to deposit SiO2 with a thickness of 200 to 300 nm on the capacitor lower electrode as a capacitor insulating layer, and extending it to the passivation layer of the InP semi-insulating substrate to form a preset insulating layer area; A DC bias wire bonding pad is manufactured on the preset insulating layer region by electron beam evaporation or magnetron sputtering, and is extended onto the capacitor insulating layer to form a capacitor upper electrode, and is extended onto the passivation layer of the InP semi-insulating substrate to form a short stub, and is extended onto the passivation layer of the P-type table to form a P electrode, and is extended onto the passivation layer of the InP semi-insulating substrate to form a second coplanar waveguide and a signal line bonding pad connected to the second coplanar waveguide; wherein, when the P electrode is formed on the passivation layer of the P-type table, the P electrode fills an opening to connect the P contact layer.

10. The method for manufacturing a bandpass waveguide structure photodetector according to claim 8, characterized in that: The S6 is specifically: By electron beam evaporation or magnetron sputtering, an N electrode is fabricated on the passivation layer of the N-type mesa, and a capacitor lower electrode and a DC bias wire bonding pad connected to the capacitor lower electrode are fabricated on the passivation layer of the InP semi-insulating substrate; wherein when the N electrode is fabricated on the passivation layer of the N-type mesa, the N electrode fills an opening to connect to the N contact layer; Depositing SiO2 with a thickness of 200 to 300 nm as a capacitor insulating layer on the capacitor lower electrode by a PECVD method, and opening a hole in the capacitor insulating layer so that the bottom of the hole is the capacitor lower electrode; A first coplanar waveguide connected to the N electrode and a first ground wire bonding pad connected to the first coplanar waveguide are manufactured on a passivation layer of an InP semi-insulating substrate by electron beam evaporation or magnetron sputtering, an upper capacitor electrode is manufactured on the capacitor insulating layer, a third coplanar waveguide connected to the upper capacitor electrode and a second ground wire bonding pad connected to the third coplanar waveguide are manufactured on the passivation layer of the InP semi-insulating substrate, a P electrode is manufactured on the passivation layer of the P-type table, a second coplanar waveguide connected to the P electrode and a signal wire bonding pad connected to the second coplanar waveguide are manufactured on the passivation layer of the InP semi-insulating substrate, a short stub connected to the P electrode is manufactured on the passivation layer of the InP semi-insulating substrate, and the short stub fills an opening on the capacitor insulating layer to connect to the lower capacitor electrode; wherein, when the P electrode is formed on the passivation layer of the P-type table, the P electrode fills the opening to connect to the P contact layer.

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