MOSCAP modulator system using piezoelectric effect to provide driving voltage

Abstract

The present invention provides a MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, capable of achieving self-drive without an external power supply. The system comprises: a piezoelectric triboelectric nanostructure, comprising an electrostatic material, a piezoelectric material, a buffer layer connected between the electrostatic and piezoelectric materials and acting as a flat plate capacitor, a metal electrode-P electrode connected to the electrostatic material, a transparent electrode-N electrode, and a bonding layer connected between the piezoelectric material and the transparent electrode-N electrode; and a metal oxide semiconductor capacitor-based microring modulator, comprising an insulating dielectric layer connected to the transparent electrode-N electrode on a side facing away from the intermediate piezoelectric material, a ridge waveguide based on an SOI substrate, and a heavily doped silicon planar layer region connected to the ridge waveguide; the transparent electrode-N electrode also serves as the upper electrode of the microring modulator, and the heavily doped silicon planar layer region serves as the lower electrode of the microring modulator; the lower electrode is connected to a contact electrode, which is a metal electrode.

Description

Technical Field

[0001] The present invention relates to the fields of silicon-based optoelectronic integration and microring resonant modulators, and specifically to a flexible electronic material integrated with a piezoelectric triboelectric nanogenerator (PTENG). The PTENG can be used as a piezoelectric driving power source to adjust the microring resonant modulator, and can be used to control the resonant wavelength of the microring resonator, thereby achieving purposes such as sensors and body monitoring. Background Art

[0002] With the advent of the Internet of Things (IoT) and big data, more and more human-computer interaction devices, such as smartphones, smart monitoring systems, and smart home systems, are becoming increasingly integrated into our daily lives. The concept of the IoT has evolved from initially connecting objects (or people) to the internet through functional wired nodes to encompass a wider range of interactive scenarios based on wireless network transmission, such as smart transportation, industrial production, intelligent environmental monitoring, and wireless network sensor applications such as AR / VR. As the IoT continues to develop, people are increasingly concerned about the power consumption and portability requirements of wireless network sensors. Therefore, self-powered sensors or systems that do not require an external power supply have become an effective solution to address power consumption issues.

[0003] As a sensor, silicon-based optical modulators have the characteristics of low power consumption and low cost. Moreover, compared with MEMS-based sensors, silicon-based optical modulators have the advantage of miniaturization and can be combined with existing CMOS processes. The micro-ring modulator based on metal oxide semiconductor capacitor (MOSCAP) uses a carrier accumulation type plasma dispersion modulation mechanism. After the current passes through, the free carriers are accumulated on both sides of the dielectric layer, providing a large modulation bandwidth while maintaining high modulation efficiency, thereby allowing for a smaller size design. In addition, the lower driving voltage and lower static loss make it a key component for the next generation of silicon-based optical modulators used in sensors.

[0004] In 2022, Chengkuo Lee et al. proposed a TENG-based MRR sensor structure, the device structure of which is as follows: Figure 1 As shown in the figure, this structure uses the TENG effect. The stress and deformation generated by external motion creates a voltage between the upper and lower electrodes of the device, biasing the aluminum nitride microring modulator. Due to the strong piezoelectric properties of aluminum nitride, the resonant frequency of the aluminum nitride microring modulator changes with the voltage generated by the TENG, forming an optical Morse code-like transmission spectrum. This is then connected to an external light source and an MCU to generate data processing signals, enabling sustainable monitoring of human motion.

[0005] Because the modulator is located in the middle of the electrode, the optical transmission loss is high and the modulation capability is limited, which limits the control range of the micro-ring modulator, thus restricting it to functional devices such as filters; 2. It is difficult to be compatible with the existing CMOS process platform, and the manufacturing process is difficult to become a device-level system. Summary of the Invention

[0006] Based on the above description, the present invention provides an integrated PTENG stress-voltage conversion platform, and combines it with the existing CMOS process to connect a silicon-based microring modulator based on the MOSCAP structure. Through external photodetectors and lasers, a resonant wavelength change monitoring system under continuous stress piezoelectric drive is formed, thereby driving the microring modulator to realize applications such as sensors without an external power supply.

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] The MOSCAP modulator system uses the piezoelectric effect to provide driving voltage, which can achieve self-driving without an external power supply, including:

[0009] A piezoelectric triboelectric nanostructure includes an electrostatic material, a piezoelectric material, a buffer layer connected between the electrostatic material and the piezoelectric material to act as a flat plate capacitor, a metal electrode-P electrode connected to the electrostatic material, a transparent electrode-N electrode, and a bonding layer connected between the piezoelectric material and the transparent electrode-N electrode; and

[0010] A micro-ring modulator based on a metal oxide semiconductor capacitor includes an insulating dielectric layer connected to a transparent electrode-N electrode away from an intermediate piezoelectric material, a ridge waveguide based on an SOI substrate, and a heavily doped silicon region of a planar layer connected to the ridge waveguide;

[0011] The transparent electrode-N electrode serves as the upper electrode of the micro-ring modulator, and the heavily doped silicon region of the flat layer serves as the lower electrode of the micro-ring modulator.

[0012] The lower electrode is connected to a contact electrode, and the contact electrode is a metal electrode.

[0013] On the basis of the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, the piezoelectric material is integrated with the transparent electrode of the silicon-based MOSCAP microring modulator through heterogeneous bonding. The piezoelectric material is first deposited on an oxide substrate with a lattice match, such as MgO, and then integrated into the microring modulator through wafer-to-wafer hydrophilic heterogeneous bonding. After bonding, the substrate is first removed by etching, and then an electrostatic material film is attached to form the main structure of the PTENG. Finally, metal electrodes, metal electrode-P electrodes, and TSV through-holes are formed through metal deposition and silicon vias.

[0015] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the electrostatic material uses a negative electrode electrostatic material, including but not limited to Polyimide, PDMS, and PTFE.

[0016] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, the piezoelectric material includes but is not limited to: PZT, AlN, BTO, and the bonding layer between the piezoelectric material and the transparent electrode-N electrode is realized by thermal oxidation or thin film deposition process, and the thickness of the piezoelectric material is 200nm~2μm.

[0017] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the thickness of the insulating dielectric layer is 5 nm to 100 nm, and the deposition method of the insulating dielectric layer includes but is not limited to thermal oxidation and thin film deposition.

[0018] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, when the piezoelectric material is PZT, when the PZT thickness is greater than or equal to 600nm, the PTENG structure can stably provide a voltage of more than 5V to drive the microring modulator for wavelength modulation.

[0019] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the insulating dielectric layer material includes but is not limited to silicon dioxide, hafnium dioxide (HfO2), zirconium dioxide, hafnium silicate, zirconium silicate, nitrided hafnium silicate, and zirconium silicate.

[0020] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, the bonding layer material includes but is not limited to silicon dioxide, hafnium dioxide (HfO2), zirconium dioxide, hafnium silicate, zirconium silicate, nitrided hafnium silicate, and zirconium silicate.

[0021] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the material of the transparent electrode-N electrode includes but is not limited to ZnO, ITO, FTO, and ITiO.

[0022] Furthermore, in the aforementioned MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, when the PTENG capacitance equals the microring modulator capacitance, the voltage obtained by the PTENG is equally transferred to the silicon-based microring of the MOSCAP structure. As the bias voltage is applied to the modulator, the resonant wavelength of the microring modulator will also drift with changes in the bias voltage.

[0023] Furthermore, for the MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, when the microring radius is 30 μm and the spacing between the microring and the silicon ridge waveguide is 500 nm, the resonant wavelength of the microring modulator changes with increasing voltage, and the modulation efficiency is 23 pm / V.

[0024] Furthermore, when a bias is applied to the lower electrode and the transparent electrode-N electrode of the microring modulator, charge accumulation occurs on the lower electrode and the transparent electrode-N electrode, affecting the effective refractive index of the material at that location through the plasma dispersion effect, and modulating the light field resonance mode according to the overlap of the light field and the carrier accumulation area.

[0025] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide driving voltage, the ridge waveguide is based on the top silicon layer on the SOI substrate, the total height of the ridge waveguide is 220nm, the lower layer height is 150nm, the upper layer height is 70nm, and the upper layer width is 470nm.

[0026] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the thickness of the bonding layer is 50-300 nm.

[0027] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the buffer layer material is silicon dioxide.

[0028] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the deposition method of the transparent electrode-N electrode includes but is not limited to thermal oxidation and thin film deposition.

[0029] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the material of the metal electrode is Au, Cu or Al.

[0030] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, a TSV through-hole is vertically opened on the system, and the filling material in the TSV through-hole is metal, including but not limited to Au, Cu or Al.

[0031] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the contact electrode is made of a metal material, and the metal material includes but is not limited to Au, Cu or Al.

[0032] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the ridge waveguide is lightly doped with silicon, and the doping methods include ion implantation and thermal diffusion.

[0033] Furthermore, in the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the lightly doped silicon is prepared by ion diffusion.

[0034] Furthermore, in the MOSCAP modulator system using the piezoelectric effect to provide a driving voltage, the doping concentration of the lightly doped silicon is 10 16 -10 19 cm 3 The doped ion types are B and P.

[0035] Based on the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the present invention further provides a sensor, specifically:

[0036] A sensor uses any of the above-mentioned MOSCAP modulator systems that utilizes the piezoelectric effect to provide a driving voltage.

[0037] Furthermore, the above-mentioned sensor is used to monitor changes in human body movement, blood sugar, and blood oxygen values.

[0038] Based on the above-mentioned MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage, the present invention also provides a resonant wavelength change monitoring system, specifically:

[0039] A resonant wavelength change monitoring system comprises an MCU, a light detector, a laser, and any one of the above-mentioned MOSCAP modulator systems for providing a driving voltage by utilizing a piezoelectric effect.

[0040] Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0041] Based on existing CMOS processes, this invention provides a system that combines a piezoelectric power source in a PTENG structure with an existing silicon-based optical device, a MOSCAP microring modulator, through bonding. When the device is subjected to external stress changes, due to structural characteristics such as the shared electrode in the design, the induced potential generated by the PTENG structure can be directly biased to the microring modulator through the capacitor design of the two structures, thereby regulating the resonant wavelength of the microring modulator and achieving microring modulator modulation. The optical characteristics of the resonant wavelength generated by the microring modulator enable it to serve as an optical detector for continuously monitoring stress changes. Controlling the wavelength of the microring resonant cavity enables precise sensing and measurement of tiny changes. Combined with the self-driven modulation provided by stress, it allows for long-term continuous product detection. Therefore, this technology is applicable to the long-term detection of surface stress or deformation.

[0042] When the piezoelectric material is PZT and the PZT thickness is greater than or equal to 600nm, the PTENG structure can stably provide a voltage of more than 5V to drive the microring modulator for wavelength modulation.

[0043] Because light field transmission is concentrated within the silicon ridge waveguide, only the doping concentration and structure of the silicon ridge waveguide, as well as the size and structural design of the microring, can affect the transmission spectrum. This allows for the flexible design of the thickness of the insulating dielectric layer in the MOSCAP structure, maintaining high modulation efficiency while matching the system capacitance of the PTENG, thereby achieving equivalent voltage conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is the SEM image of the micro-ring sensor based on the TENG structure, which is the background technology of the present invention;

[0045] Figure 2 This is a schematic diagram of the PTENG principle of the MOSCAP modulator system of the present invention that uses the piezoelectric effect to provide driving voltage;

[0046] Figure 3 The equivalent circuit diagram of the MOSCAP modulator system of the present invention that uses the piezoelectric effect to provide driving voltage;

[0047] Figure 4 This is the potential distribution diagram of the PTENG under external stress of the MOSCAP modulator system of the present invention that uses the piezoelectric effect to provide driving voltage;

[0048] Figure 5 This is a schematic structural diagram of a MOSCAP modulator system that utilizes the piezoelectric effect to provide a driving voltage according to the present invention;

[0049] Figure 6 The voltage values ​​generated by the PTENG structure of the present invention with changes in external stress under different PZT thicknesses;

[0050] Figure 7 This is a graph showing the variation of the resonant wavelength of a microring resonator with voltage in a MOSCAP modulator system that uses the piezoelectric effect to provide a driving voltage according to the present invention;

[0051] Figure 8 (a) A resonant wavelength change monitoring system according to the present invention shows the relationship between the microring transmission spectrum and time under continuous stress. Figure 8 (b) is the PTENG+MCU structure. Under continuous stress, the relationship between the voltage and time generated by the PTENG structure is shown.

[0052] In the figure, 1. electrostatic material; 2. piezoelectric material; 3. buffer layer; 4. metal electrode - P electrode; 5. transparent electrode - N electrode; 6. bonding layer; 7. insulating dielectric layer; 8. SOI substrate; 81. SiO2 insulating layer; 82. silicon substrate; 9. silicon lightly doped region; 10. silicon heavily doped region; 11. contact electrode; 12. TSV through hole. DETAILED DESCRIPTION

[0053] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0055] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediate element. In the following embodiments, "connection" should be understood as "electrical connection", "communication connection", etc., if the connected circuits, modules, units, etc. can transmit electrical signals or data to each other.

[0056] When used herein, the singular forms "a", "an", and "the" may also include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0057] The piezoelectric nanogenerator (PTENG) was invented by Professor Wang Zhonglin in 2012 and has been widely used in high-entropy mechanical energy harvesting, such as wind energy, ocean energy, and bio-mechanical energy. PTENG has been widely used in the Internet of Things due to its low cost, diverse structures, stable output, high energy conversion efficiency, excellent environmental adaptability, and eco-friendliness. The concept of PTENG is derived from displacement current, and its purpose is to harvest micron-nanoscale mechanical energy. Its working principle is as follows: Figure 2 shown. Figure 2 (a) shows a typical polymer-based PTENG structure, with PET film and Kapton film on the top and bottom. A gold film is sputtered on both the top and bottom surfaces as electrodes, and the distance between the electrodes is D. When an external force is applied, causing the electrode distance to change from D to d, a triboelectric potential layer will be generated at the film interface, as shown in Figure 2. Figure 2 As shown in (b), the system capacitance layer is changed, resulting in the current generated by free electrons flowing to the electrodes, as shown in Figure 2 (d) until steady state. When the external stress disappears and the electrode distance recovers from d to D, the potential will decrease again, and the induced potential on the two electrodes will once again generate free electrons to flow to the outside until neutralization, such as Figure 2 (c) shown.

[0058] The power generated by the PTENG is subjected to external bending and external pressure. Taking a bending frequency of 0.33Hz and a bending degree of 0.13% as an example, the maximum output voltage can reach 3.3V and the current can reach 0.6μA, and the maximum power density can reach 10.4mW / cm 3 Therefore, the current generated by the PTENG can be stored by capacitors and used to drive other application platforms, which provides a new working platform for our subsequent micro-ring modulator drive design.

[0059] Based on the problems existing in related technologies, this technical solution proposes a MOSCAP modulator system based on the combination of PTENG and the existing silicon photonic communication platform, which uses the piezoelectric effect to provide driving voltage. Its equivalent circuit diagram is shown in the figure below. Figure 3 shown.

[0060] The MOSCAP modulator system of the present invention, which utilizes the piezoelectric effect to provide a driving voltage, can achieve self-driving without an external power supply, and includes:

[0061] The piezoelectric triboelectric nanostructure, or PTENG, comprises an electrostatic material 1, a piezoelectric material 2, a buffer layer 3 connected between the electrostatic material 1 and the piezoelectric material 2 and acting as a flat plate capacitor, a metal electrode (P electrode) 4 connected to the electrostatic material 1, a transparent electrode (N electrode) 5, and a bonding layer 6 connected between the piezoelectric material 2 and the transparent electrode (N electrode) 5; and

[0062] A micro-ring modulator based on a metal oxide semiconductor capacitor, namely a MOSCAP micro-ring modulator, comprises an insulating dielectric layer 7 connected to a transparent electrode-N electrode 5 on a side away from an intermediate piezoelectric material 2, a ridge waveguide based on an SOI substrate 8, and a planar silicon heavily doped region 10 connected to the ridge waveguide;

[0063] The transparent electrode-N electrode 5 serves as the upper electrode of the micro-ring modulator, and the heavily doped silicon region of the planar layer serves as the lower electrode of the micro-ring modulator.

[0064] The lower electrode is connected to a contact electrode 11 , which is a metal electrode.

[0065] The SOI substrate 8 includes a SiO 2 insulating layer 81 and a silicon substrate 82 .

[0066] like Figure 5 Figure 1 shows the material structure of the PTENG and microring modulator system. Light transmission is concentrated in a lightly doped silicon region formed by light doping on the ridge waveguide. A heavily doped silicon slab region 10 connected to it serves as the bottom electrode of the MOSCAP. An insulating dielectric layer 7 is located between the transparent electrode-N electrode and the ridge waveguide. The transparent electrode-N electrode serves as both the top electrode of the modulator system and the bottom electrode of the PTENG structure. Silicon dioxide can be used for the insulating dielectric layer 7 and the buffer layer 3. The insulating dielectric layer 7 is deposited by PVD. The piezoelectric material 2 is transferred to the top of the MOSCAP structure via wafer-to-wafer heterojunction bonding. After bonding, the substrate is first removed by etching. Then, a thin film of electrostatic material 1 is applied using spin-on techniques, forming the main structure of the PTENG. Finally, metal deposition and through-silicon vias (TSVs) are used to form the metal electrodes, the metal-P electrode 4, and the TSVs 12.

[0067] Furthermore, a TSV through-hole is vertically opened on the system, and the filling material in the TSV through-hole is metal, including but not limited to Au, Cu or Al.

[0068] When the PTENG structure is subjected to external stress, the electrostatic material 1 and the piezoelectric material 2 will generate induced charges that converge on both sides of the middle buffer layer 3. Figure 3As shown, the buffer layer 3 acts as a flat plate capacitor between the electrostatic material 1 and the piezoelectric material 2. As the induced charge gradually increases, the charge flows through the piezoelectric material 2 to the transparent electrode - N electrode to generate an induced voltage. Figure 4 As shown, it can be seen that the potential distribution is concentrated between the PZT and the lower electrode.

[0069] Thanks to the unique MOSCAP structural design, the transparent N-electrode serves as both the bottom electrode of the PTENG structure and the top electrode of the modulator. By adjusting the thickness of the bonding layer and the insulating dielectric layer, the capacitance of the PTENG can be controlled, thereby regulating the voltage applied to the microring modulator to achieve high-speed microring modulation.

[0070] Furthermore, the thickness of the bonding layer is 50-300 nm.

[0071] Furthermore, the ridge waveguide is based on the top silicon layer on the SOI substrate 8, which is a lightly doped silicon region 9. The ridge waveguide is generally characterized by a total height of 220nm, a lower layer height of 150nm, an upper layer height of 70nm, and an upper layer width of 470nm.

[0072] Specifically, the silicon lightly doped region 9 is obtained by locally doping the upper surface of the ridge waveguide. The doping methods include ion implantation and thermal diffusion, and the common preparation method is ion diffusion.

[0073] Furthermore, the doping concentration of the lightly doped silicon region 9 is 10 16 -10 19 cm 3 The doped ion types are B and P.

[0074] The material of the insulating dielectric layer 7 includes but is not limited to silicon dioxide.

[0075] The insulating dielectric layer 7 may also be made of a high-k dielectric, such as hafnium dioxide (HfO 2 ), zirconium dioxide, hafnium silicate, zirconium silicate, or nitrided hafnium silicate or zirconium silicate.

[0076] Furthermore, the thickness of the insulating dielectric layer 7 is from 5 nm to 100 nm, and is typically 10 nm.

[0077] The deposition method of the insulating dielectric layer 7 includes, but is not limited to, thermal oxidation and various thin film deposition processes, such as CVD, PVD or ALD.

[0078] Furthermore, the bonding layer material includes but is not limited to silicon dioxide, hafnium dioxide (HfO2), zirconium dioxide, hafnium silicate, zirconium silicate, nitrided hafnium silicate, and zirconium silicate.

[0079] Deposition methods of the transparent electrode-N electrode include but are not limited to thermal oxidation and various thin film deposition processes, such as CVD, PVD or ALD.

[0080] The material of the transparent electrode (N electrode) includes TCO such as ZnO, ITO, FTO or ITiO.

[0081] Silicon dioxide will be deposited between the piezoelectric material 2 and the transparent electrode - the N electrode, which can be achieved through processes including but not limited to thermal oxidation and various thin film deposition processes, such as CVD, PVD or ALD.

[0082] The piezoelectric material 2 includes but is not limited to: PZT, AlN, BTO, etc.

[0083] The piezoelectric material 2 is deposited by a thin film deposition process, such as CVD, PVD or ALD.

[0084] The piezoelectric material 2 and the silicon-based device will be integrated through heterojunction bonding. Specifically, the piezoelectric material 2 is first deposited on a lattice-matched oxide substrate such as MgO. It is then integrated onto the microring modulator through wafer-to-wafer hydrophilic bonding. The substrate is then removed using an acidic material such as hydrochloric acid. Finally, the PZT is successfully heterojunction bonded to the microring modulator.

[0085] The thickness of the piezoelectric material 2 can be varied from 200 nm to 2 μm. The conversion efficiency ratio of stress to voltage can be controlled by adjusting the thickness and area of ​​the piezoelectric material 2 .

[0086] The electrostatic material 1 adopts the negative electrode electrostatic material 1, including Polyimide (Kapton), PDMS, and PTFE.

[0087] The metal electrode includes a metal material such as Au, Cu, or Al.

[0088] The contact metal material, such as the metal electrode, the metal electrode-P electrode 4, adopts a metal material such as Au, Cu or Al.

[0089] The working principle of the MOSCAP modulator system of the present invention that uses the piezoelectric effect to provide driving voltage is as follows:

[0090] When the device is subjected to external stress or friction, due to the PTENG effect, induced charge accumulation occurs between the electrostatic-piezoelectric material 2 and the transparent electrode-N electrode, thereby generating a potential difference. This is then connected to the lower electrode of the modulator through the electrostatic material 1 and the TSV through-hole 12, enabling current flow. PZT is selected as the piezoelectric material 2, PDMS is used as the electrostatic material, the thickness of the electrostatic material is 10μm, and the buffer layer is SiO2 with a thickness of 100nm. By designing different PZT film thicknesses to correspond to the PTENG structure, different induced voltages are generated, such as Figure 6As shown in the figure, it can be seen that PZT with different thicknesses generates different voltage values ​​under different external forces (mPa). Figure 6 (a) The thickness of PZT changes from 200nm to 2μm and is subjected to external pressure from 0MPa to 1.5*10 -2 MPa stress change. 1.5*10 -2 MPa is the pressure exerted by one foot of a 175cm tall male adult on the ground when running. Figure 6 (b) Figure 6 (a) 0~4*10 -3 MPa magnification shows that when the PZT thickness is greater than or equal to 600nm, the PTENG structure can stably provide a voltage of more than 5V to drive the micro-ring modulator for wavelength modulation. Due to the unique structure of the MOSCAP, the PTENG and the micro-ring modulator share a transparent electrode—the N electrode—which serves as the bottom electrode of the PTENG and the top electrode of the micro-ring modulator, respectively.

[0091] When a bias is applied to the bottom electrode and the transparent N-electrode of the MOSCAP, charge accumulates on these electrodes. This accumulation, through the plasma dispersion effect, affects the effective refractive index of the material at these locations. The optical field resonant mode is modulated based on the overlap between the optical field and the carrier accumulation region. According to the Drude model, the accumulated charge concentration is positively correlated with the change in the effective refractive index. In this design, the bottom electrode is a heavily doped region, and the capacitor's charge primarily accumulates on both sides of the insulating dielectric layer. This results in a high accumulated charge concentration, a significant change in the effective refractive index, and excellent electro-optical phase shifting performance.

[0092] By designing the insulating dielectric layer between the silicon ridge waveguide and the transparent electrode (N-electrode) with varying thicknesses, different microring modulator capacitance values ​​can be obtained, thereby achieving a high extinction ratio and low drive voltage while maintaining a large modulation bandwidth and rate. Furthermore, because the single-mode ridge waveguide of the microring modulator has excellent optical field confinement in the communication band, and the optical field distribution area is concentrated in the low-doping region, the overall optical communication loss is low.

[0093] When the PTENG capacitance is equal to the micro-ring modulator capacitance, that is, C PTENG =C mod When the bias voltage is applied to the modulator, the resonant wavelength of the microring modulator will also shift with the change of the bias voltage.

[0094] The electrostatic material is designed to be PDMS with a thickness of 10μm, the piezoelectric material is PZT with a thickness of 600nm, the bonding layer is SiO2 with a thickness of 100nm, the transparent electrode-N electrode is ZnO, the insulating dielectric layer is SiO2 with a thickness of 50nm, and the doping concentration of the lightly doped silicon region is 1*10 17 cm 3 The doping ion type is Boron, and the doping concentration of the heavily doped silicon area is 5*10 19 cm 3 , the doped ion species is Boron; the designed microring radius is 30μm, and the distance between the microring and the silicon ridge waveguide is 500nm. When the microring modulator applies a bias, the transmission spectrum results of the resonant wavelength changing with the bias are as follows Figure 7 As shown. Figure 7 The figure shows that the resonant wavelength of the microring modulator changes with increasing voltage, achieving a modulation efficiency of 23 pm / V. Because light field transmission is concentrated within the silicon ridge waveguide, only the doping concentration and structure of the silicon ridge waveguide, as well as the size and structural design of the microring, can influence the transmission spectrum. This allows for the flexible design of the insulating dielectric layer thickness within the MOSCAP structure, maintaining high modulation efficiency while matching the system capacitance of the PTENG, thereby achieving equivalent voltage conversion.

[0095] like Figure 7 As shown in the figure, the dotted line part is the initial setting of the resonant wavelength of the micro-ring modulator, 1550nm. From the above figure, the spectral transmittance of 1550nm under different bias voltages can be extracted, so the trend diagram of the periodic change of different spectral transmittances with voltage based on the micro-ring resonant wavelength can be obtained, as shown in the figure below. Figure 8 As shown in (a). Figure 8 (a) is the relationship between the micro-ring transmission spectrum and time under continuous stress in the PTENG+MOSCAP structure micro-ring modulator+MCU structure; the voltage periodic change trend diagram of the traditional PTENG structure directly connected to the external micro-controller (MCU) is shown in Figure 2. Figure 8 (b) When the PTENG structure is directly connected to the MCU, the induced charge generated will immediately flow out along the electrical conductor after being subjected to external stress, so the induced voltage is a pulse voltage. By introducing an optical modulator sensor between the PTENG and the MCU, the value of the induced voltage of the silicon-based micro-ring modulator depends on the capacitance value, that is, it is related to the thickness of the bonding layer 6 between the piezoelectric material 2 and the transparent electrode-N electrode in the PTENG structure. Therefore, the PTENG+MOSCAP structure micro-ring modulator+MCU structure can continuously produce a continuously changing transmission spectrum corresponding to changes in external stress, thereby more clearly separating the difference between the PTENG under external pressure and the PTENG without external pressure.

[0096] While maintaining compatibility with existing CMOS processes, only the insulating oxide thickness of the insulating dielectric layer 7 and the bonding layer 6 needs to be adjusted to control the PTENG capacitance and the micro-ring modulator capacitance. The former's adjustment is related to the voltage generated by external stress, while the latter's capacitance determines the modulation bandwidth and rate of the modulator. Furthermore, by epitaxially growing thin films of stress-sensitive materials such as PZT onto lattice-matched oxide substrates such as MgO, and then integrating them with existing silicon-based platforms through heterogeneous bonding, process modifications to CMOS process lines can be significantly reduced, while providing freedom in choosing the thickness of the stress-sensitive material. Ultimately, the availability of different PTENG structures provides a new platform for wearable devices.

[0097] The present invention also provides a sensor, which uses the MOSCAP modulator system of the present invention that utilizes the piezoelectric effect to provide a driving voltage.

[0098] Furthermore, the above-mentioned sensor is used to monitor changes in human body movement, blood sugar, and blood oxygen values.

[0099] The present invention also provides a resonant wavelength change monitoring system, comprising an MCU, a light detector, a laser, and the MOSCAP modulator system of the present invention that utilizes the piezoelectric effect to provide a driving voltage.

[0100] This solution proposes an integrated PTENG stress-voltage conversion platform, which is combined with the existing CMOS process. It is connected to a silicon-based microring modulator based on the MOSCAP structure, and through external photodetectors and lasers, it forms a monitoring system for the resonant wavelength change under continuous stress piezoelectric drive, thereby driving the microring modulator to realize applications such as sensors without an external power supply.

[0101] 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 principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A MOSCAP modulator system using a piezoelectric effect to provide a driving voltage, characterized in that: Able to achieve self-driving without external power supply, including: A piezoelectric triboelectric nanostructured power generation (PTENG) structure includes an electrostatic material, a piezoelectric material, a buffer layer connected between the electrostatic material and the piezoelectric material to act as a flat plate capacitor, a metal electrode (P electrode) connected to the electrostatic material, a transparent electrode (N electrode), and a bonding layer connected between the piezoelectric material and the transparent electrode (N electrode); and A MOSCAP micro-ring modulator based on a metal oxide semiconductor capacitor includes an insulating dielectric layer connected to a transparent electrode-N electrode on a side away from an intermediate piezoelectric material, a ridge waveguide based on an SOI substrate, and a heavily doped silicon region of a planar layer connected to the ridge waveguide; The transparent electrode-N electrode serves as the upper electrode of the micro-ring modulator at the same time. The transparent electrode material is deposited on the insulating dielectric layer through a deposition process. The heavily doped silicon region of the flat layer serves as the lower electrode of the micro-ring modulator. The lower electrode is connected to a contact electrode, and the contact electrode is a metal electrode.

2. The MOSCAP modulator system using piezoelectric effect to provide driving voltage according to claim 1, characterized in that: The piezoelectric material is integrated with the transparent electrode of the MOSCAP microring modulator through heterojunction bonding. The piezoelectric material is first deposited on an oxide substrate with a lattice match, and then integrated onto the microring modulator through wafer-to-wafer hydrophilic heterojunction bonding. After bonding, the substrate is first removed by etching, and then an electrostatic material film is attached to form the main structure of the PTENG. Finally, metal electrodes, metal electrode-P electrodes, and TSV through-holes are formed through metal deposition and silicon vias.

3. The MOSCAP modulator system using piezoelectric effect to provide driving voltage according to claim 1, characterized in that: The electrostatic material is a negative electrode electrostatic material, including but not limited to Polyimide, PDMS, and PTFE.

4. The MOSCAP modulator system using piezoelectric effect to provide driving voltage according to claim 1, characterized in that: The piezoelectric material includes but is not limited to: PZT, AlN, BTO. The bonding layer between the piezoelectric material and the transparent electrode-N electrode is realized by thermal oxidation or thin film deposition process. The thickness of the piezoelectric material is 200nm-2μm.

5. The MOSCAP modulator system using piezoelectric effect to provide driving voltage according to claim 1, characterized in that: The thickness of the insulating dielectric layer is 5 nm to 100 nm, and the deposition method of the insulating dielectric layer includes but is not limited to thermal oxidation and thin film deposition.

6. The MOSCAP modulator system using piezoelectric effect to provide driving voltage according to claim 1, characterized in that: The insulating dielectric layer material includes but is not limited to silicon dioxide, hafnium dioxide, zirconium dioxide, hafnium silicate, zirconium silicate, and nitrided hafnium silicate.

7. The MOSCAP modulator system using piezoelectric effect to provide driving voltage according to claim 1, characterized in that: The material of the transparent electrode-N electrode includes but is not limited to ZnO, ITO, FTO, and ITiO.

8. A resonant wavelength change monitoring system, characterized in that: The invention comprises an MCU, a light detector, a laser and the MOSCAP modulator system for providing driving voltage by utilizing piezoelectric effect as claimed in any one of claims 1 to 7.

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