Parallel Electrodes Research Articles

Research on Shape-Controllable Localized Heating Method Driven by Digital Microfluidics.

The localized heating technique, which minimizes high-temperature impact on thermally sensitive components and reduces impurity dispersion during encapsulation, has become a focal point in MEMS packaging research. In this study, we propose a method for localized heating at specific positions and shapes. A localized heating device, based on distributed electric field control, is constructed, where a polymer droplet on the lower substrate electrode is driven into a liquid column under the influence of a distributed electric field generated between two parallel substrate electrodes. ITO substrate electrodes with various patterns are fabricated, ensuring the shape of the formed liquid column matches the pattern. Leveraging the principles of heat transfer, the temperature of the polymer droplet is regulated via a heating stage to enable targeted heating of defined shapes and areas. Experiments delve into the impact of driving parameters on heating time and efficiency, with results affirming the proposed method's capability to govern localized heating for particular regions and configurations accurately.

Optical tweezer-assisted cell pairing and fusion for somatic cell nuclear transfer within an open microchannel.

Somatic cell nuclear transfer (SCNT), referred to as somatic cell cloning, is a pivotal biotechnological technique utilized across various applications. Although robotic SCNT is currently available, the subsequent oocyte electrical activation/reconstructed embryo electrofusion is still manually completed by skilled operators, presenting challenges in efficient manipulation due to the uncontrollable positioning of the reconstructed embryo. This study introduces a robotic SCNT-electrofusion system to enable high-precision batch SCNT cloning. The proposed system integrates optical tweezers and microfluidic technologies. An optical tweezer is employed to facilitate somatic cells in precisely reaching the fusion site, and a specific polydimethylsiloxane (PDMS) chip is designed to assist in positioning and pairing oocytes and somatic cells. Enhancement in the electric field distribution between two parallel electrodes by PDMS pillars significantly reduces the required external voltage for electrofusion/electrical activation. We employed porcine oocytes and porcine fetal fibroblasts for SCNT experiments. The experimental results show that 90.56% of oocytes successfully paired with somatic cells to form reconstructed embryos, 76.43% of the reconstructed embryos successfully fused, and 70.55% of these embryos underwent cleavage. It demonstrates that the present system achieves the robotic implementation of oocyte electrical activation/reconstructed embryo electrofusion. By leveraging the advantages of batch operations using microfluidics, it proposes an innovative robotic cloning procedure that scales embryo cloning.

Mechanically neutral and facile monitoring of thermoset matrices with ultrathin and highly porous carbon nanotube films

We examine how the physical features of single-walled carbon nanotube (SWCNT) thin films can affect monitoring thermoset polymers during their manufacturing and application. Film thickness (23, 37 and 53 nm), electrode materials and configuration, and embedding within or surface application on a polymer were all investigated. During manufacturing monitoring, thicker films provided higher sensitivity than thinner ones (ΔR/R0 = 111% (53 nm) vs. 74% (23 nm)). Electrode material and configuration showed that sputtered gold contacts allow higher sensitivity and reliability compared with conductive silver adhesive, and that parallel electrode placement provides more distinct and discreet stage measurements compared to diagonal one. The opposite trend was noted for mechanical loading, where thinner films provide a higher piezoresistive response and embedded films outperform surface applied sensors (gauge factors between 23-86 and 4-10, respectively). All thin films accurately measured curing stages as well as mechanical changes and are shown to be self-adjusting when the force increases during mechanical loading. We show that manufacturing monitoring should rely on uniformly deposited electrodes and thicker films for identification of polymerization stages, whereas embedding thinner films in the matrix is recommended for highly sensitive deformation monitoring. This work outlines how simple, overlooked parameters can easily be varied to optimize the dual-stage monitoring performance of CNT-based sensors and helps to identify what parameters should be chosen for specific applications.

High sensitivity measurement of ULF, VLF, and LF fields with a Rydberg-atom sensor.

Fields with frequencies below megahertz are challenging for Rydberg-atom-based measurements, due to the low-frequency electric field screening effect caused by the alkali-metal atoms adsorbed on the inner surface of the container. In this paper, we investigate electric field measurements in the ultralow frequency (ULF), very low frequency (VLF), and low frequency (LF) bands in a Cs vapor cell with built-in parallel electrodes. With optimization of the applied DC field, we achieve high-sensitive detection of the electric field at frequencies of 1 kHz, 10 kHz, and 100 kHz based on the Rydberg-atom sensor, with the minimum electric field strength down to 18.0 μV/cm, 6.9 μV/cm, and 3.0 μV/cm, respectively. The corresponding sensitivity is 5.7 μV/cm/Hz1/2, 2.2 μV/cm/Hz1/2, and 0.95 μV/cm/Hz1/2 for the ULF, VLF, and LF fields, which is better than a 1-cm dipole antenna. Besides, the linear dynamic range of the Rydberg-atom sensor is over 50 dB. This work presents the potential to enable more applications that utilize atomic sensing technology in the ULF, VLF, and LF fields.

PID controller design for manipulating electrorheological valves with mesh electrodes using in 2D matrix display

Abstract The electrorheological (ER) valve with parallel electrodes structure has an inherent characteristic. The electrodes gap is the same as its flow channel gap, which causes a strong coupling relationship between the applied voltages and the flow rates of the ER valve. If flow rates of ER valves in the condition of turn on operational mode were increased, their applied voltages were increased necessarily for keeping their shutdown operational mode, which brings a bunch of problems of product costs and dimensions, especially when multiple ER valves with different operational modes work together, such as application of ER valves matrix used in 2D matrix displays. The mesh electrodes structure can decouple the relationship between the electrodes gap and the flow channel gap of parallel electrodes structure. However, due to the complexity of mesh electrodes structure, a mathematic model is difficult to be established theoretically. And, a mathematic model of ER valve with mesh electrodes plays a vital role in designing its controller. By analyzing the composition elements of an ER valve with mesh electrodes, a semi experimental model was established using the parametric identification toolbox of MATLAB. The consistency between the output of recognition model and the output of validation data reaches 93.46%. Subsequently the PID controller for ER valves with mesh electrodes was designed to meet the operational demands of a 2D matrix display using Simulink. The constrain of simulation was that the pressures of flow channel inlets of ER valves, the dynamic responses of ER valves with mesh electrodes kept stable and within its operational range. The results will be helpful for applications of ER valves with mesh electrodes.

Bifurcation and dynamics of periodic solutions of MEMS model with squeeze film damping

In this paper, we study the oscillations of an idealized mass–spring model of micro-electro-mechanical system (MEMS) with squeeze film damping. The model consists of two parallel electrodes separated by a gap d: one of them is fixed, and another one is movable and attached to a linear spring with stiffness coefficient k>0. The oscillation, under the influence of AC–DC voltage V(t)=vdc+vaccos2πTt, is ruled by the following singular differential equation my′′+[A(d−y)3+Ad−y]y′+ky=θ0A2V2(t)(d−y)2.Here, y is the vertical displacement of the moving plate (y is always assumed to be less than d), m>0 is its mass, A>0 is the electrode area, and θ0>0 is the absolute dielectric constant of vacuum. Taking d as the parameter, we show the existence of saddle–node bifurcation of T-periodic solutions to the equation in the parameter space. This answers, from certain point of view, the open problem proposed by Torres in his monograph, see Torres (2015, Open Problem 2.1, p. 18). Further, we prove that the equation has exactly two classes of T-periodic solutions: as d tends to +∞, one of them uniformly tends to +∞ at the rate of d, while the minimum values of the second class tend to, or cross, 0.

Integrated design and performance optimization of three-electrode sliding discharge plasma power supply

The three-electrode sliding dielectric barrier discharge (TES-DBD) plasma actuator significantly enhances the ionization rate and momentum exchange between charged particles and neutral particles by incorporating a parallel DC electrode into the standard DBD design. This design improves the body force and induced jet velocity while allowing flexible control of the induced jet angle, overcoming the limitations of discharge extension and uncontrollable direction in traditional DBD plasma actuators. An integrated plasma power supply has been designed specifically for TES-DBD plasma actuators, streamlining the power supply management. The methodology involves designing the circuit topology for the TES-DBD power supply, followed by simulating and validating its operating principles using Multisim software. The operational performance of the power supply is evaluated through a comprehensive analysis of its electrical, thermal, and aerodynamic properties specific to TES-DBD plasma actuation.

Determination of the electron temperature and electron density in reduced pressure hydrogen peroxide (H2O2) discharge.

A reduced pressure glow discharge is produced by passing a high-power pulsed DC source of 0-500W with a frequency of 50Hz across two parallel disk electrodes. A hydrogen peroxide aqueous solution is used as a flowing gas for discharge generation. Optical emission spectroscopy is employed to diagnose the discharge generated at a reduced pressure of 0.2mbar with an electrode gap of 4cm. The spectra are recorded at a power density of 9.4 mW/cm3 and typically lie in the visible wavelength range of 380-880nm. The spectra are analyzed using the line intensity ratio method to estimate electron temperature and density. The results indicated that the electron temperature and density are, respectively, 0.87eV and 6.4 × 1014cm-3.

Gold Nanoparticle (GNP) Enhanced Electroporation of Extracellular Vesicles to Promote Gene Loading

Gene therapy is an emerging and powerful therapeutic tool for treating diverse diseases via functional genetic material delivery to targeted defective genes in cells. Extracellular vesicles (EVs) are natural carriers released by all living cells, which are gaining attention for usage in advancing efficiency of therapeutic delivery due to their various advantageous properties, including; (i) cargo protection from enzymatic degradation, (ii) tissue-specific targeting, and (iii) high biocompatibility. EVs can be isolated from a targeted set of cells and used for therapeutic delivery as they can travel back to the same cell type due to their unique surface proteins and markers to release the genes at the specified site. One of the leading methods for cargo transfection into EVs is electroporation, which utilizes short-duration voltage pulses to create pores on the EV surface membrane, during which the cargo can enter. The voltage creates a potential difference between the less electrically conductive EV membrane and the more electrically conductive internal and external EV environments leading to the formation of these pores. This process is limited by the maximum pulse amplitude and duration the EVs can withstand for maximum pore formation and cargo encapsulation while still permitting membrane recovery afterward. We specifically use microfluidic electroporation, which we have previously found to be the most efficient in loading. This technique utilizes water-in-oil droplet encapsulation of the EVs which are then electroporated by voltage application as they pass through parallel metal electrodes. As the droplets pass through the microfluidic device, the non-conductive oil phase creates a barrier allowing for specific consistent and short-pulsed voltage delivery for each EV-encapsulated conductive water droplet [1]. We aim to increase efficiency of gene therapy loading into EVs using gold nanoparticle (AuNP) enhanced electroporation to provide higher concentration, targeted, and protected gene delivery. It has been shown that AuNP can increase the loading into cells during electroporation by allocating the electric voltage onto the cell surface creating a pulse strength focusing effect, allowing more pore formation without increasing the total voltage applied [2]. Due to similar surface properties, we hypothesized that AuNPs would provide a similar increase in transfection of EVs. To test this hypothesis, we electroporated green fluorescence protein (GFP) into EVs with the introduction of AuNPs at various concentrations. Fluorescence analysis through Cytation 5 and EV concentration measurement with Nanoparticle Tracking Analysis (NTA) revealed a close to double increase in the GFP molecules per EV with the AuNP incorporation. Assessment with NTA and Transmission Electron Microscopy showed that the AuNPs did not significantly change the size, concentration, zeta potential, or morphology of the EVs, compared to the native EVs without electroporation, for retaining the EV originality and integrity. Overall, AuNPs have the capacity to increase cargo transfection into EVs, allowing high-efficiency packaging for specific therapy delivery to enhance effectiveness of the treatment.[1] Geng, T., & Lu, C. (2013). Microfluidic electroporation for cellular analysis and delivery. Lab Chip, 13(19), 3803–3821. https://doi.org/10.1039/c3lc50566a[2] Zu, Y., Huang, S., Liao, W.-C., Lu, Y., & Wang, S. (2014). Gold Nanoparticles Enhanced Electroporation for Mammalian Cell Transfection. Journal of Biomedical Nanotechnology, 10(6), 982–992. https://doi.org/10.1166/jbn.2014.1797 Figure 1

High‐Performance Flexible PbS Nanofilm Wavelength Sensor with Detection Region Ranging from DUV to NIR

AbstractIn this study, on the fabrication of a flexible wavelength sensor is reported, which is achieved by growing a layer of lead sulfide (PbS) nanofilm on both sides of a polyethylene terephthalate substrate using the chemical bath deposition method, followed by the deposition of two parallel Au interdigital electrodes. Experimental result shows that the photocurrent ratio of the two photodetectors monotonically decreases with increasing wavelength in the range from 265 nm (UV) to 2000 nm (NIR), indicating that the incident light wavelength can be distinguished by the photocurrent ratio. Notably, the as‐constructed wavelength sensor exhibits superior performance compared to most previously reported filter‐less designs, achieving an average absolute error of 11.5 nm and an average relative error of 1.1%. It is also found that the sensor exhibits excellent mechanical flexibility and environmental stability. Furthermore, by introducing the back‐end circuit, real‐time detection of the wavelength of monochromatic light and the peak wavelength of LED light are achieved, with detection errors not exceeding 2.8% and 2.6%, respectively. It is believed that the flexible PbS nanofilm wavelength sensor prepared in this study has potential application in future portable and flexible optoelectronic devices.

Impedance Characteristics of Microfluidic Channels and Integrated Coplanar Parallel Electrodes as Design Parameters for Whole-Channel Analysis in Organ-on-Chip Micro-Systems.

Microfluidics have revolutionized cell culture by allowing for precise physical and chemical environmental control. Coupled with electrodes, microfluidic cell culture can be activated or have its changes sensed in real-time. We used our previously developed reliable and stable microfluidic device for cell growth and monitoring to design, fabricate, and characterize a whole-channel impedance-based sensor and used it to systematically assess the electrical and electrochemical influences of microfluidic channel boundaries coupled with varying electrode sizes, distances, coatings, and cell coverage. Our investigation includes both theoretical and experimental approaches to investigate how design parameters and insulating boundary conditions change impedance characteristics. We examined the system with various solutions using a frequency range of 0.5 Hz to 1 MHz and a modulation voltage of 50 mV. The results show that impedance is directly proportional to electrode distance and inversely proportional to electrode coating, area, and channel size. We also demonstrate that electrode spacing is a dominant factor contributing to impedance. In the end, we summarize all the relationships found and comment on the appropriateness of using this system to investigate barrier cells in blood vessel models and organ-on-a-chip devices. This fundamental study can help in the careful design of microfluidic culture constructs and models that require channel geometries and impedance-based biosensing.

Experimental and theoretical investigations of the threshold actuation voltages of aqueous solutions, glycerol–water solutions, and ethanol–water solutions on a coplanar electrode device

In digital microfluidics, actuation voltage is critical in droplet manipulation using electrowetting-on-dielectric. Compared to parallel electrode devices, the droplet manipulation on coplanar electrodes requires a higher actuation voltage due to its structure. This study derives an equation related to the threshold actuation voltage and many critical parameters (applied frequency, surface tension, fluid conductivity, droplet volume, dielectric thickness, etc.). Our developed model has three innovations: (1) liquid and device parameters related to the threshold actuation voltage are integrated into the model, (2) the absolute value of the complex permittivity of the fluid is added into our model to clarify the conductivity-dependent and frequency-dependent threshold actuation voltage, and (3) the extrand model is used to derive the effects of the surface tension, contact angles, and droplet radius on the threshold actuation voltage. Additionally, we used many solutions for biochemical and biomedical assays—DI (Deionized) water, DMEM (Dulbecco's Modified Eagle Medium), PBS (phosphate buffered saline), glycerol–water solutions, ethanol–water solutions, potassium chloride solutions, and sodium chloride solutions—to verify the developed Vth in our model. By using the model and conducting an experiment, we investigated the Vth of different liquids on coplanar electrodes. Our model can successfully explain the difference of Vth between these solutions on coplanar electrode devices. The model and experimental data can be utilized to predict the actuation voltage for a broad range of buffers and organic solvents on coplanar electrodes.

A wireless-feeding capacitive electrode mechanism for achieving massive nanosecond parallel-discharge EDM for large-size wafer flattening

The single-crystal silicon carbide (SiC) wafer diameter is increasing beyond 8 in posing significant challenges to conventional mechanical wafer-processing methods. This study presents an innovative capacitive electrode method for electrical discharge flattening (EDF) of as-sliced large 4H-SiC wafers. The capacitive electrode can be divided into near-infinite units, which significantly reduces the working gap capacitance and enables the generation of a mass of parallel discharges with a nanosecond pulse duration (< 200 ns). This approach offers significant advantages in achieving high efficiency and surface finish simultaneously, regardless of the increase in wafer size. This novel electrode design allows wireless electricity feeding via electrostatic induction, which significantly facilitates the integration of parallel electrode units. Furthermore, a sinusoidal voltage is demonstrated for the first time to identify and promote a parallel discharge state. A model was devised to quantitatively describe the overall process. Using this model, the relationship between the gap voltage, discharge energy, and capacitive electrode properties was predicted, revealing a parallel discharge mechanism. The capacitive electrode mechanism was validated via EDF experiments on a 4H-SiC wafer. Notably, >33 parallel discharges within 6 μs were achieved in a single pulse, resulting in a minimum discharge energy of 0.312 μJ (peak current: 0.18 A, duration: 160 ns) and a surface roughness of Ra 42 nm. Moreover, a machining speed of 0.5 μm/min was achieved on a 4 in wafer, representing an improvement of an order of magnitude compared to conventional non-parallel discharge methods.

MXene-Deposited Melamine Foam-Based Iontronic Pressure Sensors for Wearable Electronics and Smart Numpads.

Iontronic pressure sensors hold significant potential to emerge as vital components in the field of flexible and wearable electronics, addressing a variety of applications spanning wearable technology, health monitoring systems, and human-machine interactions. This study introduces a novel iontronic pressure sensor structure based on a seamlessly deposited Ti3C2Tx MXene layer onto highly porous melamine foam as parallel plate electrodes and an ionically conductive electrolyte of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/thermoplastic polyurethane coupled with carbon cloth as current collecting layers for improved sensitivity and high mechanical stability of more than 7000 cycles. MXene-deposited melamine foam-based iontronic pressure sensors (MIPS) showed a high sensitivity of 5.067 kPa-1 in the range of 45-60kPa and a fast response/recovery time of 28/18ms, respectively. The high sensitivity, high mechanical stability, and fast response/recovery time of the designed sensor make them highly promising candidates for real-time body motion monitoring. Moreover, sensors are employed as a smart numpad for integration into advanced ATM security systems utilizing machine learning algorithms. This research marks a significant advance in iontronic pressure sensor technology, offering promising avenues for application in wearable electronics and security systems.

Detection of Ultraviolet Light by Graphene Oxide Derived from Epitaxial Graphene on SiC and Graphite.

Because of their tunable band gap, flexibility, and high surface-to-volume ratio, two-dimensional materials have appeared as the most promising materials for ultraviolet (UV) light sensors. Here, we report the detection of UV light by oxidized epitaxial graphene (EG) formed on the Si-face of the SiC substrate and graphene oxide (GO) produced by Hummer oxidation of graphite. Both epitaxial graphene oxide (EGO) and GO were characterized by Raman and X-ray photoelectron spectroscopy, and the devices were made simply by placing two parallel copper electrodes onto the graphene oxide layers. Irradiation of UV light onto the graphene oxides was realized by the real-time current measurements between two electrodes at a fixed bias of 1 V. The sudden upward jump of the current (Ids) upon UV light irradiation was observed in both EGO- and GO-based devices, which were returned to the original value, while the UV source was turned OFF. The photocurrent (I ph), the magnitude of the current jump by the UV irradiation, for EGO, was estimated at 8 mA with a channel distance of 2 mm and UV power of 80 mW/cm2. The I phlinearly increases with UV power. In the case of GO, I phwas estimated at 0.2 nA with a similar setup. The photoresponse time and responsivity for EGO are ∼11 s and 5.6 A/W, respectively, which are higher than those of GO. The quantum efficiencies (η) for EGO and GO are calculated as 1907 and 2.3 × 10-6 %, respectively, with an incident power of UV light at 9 mW/cm-2. Because of the advantages of the EG on SiC concerning the stability and wafer scale growth, the present study is expected to lead the development of lab-on-chip-based ultrasensitive UV sensors.

Effects of electrode configuration on the current density distribution of the electrolytic reducer

Pyroprocessing for the recycling of light water reactor spent fuel into metal nuclear fuel involves the electrolytic reduction process to convert oxides into metals. Optimization of the electrolytic cell is essential in the current engineering-scale development stage of electrolytic reduction research. This study investigates the effects of the conventional impermeable anode shroud, typically used in the development of laboratory-scale electrolytic reducers, and the effects of parallel multiple electrode configurations, aimed at the scale-up of the electrolytic reducer, on the current density distribution of the electrolytic reducer. The current density distribution was analyzed using COMSOL modeling. The exclusion of the impermeable anode shroud resulted in increased total currents under constant cell voltage conditions and contributed to the narrowing of the current density distribution on the electrodes. In addition, parallel multiple electrode configurations proved effective in increasing total currents and narrowing the current density distribution on the electrodes. These results emphasize the need to use a permeable anode shroud and a parallel multiple electrode configuration to scale-up the electrolytic reducer.

Spatially resolved capacitance-based stress self-sensing in concrete

Spatially resolved capacitance-based stress self-sensing in unmodified concrete has been demonstrated. The spatial resolution is 45 mm in one dimension, which is in the direction of the capacitance measurement. Parallel coplanar component electrodes (aluminum, 5-mm wide), attached to the concrete using double-sided adhesive tape) separated by 45 mm are used to measure the in-plane capacitance in the direction perpendicular to the length of the electrodes. Combinations of component electrodes are electrically connected to form an electrode. The capacitance ranges from ∼200 pF to ∼750 pF. The greater is the number of component electrodes in an electrode, the higher is the capacitance. The compressive loading is applied at selected areas located between adjacent component electrodes. The stress (defined as load divided by the 300 ×300-mm2 concrete area) is up to 3000 Pa. The load decreases the capacitance monotonically and reversibly. The fractional decrease in capacitance ranges from ∼0.1 % to ∼0.5 %. More spatially concentrated loading, as for loading near the edges of the specimen, gives greater fractional decrease in capacitance. The capacitance decreases with increasing inter-electrode distance. Embedded steel rebars with a 20.0-mm concrete cover do not affect the capacitance or capacitance-based sensing.

A Novel EWOD Platform for Freely Transporting Droplets in Double and Single-Plate Structures.

This study developed a novel dielectric wetting microfluidic operation platform combining parallel-plate and coplanar-plate regions with a curved surface structure as the connection structure. With the new electrowetting on dielectric (EWOD) platform, "droplet pull-out" has been successfully achieved and viewed as an essential new operation for microfluidics with the dielectric wetting technique. The EWOD system is divided into a PDMS substrate top plate and an indium tin oxide (ITO) glass substrate as a bottom layer on this chip. In the parallel-plate region, the droplets can be generated and transported through the square parallel electrodes; in the single-plate area, the droplets can be pulled out from the parallel structure, transported and mixed through the common grounded coplanar electrodes. In dielectric wetting performance testing, coplanar electrodes can apply a maximum driving force of 31.22 µN to DI water and 13.38 µN to propylene carbonate (PC). This driving force is sufficient to detach the sample from the top cover and pull the sub-droplet from the parallel plate structure for DI water, PC and polyethylene glycol diacrylate (PEGDA) buffer. The novel EWOD system also possesses the advantage of precise volume control for liquid samples; the volume error of the generated droplet can be controlled within 0.1% to 2%.

Long‐Range Charge Carrier Transport in Planar Polymer Bulk‐Heterojunction Photovoltaic Cells

One‐dimensional scanning optical beam‐induced current (OBIC) measurements have been carried out on polymer bulk heterojunction (BHJ) photovoltaic cells with a planar, or lateral configuration. The planar P3HT:PCBM cells have parallel aluminum or gold electrodes that are 390 to 560 micrometers apart. When a focused laser beam is scanned across the electrode gap, photocurrent or photovoltage is recorded as a function of beam position along with the transmission of the excitation beam. Despite the large electrode gap size, cells with symmetric Al/Al electrodes exhibit significant photocurrent and photovoltage which are the highest at the electrode interfaces and null at the cell center. The OBIC in these large planar polymer BHJ cells is attributed to the metal/BHJ blend Schottky junction. The larger Schottky barrier of the Al/BHJ junction gives rise to a stronger OBIC response than the Au/BHJ junction. The photocurrent and photovoltage always have opposite signs and are antisymmetric about the cell center. In asymmetric Al/Au cells, the electrode work function difference contributes an additional built‐in field/potential drop and significantly modifies the photocurrent and photovoltage profiles. The depletion width of the Al/BHJ Schottky junction is 110–120 μm, while the minority electron diffusion length is determined to be 43.8 μm.

Design and analysis of mode-matched decoupled mass MEMS gyroscope with improved thermal stability

This paper presents an efficient design approach for microelectromechanical systems (MEMS) gyroscope considering the design constraint of MEMSCAP’s Silicon-on-Insulator Multi-User MEMS Processes (SOIMUMPs). A design for a decoupled mass MEMS resonant gyroscope with tuning electrodes is presented to minimize cross-axis coupling and optimize the gyroscope’s performance. The device features a size of 1.8 ×2.772 mm2 . A decoupled mass MEMS gyroscope has been designed using a novel mechanical beam configuration that optimizes the structural design to reduce unwanted interactions between drive and sense axes motions. Mode order has been achieved by obtaining the first two modes as drive and sense modes at 9946.3 Hz and 10 202.7 Hz, respectively. Parallel plate electrostatic tuning electrodes have been added to adjust and match the drive and sense modes at the resonant frequencies of 9946 Hz. This mode matching is crucial for optimizing gyroscope performance, accuracy, and sensitivity. The effects of temperature variation on the performance of the designed decoupled mass MEMS gyroscope have been investigated, particularly in terms of its mode-matched operation achieved using tuning electrodes. Finite element method (FEM) simulations were conducted, demonstrating that thermal stability was achieved, and mode-matched operation was maintained within the temperature range of −40 °C to 80 °C. The gyroscope exhibits enhanced performance compared to existing MEMS gyroscopes under mode-matched conditions, featuring a lower temperature coefficient of frequency (TCF) at 0.0415 Hz °C−1 in the drive mode and 0.0165 Hz °C−1 in the sense mode. FEM analysis for the fabrication process tolerances has been done, where MEMS gyroscope’s resonant frequencies, output capacitance, output displacement, and sense mode quality factor have shown negligible changes to fabrication process tolerances. Transient analysis was conducted using CoventorWare MEMS+ 3D schematic, which was integrated with MATLAB Simulink to measure the MEMS gyroscope’s output response, which corresponded with the varying input angular velocity signal.