Trigger Voltage Research Articles

High Area Efficiency Bidirectional Silicon-Controlled Rectifier for Low-Voltage Electrostatic Discharge Protection

Continuously scaling down and decreasing operation voltages of ICs, from the 5 V TTL-compatible voltage to 3.3 V, then 1.2 V, and now 0.8 V for low-power ICs, results in more stringent electrostatic discharge protection design requirements, such as a narrow ESD design window, low operation voltage, and high ESD robustness. Based on traditional diode string and diode-triggered silicon-controlled rectifiers, an enhanced diode-triggered silicon-controlled rectifier is proposed to meet the requirements of low-voltage integrated circuits as bidirectional electrostatic discharge protection. The new device employs an additional PMOS and NMOS in the N-well and P-well, respectively, to offer additional current paths along the surface to significantly enhance its robustness. TCAD simulation shows that the device is triggered by both the diode strings and embedded MOS, making the device turn on faster and the current distribution more uniform during the ON state owing to the additional surface current paths. The proposed new device has excellent dual-directional ESD protection performance with a figure of merit of 4.01 mA/um2, which is about a 71% improvement compared with the conventional diode-triggered silicon-controlled rectifier. It also has higher area efficiency, lower trigger voltage, lower current leakage, and a faster turn-on speed. The proposed enhanced diode-triggered silicon-controlled rectifier is an attractive ESD protection solution for ultra-low-voltage ICs.

Fluorination-mitigated high-current degradation of amorphous InGaZnO thin-film transistors

As growing applications demand higher driving currents of oxide semiconductor thin-film transistors (TFTs), severe instabilities and even hard breakdown under high-current stress (HCS) become critical challenges. In this work, the triggering voltage of HCS-induced self-heating (SH) degradation is defined in the output characteristics of amorphous indium-gallium-zinc oxide (a-IGZO) TFTs, and used to quantitatively evaluate the thermal generation process of channel donor defects. The fluorinated a-IGZO (a-IGZO:F) was adopted to effectively retard the triggering of the self-heating (SH) effect, and was supposed to originate from the less population of initial deep-state defects and a slower rate of thermal defect transition in a-IGZO:F. The proposed scheme noticeably enhances the high-current applications of oxide TFTs.

A Pulsewidth Adjustable Trigger Method for Reverse Blocking Diode Thyristor to Suppress Current Filamentation and Improve di/dt Capability

In this paper, to suppress the current filamentation and improve di/dt capability, a pulse width adjustable trigger method based on Marx generator for reverse blocking diode thyristor (RBDT) is proposed. The importance of trigger voltage pulse width for RBDT is firstly illustrated. The influence of the width of the voltage trigger pulse on RBDT is simulated in TCAD and verified by experiments. It is turned out that the turn-on delay time can be reduced when the width of voltage trigger pulse is shorter than 800ns. When the width of the voltage trigger pulse further increases, the turn-on delay time becomes saturated. It is shown in the simulations that wider trigger voltage pulse can suppress the current filamentation in RBDT. The simulation result is validated by comparative experiments with two different widths of voltage trigger pulse generated by Marx generator at different main voltages. The switching loss of RBDT triggered by voltage pulse width of 1000ns is smaller than that by voltage pulse width of 240ns under the same condition. Besides, RBDT triggered by voltage pulse width of 1000ns can even survive when the maximum di/dt per unit area is about 16.7kA/μs/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at the main voltage of 970V. However, RBDT triggered by voltage pulse width of 240ns fails at the main voltage of 920V. Finally, the sensitivity of the proposed trigger method is verified.

A novel robust SCR with high holding voltage for on-chip ESD protection of industry-level bus

In an industry-level bus, strong electrostatic interference seriously threatens the reliability of chips. However, the holding voltage (Vh) and robustness of traditional silicon-controlled rectifier (SCR) cannot meet the electrostatic discharge (ESD) window of industry-level applications. To better cope with extreme environments, this paper proposes a novel SCR with high robustness and latch-up immunity for on-chip ESD protection of the industry-level RS485 bus. By incorporating a surface current diverting path into the traditional SCR, the ESD characteristics of the proposed device are significantly improved. Through two-dimensional device simulation, the ESD characteristics of traditional SCR, proposed P-Well Floating SCR (PFSCR) and proposed P-Well Grounded SCR (PGSCR) are compared, with a focus on exploring the role of surface discharge path. Three types of SCR are realized based on the 0.18 μm BCD process. The transmission line pulse (TLP) test results show that PGSCR (13.64 V) has a higher Vh and higher robustness than traditional SCR (2.13 V) and PFSCR (4.39 V). In addition, the trigger voltage (Vt1:22.9 V) and failure current (It2:18.49A) of the PGSCR fully meet the ESD window of the target chip.

A microplasma device and its switching behavior triggered by modulated pulse signal

Since the physical and electrical properties of plasmas are similar to those of semiconductor devices, plasma devices have been proposed to be good candidates for switching controlled devices when applied in harsh environments. In the proposed paper, a microplasma device with a dielectric barrier structure constructed with three electrodes (two driven electrodes and one trigger electrode) is fabricated, and the electrical characteristics of the proposed device are investigated in 2 kPa of argon. From the experimental results, a stable conducting current is obtained through the two driven electrodes in the device due to gas discharge, since the hysteresis characteristic of discharge plasmas (discharge is still maintained when the driven voltage is below the breakdown voltage of the gas because of the existence of residual charge particles), the device can be switched from the OFF to ON state through pre-discharge by a pulse applied to the trigger electrode. While in the device ON state, this trigger voltage attracts channel charged particles to the surface of the dielectric layer, quenching the discharge plasma current and the device can be switched from ON to OFF state. The trigger pulse that makes the device switch successfully goes from single to continuous up to 80 kHz. The influence of pulse parameters on the switching process is also investigated, pulse amplitude and pulse width are found to be important to determine whether the device can switch ON or OFF, peak current after switching, and the response speed of switching ON current; however, these switching parameters are barely affected by the rise and fall time of the pulse. The results are significant for the application of microplasma switching devices.

Temperature dependent polaronic contribution on conduction mechanism in ceria-based devices

The role of temperature dependent polaron density in current conduction mechanism of CeO2-based devices is investigated where CeO2−x films were deposited at different Ar:O2 ratios at room temperature using rf sputtering. I–V measurements on metal–oxide–semiconductor (MOS) devices at different temperatures show a three order current change in unipolar and bipolar switching having triggering voltages ranging from ±0.7 V at 80–100 °C to ∼±1.0 V at 150 and 200 °C and are reproducible in repeat cycles. Temperature dependent x-ray photoelectron spectroscopy (XPS) and grazing incidence x-ray diffraction (GIXRD) studies indicate along with stoichiometry dependent polaron contribution, the change in lattice parameters of polycrystalline CeO2 film also contributes to the resistive switching properties of CeO2-based devices with temperature. Oxygen vacancy movements in the form of hopping of polarons between the nearest neighbours and next to nearest neighbour sites as well facilitate the transitions at elevated temperatures. As predicted in the theoretical model, it is experimentally verified here that the conduction path created at elevated temperature vanishes at relatively higher temperatures due to too frequent polaron hopping. It is further observed that the density of polarons also increases with temperature that in turn hinders the switching behaviour of the devices at elevated temperatures.

A Marx generator based on thyristors triggered in a shock ionization wave mode

Recently, a new trigger mode of thyristor which is called shock ionization wave mode is researched. Compared with the conventional trigger mode, this trigger mode can turn on the thyristor rather fast. In this mode, a trigger voltage with a high amplitude and fast rising speed is applied at both ends of the thyristor. Many single-tube conduction experiments are reported while the conduction threshold of shock ionization wave mode has not been investigated. Besides, the application of this trigger mode in some pulse power topology remains blank which is useful for this mode. In this paper, to explore the impact ionization wave mode conduction threshold of commercial thyristor, fast front high voltage nanosecond pulses are generated by avalanche tube Marx circuit. Pulse signals of different amplitudes are realized through the voltage division resistor. The impact ionization wave mode trigger threshold for commercial thyristors is about 2500 V in amplitude and 250 V/ns in voltage rising speed and the higher the rated parameter of the thyristor, the higher the threshold. To broaden the application of this mode, a novel Marx generator based on thyristors is proposed. A four-stage Marx generator is constructed and the amplitude of the output voltage can reach 1869 V.

Study on discharge characteristics of six-gap gas switch with corona assisted triggering.

To improve the triggering characteristics of the gas switch used for linear transformer driver, a method of corona assisted triggering based on the pre-ionization in switch gaps is proposed and applied to a six-gap gas switch. The principle is demonstrated by electrostatic field analysis and verified by the experimental study on the discharge characteristics of the gas switch. The results indicate that when the gas pressure is 0.3 MPa, the self-breakdown voltage remains about ±80kV, and its dispersivity is lower than 3%. The effect of corona assisted triggering on the triggering characteristics increases with the higher permittivity of the inner shield. The positive trigger voltage of the switch with the proposed method can be reduced from 110 to 30kV at a charging voltage of ±80kV when the jitter is equal to that of the original switch. There are no pre-fire or late-fire when the switch operates continuously for 2000 shots.

Numerical modeling of different streamer breakdown modes of gas switch under the external circuit

Gas spark switches had been applied extensively in the field of pulse power technology on account of the advantages of a simple structure, short breakdown time, and high through-current capability. This paper investigates the streamer breakdown process in a two-electrode switch in a nitrogen environment under atmospheric pressure using a numerical method. First, a two-dimensional fluid simulation was carried out for the streamer generated under the negative and positive trigger voltages, and the difference in the breakdown mechanism in the two modes was analyzed. The study showed that when a negative trigger voltage is applied to the rod electrode, a negative streamer from the cathode to the anode will first be formed, and then a positive streamer from the anode to the cathode will be formed. When a positive trigger voltage is applied to the rod electrode, the streamer propagation mechanism is significantly different from that obtained when a negative voltage is applied. In this case, the breakdown mode is a cathode-directed streamer. Finally, we investigated the effect of circuit parameters on the breakdown process. The time scale of breakdown varies greatly with the capacitance. The significant difference in the breakdown process may come from the charging process of the capacitor. The larger the capacitance is, the slower the charging process will be.

Opportunities and Challenges in Power Management Systems for Triboelectric Nanogenerators

Triboelectric nanogenerators (TENGs) have tremendous potential for generating energy from ambient mechanical energy and human motion. It is impossible to use a TENG as a power source for an electronic system due to its high-voltage and low-current properties of generated signals. Also, the high impedance of the TENG cannot meet the low impedance requirement of electronic devices. TENG devices need efficient and secure power management solutions to overcome the issue. Recently, different power management techniques with matched impedance and regulated output power have been proposed to efficiently utilize a TENG as a power source. These power management techniques include direct current (dc) buck conversion, capacitive transformation, rectification, electromagnetic transformation, integrated circuit switch, voltage trigger switch, travel switch, and transistor switches. This paper reviews the recent advancements in power management for TENGs and not only carefully studies their importance in the electronic control of triboelectric power but also highlights their existing problems and potential developments in the field.

MOSs-String-Triggered Silicon-Controlled Rectifier (MTSCR) ESD Protection Device for 1.8 V Application

In this work, a new low voltage-triggered silicon-controlled rectifier named MTSCR is realized in a 65 nm CMOS process for low voltage-integrated circuits electrostatic discharge (ESD) protections. The MTSCR incorporates an external NMOSs-string, which drives the internal NMOS (INMOS) of MTSCR to turn on, and then the INMOS drive SCR structure to turn on. Compared with the existing low trigger voltage (Vt1) ESD component named diodes-string-triggered SCR (DTSCR), the MTSCR can realize the same low Vt1 characteristic but less area penalty of ~44.3% reduction. The results of the transmission line pulsing (TLP) measurement shows that the MTSCR possesses above 2.42 V holding voltage (Vh) and a low Vt1 of ~5.03 V, making it very suitable for the ESD protections for 1.8 V input/output (I/O) ports in CMOS technologies.

Enhanced Performance of Series Microexploding Bridge Planar Discharge Switch Integrated With Exploding Foil

To achieve the low energy, miniaturization, and low cost of the exploding bridge foil initiator, single and series microexploding bridge planar discharge switch (MEB-PDS) coplanar and cocathode integrated with exploding bridge foil is fabricated by magnetron sputtering and photolithography forming etching in this work. The maximum electrostatic field strength and breakdown voltage of the MEB-PDS are calculated by multiphysics field theory. The breakdown voltage, conduction performance, MEB electrical explosion performance, and integrated exploding foil initiator (EFI) of the MEB-PDS have been tested. The relationship between breakdown voltages and design parameters, variation law between conduction time and design parameters, operating voltages and trigger voltages, and the matching between operating voltages and trigger voltages of MEB-PDS are analyzed. The results show that the breakdown voltages of single-bridge and three-series MEB-PDS can meet the insulation requirements at the operating voltage. The plasma clouds generated by the three-series MEB-PDS converge and superimpose, which results in its better conduction performance and operating reliability than single MEB-PDS. Based on the optimization of MEB structure parameters, the breakdown voltage of the three-series MEB-PDS is 2.848 kV at a trigger voltage of 0.600 kV. The 50% ignition voltage sensitivity U (50%) of the corresponding integrated exploding foil initiator is 1.191 kV, and the 99.9% ignition voltage sensitivity U (99.9%) is 1.269 kV. Compared with other types of spark gap discharge switches, U (99.9%) is reduced by 11.07%. The trigger voltage of the switch is reduced from ∼1.5 to 0.6 kV.

Design and Analysis of a Fluid-Filled RF MEMS Switch

In the present study, a fluid-filled RF MEMS (Radio Frequency Micro-Electro-Mechanical Systems) switch is proposed and designed. In the analysis of the operating principle of the proposed switch, air, water, glycerol and silicone oil were adopted as filling dielectric to simulate and research the influence of the insulating liquid on the drive voltage, impact velocity, response time, and switching capacity of the RF MEMS switch. The results show that by filling the switch with insulating liquid, the driving voltage can be effectively reduced, while the impact velocity of the upper plate to the lower plate is also reduced. The high dielectric constant of the filling medium leads to a lower switching capacitance ratio, which affects the performance of the switch to some extent. By comparing the threshold voltage, impact velocity, capacitance ratio, and insertion loss of the switch filled with different media with the filling media of air, water, glycerol, and silicone oil, silicone oil was finally selected as the liquid filling medium for the switch. The results show that the threshold voltage is 26.55 V after filling with silicone oil, which is 43% lower under the same air-encapsulated switching conditions. When the trigger voltage is 30.02 V, the response time is 10.12 μs and the impact speed is only 0.35 m/s. The frequency 0-20 GHz switch works well, and the insertion loss is 0.84 dB. To a certain extent, it provides a reference value for the fabrication of RF MEMS switches.

Prediction of the breakdown voltage and breakdown area of gas switches based on ionization integral

Gas spark switches have a simple structure and high current capacity and are widely used in the field of pulsed power. The breakdown path of gas switches affects their jitter and lifetime. Particle simulations are used to analyze the breakdown path, which requires a large amount of computation resources. In this paper, in order to calculate the ionization integral value of electrode gaps, a simulation-based method using a simplified model is studied. The integration of the ionization coefficient along the E-field curves is calculated for the electrode gap and is used to determine if breakdown occurs for a given curve. The breakdown region of two-electrode self-breakdown switches is estimated using the distribution of breakdown curves, and the trigger voltage of a three-electrode gas-trigger switch is estimated by analyzing the curves. By applying the ionization integral value to different paths to reach the streamer formation condition as the breakdown criterion, the operating voltage and erosion region of the electrodes are estimated. The numerical results for an environmental pressure of 0.2 MPa are in good agreement with the experimental results from a triggering experiment that uses a three-electrode gas-triggered switch. This ionization integral model can be used to predict the breakdown voltage and breakdown region of gas switches, which is conducive to improving the performance of gas switches.

Research on the Operating Characteristics of Electrically Triggered Vacuum Surface Flashover Switch

A novel configuration of electrically triggered vacuum surface flashover switch (VSFS) is introduced, and switches based on alumina, quartz, and aluminum nitride are fabricated. The main switch operation characteristics (flashover voltage, turn-on time, delay time, jitter, repetitive frequency ability, and lifetime) and their influencing factors (operation voltage, loop current, trigger current, and trigger waveform) are experimentally investigated. The results show that the dc flashover voltages for both switches tested in vacuum are 2–4 times higher than the voltages tested at 1 atm. The switch turn-on time is mostly affected by the operation voltage and loop resistance, while the switch delay time is mainly influenced by the front edge of the trigger voltage pulse. Delay times of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\approx 70$ </tex-math></inline-formula> ns with a corresponding jitter of less than 3.1 ns are observed for both switches. The repetitive frequency ability of both switches is better than 60 Hz@27.5 kV and can reach 100 kHz@6 kV. The delay time, turn-on time, and jitter of alumina switch remained unchanged during <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\approx 105~000$ </tex-math></inline-formula> triggered discharges (@27.5 kV, 50- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> load, 60 Hz). The optimum operating mode of the switch is determined from the experimental results.

Optimization of Flow Cytometric Sorting Parameters for High-Throughput Isolation and Purification of Small Extracellular Vesicles.

Small extracellular vesicles (sEV) can be released from all cell types and carry protein, DNA, and RNA. Signaling molecules serve as indicators of the physiological and pathological state of a cell. However, there is no standard method for sEV isolation, which prevents downstream biomarker identification and drug intervention studies. In this article, we provide a detailed protocol for the isolation and purification of 50-200 nm sEV by a flow cell sorter. For this, a 50 µm nozzle and 80 psi sheath fluid pressure were selected to obtain a good sorting rate and stable side stream. Standard sized polystyrene microspheres were used to locate populations of 100, 200, and 300 nm particles. With additional optimization of the voltage, gain, and forward scatter (FSC) triggering threshold, the sEV signal could be separated from the background noise. These optimizations provide a panel of critical sort settings that enables one to obtain a representative population of sEV using FSC vs. side scatter (SSC) only. The flow cytometry-based isolation method not only allows for high-throughput analysis but also allows for synchronous classification or proteome analysis of sEV based on the biomarker expression, opening numerous downstream research applications.

Single-event burnout hardening evaluation with current and electric field redistribution of high voltage LDMOS transistors based on TCAD Simulations

—A single-event burnout (SEB) hardened design based on high voltage lateral double-diffused metal-oxide-silicon (LDMOS) devices with an optimal partial buried oxide (BOX) layer and a N-buffer layer is firstly proposed in this paper. By analyzing the response of surface electric field and transient current, the optimal parameters of hardened layers are selected. Simulation results reveal that an optimal buffer layer can suppress the peak electric field from 4.5 MV/cm to 2 MV/cm, recreate the position of peak electric field and an optimal BOX layer can reconstruct the path of electron and hole currents, reducing the risk of parasitic bipolar-junction-transistor (BJT). By contrast, the SEB triggering voltage can be improved from 197 V to 396 V, with an increase of 100%. And the ratio of safe operating area (SOA) with SEB to breakdown voltage (BV) can be increased from 30% to 69%. In the case of heavy-ions with different energies, the SEB hardened LDMOS also has better performance than the conventional one.

Modeling and Experimental Studies of a Multi-Gap Gas Switch for Linear Transformer Drivers

This work is presenting the modeling of and the experimental studies performed on multi-gap gas switch (MGS) designed for linear transformer drivers (LTD). The MGS employs corona discharge in dry air for voltage grading across its six gaps, and therefore, achieves compactness and environmentally friendliness. Circuit modeling of the MGS was performed, followed by analysis and tests on corona current and voltage grading, showing a good self-break property of the switch. Trigger properties of the MGS were subsequently analyzed and experimentally investigated. The modeling and analysis were verified by evaluation experiments. The MGS was fired for 10020 shots in a typical LTD brick with a charging voltage of ±90 kV, which is 60% of the self-break voltage of the MGS when pressurized with 3.13 ata dry air, and a peak discharging current of 23.7 kA. The standard deviation of the time-delays between the trigger voltage and the discharging current is 3.3 ns for all the shots, during which only one pre-fire of the MGS occurred.

Advanced electro-heat conversion properties of microcrystalline graphite-based composite phase change material with the three-dimensional framework

Form-stable composite phase change material (PCM) with high latent heat is widely used in thermal energy storage application. The skeleton structure and thermophysical properties of the supporting material are greatly important to the energy efficiency of the composite PCM. This work is to design the supporting material with specific 3D carbon framework for composite PCMs using the CaCO3-templated assembly technique, following to explore the electro-heat conversion ability of composites. Microcrystalline graphite is used as the skeleton, CaCO3 as the template, and monocrystal white sugar as the carbon source. By designing the content of template, the 3D framework structure of supports can be tailored. Results show the designed support material has a higher cumulative pore volume than the raw material of 64 %, leading to an increment of the loading capacity of 12–20 %, due to the formation of the cotton-shaped carbonization connection products. Then, the stearic acid-type composite shows the thermal conductivity is improved by 104.86 % than the pure PCM, causing faster heat storage and release rate. At last, it proved that the electro-heat conversion of the composite can be achieved at low trigger voltage. The conversion efficiency increases with the voltage rising and the bulk density improving, reaching to 75.61 % at a voltage of 4.5 V with a bulk density of 0.774 g cm−3.

A high performance RC-INV triggering SCR under 0.25 µm process

PurposeAs it is known, the electrostatic discharge (ESD) protection design of integrated circuit is very important, among which the silicon controlled rectifier (SCR) is one of the most commonly used ESD protection devices. However, the traditional SCR has the disadvantages of too high trigger voltage, too low holding voltage after the snapback and longer turn-on time. The purpose of this paper is to design a high-performance SCR in accordance with the design window under 0.25 µm process, and provide a new scheme for SCR design to reduce the trigger voltage, improve the holding voltage and reduce the turn-on time.Design/methodology/approachBased on the traditional SCR, an RC-INV trigger circuit is introduced. Through theoretical analysis, TCAD simulation and tape-out verification, it is shown that RC-INV triggering SCR can reduce the trigger voltage, increase the holding voltage and reduce the turn-on time of the device on the premise of maintaining good robustness.FindingsThe RC-INV triggering SCR has great performance, and the test shows that the transmission line pulse curve with almost no snapback can be obtained. Compared with the traditional SCR, the trigger voltage decreased from 32.39 to 16.24 V, the holding voltage increased from 3.12 to 14.18 V and the turn-on time decreased from 29.6 to 16.6 ns, decreasing by 43.9% the level of human body model reached 18 kV+.Originality/valueUnder 0.25 µm BCD process, this study propose a high-performance RC-INV triggering SCR ESD protection device. The work presented in this paper has a certain guiding significance for the design of SCR ESD protection devices.