Electrostatic Discharge Immunity Research Articles

Design for EMI/ESD Immunity for Flexible and Wearable Electronics

Proliferation of flexible, wearable and portable electronics come with new challenges of system reliability. Particularly, flexible and wearable electronics cause more frequent and are more susceptible to electromagnetic interference (EMI) effects and electrostatic discharge (ESD) failures, and have unique requirements for design-for-reliability (DfR) associated with EMI and ESD immunity to achieve electromagnetic compatibility (EMC) compliance. This paper outlines the key challenges in design for EMI and ESD immunity for wearable microsystems and discusses potential design for EMI/ESD immunity solutions.

Practical Papers, Articles and Application Notes

Electrostatic discharge (ESD) can affect the performance of an electronic product and one of the ESD coupling paths to the electronic circuit is through the interfacing cables of the product. The first paper, “Extraction of a SPICE Model for Investigating the Cable Discharge Event in Flat Ribbon Cables Based on Transmission Line Theory,” develops a SPICE model for the cable discharge event (CDE) with specific focus on flat ribbon cables (FRCs), which are widely used in many electronic products. The proposed method can also be expanded to the other types of cables to evaluate CDE. With the equivalent circuit, it allows early evaluation of the product's ESD immunity before final design and compliance test.

Editorial Introduction to the Special Issue on Electrostatic Discharge and Immunity—From IC to System

The papers in this special issue focus on scientific contributions in the field of electrostatic discharge (ESD) and immunity—from integrated circuits (ICs) to system. ESD can damage or disrupt electronic systems. With continued scaling of ICs, a combined approach of IC and system forms the best path for understanding and ensuring robustness. This relates to the IC itself: input/output (I/O) structures, power distribution network (PDN), interfaces between IP blocks, as well as the interaction of external protection devices with internal ESD protection structures during system level stress. To effectively protect the ICs fabricated in the advanced nanoscale CMOS processes, the turn-on speed of ESD protection devices must be enhanced to quickly discharge ESD current before the internal circuits are damaged by ESD stresses. Not only component level ESD events, the system level ESD test specified in the IEC 61000-4-2 standard has been used to verify ESD immunity of the microelectronics products. During system level ESD testing, the ESD problems relates to soft failures. So far, only few models for soft failures have been reported. It becomes visible that well designed hard failure protection can also reduce the likelihood of soft failures as most of the current is diverted from the IC and will not disturb the PDN of the IC. ESD robustness in the system level and component level are both important to meet the electromagnetic compatibility (EMC) regulations and/or standards in the industry.

Effects of nematic liquid crystal doped with multi-walled carbon nanotube on electro-optic properties and electrostatic discharge immunity of liquid crystal display device

ABSTRACT Electrostatic discharge is a vexing problem in liquid crystal display device, which can cause abnormal display. Conventional solutions for liquid crystal doped with antistatic agent usually introduce additional impurity ions and increases the power consumption of liquid crystal display device. In this study, multi-walled carbon nanotube doped liquid crystal cells without obvious clusters are successfully fabricated. Comparing the electro-optic properties of undoped and doped cells, it is verified that doping does not negatively affect the liquid crystal cells with E7 host by measuring basic parameters such as relative permittivity, threshold voltage and response time. The liquid crystal cells are then tested using an electrostatic discharge generator to simulate the human-machine air discharge that occurs during actual operation. The immunity of the doped versus undoped cells is quantitatively compared in terms of the duration of so-called image sticking, it is found that the electrostatic discharge immunity of cell has a significant relationship with electrical conductivity. In addition, the relationship between the conductivity and relaxation time of image sticking is obtained by theory. It is determined that doping carbon nanotubes into E7 can effectively improve the electrostatic discharge immunity of liquid crystal display device without negatively affecting practical application.

Analysis of the ESD Reconstruction Methodology Based on Current Probe Measurements and Frequency Response Compensation for Different ESD Generators and Severity Test Levels

System-level electrostatic discharge testing according to IEC 61000-4-2 has been the main standardized electrostatic discharge immunity testing procedure for the last few decades. The correlation between a failed test result and the injected electrostatic discharge current waveform characteristics, as well as the reduced reproducibility of the standard methodology, have always concerned product manufacturers and test engineers. In an effort to accurately reconstruct the electrostatic discharge current during immunity testing, researchers are focusing more and more on the usability of current probes in capturing the injected current in “real time”. In this article, the results of a proposed methodology, based on current probe measurements and a frequency response compensation method, published in recent bibliography, for different test levels and electrostatic discharge generators are presented, aiming to highlight the advantages and disadvantages of the method, investigate its universal applicability, and introduce points of future work toward the current reconstruction during system-level electrostatic discharge testing effort.

ESD Design and Analysis by Drain Electrode-Embedded Horizontal Schottky Elements for HV nLDMOSs

Electrostatic discharge (ESD) events can severely damage miniature components. Therefore, ESD protection is critical in integrated circuits. In this study, drain-electrode-embedded horizontal Schottky diode contact modulation and Schottky length reduction modulation were performed on a high-voltage 60-V n-channel laterally diffused metal-oxide–semiconductor transistor (nLDMOS) element. The effect of the on-voltage characteristics of cascade Schottky diodes on ESD protection was investigated. By using a transmission-line pulse tester, the trigger voltage, holding voltage, and secondary breakdown current (It2) of the nLDMOS element were determined using the I–V characteristic. As the N+ area was gradually replaced by the parasitic Schottky area at the drain electrode, an equivalent circuit of series Schottky diodes formed, which increased the on-resistance. The larger the Schottky area was the higher the It2 value was. This characteristic can considerably improve the ESD immunity of nLDMOS components (highest improvement of 104%). This is a good strategy for improving ESD reliability without increasing the production steps and fabrication cost.

Electrostatic Discharge Simulation and Experimental Verification of a Simple PCB Device

In this paper, a simple device under electrostatic discharge (ESD)event is considered. This work presents a simple experimental and simulated setup to measure ESD‐induced voltage to trace on a printed circuit board (PCB) when ESD current is injected directly onto the lumped element. Based on an ESD immunity test platform and ESD full‐wave model, the waveform of coupling voltage, which induced on a PCB, are measured at different discharging position. The voltage waveform of resistor on PCB with chip and without chip are compared to analyze the difference in two cases. The paper proposes a method that compares the measured results of experiment with simulation of full‐wave model. It is found that the results of simulation and experiment is in good match on the whole.

Robust ESD-Reliability Design of 300-V Power N-Channel LDMOSs with the Elliptical Cylinder Super-Junctions in the Drain Side

The weak ESD-immunity problem has been deeply persecuted in ultra high-voltage (UHV) metal-oxide-semiconductor field-effect transistors (MOSFETs) and urgently needs to be solved. In this paper, a UHV 300 V circular n-channel (n) lateral diffused MOSFET (nLDMOS) is taken as the benchmarked reference device for the electrostatic discharge (ESD) capability improvement. However, a super-junction (SJ) structure in the drain region will cause extra depletion zones in the long drain region and reduce the peak value of the channel electric field. Therefore, it may directly increase the resistance of the device to ESD. Then, in this reformation project for UHV nLDMOSs to ESD, two strengthening methods were used. Firstly, the SJ area ratio changed by the symmetric eight-zone elliptical-cylinder length (X) variance (i.e., X = 5, 10, 15 and 20 μm) is added into the drift region of drain side to explore the influence on ESD reliability. From the experimental results, it could be found that the breakdown voltages (VBK) were changed slightly after adding this SJ structure. The VBK values are filled between 391 and 393.5 V. Initially, the original reference sample is 393 V; the VBK changing does not exceed 0.51%, which means that these components can be regarded as little changing in the conduction characteristic after adding these SJ structures under the normal operating conditions. In addition, in the ESD transient high-voltage bombardment situation, the human-body model (HBM) capability of the original reference device is 2500 V. Additionally, as SJs with the length X high-voltage P-type well (HVPW) are inserted into the drain-side drift region, the HBM robustness of these UHV nLDMOSs increases with the length X of the HVPW. When the length X (HVPW) is 20 μm, the HBM value can be upgraded to a maximum value of 5500 V, the ESD capability is increased by 120%. A linear relationship between the HBM immunity level and area ratio of SJs in the drains side in this work can be extracted. The second part revealed that, in the symmetric four-zone elliptical cylinder SJ modulation, the HBM robustness is generally promoted with the increase of HVPW SJ numbers (the highest HBM value (4500 V) of the M5 device improved by 80% as compared with the reference device under test (DUT)). Therefore, from this work, we can conclude that the addition of symmetric elliptical-cylinder SJ structures into the drain-side drift region of a UHV nLDMOS is a good strategy for improving the ESD immunity.

Layout Strengthening the ESD Performance for High-Voltage N-Channel Lateral Diffused MOSFETs

An electrostatic discharge (ESD) event can negatively affect the reliability of integrated circuits. Therefore, improving on ESD immunity in high-voltage (HV) n-channel (n) lateral diffused metal–oxide–semiconductor field-effect transistor (HV nLDMOS) components through drain-side layout engineering was studied. This involved adjusting the operating voltage, improving the non-uniform turned-on phenomenon, and examining the effects of embedded-device structures on ESD. All proposed architectures for improving ESD immunity in this work were measured and evaluated using a transmission-line pulse system. The corresponding trigger voltage (Vt1), holding voltage (Vh) and secondary breakdown current (It2) results of the tested devices were obtained. This paper first addresses the drift-region length modulation to design different operating voltages, which decreased as the drift region length and shallow trench isolation (STI) length shrunk. When an HV nLDMOS device decreased to the shortest drift region length, the Vt1 and Vh values were closest to 21.85, and 9.27 V, respectively. The It2 value of a low-voltage operated device could be increased to a maximum value of 3.25 A. For the channel width modulation, increasing the layout finger number of an HV LDMOS device did not really help the ESD immunity that because it may suffer the problem of non-uniform turned-on phenomenon. Therefore, adjusting the optimized channel width was the best one method of improvement. Furthermore, to improve the low ESD reliability problem of nLDMOS devices, two structures were used to improve the ESD capability. The first was a drain side—embedded silicon-controlled rectifier (SCR). Here, the SCR PNP-arranged type in the drain side had the best ESD capability because the SCR path was short and had been prior to triggering; however, it also has a latch-up risk and low Vh characteristic. By removing the entire heavily doped drain-side N+ region, the equivalent series resistance in the drain region was increased, so that the It2 performance could be increased from 2.29 A to 3.98 A in the structure of a fully embedded drain-side Schottky diode. This component still has sufficiently high Vh behaviour. Therefore, embedding a full Schottky-diode into an HV nLDMOS in the drain side was the best method and was efficient for improving the ESD/Latch-up abilities of the device. The figure of merit (FOM) of ESD, Latch-up, and cell area considerations improved to approximately 80.86%.

Electrostatic Charging of a Human Body Caused by Activities and Material Combinations in Hospitals

Electrostatic charging of hospital personnel and patients during various activities increases the risk of electrostatic discharge (ESD) malfunctions of medical devices and the likelihood of patients’ adverse events. Therefore, the test level for ESD immunity of medical devices, specified in the IEC 60601-1-2 standard needs to reflect the reasonably maximum electrostatic voltages during usage. This study investigated the effects of material combinations and relative humidity on the body voltage while performing two routine clinical activities of lying down on a hospital bed and transferring to a bed using a sliding board. The peak body voltages in nearly 50% of the lying down experiments and 40% of sliding tests exceeded the test voltage level in the IEC 60601-1-2 standard (i.e., 15 kV). Using cotton blankets in lying down experiments and nylon sheets during sliding experiments resulted in 50% and 40% larger median than the median including all combinations, respectively. Sliding boards with antistatic coating reduced the peak body voltage by 24% on average, however, 33% of the tests still exceeded 15 kV. Based on the findings, recommendations are provided for healthcare facilities and medical device manufacturers to mitigate the risks of ESD malfunctions.

Design and Implementation of ESD Immunity Test for a Combustible Gas Alarm Device

In this paper, a series of electromagnetic compatibility tests were carried out on a combustible gas alarm device. In order to ensure the Electrostatic Discharge (ESD) performance of the device, some targeted solutions for electrostatic protection were proposed. Finally, the device passed the test based on analysis and rectification and met the evaluation index in GB/T 1726.3-2018 well, which is very significant to improve the quality and reliability for this kind of products.

Обеспечение электромагнитной совместимости морской техники при возникновении электростатических разрядов

The paper describes the problem of electromagnetic compatibility for electrostatic discharge (ESD), which is most actual for ships where all systems are highly automated and susceptible to ESD digital technology. The results of electromagnetic compatibility tests of ship systems after their installation on the vessel allow to conclude that it is not enough to fulfill only the existing ESD immunity requirements of the Russian Maritime register of shipping which are currently confirmed by ESD tests in the laboratory. ESD methods and reasons have been analyzed. The possible accumulated potentials and parameters of currents, voltages and field strengths during discharge are presented. The existing ESD immunity standards are being considered. The scheme of the developed and certified generator of electrostatic discharges ESD – 25000 is presented. The most frequent defects under the influence of ESD are given. There have been formulated the equivalent schemes of the electric equipment housing at different lengths of grounding of the housing and the methods of connecting the cover with the housing. The results of measurements of electric field and magnetic field parameters are presented. The results of modeling and experiments are compared. The developed sensors, methods of their calibration and obtained technical characteristics are being tested. There are given the parameters and forms of ESD voltage and current, experimental data of ESD secondary effects in the EE hull and adjacent equipment, results of discharges in the ship's cable, interference in the supply network through secondary power sources. The most effective design and ESD protection methods have been analyzed

Electrostatic-Discharge-Immunity Impacts in 300 V nLDMOS by Comprehensive Drift-Region Engineering

Electrostatic discharge (ESD) events are the main factors impacting the reliability of Integrated circuits (ICs); therefore, the ESD immunity level of these ICs is an important index. This paper focuses on comprehensive drift-region engineering for ultra-high-voltage (UHV) circular n-channel lateral diffusion metal-oxide-semiconductor transistor (nLDMOS) devices used to investigate impacts on ESD ability. Under the condition of fixed layout area, there are four kinds of modulation in the drift region. First, by floating a polysilicon stripe above the drift region, the breakdown voltage and secondary breakdown current of this modulation can be increased. Second, adjusting the width of the field-oxide layer in the drift region when the width of the field-oxide layer is 5.8 μm will result in the minimum breakdown voltage (105 V) but the best secondary breakdown current (6.84 A). Third, by adjusting the discrete unit cell and its spacing, the corresponding improved trigger voltage, holding voltage, and secondary breakdown current can be obtained. According to the experimental results, the holding voltage of all devices under test (DUTs) is greater than that of the reference group, so the discrete HV N-Well (HVNW) layer can effectively improve its latch-up immunity. Finally, by embedding different P-Well lengths, the findings suggest that when the embedded P-Well length is 9 μm, it will have the highest ESD ability and latch-up immunity.

Evaluating Characteristics of Electrostatic Discharge (ESD) Events in Wearable Medical Devices: Comparison With the IEC 61000-4-2 Standard

Electrostatic discharge (ESD) malfunctions in wearable medical devices have resulted in injuries and deaths. The U.S. Food and Drug Administration (FDA) recommends medical device manufacturers to qualify the electromagnetic compatibility of their products according to the IEC 60601-1-2 collateral standard, within which the IEC 61000-4-2 standard is the recommended ESD immunity test method. This paper shows that the IEC 61000-4-2 standard does not provide adequate immunity for wearable medical devices, due to the differences between the test setup and the real usage. The peak and maximum time derivative of the ESD current and transient magnetic fields were measured during realistic discharge scenarios, where a metal piece, in lieu of a wearable device, was worn around human hand or waist. At five voltage levels from 2 to 10 kV, the peak currents and their maximum time derivatives for realistic discharge scenarios were larger than the most severe discharges obtained from the IEC 61000-4-2 test configuration. This discrepancy between the current results from the IEC 61000-4-2 standard setup and the realistic discharge scenarios indicates that the ESD immunity standard for wearable devices needs to be changed with realistic test configurations, to prevent device malfunctions that can subsequently jeopardize patient safety.

ESD-Reliability Analysis and Strategy of the GaN-Based Light-Emitting Diodes

Compounds such as GaN, ZnSe, and SiC are the compounds that currently hold the most potential in developing blue light-emitting diodes (LEDs) and blue laser diodes (LDs). Speaking of the physical property, the gallium nitride belongs to a direct bandgap material with an obviously super luminous efficiency; therefore, the gallium nitride has the dominate tendency than that of others materials. Although the gallium nitride has excellent physical properties, but in actually it is suffered many challenges during the manufacture process. Especially, it is extremely sensitive to the electrostatic discharge (ESD) threat. In other words GaN diodes generally exhibit very low anti-ESD capabilities when in HBM, MM reversed bias modes. These LEDs in the MM stress situation, its ESD immunity level usually is only about 50-V extremely low anti-ESD ability. Therefore, in this paper, GaN LED DUTs will be stressed and investigated under HBM and MM pulses bombardments, and the aim of this work is to describe a detailed investigation of the factors that limit the robustness of GaN-based LEDs under ESD transient events; finally they will provide some countermeasures in ESD reliability consideration.

Испытания на электростатическую устойчивость в производстве электроники

Испытания на электростатическую устойчивость в производстве электроники

Study of Charged Frame ESD Immunity Testing Specified in ISO 7176-21

The EMC product standard for electrically powered wheelchairs is ISO 7176-21, which requires charged frame electrostatic discharge (ESD) immunity testing. When a moving wheelchair carrying a buildup of electrostatic charge due to triboelectrification of the wheels and floor comes into contact with a grounded metal object, the resulting air-gap discharge may cause the wheelchair to malfunction. Since the IEC 61000-4 series does not cover immunity testing that simulates such ESD events, ISO 7176-21 independently provides the test method. Currently, many companies are developing personal care robots to assist human in daily activities. Considering the risk presented by such robots that involve physical contact with humans, the charged frame ESD test will be a test item for the safety validation of personal care robots that are mobile and battery powered. In practice, however, when charged frame ESD tests are conducted according to the test procedure specified in ISO 7176-21, some issues and questions arise in regard to such matters as the means of charging the robot under test, the material of the insulating support on which to place the robot, and simulation of discharge from a robot rider or wearer. This paper investigates the test procedure of ISO 7176-21 and proposes modifications for enabling charged frame ESD testing to be properly carried out for personal care robots.

Causes of the ESD immunity testing problems in the IEC 61000-4-2 standard

To resolve the poor reproducibility of the electrostatic discharge (ESD) immunity test platform which is specified in the standard IEC 61000-4-2, using a newly designed ESD testing system, the effects of the switch action of ESD generator, the discharge current and its derivative, the radiation field and the imperfect specification of the test method on the testing results were studied. It was found that the effect of the switch action of ESD generator on the testing results was very distinct, and the radiation field caused by the switch action was one of the main cause of the different testing results; different discharge current and current derivative were caused by different ESD generators, which would cause different testing results; the imperfect specification of the test method in the standard was the other reason.

Improvements for electrostatic discharge immunity in thermal printing head

Electrostatic discharge (ESD) is one of the important sources of electromagnetic interference which would cause a reversible or permanent damage in modem electronic equipment. ESD may be introduced by the human body operating the electronic equipment or accumulated by friction, heating or other reasons when the electronic equipment is working. In this paper we use the print head of the thermal printer (TPH) suffered from electrostatic hazard as an example to analyze the reasons of the ESD happening, and some necessary improvements measures for protection of the TPH are also suggested.

The Measurements and Countermeasures of Electromagnetic Compatibility in CNC System

Because CNC systems are usually used in industrial sites, their immunity measurements are very important, this paper introduced how to perform the measurement of electrostatic discharge immunity, surge immunity, electrical fast transient burst immunity and voltage dips and short interruptions immunity. According to experience, it is not so easy to pass the measurements, this paper detailed suitable devices or other countermeasures to solve the problems in order to pass the four measurement items mentioned above.