Substrate Voltage Research Articles

An Approach to Extract the Trap States via the Dynamic Ron Method With Substrate Voltage Applied During the Recovery Time

An Approach to Extract the Trap States via the Dynamic R_on Method With Substrate Voltage Applied During the Recovery Time

Accuracy of endocardial abnormal electrogram characterization using a 17-AHA-segmental late boundary and voltage-dependent sensitivity annotation for ventricular tachycardia ablation

Abstract Background Substrate-based catheter ablation of ventricular tachycardia (VT) has become the mainstay therapy for patients with scar-related VT. Correct identification and timing of abnormal near-field EGMs and discerning it from far-field EGMs, is key for procedural success. The novel CARTO™ Late Activation Mapping (LAM) module provides fast and accurate annotation of near-field EGMs including late abnormal ventricular activation. For the algorithm to succeed, a late boundary (LB) annotation line should be positioned immediately behind the normal near-field EGM, however, since the timing of normal local near-field activation varies greatly throughout the endocardium, there is currently no consensus for the optimal LB positioning. We hypothesized that 17-AHA segmental annotation of the endocardial LB followed by scar-dependent sensitivity settings, will improve the accuracy of the near-field EGM characterization. Purpose To evaluate the accuracy of endocardial abnormal EGM characterization using a 17-AHA-segmental late boundary and voltage-dependent sensitivity annotation as compared to conventional mid-QRS LB positioning. Methods Five high-resolution substrate voltage maps were obtained from 5 patients (80% male, 68±7 years old, 80% ischemic cardiomyopathy) that underwent a catheter-based ablation for scar-related VT. A personalized CT-derived anatomical reconstruction of the 17-segment AHA model was co-registered offline with the electroanatomic voltage map, using ADAS3D software. Per segment, individual LB timings were set at the highest sensitivity. A gold standard annotation map was created by two independent experts after manual scrutiny of individual EGMs. Next, the expert map was compared to automatic maps created from segmental LB and mid-QRS LB positions at normal, high, highest or mixed (normal/high or normal/highest) sensitivities, focusing on EGM voltage and activation accuracy. Results A mean of 2041±1028 points per map were analyzed. Correct correlation of EGM annotation was found on average in 91% (activation) and 81% (voltage) for all segmental LB positioned maps (segLB), and in 83% (activation) and 77% (voltage) for all mid-QRS LB positioned maps (mid-QRSLB). The highest correlation with expert map for both activation and voltage annotation was found in the mixed sensitivity normal/highest map with segmental LB positioning (activation 98%, voltage 88%). The correlation on activation was significantly superior in the segLB map when compared to the normal sensitivity maps (p=0.0008 for mid-QRSLB and p=0.02 for segLB). For correlation on voltage, the segLBmap with mixed sensitivity was significantly superior compared to three mid-QRSLB maps at normal (p=0.04), high and highest (p=0.01) sensitivity. Conclusion Individualized, 17-AHA-segmental late boundary and voltage-dependent sensitivity annotation provides a possible accurate and clinically-relevant framework for substrate assessment. Prospective validation is needed.

Coronary sinus signal amplitude: A predictor of the atrial substrate and low voltage areas.

Low voltage areas (LVA) are pivotal in atrial fibrillation (AF) pathogenesis, influencing local left atrial LA excitation and perpetuating AF occurrences. While pulmonary vein isolation (PVI) with cryo-balloon (CB) ablation is effective for AF, it doesn't provide insights into the LA substrate or detect LVA, which affects ablation success rates. This study examines whether LA voltage and LVAs can be anticipated by analyzing the voltage signal amplitude at the coronary sinus (CS) catheter, which is standard in CB and radiofrequency ablation procedures. A retrospective analysis of 284 patients with recurrent AF undergoing RF catheter ablation was conducted at a high-volume EP center in Germany. The correlation between LA voltage and LVA with the CS signal was explored. The signal amplitude in the CS significantly correlated with voltage in LA walls, particularly in the proximal CS (correlation coefficient ρ=0.81, p<0.001). A CS signal cut-off of 1.155mV effectively predicted severe atrial LVAs (>40%) with a sensitivity of 90.7% and a specificity of 100%. While a threshold of 1.945mV identified patients with no significant atrial LVAs (<5%) with a sensitivity of 88% and a specificity of 50% (AUC: 0.81, 95% CI: 0.71-0.89, p<0.001). The CS signal amplitude is associated with the LA voltage. Due to its potential as a diagnostic tool for atrial LVAs, the signal amplitude in the CS could provide valuable information about the LA substrate, especially when 3D mapping is not feasible.

Correlation between Crystallite Characteristics and the Properties of Copper Thin Film Deposited by Magnetron Sputtering: Bias Voltage Effect

This work investigates the properties of copper thin films deposited by magnetron sputtering. The substrate is biased by a negative voltage (Vs), which controls the energy ions bombardment during the deposition of the thin films. In order to focus solely on the ions energy contribution, the power supply was fixed and the working pressure was selected at 5 Pa. This ensures energetic sputtered particles completely thermalized, by a sufficient number of collisions with the Argon gas. X-ray diffraction analysis revealed that substrate voltage Vs affects essentially the structure and size of the formed crystallites. The preferred orientation (111) and the larger crystallite size (30 nm) were achieved at Vs = - 60 V. The Cu (111)/(200) peak intensity ratio is maximal (12.55) at - 60 V, corresponding to the lowest resistivity value (6.33 mW.cm). Optimum corrosion resistance of the deposited thin film was achieved at -60 V. At high crystallite sizes, nanoindentation analysis showed a thin film that is more elastic (133 GPa) and less hard (1.96 GPa).

A HCI-hardened self-healing operational amplifier circuit

In this paper, a self-healing operational amplifier circuit to deal with hot carrier injection (HCI) effect is proposed. An inverter-based operational amplifier is implemented. The influence degree of HCI effect to performance of the operational amplifier is studied which utilizes an equivalent circuit model of HCI effect. A monitoring circuit is proposed to monitor the degree of HCI degradation. A charge pump circuit is utilized to generate a corresponding voltage according to the result of monitoring circuit. The output voltage of the charge pump circuit is feedback to tune the substrate voltage of the operational amplifier (and the monitoring circuit) to mitigate degradation. The simulation results show that the self-healing operational amplifier can maintain the performance at low temperature and room temperature for 50 years (and high temperature for 30 year) under HCI effect. The gain of the inverter-based operational amplifier without self-healing is reduced from 45 dB to 9.6 dB after 50 years, and the gain of the self-healing operational amplifier will maintain at about 46 dB among 50 years. The influence of HCI effect on bandwidth and phase margin is less than that of temperature and process corner. The lifetime of self-healing operational amplifier circuit is >5 times longer than lifetime of based on inverter operational amplifier circuit without self-healing. In addition, the self-healing operational amplifier is robust to process corner.

Bottom Contact 100nm Channel-Length α-In2 Se3 In-Plane Ferroelectric Memory.

Owing to the emerging trend of non-volatile memory and data-centric computing, the demand for more functional materials and efficient device architecture at the nanoscale is becoming stringent. To date, 2D ferroelectrics are cultivated as channel materials in field-effect transistors for their retentive and switchable dipoles and flexibility to be compacted into diverse structures and integration for intensive production. This study demonstrates the in-plane (IP) ferroelectric memory effect of a 100nm channel-length 2D ferroelectric semiconductor α-In2 Se3 stamped onto nanogap electrodes on Si/SiO2 under a lateral electric field. As α-In2 Se3 forms the bottom contact of the nanogap electrodes, a large memory window of 13V at drain voltage between ±6.5V and the on/off ratio reaching 103 can be explained by controlled IP polarization. Furthermore, the memory effect is modulated by the bottom gate voltage of the Si substrate due to the intercorrelation between IP and out-of-plane (OOP) polarization. The non-volatile memory characteristics including stable retention lasting 17 h, and endurance over 1200 cycles suggest a wide range of memory applications utilizing the lateral bottom contact structure.

Three-Phase Motor Inverter and Current Sensing GaN Power IC.

A three-phase GaN-based motor inverter IC with three integrated phase current mirror sensors (sense-FETs or sense-HEMTs, 1200:1 ratio), a temperature sensor, and an amplifier is presented and experimentally operated. The three low-side currents are read out by virtual grounding transimpedance amplifiers. A modified summed DC current readout circuit using only one amplifier is also discussed. During continuous 24 V motor operation with space-vector pulse width modulation (SVPWM), the sensor signal is measured and a bidirectional measurement capability is verified. The measured risetime of the sensor signal is 51 ns, indicating around 7 MHz bandwidth (without intentional optimization for high bandwidth). The IC is operated up to 32 V on DC-biased semi-floating substrate to limit negative static back-gating of the high-side transistors to around -7% of the DC-link voltage. Analysis of the capacitive coupling from the three switch-nodes to the substrate is calculated for SVPWM based on capacitance measurement, resulting in four discrete semi-floating substrate voltage levels, which is experimentally verified. Integrated advanced power converter topologies with sensors improve the power density of power electronics applications, such as for low-voltage motor drive.

Astronomical Camera Based on a CCD261-84 Detector with Increased Sensitivity in the Near-Infrared

Herein, we describe the design, implementation and operation principles of an astronomical camera system, based on a large-format CCD261-84 detector with an extremely thick 200 μm substrate. The DINACON-V controller was used with the CCD to achieve high performance and low noise. The CCD system photometric characteristics are presented. A spatial autocorrelation analysis of flat-field images was performed to reveal the dependence of substrate voltage on the lateral charge spreading. The investigation of the dispersion index for the optimal choice of exposure time is discussed. Studies of the patterns of fringes were carried out in comparison with previous detectors. The amplitude of fringes with CCD261-84 was significantly lower, compared to previous-generation detectors. The results of using a new camera for imaging and spectral observations at the Russian 6 m telescope with the SCORPIO-2 multimode focal reducer are considered. The developed CCD camera system makes it possible to significantly increase the sensitivity in the 800–1000 spectral range.

A novel substrate Voltage-assisted RESURF technique in SOI LDMOS with a heavily doped drift region

A novel substrate voltage-assisted (SVA) reduced surface field (RESURF) technique in SOI lateral double-diffused Metal-Oxide-Semiconductor (LDMOS) with a heavily doped drift region is proposed. Without any additional masks and processes, an external control circuit is designed to adaptively control the substrate voltage in the technique. The co-simulation based on TCAD and the circuit is implemented to explore the mechanism of the SVA RESURF technique. In the off-state, a negative bias is applied to the substrate, which induces positive charges to compensate for the heavily doped ionizing acceptors in the drift region. The breakdown voltage is improved and remains at the same level as the conventional RESURF device. In the on-state, a zero bias is applied to the substrate, and heavy doping in the drift region can achieve low specific on-resistance compared to the RESURF device with a lightly doped drift region. As a result, the proposed technique reconstructs the charge balance and the conventional RESURF condition. The simulation results show reduced specific on-resistance, low drain leakage current, large saturation current, high transconductance and cut-off frequency, decreased turn-on/off characteristics and improved FOM and BFOM compared with the conventional RESURF technique. Furthermore, an analytical model is developed to optimize the substrate voltage for the maximum breakdown voltage in the external control circuit design of the proposed technique.

Effect of Substrate Bias Voltage on Microstructure and Mechanical Properties of Cr-Nb-Ti-Zr-N-O Ceramic Thin Films Produced by Reactive Sputtering

Hard coatings are applied in various applications to protect substrates from wear and corrosion. In the present study, multi-element ceramic films are deposited by reactive sputtering. The level of substrate bias voltage (−50, −125 and −200 V) is changed to investigate the structural and mechanical properties of Cr-Nb-Ti-Zr-N thin films. Chemical analysis (using EDS, XRD and Raman spectroscopy) reveals that these thin films (with a high amount of oxygen) are composed of a nanocomposite phase structure (amorphous and nano-crystalline phases). CrO2 and NbxN crystalline phases exist in an amorphous matrix in the coatings. By increasing the substrate voltage (from −50 to −200 V), the nitrogen content (from 30 to 40 at. %) increases, and CrxN crystalline phases are generated in S125 and S200. Morphological, topological and image analysis (employing FESEM and AFM) data show that the intermediate level of substrate bias voltage (sample S125) can produce a uniform surface with minimum defect density (15%). In addition, S125 has the minimum level of roughness (16.6 nm), skewness (0.2) and kurtosis (2.8). Therefore, the hardness, toughness and wear resistance (extracted from indentation and scratch tests) of this sample is maximum (H is 24.5 GPa and H/E is 0.107), while sample S50 shows complete fracture and delamination.

Thermally stressed thermoelectric microbeam supported by Winkler foundation via the modified Moore–Gibson–Thompson thermoelasticity theory

AbstractThis article offers the first investigation into the thermoelectric vibration of microscale Euler‐Bernoulli beams resting on an elastic Winkler base. We developed the system of equations for thermoelastic microbeams using elastic basis theory and the generalized Moore–Gibson–Thompson (MGT) thermal transport framework with a single‐phase delay. At the front of the microbeam, a graphene strip connected to an electrical power source was employed to generate heat. In addition, the influence of an ultra‐short‐pulsed laser on the vibration of a microbeam is studied, taking into account its heating effect. The microbeam system variables were analyzed after solving the mathematical equations by applying the Laplace transform technique. Graphs showing how different inputs affect different mechanical fields, such as Winkler substrate stiffness, voltage, electrical resistance, and temperature modulus pulses, are also presented. An increase in the Winkler modulus and the shear modulus of the foundation was found to decrease the amount of deflection and axial deformation in the microbeams. The increased beam stiffness has resulted in this decrease.

The relationship between high dominant frequency and low voltage areas in patients with atrial fibrillation: digital twin study

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): a grant [2022R1I1A1A0106342211] from the Basic Science Research Program run by the National Research Foundation of Korea (NRF) which is funded by the Ministry of Science, ICT &amp; Future Planning (MSIP) Background It has been suggested that the high dominant frequency (DF) site plays an atrial fibrillation (AF) driver, but its relationship with the atrial substrate voltage map (Vm) in the entire chamber AF map has yet to be studied. We explored the relationship between the DF site during AF and Vm in the entire chamber maps by applying the human left atrial (LA) electroanatomical map (EAM) to the digital twin AF map. Methods We acquired LA substrate Vm (at sinus rhythm, &amp;gt;800 points bipolar electrograms) of 110 patients with persistent AF (male 72.7%, 58.7±9.8 years old) who underwent AF catheter ablation. We applied EAM to digital twins (0.4 million nodes), reflecting anatomy, histology, and electrophysiology. We evaluated the highest 10% DF areas for 6 sec after inducing virtual AF. The correlation between the highest 10% DF and the low Vm areas (&amp;lt;0.2mV) was evaluated in the LA region of 10 segments. Results The mean voltage of the entire LA area was 1.96±0.85 mV (2.19±0.82 mV extra-PV area, 1.33±0.93 mV PV area) in 110 patients. The correlation between low Vm and high DF areas was not significant in the entire LA (r=0.106, p&amp;lt;0.001), extra-PV (r=0.157, p&amp;lt;0.001), and PV (r=0.079, p=0.097) areas. In the LA 10 segment regional analysis, 72 patients (65.5%) showed the co-localization of the highest DF in the region with the lowest Vm, and 14 patients (12.7%) had the lowest Vm segment in the region with the highest DF. The mean voltage where high DF appeared was 0.69±1.35 mV, and the mean voltage of the region where high DF did not appear was 0.59±1.15 mV (p=0.171). Conclusion High DF site, a parameter representing a localized focal source, had statistically significant but very poor correlations with LA extra-PV voltage substrate in patients with persistent AF.

ISFET Pixel Array With Selectable Sensitivity and Bulk-Based Offset-Drift Nullification Capability for Reduction of Non-Ideality Effects

This article presents a monolithic, cost-effective, label free, low power, robust <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times2$ </tex-math></inline-formula> fully differential ion-sensitive field-effect transistor (ISFET) pixel array aimed at pH sensing. Each pixel is based on a differential readout architecture which eliminates need for additional non-ideality compensation circuitry. Additionally, the design offers the capability to correct for residual drift and trapped charge offset through substrate-based voltage adjustment during calibration. The design also provides a unique ability for selecting pH sensitivity according to the desired mode of operation which has not been demonstrated previously. We present experimental results obtained from the pixel array fabricated in an unmodified AMS <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.35~\mu \text{m}$ </tex-math></inline-formula> CMOS process using a 3.3 V power supply. Each pixel demonstrates a differential sensitivity of 61 mV/pH when operated in high sensitivity mode and 25 mV/pH when operated in high non-ideality rejection mode over the entire pH range, with the ability to remove the already small drift of 0.3 mV/min and any offset mismatch by adjusting the substrate voltage.

High-Performance Carbon Nanodots/Graphene Heterojunction Solar-Blind Ultraviolet Photodetector via Vertical Structure

The vertical-structure heterojunction has been highlighted as a promising candidate for the solar-blind ultraviolet (UV) photodetector (PD) due to the control of its channel length and the strong electric field-induced high carrier mobility. Meanwhile, carbon nanodot (CND) has drawn great attention to be playing an essential role in absorbing solar-blind UV waves as the active layer of the PD. However, CND prepared for solar-blind UV PDs, independent of sophisticated manufacturing method and extreme process conditions, has yet to be well developed. Herein, for the very first time, a vertical structure CNDs/graphene heterojunction type solar-blind UV PD is introduced, where the CND and the graphene are used as the photosensitive layer and the transparent electrode, respectively. Particularly, the CND is fabricated with a low-cost and one-step electrochemical strategy. The device realizes an optimized performance tradeoff, presenting responsivity of 76.01 mA/W, normalized detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4.17\times 10^{{10}}$ </tex-math></inline-formula> Jones, and rise/decay time of 0.54/0.27 s under the illumination of 1.47 mW/cm2 at 254-nm wavelength, along with the bias voltage of −5 V and the substrate voltage of 10 V applied. The results show that this work has unlocked the critical bottleneck of developing a graphene-based solar-blind UV PD with higher responsivity, greater detectivity, and shorter response time, unveiling the potential for missile warning, flame detection, and other areas of interest.

Role of K364 next to the active site cysteine in voltage-dependent phosphatase activity of Ci-VSP

Voltage-sensing phosphatase (VSP) consists of the voltage sensor domain (VSD) similar to that of voltage-gated ion channels and the cytoplasmic phosphatase region with remarkable similarity to the phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Membrane depolarization activates VSD, leading to dephosphorylation of three species of phosphoinositides (phosphatidylinositol phosphates (PIPs)), PI(3,4,5)P3, PI(4,5)P2, and PI(3,4)P2. VSP dephosphorylates 3- and 5-phosphate of PIPs, unlike PTEN, which shows rigid 3-phosphate specificity. In this study, a bioinformatics search showed that some mammals have VSP orthologs with amino acid diversity in the active center motif, Cx5R, which is highly conserved among protein tyrosine phosphatases and PTEN-related phosphatases; lysine next to the active site cysteine in the Cx5R motif was substituted for methionine in VSP orthologs of Tasmanian devil, koala, and prairie deer mouse, and leucine in opossum. Since lysine at the corresponding site in PTEN is known to be critical for enzyme activities, we attempted to address the significance of amino acid diversity among VSP orthologs at this site. K364 was changed to different amino acids in sea squirt VSP (Ci-VSP), and voltage-dependent phosphatase activity in Xenopus oocyte was studied using fluorescent probes for PI(4,5)P2 and PI(3,4)P2. All mutants retained both 5-phosphatase and 3-phosphatase activity, indicating that lysine at this site is dispensable for 3-phosphatase activity, unlike PTEN. Notably, K364M mutant showed increased activity both of 5-phosphatase and 3-phosphatase compared with the wild type (WT). It also showed slower kinetics of voltage sensor motion. Malachite green assay of K364M mutant did not show significant difference of phosphatase activity from WT, suggesting tighter interaction between substrate binding and voltage sensing. Mutation corresponding to K364M in the zebrafish VSP led to enhanced voltage-dependent dephosphorylation of PI(4,5)P2. Further studies will provide clues to understanding of substrate preference in PIPs phosphatases as well as to customization of a molecular tool.

Buffer Traps Effect on GaN-on-Si High-Electron-Mobility Transistor at Different Substrate Voltages.

Substrate voltage (VSUB) effects on GaN-on-Si high electron mobility transistors (HEMTs) power application performance with superlattice transition layer structure was investigated. The 2DEG conductivity and buffer stack charge redistribution can be affected by neutral/ionized donor and acceptor traps. As the donor/acceptor traps are excessively ionized or de-ionized by applying VSUB, the depletion region between the unintentionally doped (UID)/Carbon-doped (C-doped) GaN layer may exhibit a behavior similar to the p-n junction. An applied negative VSUB increases the concentration of both the ionized donor and acceptor traps, which increases the breakdown voltage (BV) by alleviating the non-uniform distribution of the vertical electric field. On the other hand, an applied positive VSUB causes the energy band bending flattener to refill the ionized traps and slightly improves the dynamic Ron degradation. Moreover, the amount of electrons injected into the buffer stack layer from the front side (2DEG channel/Ohmic contact) and the back side (AlN nucleation layer/superlattice transition layer) are asymmetric. Therefore, different VSUB can affect the conductivity of 2DEG through the field effect, buffer trapping effect, and charge redistribution, which can change the electrical performance of the device.

Designed and Produced the Rotary Substrate Holder and Its Optimized in Angular DC Magnetron Co-Sputtering System

We report the design approach of a home-built rotary substrate holder on simple rotation stages for low-pressure vacuum applications. The result of designing and fabricating the rotary substrate holder that it can be successfully used to rotate the substrate in a low-pressure vacuum application without pressure fl uctuations and leakage. Then we investigated the suitable thin fi lm deposition by fabricating optimal multilayer coatings under three variable operating conditions: Speed of substrate, deposition time, and discharge voltage. The thin film deposition result of three copper targets was mounted on each magnetron gun, providing a total of three magnetron guns. The thin fi lm was deposited on a glass slide at room temperature using a custom-built angular DC magnetron co-sputtering system. Analysis of variance for the response surface regression model of film thickness as a function of the three independent variables shows that substrate rotation speed, sputtering time, sputtering voltage, and coeffi cient of squared sputtering time are the most signifi cant factors in determining the optimum film thickness. The optimum thin-film deposition with substrate rotation speed, sputtering time, and sputtering voltage of 10 rpm, 8.61 min, and 200%V, respectively, maximizes the thickness of 72.036 nm.

Suppression of decay time in transient drain current of back-gated GaN HEMT under UV exposure

Photodetectors based on an AlGaN/GaN high electron mobility transistor on Si have a long decay time after removal of light irradiation because of the large number of defects. This behavior is unsuitable for applications that require fast response. In several papers, though decay time was suppressed by thermal heating, it has problems such as fabrication complexity and power consumption. In this paper, we propose a substrate voltage (V sub) application method for suppressing decay time, which modulates the V sub immediately after the removal of UV irradiation, which promotes injecting electrons from two-dimensional electron gas to the carbon-doped GaN (C-GaN) layer. The decay time was suppressed from 75 to 2 s. Moreover, the effectiveness of reset voltage application is confirmed by a demonstration that changes the UV intensity continuously.

Fully reversible magnetoelectric voltage controlled THz polarization rotation in magnetostrictive spintronic emitters on PMN-PT

THz polarization control upon generation is a crucially missing functionality. THz spintronic emitters based on the inverse spin Hall effect (ISHE) allow for this by the strict implicit orthogonality between their magnetization state and the emitted polarization. This control was until now only demonstrated using cumbersome external magnetic field biasing to impose a polarization direction. We present here an efficient voltage control of the polarization state of terahertz spintronic emitters. Using a ferromagnetic spin pumping multilayer exhibiting simultaneously strong uniaxial magnetic anisotropy and magnetostriction in a crossed configuration, an emitter is achieved where, in principle, the stable magnetization direction can be fully and reversibly controlled over a 90° angle span only by an electric voltage. To achieve this, an engineered rare-earth based ferromagnetic multilayer is deposited on a piezoelectric (1−x)[Pb(Mg0.33Nb0.66)O3]−x[PbTiO3] (PMN-PT) substrate. We demonstrate experimentally a reversible 70° THz polarization rotation by sweeping the substrate voltage over 400 V. This demonstration allows for a fully THz polarization controlled ISHE spintronic terahertz emitter not needing any control of the magnetic bias.

Low-energy electron beam generation in inductively coupled plasma via a DC biased grid

Low-energy electron beam generation using a DC biased grid was investigated in an inductively coupled plasma (ICP). The electron beam was measured in argon gas at various pressures, ICP source powers, and substrate voltages (V sub). At a low ICP source power (50 W), an electron beam was generated even at small values of V sub (10 V), however at a high ICP source power (200 W), an electron beam was only generated when a higher voltage (30 V) was applied due to the short sheath thickness on the grid surface. The sheath on the grid surface is an important factor for generating electron beams because low-energy electrons are blocked. If the sheath thickness to small, a high voltage should be applied to generate an electron beam, as accelerate regions cannot exist without the sheath. At high pressure, since electrons experience numerous neutral collisions, a high substrate voltage is needed to generate an electron beam. However, if the applied substrate voltage becomes too high (40 V) at high pressure, high-energy electrons result in secondary plasma under the grid. Therefore, maintaining a low pressure and low ICP source power is important for generating electron beams.