An online fast multi-track locating algorithm for high-resolution single-event effect test platform

To improve the efficiency and accuracy of single-event effect(SEE)research at the Heavy Ion Research Facility at Lanzhou,Hi’Beam-SEE must precisely localize the position at which each heavy ion hitting the integrated circuit(IC)causes SEE.In this study,we propose a fast multi-track location(FML)method based on deep learning to locate the position of each particle track with high speed and accuracy.FML can process a vast amount of data supplied by Hi’Beam-SEE online,revealing sensitive areas in real time.FML is a slot-based object-centric encoder-decoder structure in which each slot can learn the location information of each track in the image.To make the method more accurate for real data,we designed an algorithm to generate a simulated dataset with a distribution similar to that of the real data,which was then used to train the model.Extensive comparison experiments demonstrated that the FML method,which has the best performance on simulated datasets,has high accuracy on real datasets as well.In particular,FML can reach 238 fps and a standard error of 1.6237μm.This study discusses the design and performance of FML.

Temperature dependence of single-event transients in SiGe heterojunction bipolar transistors for cryogenic applications

We experimentally demonstrate that the dominant mechanism of single-event transients in silicon-germanium heterojunction bipolar transistors(SiGe HBTs)can change with decreasing temperature from+20℃to-180℃.This is accomplished by using a new well-designed cryogenic experimental system suitable for a pulsed-laser platform.Firstly,when the temperature drops from+20℃to-140℃,the increased carrier mobility drives a slight increase in transient amplitude.However,as the temperature decreases further below-140℃,the carrier freeze-out brings about an inflection point,which means the transient amplitude will decrease at cryogenic temperatures.To better understand this result,we analytically calculate the ionization rates of various dopants at different temperatures based on Altermatt's new incomplete ionization model.The parasitic resistivities with temperature on the charge-collection pathway are extracted by a two-dimensional(2D)TCAD process simulation.In addition,we investigate the impact of temperature on the novel electron-injection process from emitter to base under different bias conditions.The increase of the emitter-base junction's barrier height at low temperatures could suppress this electron-injection phenomenon.We have also optimized the built-in voltage equations of a high current compact model(HICUM)by introducing the impact of incomplete ionization.The present results and methods could provide a new reference for effective evaluation of single-event effects in bipolar transistors and circuits at cryogenic temperatures,and could provide a new evidence of the potential of SiGe technology in applications in extreme cryogenic environments.

Synergistic effect of total ionizing dose on single-event gate rupture in SiC power MOSFETs

The synergistic effect of total ionizing dose(TID) and single event gate rupture(SEGR) in SiC power metal–oxide–semiconductor field effect transistors(MOSFETs) is investigated via simulation. The device is found to be more sensitive to SEGR with TID increasing, especially at higher temperature. The microscopic mechanism is revealed to be the increased trapped charges induced by TID and subsequent enhancement of electric field intensity inside the oxide layer.

Scaling effects of single-event gate rupture in thin oxides

The dynamics of the excess carriers generated by incident heavy ions are considered in both SiO2 and Si substrate. Influences of the initial radius of the charge track, surface potential decrease, external electric field, and the LET value of the incident ion on internal electric field buildup are analyzed separately. Considering the mechanisms of recombination, impact ionization, and bandgap tunneling, models are verified by using published experimental data. Moreover, the scaling effects of single-event gate rupture in thin gate oxides are studied, with the feature size of the MOS device down to 90 nm. The walue of the total electric field decreases rapidly along with the decrease of oxide thickness in the first period （1 2 nm to 3.3 nm）, and then increases a little when the gate oxide becomes thinner and thinner （3.3 nm to 1.8 nm）.

Investigation of maximum proton energy for qualified ground based evaluation of single-event effects in SRAM devices

Existing standards show a clear discrepancy in the specification of the maximum proton energy for qualified ground-based evaluation of single-event effects,which can range from 180 to 500 MeV. This work finds that the threshold linear energy transfer of a tested device is a critical parameter for determining the maximum proton energy. The inner mechanisms are further revealed. Highenergy deposition events(>10 MeV) in sensitive volumes are attributed to the interaction between protons and the tungsten vias in the metallization layers.

Single-event effects induced by medium-energy protons in 28 nm system-on-chip

Single-event effects(SEEs)induced by mediumenergy protons in a 28 nm system-on-chip(SoC)were investigated at the China Institute of Atomic Energy.An on-chip memory block was irradiated with 90 MeV and 70 MeV protons,respectively.Single-bit upset and multicell upset events were observed,and an uppermost number of nine upset cells were discovered in the 90 MeV proton irradiation test.The results indicate that the SEE sensitivities of the 28 nm SoC to the 90 MeV and 70 MeV protons were similar.Cosmic Ray Effects on Micro-Electronics Monte Carlo simulations were analyzed,and it demonstrates that protons can induce effects in a 28 nm SoC if their energies are greater than 1.4 MeV and that the lowest corresponding linear energy transfer was 0.142 MeV cm^2 mg^-1.The similarities and discrepancies of the SEEs induced by the 90 MeV and 70 MeV protons were analyzed.

Prototype of single-event effect localization system with CMOS pixel sensor

The single-event effect(SEE) is a serious threat to electronics in radiation environments. The most important issue in radiation-hardening studies is the localization of the sensitive region in electronics to the SEE. To solve this problem, a prototype based on a complementary metal oxide semiconductor(CMOS) pixel sensor, i.e., TopmetalM, was designed for SEE localization. A beam test was performed on the prototype at the radiation terminal of the Heavy Ion Research Facility in Lanzhou(HIRFL). The results indicated that the inherent deflection angle of the prototype to the beam was 1.7°, and the angular resolution was 0.6°. The prototype localized heavy ions with a position resolution of 3.4 μm.

Analysis of single-event transient sensitivity in fully depleted silicon-on-insulator MOSFETs

Based on 3 D-TCAD simulations, single-event transient(SET) effects and charge collection mechanisms in fully depleted silicon-on-insulator(FDSOI) transistors are investigated. This work presents a comparison between28-nm technology and 0.2-lm technology to analyze the impact of strike location on SET sensitivity in FDSOI devices. Simulation results show that the most SET-sensitive region in FDSOI transistors is the drain region near the gate. An in-depth analysis shows that the bipolar amplification effect in FDSOI devices is dependent on the strike locations. In addition, when the drain contact is moved toward the drain direction, the most sensitive region drifts toward the drain and collects more charge. This provides theoretical guidance for SET hardening.

Single-event-effect propagation investigation on nanoscale system on chip by applying heavy-ion microbeam and event tree analysis

The propagation of single-event effects(SEEs)on a Xilinx Zynq-7000 system on chip(SoC)was inves-tigated using heavy-ion microbeam radiation.The irradia-tion results reveal several functional blocks’sensitivity locations and cross sections,for instance,the arithmetic logic unit,register,D-cache,and peripheral,while irradi-ating the on-chip memory(OCM)region.Moreover,event tree analysis was executed based on the obtained microbeam irradiation results.This study quantitatively assesses the probabilities of SEE propagation from the OCM to other blocks in the SoC.

Catalytic Cracking of Cycloparaffins Admixed with Olefins:1. Single-Event Microkinetic(SEMK) Modeling

Single-event microkinetic(SEMK) model of the catalytic cracking of methylcyclohexane admixed with 1-octene over REUSY zeolites at 693 K—753 K in the absence of coke formation is enhanced. To keep consistency with the wellknown carbenium ion chemistry, hydride transfer forming and consuming allylic carbenium ions in the aromatization of cycloparaffins are further investigated and differentiated. The reversibility of endocyclic β-scission and cyclization reactions is refined by accounting explicitly for the reacting olefins and resulting cycloparaffins in the corresponding thermodynamics. 24 activation energies for the reactions involved in the cracking of cycloparaffins are obtained by the regression of 15 sets of experimental data upon taking the resulting 37 main cracking products, i. e., responses into account. The enhanced SEMK model can adequately describe the catalytic behavior of 37 main products with conversion and temperature.

Catalytic Cracking of Cycloparaffins Admixed with Olefins:2. Single-Event Microkinetic(SEMK) Assessment

The developed SEMK model is used to provide an insight into the contribution of individual reactions in the cracking of methylcyclohexane as well as the site coverage by various carbenium ions. The preferred reaction pathways for the conversion of methylcyclohexane are hydride transfer reactions followed by PCP-isomerizations, deprotonation and endocyclic β-scission, accounting for 61%, 22% and 12% of its disappearance, respectively, at 693 K and 30% conversion of methylcyclohexane. Protolysis plays a minor role in the cracking of methylcyclohexane. Once cyclic diolefins are formed, all of them can be instantaneously transformed to aromatics, which are easily interconverted via disproportionation. Judging from the carbenium ion concentrations it is evident that, at the investigated operating conditions, less than 5% of the acid sites are covered by carbenium ions, less than 2% of which corresponds to cyclic type species including allylic ones.

Mechanism of single-event transient pulse quenching between dummy gate isolated logic nodes

As integrated circuits scale down in size, a single high-energy ion strike often affects multiple adjacent logic nodes.The so-called single-event transient（SET） pulse quenching induced by single-event charge sharing collection has been widely studied. In this paper, SET pulse quenching enhancement is found in dummy gate isolated adjacent logic nodes compared with that isolated by the common shallow trench isolation（STI）. The physical mechanism is studied in depth and this isolation technique is explored for SET mitigation in combinational standard cells. Three-dimensional（3D） technology computer-aided design simulation（TCAD） results show that this technique can achieve efficient SET mitigation.

Impact of proton-induced alteration of carrier lifetime on single-event transient in SiGe heterojunction bipolar transistor

This paper presents an investigation into the impact of proton-induced alteration of carrier lifetime on the singleevent transient(SET) caused by heavy ions in silicon–germanium heterojunction bipolar transistor(SiGe HBT).The ioninduced current transients and integrated charge collections under different proton fluences are obtained based on technology computer-aided design(TCAD) simulation.The results indicate that the impact of carrier lifetime alteration is determined by the dominating charge collection mechanism at the ion incident position and only the long-time diffusion process is affected.With a proton fluence of 5 × 1013 cm-2, almost no change is found in the transient feature, and the charge collection of events happened in the region enclosed by deep trench isolation(DTI), where prompt funneling collection is the dominating mechanism.Meanwhile, for the events happening outside DTI where diffusion dominates the collection process, the peak value and the duration of the ion-induced current transient both decrease with increasing proton fluence, leading to a great decrease in charge collection.

Development of Contactless Method of the DUT Heating during Single-Event Effect Tests

This paper presents two approaches to perform the electronic device heating during radiation hardness assurance tests.Commonly used conductive heating approach is compared with contactless laser-based approach,characteristics and limitations of these methods are described.Experimental results for temperature dependence of single-event latchup(SEL)cross-section during heavy ion irradiation along with some aspects of physics-based numerical simulation of heat transfer processes are presented.

Frobenius代数的Segre积

根据Segre积的定义,证明了两个Frobenius代数的Segre积仍然是Frobenius代数,并在此基础上研究了两个Frobenius代数Segre积对应的扭超势和Nakayama自同构.

Experimental and simulation studies of single-event transient in partially depleted SOI MOSFET

In this study, we investigate the single-event transient（SET） characteristics of a partially depleted silicon-on-insulator（PDSOI） metal-oxide-semiconductor（MOS） device induced by a pulsed laser.We measure and analyze the drain transient current at the wafer level. The results indicate that the body-drain junction and its vicinity are more SET sensitive than the other regions in PD-SOI devices.We use ISE 3D simulation tools to analyze the SET response when different regions of the device are hit. Then, we discuss in detail the characteristics of transient currents and the electrostatic potential distribution change in devices after irradiation. Finally, we analyze the parasitic bipolar junction transistor（p-BJT） effect by performing both a laser test and simulations.

分次近似Frobenius代数的Segre积

文章主要研究分次近似Frobenius代数,提出了k-近似Frobenius代数的概念,证明了两个k-近似Frobenius代数的Segre积还是k-近似Frobenius代数,并且对分次近似Frobenius代数的Frobenius空间进行了直和分解.

星用功率VDMOS器件SEGR效应研究

对源漏击穿电压为400 V和500 V的N沟功率VDMOS器件进行碘离子单粒子辐照实验,讨论了不同偏置下两种功率器件的SEGR效应。研究结果显示:栅源电压为0 V、漏源电压为击穿电压时,器件未发生单粒子效应,表明两种星用功率器件的抗单粒子效应能力达到技术指标要求。

功率MOSFET抗单粒子加固技术研究

针对功率MOSFET的单粒子效应(SEE)开展了工艺加固技术研究,在单粒子烧毁(SEB)加固方面采用优化的体区掺杂工艺,有效降低了寄生双极晶体管(BJT)增益,抑制了单粒子辐照下的电流正反馈机制。在单粒子栅穿(SEGR)加固方面,通过形成缓变掺杂的外延缓冲层来降低纵向电场梯度,减弱了非平衡载流子在栅敏感区的累积,并开发了台阶栅介质结构提升栅敏感区的临界场强。实验结果表明,经过加固的功率MOSFET在满额漏源工作电压和15 V栅源负偏电压的偏置条件下,单粒子烧毁和栅穿LET值大于75 MeV·cm^(2)/mg。在相同辐照条件下,加固器件的栅源负偏电压达到15~17 V,较加固前的7~10 V有显著提升。

高k栅介质增强型β-Ga_(2)O_(3) VDMOS器件的单粒子栅穿效应研究

以增强型β-Ga_(2)O_(3)VDMOS器件作为研究对象,利用TCAD选择不同的栅介质材料作为研究变量,观察不同器件的单粒子栅穿效应敏感性。高k介质材料Al_(2)O_(3)和HfO_(2)栅介质器件在源漏电压200 V、栅源电压-10 V的偏置条件下能有效抵御线性能量转移为98 MeV·cm^(2)/mg的重离子攻击,SiO_(2)栅介质器件则发生了单粒子栅穿效应(Single event gate rupture,SEGR)。采用HfO_(2)作为栅介质时源漏电流和栅源电流分别下降92%和94%,峰值电场从1.5×10^(7)V/cm下降至2×10^(5)V/cm,避免了SEGR的发生。SEGR发生的原因是沟道处累积了大量的空穴,栅介质中的临界电场超过临界值导致了击穿,而高k栅介质可以有效降低器件敏感区域的碰撞发生率,抑制器件内电子空穴对的进一步生成,降低空穴累积的概率。