CONVERSION MODEL OF THE RADIATION-INDUCED INTERFACE-TRAP BUILDUP AND ITS HARDNESS ASSURANCE APPLICATIONS

The model, which confirms that the interaction of trapped positive charges ((hydrogenous species)) in the oxide and electrons from the substrate is an important component of radiation-induced interface-trap buildup, is presented. The “one-to-Koi” relationship between the number of trapped holes annealed and number of interface-trap generated is used for prediction of MOS device response in space environment. The model of enhanced low dose rate effect (ELDRS) is proposed. ELDRS conversion model is based on the assumption that there are two types of traps: shallow and deep. The time constants of these traps are different and correspond to interface-trap buildup at high dose rates for shallow traps and at low dose rates for deep traps. The possible physical mechanism of ELDRS effect elimination in the silicon-germanium (SiGe) bipolar transistors is described. The original mechanism of interface-trap buildup saturation based on radiation-induced charge neutralization (RICN) effect is presented

On the effects of total ionizing dose in silicon-germanium BiCMOS platforms

The objective of the proposed research is to analyze the effects of total ionizing dose (TID) on highly scaled CMOS and Silicon-Germanium Heterojunction Bipolar Transistors (SiGE HBTs). TID damage is caused by a build-up of charge at sensitive Si-SiO₂ interfaces and may cause device or circuit failure. TID damage is due to an accumulation of radiation particle strikes seen in extreme environments, such as space.M.S

Qualifying silicon-germanium electronics for harsh radiation environments

The objective of this thesis is to investigate the robustness of Silicon-Germanium Heterojunction Bipolar Transistors (SiGe HBTs) to radiation-induced damage. The work described in this document delves into both total ionizing dose (TID) and single-event effect (SEE) mechanisms. Background information is provided for the general operation of SiGe HBTs and basic radiation effects (generic and specifically for SiGe HBTs). Four unique investigations are covered in this work: the first two focus on TID effects for high dose environments and to investigate enhanced-low-dose-rate-sensitivity, and the latter two studies investigate advances in hardening SiGe HBT profiles and methods to conduct SEE experiments using pulsed-lasers in place of highly energetic ionized particles.Ph.D

Radiation hardness studies of a 130 nm Silicon Germanium BiCMOS technology with a dedicated ASIC

We present the radiation hardness studies on the bipolar devices of the 130 nm 8WL Silicon Germanium (SiGe) BiCMOS technology from IBM. This technology has been proposed as one of the candidates for the Front-End (FE) readout chip of the upgraded Inner Detector (ID) and the Liquid Argon Calorimeter (LAr) of the ATLAS Upgrade experiment. After neutron irradiations, devices remain at acceptable performances at the maximum radiation levels expected in the Si tracker and LAr calorimeter

Modeling of Total Ionizing Dose Effects in Advanced Complementary Metal-Oxide-Semiconductor Technologies

abstract: The increased use of commercial complementary metal-oxide-semiconductor (CMOS) technologies in harsh radiation environments has resulted in a new approach to radiation effects mitigation. This approach utilizes simulation to support the design of integrated circuits (ICs) to meet targeted tolerance specifications. Modeling the deleterious impact of ionizing radiation on ICs fabricated in advanced CMOS technologies requires understanding and analyzing the basic mechanisms that result in buildup of radiation-induced defects in specific sensitive regions. Extensive experimental studies have demonstrated that the sensitive regions are shallow trench isolation (STI) oxides. Nevertheless, very little work has been done to model the physical mechanisms that result in the buildup of radiation-induced defects and the radiation response of devices fabricated in these technologies. A comprehensive study of the physical mechanisms contributing to the buildup of radiation-induced oxide trapped charges and the generation of interface traps in advanced CMOS devices is presented in this dissertation. The basic mechanisms contributing to the buildup of radiation-induced defects are explored using a physical model that utilizes kinetic equations that captures total ionizing dose (TID) and dose rate effects in silicon dioxide (SiO2). These mechanisms are formulated into analytical models that calculate oxide trapped charge density (Not) and interface trap density (Nit) in sensitive regions of deep-submicron devices. Experiments performed on field-oxide-field-effect-transistors (FOXFETs) and metal-oxide-semiconductor (MOS) capacitors permit investigating TID effects and provide a comparison for the radiation response of advanced CMOS devices. When used in conjunction with closed-form expressions for surface potential, the analytical models enable an accurate description of radiation-induced degradation of transistor electrical characteristics. In this dissertation, the incorporation of TID effects in advanced CMOS devices into surface potential based compact models is also presented. The incorporation of TID effects into surface potential based compact models is accomplished through modifications of the corresponding surface potential equations (SPE), allowing the inclusion of radiation-induced defects (i.e., Not and Nit) into the calculations of surface potential. Verification of the compact modeling approach is achieved via comparison with experimental data obtained from FOXFETs fabricated in a 90 nm low-standby power commercial bulk CMOS technology and numerical simulations of fully-depleted (FD) silicon-on-insulator (SOI) n-channel transistors.Dissertation/ThesisPh.D. Electrical Engineering 201

Ionizing radiation e\ufb00ects in nanoscale CMOS technologies exposed to ultra-high doses

This thesis studies the e\ufb00ects of radiation in nanoscale CMOS technologies exposed to ultra-high total ionizing doses (TID), up to 1 Grad(SiO2). These extreme radiation levels are orders of magnitude higher that those typically experienced by space applications (where radiation e\ufb00ects in electronic are of concern). However, they can be found in some speci\ufb01c applications like the large-hadron-collider (LHC) of CERN, and, in particular, in its future upgrade, the high-luminosity LHC (HL-LHC). The study at such high doses has both revealed new phenomena, and has contributed to a better understanding of some of the already known radiation-induced e\ufb00ects. The radiation response of four di\ufb00erent CMOS technology nodes, i.e., 130, 65, 40 and 28 nm, coming from di\ufb00erent manufacturers, has been investigated in di\ufb00erent conditions of temperature, bias, dose-rate and for di\ufb00erent transistor\u2019s sizes, providing an unique and comprehensive set of data about the ultra-high TID-induced phenomena in modern CMOS technologies. This study has con\ufb01rmed that the thin gate oxide of nanoscale technologies is extremely robust to radiation, even at ultra-high doses. The main cause of performance degradation has been identi\ufb01ed in the presence of auxiliary oxides such as shallow trench insulation oxides (STI) and spacers. Both radiation-induced drain-to-source leakage current increase and radiation-induced narrow channel e\ufb00ect (RINCE) are caused by positive charge trapped in the STI. In this work, thanks to exposures to very high TID levels and to measurements performed in di\ufb00erent conditions of temperature and bias, we show that the two e\ufb00ects are provoked by charge trapped in di\ufb00erent locations along the trench oxide. Moreover, a new unexpected ultra-high-dose drain current increase (UCLI) e\ufb00ect, a\ufb00ecting narrow and long nMOS transistors, has been observed. In-depth studies of the radiation-induced short channel e\ufb00ect (RISCE), related to the presence of the spacers, have shown that, at ultra-high doses, the degradation mechanism consists of two phases. A \ufb01rst increase of the series resistance, caused by the radiation-induced charge trapping in the spacers, is followed by a threshold voltage shift provoked by the transport of hydrogen ions from the spacers to the gate oxide. This model has been validated by several static measurements, TCAD simulations and charge pumping measurements. The dependencies of these e\ufb00ects on bias, temperature and size of the transistors have also been studied in detail. Moreover, an unexpected true dose-rate sensitivity has been measured in both nMOS and pMOS transistors in 65 and 130 nm technologies, although the radiation response of MOS devices is considered insensitive to true dose-rate e\ufb00ects. The current degradation in samples irradiated at a dose-rate comparable to that expected in the HL-LHC is larger by a factor of 3c2 than that measured in the typical quali\ufb01cation test, usually carried out with a much higher dose-rate. This is clearly of serious concern for the quali\ufb01cation of circuits designed for the particle detectors of the HL-LHC

Reliability investigations of bipolar silicon phototransistor arrays for space applications

[FR] Les travaux de thèse s'inscrivent dans le contexte d'une évaluation de la fiabilité de matrices de phototransistors bipolaires en technologie silicium pour des applications de codage optique angulaire en environnement spatial. Après un état de l'art relatif aux technologies des phototransistors et un rappel sur leur fonctionnement physique, les conditions environnementales spécifiques liées au domaine spatial sont décrites. La caractérisation des paramètres électro-optiques des phototransistors, associée à une phase préliminaire de métrologie, a été effectuée à partir de bancs dédiés. L'étude de la sensibilité aux charges mobiles de technologies issues de différents fondeurs, habituellement piégées aux interfaces et identifiée comme un mécanisme fortement pénalisant en terme de durée de vie opérationnelle, a permis d'optimiser et fiabiliser une nouvelle source européenne. Une méthodologie originale basée sur le concept des plans d'expérience D-optimal a été mise en œuvre et validée. L'objectif est d'estimer le taux de dégradation d'un ou de plusieurs paramètres clés du composant en fonction des conditions environnementales imposées par l'orbite de rotation du satellite à partir d'un nombre limité d'expériences réalisées au sol.[EN] The research activities presented in this thesis are related to the specific contextof the qualification tests, for space missions, of new sources of silicon phototransistor arraysfor optical angular encoders. Our studies on a first source revealed the fragility of thattechnology in active storage and ionizing radiation because of its sensitivity to oxidestrapped charges. Then, a study on a second set of components was performed in order toanalyze the reliability of phototransistors subjected to several constraints in terms of bothionizing and displacement doses. The methodology of Design of Experiments was for thefirst time implemented and validated in this context. Thanks to this methodology, it ispossible to obtain an estimate of the degradation of one or more key parameters of thecomponent in environmental conditions for a given mission profile with a limited number ofexperiments.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF

Radiation effects in III-V compound semiconductor heterostructure devices

The radiation effects in III-V heterojunction devices are investigated in this thesis. Two types of heterojunction devices studied are InGaP/GaAs single heterojunction bipolar transistors (SHBTs) and GaN-based heterojunction light emitting diodes (LEDs). InGaP/GaAS HBTs are investigated for high energy (67 and 105 MeV) proton irradiation effects while GaN heterojunction LEDs are studied for neutron irradiation effects. A compact model and the parameter extraction procedures for HBTs are developed, and hence the I[subscript C]--V[subscript CE] characteristics of pre- and post-irradiation HBTs can be simulated by employing the developed model. HBTs are electrically characterized before and after proton irradiation. Overall, the studied HBT devices are quite robust against high energy proton irradiation. The most pronounced radiation effect shown in SHBTs is gain degradation. Displacement damage in the bulk of base-emitter space-charge region, leading to excess base current, is the responsible mechanism for the proton-induced gain degradation. The performance degradation depends on the operating current and is generally less at higher currents. Compared to the MBE grown devices, the MOVPE grown HBTs show superior characteristics both in initial performance and in proton irradiation hardness. The 67 MeV protons cause more damage than 105 MeV protons due to their higher value of NIEL (non-ionizing energy loss). The HBT I-V characteristics of pre- and post-irradiated samples can be simulated successfully by employing the developed model. GaN heterojunction LEDs are electrically and optically characterized before and after neutron irradiation. Neutron irradiation causes changes in both the I-V characteristic and the light output. Atomic displacement is responsible for both electrical and optical degradation. Both electrical and optical properties degrade steadily with neutron fluence producing severe degradation after the highest fluence neutron irradiation. The light output degrades by more than 99% after 1.6x10¹⁵ n/cm² neutron irradiation, and the radiation damage depends on the operating current and is generally less at higher currents

Investigation of radiation-hardened design of electronic systems with applications to post-accident monitoring for nuclear power plants

This research aims at improving the robustness of electronic systems used-in high level radiation environments by combining with radiation-hardened (rad-hardened) design and fault-tolerant techniques based on commercial off-the-shelf (COTS) components. A specific of the research is to use such systems for wireless post-accident monitoring in nuclear power plants (NPPs). More specifically, the following methods and systems are developed and investigated to accomplish expected research objectives: analysis of radiation responses, design of a radiation-tolerant system, implementation of a wireless post-accident monitoring system for NPPs, performance evaluation without repeat physical tests, and experimental validation in a radiation environment. A method is developed to analyze ionizing radiation responses of COTS-based devices and circuits in various radiation conditions, which can be applied to design circuits robust to ionizing radiation effects without repeated destructive tests in a physical radiation environment. Some mathematical models of semiconductor devices for post-irradiation conditions are investigated, and their radiation responses are analyzed using Technology Computer Aided Design (TCAD) simulator. Those models are then used in the analysis of circuits and systems under radiation condition. Based on the simulation results, method of rapid power off may be effectively to protect electronic systems under ionizing radiation. It can be a potential solution to mitigate damages of electronic components caused by radiation. With simulation studies of photocurrent responses of semiconductor devices, two methods are presented to mitigate the damages of total ionizing dose: component selection and radiation shielding protection. According to the investigation of radiation-tolerance of regular COTS components, most COTS-based semiconductor components may experience performance degradation and radiation damages when the total dose is greater than 20 K Rad (Si). A principle of component selection is given to obtain the suitable components, as well as a method is proposed to assess the component reliability under radiation environments, which uses radiation degradation factors, instead of the usual failure rate data in the reliability model. Radiation degradation factor is as the input to describe the radiation response of a component under a total radiation dose. In addition, a number of typical semiconductor components are also selected as the candidate components for the application of wireless monitoring in nuclear power plants. On the other hand, a multi-layer shielding protection is used to reduce the total dose to be less than 20 K Rad (Si) for a given radiation condition; the selected semiconductor devices can then survive in the radiation condition with the reduced total dose. The calculation method of required shielding thickness is also proposed to achieve the design objectives. Several shielding solutions are also developed and compared for applications in wireless monitoring system in nuclear power plants. A radiation-tolerant architecture is proposed to allow COTS-based electronic systems to be used in high-level radiation environments without using rad-hardened components. Regular COTS components are used with some fault-tolerant techniques to mitigate damages of the system through redundancy, online fault detection, real-time preventive remedial actions, and rapid power off. The functions of measurement, processing, communication, and fault-tolerance are integrated locally within all channels without additional detection units. A hardware emulation bench with redundant channels is constructed to verify the effectiveness of the developed radiation-tolerant architecture. Experimental results have shown that the developed architecture works effectively and redundant channels can switch smoothly in 500 milliseconds or less when a single fault or multiple faults occur. An online mechanism is also investigated to timely detect and diagnose radiation damages in the developed redundant architecture for its radiation tolerance enhancement. This is implemented by the built-in-test technique. A number of tests by using fault injection techniques have been carried out in the developed hardware emulation bench to validate the proposed detection mechanism. The test results have shown that faults and errors can be effectively detected and diagnosed. For the developed redundant wireless devices under given radiation dose (20 K Rad (Si)), the fault detection coverage is about 62.11%. This level of protection could be improved further by putting more resources (CPU consumption, etc.) into the function of fault detection, but the cost will increase. To apply the above investigated techniques and systems, under a severe accident condition in a nuclear power plant, a prototype of wireless post-accident monitoring system (WPAMS) is designed and constructed. Specifically, the radiation-tolerant wireless device is implemented with redundant and diversified channels. The developed system operates effectively to measure up-to-date information from a specific area/process and to transmit that information to remote monitoring station wirelessly. Hence, the correctness of the proposed architecture and approaches in this research has been successfully validated. In the design phase, an assessment method without performing repeated destructive physical tests is investigated to evaluate the radiation-tolerance of electronic systems by combining the evaluation of radiation protection and the analysis of the system reliability under the given radiation conditions. The results of the assessment studies have shown that, under given radiation conditions, the reliability of the developed radiation-tolerant wireless system can be much higher than those of non-redundant channels; and it can work in high-level radiation environments with total dose up to 1 M Rad (Si). Finally, a number of total dose tests are performed to investigate radiation effects induced by gamma radiation on distinct modern wireless monitoring devices. An experimental setup is developed to monitor the performance of signal measurement online and transmission of the developed distinct wireless electronic devices directly under gamma radiator at The Ohio State University Nuclear Reactor Lab (OSU-NRL). The gamma irradiator generates dose rates of 20 K Rad/h and 200 Rad/h on the samples, respectively. It was found that both measurement and transmission functions of distinct wireless measurement and transmission devices work well under gamma radiation conditions before the devices permanently damage. The experimental results have also shown that the developed radiation-tolerant design can be applied to effectively extend the lifespan of COTS-based electronic systems in the high-level radiation environment, as well as to improve the performance of wireless communication systems. According to testing results, the developed radiation-tolerant wireless device with a shielding protection can work at least 21 hours under the highest dose rate (20 K Rad/h). In summary, this research has addressed important issues on the design of radiation-tolerant systems without using rad-hardened electronic components. The proposed methods and systems provide an effective and economical solution to implement monitoring systems for obtaining up-to-date information in high-level radiation environments. The reported contributions are of significance both academically and in practice