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Spin-driven thermoelectric (STE) generation based on the combination of the spin Seebeck effect (SSE) and inverse spin Hall effect is an alternative to conventional semiconductor-based thermocouples as it is large scale, low cost, and environment-friendly. The STE device is thought to be radiation hard, making it attractive for space and nuclear technology applications. By using magnetometry, transmission electron microscopy, and the hard X-ray photoemission spectroscopy (HAXPES) measurements, we show that an STE device made of single-crystalline Y3Fe5O12 (YIG)/Pt heterostructures has tolerance to irradiation of high-energy heavy ion beams. We used 200 MeV gold ion beams modeling cumulative damages due to fission products emitted from the surface of spent nuclear fuels. By varying the dose level, we confirmed that the thermoelectric and magnetic properties of the single-crystalline YIG/Pt STE device are finite at the ion-irradiation dose up to 1012 ions/cm2 fluence. In addition, the HAXPES measurements were performed to understand the effects at the interface of YIG/Pt. The HAXPES data suggest that the chemical reaction regarding Fe and O that diminishes the SSE signals is promoted with the increase of the irradiation dose. The understandings of the damage analysis in YIG/Pt are beneficial for developing better STE devices applicable to harsh environmental usages. [ABSTRACT FROM AUTHOR]

An on-chip measurement circuit that was specifically designed to capture the high-speed transient characteristics of photocurrent is employed to measure total-ionizing-dose (TID)-induced leakage from 10 keV X-rays. This circuit uses a photocurrent-controlled oscillator (PCO) to produce an analog frequency, which provides linearity comparable to traditional, off-chip methods of TID measurement. The circuit was fabricated in a sub-50 nm, fully depleted silicon-on-insulator (FD-SOI) technology. TID-induced leakage currents were measured using the circuit and results were compared to off-chip direct measurements from identical transistor arrays. Additionally, potential in situ applications of this circuit in conjunction with a TID-compensating back-gate biasing technique are explored. [ABSTRACT FROM AUTHOR]

The effects of buried-well potential perturbation under the buried-oxide (BOX) layer are studied in both a heavy-ion single event upset (SEU) test and a high-energy proton-SEU test of a silicon-on-insulator (SOI) dual interlocked storage cell (DICE)-based flip-flop. Their dependence on incident angle and back bias is discussed. We fabricated both DICE-based flip-flop and conventional flip-flop, which are designed as 80 000-stage shift-register chains. In a heavy-ion test, a considerable number of SEUs were observed at back bias exceeding 2.4 V, and a ten-times larger SEU-cross section was finally recorded at back bias of 3.0 V compared with the total active area of a DICE-based flip-flop cell. This marks the first case where DICE topology was found to be broken by buried-well potential perturbation on an SOI DICE-based flip-flop. In a proton test, one error was observed at back bias of 2.0 V. The SEU rate in the Van Allen belt at an altitude of 2300 km and an inclination of 90° was estimated as being once every 5 years. [ABSTRACT FROM AUTHOR]

This article investigates heavy-ion irradiation effects on perpendicular magnetic anisotropy spin-transfer torque magnetic tunnel junction devices (PMA STT-MTJs). The radiative campaign took place at the Université Catholique de Leuven (UCL) facility. The considered devices consist of STT p-MTJs purely magnetic memories and they were fabricated at SPINTEC using the most advanced CoFeB-MgO MTJ technology. Single-event upset (SEU) tolerance and modification of magnetic properties has been investigated. [ABSTRACT FROM AUTHOR]

The radiation response of TaOx-based resistive memory (RRAM) devices fabricated in academic (Set A) and industrial (Set B) settings was compared. Ionization damage from a 60Co gamma source did not cause any changes in device resistance for either device type, up to 45 Mrad(Si). Displacement damage from a heavy ion beam caused a decrease in resistance at 1 × 1021 oxygen displacements per cm3 in Set B devices in the high-resistance state (HRS); meanwhile, Set A devices did not exhibit any decrease in resistance due to displacement damage. Both types of devices exhibited an increase in resistance around 3 ×1022 oxygen displacements per cm3, possibly due to the damage at the oxide/metal interfaces. These extremely high levels of damage represent near-total atomic disruption, and if this level of damage was ever reached, other circuit elements would likely fail before the RRAM devices in this article. Overall, both sets of devices were much more resistant to radiation effects than the similar devices reported in the literature. Displacement damage effects were only observed in the Set A devices once the displacement-induced oxygen vacancies surpassed the intrinsic vacancy concentration in the devices, suggesting that high oxygen vacancy concentration played a role in the devices’ high tolerance to displacement damage. [ABSTRACT FROM AUTHOR]

Novel design techniques for efficient testability are developed and have been implemented in a 14-/16-nm bulk FinFET node technology characterization vehicle. The result of this paper was the measurement of over 300 000 SETs across 12 combinational logic variants and 415 000 SEUs in three D-flip-flop designs over a large test matrix of heavy-ion linear energy transfer, angle of incidence, and supply voltage in only 319 test runs with a total test time of 108 h. A similar-sized data set with equivalent technology coverage, using the traditional serial testing approach as used in previous work, would typically require thousands of test runs and a significant number of additional hours of testing. The methodologies developed in this paper are technology agnostic and have provided the capability to efficiently characterize the radiation-induced response of the 14-/16-nm FinFET technology generation and yielded insights for assessing the feasibility for incorporation in systems requiring radiation resiliency. [ABSTRACT FROM PUBLISHER]

This paper describes a circuit called dynamic and applicative measurement of single events in logic (DAMSEL), which can individually measure the impact of single event upsets and single-event transients (SETs) in realistic, synchronous digital circuits. Heavy-ion and pulsed laser test results are presented. Both a simple digital and an analog simulation methodology are demonstrated to provide similar cross sections to those observed during the tests. Overall, the DAMSEL structure has many advantages over current circuits used for measuring SETs, including the ease with which test results can be extrapolated to real designs. [ABSTRACT FROM PUBLISHER]

Heavy-ion-induced degradation in the reverse leakage current of SiC Schottky power diodes exhibits a strong dependence on the ion angle of incidence. This effect is studied experimentally for several different bias voltages applied during heavy-ion exposure. In addition, TCAD simulations are used to give insight on the physical mechanisms involved. [ABSTRACT FROM PUBLISHER]

Experimental results on ion-induced leakage current increase in 4H-SiC Schottky power diodes are presented. Monte Carlo and TCAD simulations show that degradation is due to the synergy between applied bias and ion energy deposition. This degradation is possibly related to thermal spot annealing at the metal semiconductor interface. This thermal annealing leads to an inhomogeneity of the Schottky barrier that could be responsible for the increase leakage current as a function of fluence. [ABSTRACT FROM PUBLISHER]

Heavy ion irradiation increases the leakage current in reverse-biased SiC Schottky diodes. This letter demonstrates, via molecular dynamics simulations, that a combination of bias and ion-deposited energy is required to produce the degradation. [ABSTRACT FROM AUTHOR]

We report on a measurement of low energy ion irradiation effects on as-grown films of SiO_2 on a Si substrate. Beams of normally incident Na^ + ions with kinetic energies of 2 keV to 5 keV were focused onto \sim 1900 \ \AA SiO_2 films. Aluminum top metal contacts were subsequently deposited onto these targets such that irradiated regions and unexposed (pristine) regions of the target could be compared using capacitance–voltage (C–V) measurements of individual metal-oxide-semiconductor (MOS) devices. The C–V data reveal an energy-dependent shift in the flatband voltage (VFB) that can be returned to its near-pristine value by a low temperature anneal. An increase in the density of interface states (Dit) inferred from the C–V curves is found to have a superlinear dependence on the incident kinetic energy. These data are consistent with previously observed UV radiation effects on MOS oxides, where transferred energy leads to electron-hole pair production and the diffusion and trapping of holes throughout the oxide. Our measured trapped hole densities are compared with calculated densities, which are based on the incident ion dose and the predicted ion implantation range, to arrive at a fractional yield for hole survival and measurement within an encapsulated MOS device. [ABSTRACT FROM AUTHOR]

Circuit parameters and configuration are very important when studying the synergistic effects total dose/SET. We explore a method combining dynamic parameter measurement and spectrum analysis which lead to a better understanding of this complex phenomenon. In this paper symbolic circuit analysis is used to obtain the relationship between input, output and noise injection due to photocurrent generation in the form of a rational function using symbolic variables in the complex frequency domain. This simulation technique was able to predict the impact of (i) total dose level, (ii) circuit parameters, and (iii) the injected energy on the ASET shapes. Basic mechanisms as field collapse and collection efficiency were also predicted and assessed. [ABSTRACT FROM PUBLISHER]

A non-volatile memory element called a perpendicular-anisotropy magnetic tunnel junction was fabricated using CoFeB/MgO/CoFeB film stack technology. It exhibits two stable resistance values, high or low, depending on the relative directions of the magnetizations of the two ferromagnetic CoFeB layers. After being programmed into the high resistance state with a current injection scheme based on the spin transfer torque theory, the tunnel junction was exposed to 15-MeV Si ions under different voltage stress conditions. The tested structure remained in the programmed high resistance state after being bombarded with 10–100 Si ions, even under the stressed situations. A time-domain analysis proved that this result is due to the perfect immunity of the tested magnetic tunnel junction to single event upsets. Some degradation in resistance due to the heavy-ion irradiation was detected through a precise parameter analysis based on a tunneling theory but it was negligibly small (1%). There were no statistically significant changes in the thermal stability factor before and after irradiation, and this means the long-term retention properties remained unchanged. [ABSTRACT FROM PUBLISHER]

We present an experimental methodology developed to probe the clustered defect formation in GaAs devices under both neutron and ion irradiations. The strengths, limitations, and path forward to gather structural defect information will be addressed. [ABSTRACT FROM PUBLISHER]

Scintillating screens are commonly used at accelerator facilities. However, their imaging qualities are not well understood, especially for high-current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies of 4.8 and 11.4 MeV/u. For ion beam applications, the exact reproduction of the beam profile is of great importance. Due to the impact by ions, the dose rate during beam delivery is more than 10 orders of magnitude higher as for other applications of scintillators in typical nuclear physics experiments. To validate the imaging quality of the scintillators, different profile measurement methods are compared. Ceramic Al2O3 showed the best results compared to other ceramics like ZrO2:Y or quartz glass Herasil 102. The imaging properties of the materials can depend significantly on the ion energy. For Al2O3 irradiated with a Ca beam the of 4.8 MeV/u, the results agree with the reference methods. However, for 11.4 MeV/u, the screen image does not reflect the beam distribution, which cannot be attributed to material degradation. A model is under development taking into account the radial dose distribution along the ion track as well as the overlap of tracks. For Al2O3, this model can describe the observed saturation effect and is able to reconstruct saturated images. The basics and applications of this model are discussed. Detailed spectroscopic investigations were performed to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectra with respect to the beam intensity was found for most of the scintillators. [ABSTRACT FROM PUBLISHER]

Single-event upsets are studied in digital logic cells in a radiation-hardened CMOS SOI technology. The sensitivity of SEU to different strike locations and hardening approaches is explored using broadbeam and focused beam experiments. Error distributions in chains of logic flip-flops are studied to determine the impact of various cell designs and hardening techniques on upset uniformity. [ABSTRACT FROM PUBLISHER]

Digital single-event transient (SET) measurements in a bulk 65-nm process are compared to transients measured in 130-nm and 90-nm processes. The measured SET widths are shorter in a 65-nm test circuit than SETs measured in similar 90-nm and 130-nm circuits, but, when the factors affecting the SET width measurements (in particular pulse broadening and the parasitic bipolar effect) are considered, the actual SET width trends are found to be more complex. The differences in the SET widths between test circuits can be attributed in part to differences in n-well contact area. These results help explain some of the inconsistencies in SET measurements presented by various researchers over the past few years. [ABSTRACT FROM AUTHOR]

At GSI, the Helmholtz Centre for Ion Research, the properties of scintillation screens, irradiated by an ion beam, were studied. For various materials, the different ion beams H+, C2+, Ar10+, Ni9+, Ta24+, and U28+ in the energy range from 4.8-11.4 MeV/u were applied with currents ranging from nA to some mA, delivered by the heavy ion LINAC at GSI. Scintillation screens are widely used for qualitative ion beam profile monitoring. However, precise measurements of the beam profile yield ambivalent results, especially for high beam currents. Thus, the properties (light yield, beam width, and higher statistical moments) of well-known scintillators, ceramic materials, and different quartz glasses are compared. The image of each ion beam pulse was recorded by a digital CCD camera and individually evaluated. A change of the imaged ion beam shape was observed for some materials. The recorded beam profile shows dependence on the scintillator material. Even for low beam intensities (17 nA) a difference in the beam width of about 25% was measured. Additionally, the light yield and beam width depend significantly on the screen temperature, which is increased by the ion impact. For ZrO2 : Al the influence of the screen temperature on the statistical moments was investigated. Furthermore the spectra of scintillation screens were studied in the region from 350 to 750 nm for the irradiation with H+ and Ta24+ ions. Empirical results are discussed and give rise to further investigations on the materials. [ABSTRACT FROM AUTHOR]

Novel techniques have been developed to simulate particle transport in arbitrarily complex back-end-of-line topologies. They are shown to be critical for single event effect analyses of new device structures for 65 nm CMOS technologies and beyond. The salient features of the new modeling methods are illustrated by the simulation results taken from several case studies of particle-induced radiation problems in the back end. [ABSTRACT FROM AUTHOR]