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[en] This conference proceedings contains 78 papers all of which are indexed separately. Topics covered include: basic radiation mechanisms in materials and devices; energy deposition and dosimetry; system responses from SGEMP, IEMP, and EMP; basic processes in SGEMP, IEMP, and EMP; radiation effects in MOS microcircuits; and space radiation effects and spacecraft charging

[en] MOS devices, such as charge-coupled devices and MOSFET's, are being investigated for use in imaging, signal processing and detector preamplifier applications in which the detector and its immediately associated electronics are operated at low temperatures (less than or equal to 80 K). Recent experiments on MOS capacitors and devices at approximately 80 K have established that when hole-electron pairs are generated in the SiO₂ insulating layer by ionizing radiation the electrons are rapidly swept out of the oxide while the holes remain essentially immobile at or near their point of creation. As a result, the holes cause large flatband or threshold voltage shifts per unit dose in MOS structures. In contrast to the highly process-dependent ''permanent'' trapping of a small fraction of the radiation-generated holes observed at room temperature, the retention of the holes in SiO₂ at approximately 80 K is largely process-independent and is a consequence of a strongly temperature-dependent hole transport mechanism. The present paper discusses two related investigations of radiation-induced charge buildup in SiO₂ at approximately 80 K. In the first study, the retention of holes at low temperature is exploited to provide a direct measure of hole-electron pair yield per unit radiation dose as a function of electric field for high-energy ionizing radiation. In the second study the response of MOS capacitors to short pulse high dose irradiation at approximately 80 K is investigated, and mechanisms which impose limits on the oxide charge buildup are examined

[en] The transient response of SiO₂ gate-insulator MOS capacitors to pulsed electron beam irradiation was studied. The radiation-induced flatband voltage shift (ΔV/sub FB/) in SiO₂ MOS capacitors was measured with a fast C--V technique from 70 μsec to 1000 sec after a 60 krad radiation pulse for temperatures from 80 to 293 K. In complementary experiments, the post-irradiation charge displacement in the MOS capacitors was measured with an integrating picoammeter. By correlating the relaxation of the flatband voltage with integrated current measurements, it was established that the measured response is dominated by hole transport and trapping in the SiO₂ film. The temporal and temperature dependences of the hole transport are well described by a stochastic hopping model based on a continuous time random walk (CTRW). The essential feature of the CTRW is that the transport occurs via a carrier hopping (phonon assisted) process between localized sites randomly distributed in the amorphous SiO₂. Since the carriers do not require excitation to the band edges in order to be mobilized, the activation energy for conduction (tunneling) is independent of the optical excitation energy

[en] The transient response, or flat-band voltage recovery, in a number of pedigreed SiO₂ gate insulator MOS capacitors following exposure to a pulsed 13-MeV electron beam was studied as a function of time, temperature, and applied bias. A quantitative comparison of the response characteristics of the different oxides is made. It is found generally that the response consists of two stages. The first (early time) stage in most cases encompasses most of the recovery and is dominated by hole transport through the insulator film to the interface. This hole transport recovery stage in all the oxides studied is well described by the stochastic model of hopping transport based on a continuous time random walk used previously in the analysis of hole transport in SiO₂. It is further shown that all the main features of the hole transport are consistent with a model of the holes moving via polaron hopping between localized sites in the SiO₂. The second or long-term stage of recovery commences after cessation of the hole transport in the oxide and is found to vary significantly in its importance and time of onset among the various oxides. This stage involves a radiation-induced buildup of interface states and possibly, in some cases, an annealing of a trapped-hole distribution near the SiO₂/Si inerface

[en] In a prior publication, Winokur and Sokoloski reported that the nature and magnitude of the buildup of interface states in MOS capacitors under positive bias was the same for both penetrating Co⁶⁰ γ and nonpenetrating 10.2 eV uv radiation. They suggested that the buildup of interface states in MOS capacitors subjected to highly ionizing radiation was not due to the direct interaction of radiation at the interface or to a structural modification of the SiO² layer, but resulted from the production of electron-hole pairs in the insulator and the subsequent transport of holes to the interface. In the work reported on in this paper, the uv-Co⁶⁰ study was repeated (adding negative bias) on another set of thermally grown oxides and the interface-state density was monitored as a function of time from 40 ms to 400 s following a 4-μs electron pulse using a fast C-V technique. From the results of the latter experiment, it is reported that in addition to hole transport to the interface, some slow (relative to the hole transport time) interaction of the holes in the interface region appears to be responsible for the buildup of interface states. In addition, in both the uv-Co⁶⁰ study and the interface-state density with time study, the effects of lateral inhomogeneities were separated from interface states by measuring the frequency dependence of the C-V traces and by measuring the Gray-Brown shift between room temperature and liquid nitrogen temperature. It is shown that all three irradiations, uv, Co⁶⁰, and e-beam, produce interface states

[en] SiC transistors can operate at very high temperatures and survive very high radiation doses. These characteristics make SiC potentially the ideal technology for nuclear power applications. In this paper the authors report, for the first time, on the active in-core irradiation of 6H-SiC depletion-mode junction field-effect transistors (JFETs) at 25 and 300 C in a nuclear reactor operated at 200 kW. No significant degradation in the device characteristics was observed until the total neutron fluence exceeded 10¹⁵ n/cm² for irradiation at 25 C, and no significant changes were observed even at 5 x 10¹⁵ n/cm² at 300 C. The results of this experiment may also indicate exciting evidence for the anneal of neutron displacement damage for devices irradiated at 300 C

[en] This paper examines the effects of neutron irradiation on ferroelectric (FE) lead-zirconate-titanate (PZT) thin films. The data show only a slight loss in the FE switched charge, as measured by the hysteresis loop, up to 1 x 10¹⁵ n/cm². The retained polarization, as measured by a pulse technique, showed a larger loss of remnant polarization which saturated at the lowest fluence measured (1 x 10¹³ n/cm²). However, in neither case does it appear that the film was degraded sufficiently to cause devices made from sol-gel PZT to fail at fluences at or below 1 x 10¹⁵ n/cm². The endurance characteristics of the film were unchanged due to neutron irradiation

[en] Neutron-induced displacement damage effects in n-channel, depletion-mode junction-field-effect transistors (JFETs) fabricated on 6H-silicon carbide are reported as a function of temperature from room temperature (RT) to 300 C. The data are analyzed in terms of a refined model that folds in recently reported information on the two-level ionization energy structure of the nitrogen donors. A value of 5 ± 1 cm^-3 per n/cm² is obtained for the deep-level defect introduction rate induced by the neutron irradiation. Due to partial ionization of the donor atoms at RT, the carrier removal rate is a function of temperature, varying from 3.5 cm^-1 at RT to 4.75 cm^-1 at 300 C. The relative neutron effect on carrier mobility varies with temperature approximately as T^-7/2, dropping by an order of magnitude at 300 C compared with the RT effect. The results offer further support for the use of SiC devices in applications which combine high-temperature and severe radiation environments, where the use of Si and GaAs technologies is limited

[en] We focus on radiation-induced interface traps, describing first how they fit into the overall radiation response of metal-oxide-semiconductor (MOS) structures. Detailed measurements of the time, field and temperature dependences of the build-up of radiation-induced interface traps indicate three processes by which the build-up occurs. The largest of these is the slow two-stage process described by McLean and co-workers, which is rate-limited by the hopping transport of hydrogen ions. Two other faster processes also contribute small interface trap build-ups in gate oxides. The processes seem to be controlled by hole transport to the Si/SiO₂ interface and by neutral hydrogen diffusion respectively. We also discuss several models which fall into three classes, corresponding roughly to the three processes observed experimentally. Other topics discussed briefly are dose dependence, field oxide effects, chemical and processing dependences and scaling effects. (author)