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This paper presents modeling and measurements of single event transients in a commercial 45 nm SOI device technology. SETs in clock circuits and pass gates can cause upsets in circuit structures hardened against single event upsets. Index Terms--Modeling, radiation event, single event transient (SET), single event upset (SEU), soft error.

Device-level current transients are induced by injecting carriers using two-photon absorption from a subbandgap pulsed laser and recorded using wideband transmission and measurement equipment. These transients exhibit three distinct temporal trends that depend on laser pulse energy as well as the transverse and vertical charge generation location. The nature of the current transient is controlled by both the behavior of the subcollector-substrate junction and isolation biasing. However, substrate potential modulation, due to deformation of the subcollector-substrate depletion region, is the dominant mechanism affecting transient characteristics. Index Terms--Current transient, electrostatic potential modulation, SiGe HBT, two-photon absorption.

The effects of device orientation on heavy ion-induced multiple-bit upset (MBU) in 65 nm SRAMs are examined. The MBU response is shown to depend on the orientation of the device during irradiation. The response depends on the direction of the incident ion to the n- and p-wells of the SRAM. The MBU response is simulated using Monte Carlo methods for a space environment. The probability is calculated for event size. Single-bit upsets in the space environment account for 90% of all events with exponentially decreasing probabilities of larger MBU events. Index Terms--Multiple-bit upset, MBU, MCU, SEU, heavy ion, SRAM, MRED, GEANT4, soft error.

Microbeam measurements and TCAD simulations are used to examine the effects of ion angle of incidence on the charge collected from events occurring in a Silicon Germanium (SiGe) Heterojunction Bipolar Transistor (HBT). The results identify the geometrically driven charge-collection mechanisms that dominate the low LET broad beam SEU response. The deep trench isolation that surrounds the transistor significantly modulates the charge transport and, therefore, the charge collected by the collector. A new way of estimating critical charge, [Q.sub.crit], for upset in SiGe HBT circuits is proposed based on TCAD simulation results and measured broadbeam data. Index Terms--Deep trench isolation (DTI), HBT, IBICC, silicon germanium (SiGe), single event upset (SEU), TCAD.

Single event latchup (SEL) in a 65 nm CMOS technology is examined with respect to strike angle of incidence and variations in device temperature. A significant difference in device sensitivity is observed with a change in the orientation of grazing angle strikes. The impact of an extremely high aspect ratio sensitive volume on SEL rate is discussed. It is suggested that SEL experiments should be conducted at various lateral orientations when near-grazing beam angles are tested. Index Terms--Radiation effects, single event latchup, 65 nm.

This work draws on experimental and simulation results to derive a generalized SEU response model for bulk SiGe HBTs. The model was validated using published heavy ion and new proton data gathered from high-speed HBT digital logic integrated circuits fabricated in the IBM 5AM SiGe BiCMOS process. Calibrating to heavy ion data was sufficient to reproduce the proton data without further adjustment. The validated model is used to calculate upset event rates for low-earth and geosynchronous orbits under typical conditions. Index Terms--Deep trench isolation, Geant4, geosynchronous orbit, low-earth orbit, rate prediction, silicon-germanium HBT, single-event upset.

Delayed charge collection from ionizing events outside the deep trench can increase the SEU cross section in deep trench isolation technologies. Microbeam test data and device simulations demonstrate how this adverse effect can be mitigated through substrate engineering techniques. The addition of a heavily doped p-type charge-blocking buried layer in the substrate can reduce the delayed charge collection from events that occur outside the deep trench isolation by almost an order of magnitude, implying an approximately comparable reduction in the SEU cross section. Index Terms--Deep trench isolation, Ion Beam Induced Charge Collection (IBICC), silicon germanium, Single Event Upset (SEU), substrate engineering.

The probability of proton-induced multiple-bit upset (MBU) has increased in highly-scaled technologies because device dimensions are small relative to particle event track size. Both proton-induced single event upset (SEU) and MBU responses have been shown to vary with angle and energy for certain technologies. This work analyzes SEU and MBU in a 130 nm CMOS SRAM in which the single-event response shows a strong dependence on the angle of proton incidence. Current proton testing methods do not account for device orientation relative to the proton beam and, subsequently, error rate prediction assumes no angular dependencies. Proton-induced MBU is expected to increase as integrated circuits continue to scale into the deep sub-micron regime. Consequently, the application of current testing methods will lead to an incorrect prediction of error rates. Index Terms--Energy deposition cross section, multiple-bit upset (MBU), MRED, single event upset (SEU), SRAM, proton effects.

We present an investigation of the observed variations in the total dose tolerance of the emitter-base spacer and shallow trench isolation oxides in a commercial 200 GHz SiGe HBT technology. Proton, gamma, and X-ray irradiations at varying dose rates are found to produce drastically different degradation signatures at the various oxide interfaces. Extraction and analysis of the radiation-induced excess base current, as well as low-frequency noise, are used to probe the underlying physical mechanisms. Two-dimensional calibrated device simulations are employed to correlate the observed results to the spatial distributions of carrier recombination in forward- and inverse-mode operation for both pre- and post-irradiation levels. Possible explanations of our observations are offered and the implications for hardness assurance testing are discussed. Index Terms--Dose enhancement, hardness assurance, low-frequency noise, silicon-germanium (SiGe), hetero-junction bipolar transistor, total ionizing dose.