This attempt at circuit level single event effects (SEE) hardening of SiGe HBT logic provides the first reported indication of the level of sensitivity in this important technology. Characterization over data rate up to 3 Gbps and over a broad range of heavy ion LET's provides important clues to upset mechanisms and implications for upset rate predictions. We augment ion test data with pulsed laser SEE testing to indicate the sensitive targets within the circuit and to provide insights into the upset mechanism(s).

Experimental test methods and analysis tools are demonstrated to assess particle-induced bit errors on fiber optic link receivers for satellites. Susceptibility to direct ionization from low LET particles is quantified by analyzing proton and helium ion data as a function of particle LET. Existing single event analysis approaches are shown to apply, with appropriate modifications, to the regime of temporally (rather than spatially) distributed bits, even though the sensitivity to single events exceeds conventional memory technologies by orders of magnitude. The cross-section LET dependence follows a Weibull distribution at data rates from 200 to 1000 Mbps and at various incident optical power levels. The LET threshold for errors is shown, through both experiment and modeling, to be 0 in all cases! The error cross-section exhibits a strong inverse dependence on received optical power in the LET range where most orbital single events would occur, thus indicating that errors can be minimized by operating links with higher incident optical power. Also, an analytic model is described which incorporates the appropriate physical characteristics of the link as well as the optical and receiver electrical characteristics. Results indicate appropriate steps to assure suitable link performance even in severe particle orbits.

Individual ionizing heavy ion events are shown to cause two or more adjacent memory cells to change logic states in a high density CMOS SRAM. A majority of the upsets produced by normally incident heavy ions are due to singleparticle events that causes a single cell to upset. However, for grazing angles a majority of the upsets produced by heavy-ion irradiation are due to single-particle events that cause two or more cells to change logic states.Experimental evidence of a single proton-induced spallation reaction that causes two adjacent memory cells to change logic states is presented. Results from a dual volume Monte-Carlo simulation code for proton-induced single-event multiple upsets are within a factor of three of experimental data for protons at normal incidence and 70 degrees.

We present data on recent optocoupler in-flight anomalies and the subsequent ground test irradiation performed. Discussions of the single event mechanisms involved, transient filtering analysis, and design implications are included. Proton-induced transients were observed on higher speed optocouplers with a unique dependence on the incidence particle angle. The results indicate that both direct ionization and nuclear reaction-related mechanisms are responsible for the single events observed.

Index Terms-Ground testing, modeling, SiGe, silicon germanium, single event effect, single event upset.

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Radiation-induced permanent degradation and single event transient effects for optocouplers are discussed in this paper. These two effects are independent to the first order and will be addressed separately. Displacement damage-induced degradation of optocoupler current transfer ratio is reviewed. New data are presented that show the importance of application specific testing and that generalized quantification of optocoupler CTR degradation can lead to incorrect predictions of actual circuit performance in a radiation environment. Data are given for various circuit loading and drive current parameters. Previous work that introduces the idea that two mechanisms exist for inducing transients on the optocoupler output is discussed. New data are presented that extends the evidence of this dual mechanism hypothesis. In this work measurements show that single event transient cross sections and transient propagation varies with circuit filtering. Finally, we discuss utilization of the optocouplers in the space environment. New data are applied to two examples: one on permanent degradation and the other on single event transient rates in high bandwidth applications.