Radiation Effects

Abstract

The effects of the space radiation environment on semiconductor device response are reviewed. Semiconductor devices in space can be exposed to energetic particles that can cause device degradation and system failure. The space environment consists primarily of protons, electrons, and heavy ions. Ionizing radiation (electrons and protons) can induce significant charge buildup in oxides, causing large threshold voltage shifts, and decreases in carrier mobility and bipolar transistor gain. This can result in large increases in the static power current of an IC, degradation in timing, and potential loss of functionality. In the space environment, heavy ions and protons can cause single‐event effects. There are two general classes of single‐event effects: soft errors and hard errors. Soft errors cause no permanent damage and may be correctable. Single‐event upsets are one type of soft error. If the error rate caused by soft errors is too high, performance degradation and even system failure can result. Hard errors cause permanent damage to devices. As integrated circuit technologies advance, they are becoming more prone to soft errors caused by energetic ions. In fact, soft errors caused by energetic particles present in the terrestrial environment and emitted from metal impurities are rapidly making single‐event upset a major reliability concern for ground‐based commercial ICs.

Analytical models for total dose ionization effects in MOS devices.

“…These deviations can be caused by a nonlinear spatial distribution of trapped holes or by a crossover from tunneling-to thermal emission-dominated annealing. The room-temperature curve in Figure 2 departs from the linear expression for times earlier than 2 10 sec. This is likely due to thermal emission which is considered next.…”

“…For nchannel devices interface traps are negatively charged, and for p-channel devices interface traps are positively charged. Excellent summaries of total dose effects are given in references [1] [2],…”