ight data and correlation of SEB rate with the applied voltage on the CRUX experiment that appear in [Bart-98]. The bias dependence is expected based on electric field dependence of the problem as described in [Titu-96, and references therein]. If proton-induced hard failure is possible, then heavy ion induced hard failure would also be possible. The determination of which failure mode would be more likely depends on the particle environment internal to the satellite and on the relative sensitivities of the device in question. [Bart-98] compares two sets of power MOSFETS flown on the CRUX experiment and shows that on a given satellite, proton-induced burnout may dominate for one device while heavy ion burnout dominates for another. In practice, power MOSFET applications typically de-rate the devices to improve reliability, avoid gate rupture, and prevent burnout. With proper de-rating, the threat of proton-induced burnout can be avoided. 4.3.3 Stuck Bits: The key paper introducing this topic was presented by Oldham, et al., in 1993 with the title "Total Dose Failures in Advanced Electronic from Single Ions," [Oldh-93]. Their work describes the ability of a single ion to deposit sufficient energy along its path to result in localized increases in trapped oxide charge and interface state generation. In fact, for small feature sizes, an entire transistor gate can be affected and undergo failure as a result of localized dose deposition and threshold voltage shift. The initial work in DRAMs resulted in bits which could not be rewritten, hence the term "stuck bits". This effect can occur in any device type, and is not just a problem for memories. Their paper also points out the expected increasing importance of this problem with decreasing feature size, and this has since been observed. The following year, Poivey, et al. expanded the study in terms of device types, ion species, and analysis. In that paper, the more formal term "Single Hard Error (SHE)" was introduced [Poiv-94]. At present, proton-induced stuck bits are