Total-dose issues for microelectronics in space systems

Ionizing radiation has been a problem for space-system microelectronics from the earliest satellites. Much progress has been made in understanding the physical mechanisms that cause total-dose-induced failure, and this knowledge has been applied to hardened-technology development. Many of the hardened technologies are no longer available, however, and hence more commercial off-the-shelf components are being used. This situation presents a challenge for system designers, since the commercial parts typically have lower failure levels and larger variability in response. In addition, recent studies have uncovered new challenges for total-dose hardness assurance in the form of 1) an enhanced low dose-rate sensitivity of bipolar linear microcircuits, 2) an effect of burn in on CMOS microcircuit total-dose response, and 3) an enhanced effect of plastic packaging on the burned-in effect for CMOS circuits. These issues are addressed as they relate to the space-system ionizing radiation environment.