Noise analysis of integrated bulk current sensors for detection of radiation induced soft errors

Abstract

Current CMOS technologies show an increasing susceptibility to a rising amount of failure sources. This includes also radiation induced soft errors, which requires countermeasures on several design levels. Hereby, Bulk Built-In Current Sensors represent a promising approach on circuit level. However, it is expected that these circuits, like similar sensors measuring substrate effects, are strongly susceptible to substrate noise. The intention of this work is an in-depth noise analysis of representative bulk sensor based on extracted layout data. Thereby, several aspects are considered, like sensor activation thresholds, impact of the distance to the noise source, and noise generation by a test circuits. Results indicate that already rms values of 5 to 10 % of the supply voltage can lead to false detections and that these values are in the same order of magnitude as the noise generated by test circuits.