An Investigation of Single-Event Transients in C-SiGe HBT on SOI Current Mirror Circuits

The single-event effect sensitivity of three different commonly employed current mirror circuits, as well as an unconventional inverse-mode current mirror, all implemented in C-SiGe (NPN + PNP) HBT on SOI technology are investigated. Comparisons of the measured data of the basic NPN and PNP current mirror circuits show higher single-event radiation tolerance of PNP SiGe HBTs compared with NPN SiGe HBTs. The concept of utilizing inverse-mode SiGe HBTs in current mirror circuits is investigated. Measurement results validate the feasibility of employing inverse-mode PNP SiGe HBTs in current mirrors and show an excellent resilience against ion-strikes. Full 3-D NanoTCAD models of the SiGe HBTs are developed and used in mixed-mode TCAD simulations (within Cadence) to validate the measurement results. Finally, based on the measurement data and analysis of the four current mirrors, some practical suggestions and observations are offered for operation of such circuits in extreme environments.