A comparison of the radiation tolerance of the STC bipolar, CMOS and merged bipolar/CMOS processes

This paper reports an assessment of the tolerance of STC’s bipolar, CMOS and ‘merged’ bipolar/CMOS processes to gamma total dose, dose rate and neutron fluence radiation effects. The objective of the assessment was to characterise process performance under worst case and near to worst case criteria when subjected to nuclear radiation up to the tactical level in accordance with BS 9000. Total dose irradiation was performed on the bipolar, CMOS and BiCMOS technologies with 9 Mrads (Si), 10-12 krads (Si) and 10-30 krads (Si) performance levels reported, respectively. Under dose rate conditions, transient upset, latch-up and photocurrent are reported with latch-up immunity reported for the bipolar 2 process and simultaneous latch-up and transient upset reported for both the bulk CMOS and BiCMOS processes. Neutron fluence testing was performed with the onset of failure for the CMOS reported at the 5 × 1014 neutrons/cm level and onset of failure for the bipolar and BiCMOS reported in the range 5 × 1014 to 5 × 1014 neutrons/cm2.