Femtoampere sensitive current measurement ASIC in 22 nm technology

Ultra low current measurement has a wide range of applications spanning varied fields of science. The front end electronics of radiation monitors demand circuits capable of measuring currents as low as femto amperes. Current to frequency converters forms the heart of such low current measurement circuits. Majority of the reported designs for such circuits are realized in 350 nm technology node or higher. Lower nodes suffer from the limitation of leakage currents which impedes such measurements. In this paper, a 22 nm FDSOI technology node is analyzed as a potential technology for low current measurements. A test structure has been designed and its capability to measurement currents with 1 fA sensitivity has been demonstrated.