Deep Cryogenic Temperature TDDB in 45-nm PDSOI N-channel FETs for Quantum Computing Applications.

We have investigated and report here for the first time time-dependent dielectric breakdown (TDDB) in 45-nm RFSOI n-channel floating body MOSFETs at cryogenic temperatures. DC constant voltage stress is applied at the gate while the substrate chuck temperature is varied from 300K down to 10K. While t63 decreases with increasing temperature, shape parameter beta shows an inverted U-shaped behavior which is explained using the bandgap model. Three levels of activation energy are seen for high, low and deep low temperatures where the activation energy decreases from high to deep low temperatures. The observed behavior is further explained using carrier energy shift in the bandgap as per the percolation theory.