Lessons Learned from Low-Frequency Noise Studies on Fully Depleted UTBOX Silicon-On-Insulator nMOSFETs

Abstract

The low-frequency (LF) noise behavior of Fully Depleted (FD) Ultrathin Buried Oxide (UTBOX) Silicon-on-Insulator (SOI) nMOSFETs is described from the perspective of the three major noise sources: 1/f-like or flicker noise, associated with carrier trapping/detrapping in the gate oxide; Generation-Recombination (GR) noise due to processing-induced defects in the thin silicon film and single-oxide-trap-related Random Telegraph Noise (RTN). It is shown that the fully depleted nature of the thin silicon films (<20 nm) offers the unique opportunity to study and demonstrate the front-back coupling of the 1/f noise. At the same time, a large variability is induced in the noise magnitude by the Lorentzian noise, related with GR events through defects in the silicon film. A method to discriminate oxide- from film-defects-related Lorentzian noise is pointed out. Finally, the implications for future fully depleted fin-type of devices will also be discussed.