Low-frequency noise behavior of n-channel UTBB FD-SOI MOSFETs

Abstract

The low-frequency noise (LFN) behavior of ultra thin body and buried oxide (UTBB) fully-depleted (FD) silicon-on-insulator (SOI) n-channel MOSFETs has been explored, emphasizing on the contribution of the buried-oxide (BOX) and the Si-BOX interface to the total drain current noise level. In order to successfully distinguish the different noise sources, measurements under different front and back gate voltages were performed. The noise spectra for all bias conditions consist of both flicker and Lorentzian-type noise components. A fitting method was used to extract the parameters of the LFN. It is shown that the flicker noise follows the carrier number with correlated mobility fluctuations model at both interfaces and the Si/BOX interface contributes to the total LFN level, even without back gate bias voltage. The front and back gate voltage dependence of the Lorentzian time constants indicates a uniform distribution of generation-recombination (g-r) centers within the silicon film. In addition, when the Si/BOX interface is accumulated, interface traps at the front gate are activated due to higher front gate voltages, giving rise to a different type of g-r noise.