Subthreshold 1/f noise measurements in MOS transistors aimed at optimizing focal plane array signal processing

In focal plane signal processing applications it is imperative to minimize noise in the associated input circuit. The latter usually consists of MOS transistor preamplifiers and multiplexers. This paper concentrates on the 1/f noise generation in NMOS input signal processing circuits. A 1/f noise model for the subthreshold region is derived and correlated with 1/f noise measurements of NMOS transistors. This model is unique in that slow and fast surface states can be modeled separately. Typical values for slow and fast surface state densities from measured data and model correlation were found to be N _{ss s}=1×10¹¹ cm^-2 eV^-1 and N _{ss f}=3×10¹⁰ cm^-2 eV^-1, respectively. The order of magnitude of these results correlate well with published data 1–3]. The importance of these results is that process changes to minimize the 1/f noise can be monitored and the required minimization of 1/f noise for focal plane signal processing circuits can be achieved.