Uncooled THz/sub-THz Rectifying Detectors: FET vs. SBD

Abstract

The parameters (responsivity R and noise equivalent power (NEP)) of long channel unbiased (zero drain-source bias (VDS = 0)) silicon field effect transistors (FET) as THz/sub-THz detectors with account of some parasitics were considered. These parameters and their radiation frequency ν dependences are compared with those of contemporary Schottky barrier diode (SBD) THz/sub-THz detectors. To describe and compare the known experimental data for both of detectors similar models, taking into account the parasitics (some FET or SBD resistances and capacities), were used. It is shown that taking into account the parasitics and detector-antenna impedance matching one can describe Si FET detector parameters and estimate the performance limits of such detectors. The R and NEP radiation frequency ν dependences are similar for FET and SBD detectors and are proportional to ν-2 or to ν-4. The model used for SBD detectors describes well the known experimental data for optical NEPopt but for Si FET ones the sufficient scatter in experimental data is observed. The reason of it seems is mainly due to non-optimized technologies for FETs as detectors for THz/sub-THz radiation.