Optimization Of Thz Response Of Strained-Si Modfets

This paper reports on the study of strained-Si n-channel MODFETs as detectors of sub-THz radiation. Simulations based on a bi-dimensional hydrodynamic model for the charge transport coupled to a Poisson equation solver were performed. A charge boundary condition for the floating drain contact was implemented to obtain the photovoltaic response of the device. Time-domain simulations were performed to generate the stationary time series needed to obtain the photovoltaic response. A non-resonant THz photo-response was obtained in agreement with experimental results and theoretical works on plasma waves devices. It was found that the photovoltaic response of s-Si MODFETs with non self-aligned gates is strongly influenced by both gate's length and topology. In particular, it was demonstrated that at frequencies around 0.3 THz a double-finger gate delivers a stronger PV response than a conventional single-finger gate structure. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim