Intrinsic cut off frequency of Si and GaAs based Resonant Tunneling Diodes

The amazing progress of SOI wafer technology has made possible to realize Si quantum wells of dimension lower than 10 nm, the typical range required for resonant tunneling diode (RTD) application. On the basis of an original physically-based analytical model, the theoretical DC and AC performances of AlAs/GaAs and HfO₂/Si based RTD has been compared in this work. It turns out that GaAs devices exhibit higher performances than Si device of same dimensions, both in term of current peak and maximum intrinsic frequency (THz range for GaAs RTD, GHz range for Si RTD). However, similar performances can still be achieved in principle using Si device, by further reducing tunnel barrier thicknesses and quantum well dimension.