Study of random dopant fluctuation in PNPN feedback FET

摘要

The impact of random dopant fluctuation (RDF) on the performance variation of a PNPN feedback field effect transistor (PNPN FBFET) is investigated using a 3D technology computer aided design tool. To investigate RDF-induced device performance variation (e.g. threshold voltage (VTH) variation), the nominal doping profile of each region in a PNPN FBFET is separately randomized. Consequently, in terms of RDF-induced VTH variation, the channel-2 region (i.e. gated channel region) plays a key role as a main contributor to VTH variation, as it is the most decisive region for determining gate-to-channel controllability. As an example, the value of sigma V-TH resulting from the channel-2 region is nine times higher than that from the channel-1 region. Based on the simulation results, guidelines for variation-immune device design are comprehensively discussed.