A ferroelectric based electrostatic doping (Fe-ED) technique is proposed, as the alternative to chemical doping, providing non-volatile and programmable free electrons and holes for nanoscale devices. We show that Fe-ED achieves non-volatility and reconfigurability via the ferroelectric film inserted into the polarity gate, producing the reconfigurable nanosheet FETs (NSFETs) without the requirement of a constant bias. Thanks to the naturally formed lightly doped drain structures and the extremely high doping concentration over cm-3 in source/drain (S/D) regions, Fe-ED NSFETs exhibit the promising potential benefits for device scaling including the improved subthreshold swing, the suppressed drain-induced barrier lowering, and the ultralow S/D region resistance. Our study suggests a promising doping strategy of Fe-ED for versatile reconfigurable nanoscale transistors and highly integrated circuits. © 1980-2012 IEEE.