An ultra-fast erasing process that acts within 200 ns is demonstrated in a junctionless gate-all-around nanowire silicon-oxide-nitride-oxide-silicon device. Rapid erasing is enabled with the use of instantaneous thermal excitation (TE) through a double-ended gate structure. Charges inside the silicon nitride layer are de-trapped by Joule heating. Moreover, an in-situ self-annealing effect accompanied by the TE erase method is achieved; hence, both the tunnel oxide quality and the retention characteristics are less degraded compared with the conventional Fowler-Nordheim erase method.