Large-grain polysilicon-on-insulator (LPSOI) MOSFETs, formed from amorphous silicon by high-temperature metal-induced-lateral-crystallization (MILC) have been reported to operate in gigahertz range for the first time. Large dimensional (W/L=240/1.2 /spl mu/m) LPSOI NMOSFETs and PMOSFETs display a maximum transconductance (g/sub m max/)=68 mS/mm and 48 mS/mm at V/sub DS/=3 V, respectively. The unity short circuit current gain frequencies (f/sub T/) of NMOSFET and PMOSFET have been found to reach 3.4 GHz and 2.6 GHz at channel length of 1.2 /spl mu/m. With channel length scaling, higher f/sub T/ can be achieved and have been demonstrated with the measured value of 5.1 GHz f/sub T/ for PMOSFET with a channel length of 0.7 /spl mu/m. The f/sub T/ value obtained is the highest among silicon FETs fabricated on nonsingle crystal silicon substrates.