Extra low voltage DRAM/SOI technologies were developed using (1) modified MESA isolation without parasitic MOS operation, (2) dual gate CMOS for low Vth control, (3) optimized layout using both body-tied and floating body MOSFET's, and (4) reduced Cb/Cs ratio. Completely redesigned low voltage scheme 16MDRAM/SOI was successfully realized and functional operation was obtained at very low supply voltage below 1V.