Optimal UTB FD/SOI device structure using thin BOX for sub-50-nm SRAM design

In this letter, the random dopant fluctuation effect in ultrathin-body (UTB) fully depleted/silicon-on-insulator (FD/SOI) devices is analyzed. We show that due to larger variability and asymmetry in threshold voltage V/sub t/ distribution, it will be difficult to use UTB FD/SOI devices for sub-50-nm static random access memory (SRAM) design. Using thinner buried oxide (BOX) FD/SOI devices, the asymmetry in the V/sub t/ spread can be reduced. We present a viable concept of FD/SOI SRAM and predict that a thin-BOX device is the optimal FD/SOI structure for SRAM in sub-50-nm technology nodes.