Contact resistance measurement of a 130-nm-diameter poly-Si plug on a lightly doped single diffusion region in giga-bit DRAMs

A practical method to extract the contact resistance of a phosphorus-doped poly-Si plug formed on a lightly phosphorus-doped diffusion region in giga-bit DRAM memory cells is proposed. A contact resistance diameter of 130 nm is experimentally obtained by the substrate bias change measurement, which can separate the resistance of a bias-dependent lightly-doped diffusion layer from the total contact chain resistance. This method is effective for process technology development of a low resistance contact formation in giga-bit DRAMs.