Hiroki Koga

Enhancement of data retention time for giga-bit DRAMs using SIMOX technology

Both N-type and P-type stacked capacitor DRAM cells (L/sub g/=0.4 /spl mu/m) were fabricated on ultra-thin SIMOX substrates, and the data retention time was compared with that of a bulk counterpart. A data retention time of 550 sec (at 25/spl deg/C) could be achieves using ultra-thin SIMOX substrates, which is 6 times longer than that of the bulk memory cell. Specifically it is demonstrated that a P-type stacked capacitor cell on an ultrathin SIMOX substrate is very attractive and promising for future giga-bit DRAM cells.<<ETX>>

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.