Parasitic capacitance effects of the multilevel interconnects in DRAM circuits

The parasitic capacitance effects of the multilevel interconnects in DRAM circuits have been studied. Signal crosstalk such as intra- and inter-bit-line-to-bit-line coupling, bit-line-to-work-line coupling, and substrate noise coupling resulting from various parasitic capacitances between interconnects are presented. The intra-bit-line capacitance coupling and bit-line capacitance imbalance effects reduce the initial voltage difference between bit lines and degrade the sense amplifier sensing speed. The inter-bit-line capacitive coupling and bit-line-to-word-line signal crosstalk introduce significant array noise in multimegabit DRAMs. The depletion capacitance between n⁺ diffusion and p substrate offers a channel of the substrate interference noise during sense amplifier amplification