US Patent 10128327 DRAM interconnect structure having ferroelectric capacitors exhibiting negative capacitance

An interconnect structure for use in coupling transistors in an integrated circuit is disclosed, including various configurations in which ferroelectric capacitors exhibiting negative capacitance are coupled in series with dielectric capacitors. In one embodiment, the negative capacitor includes a dielectric/ferroelectric bi-layer. When a negative capacitor is electrically coupled in series with a conventional dielectric capacitor, the series combination behaves like a stable ferroelectric capacitor for which the overall capacitance can be measured experimentally, and tuned to a desired value. The composite capacitance of a dielectric capacitor and a ferroelectric capacitor having negative capacitance coupled in series is, in theory, infinite, and in practice, very large. A series combination of positive and negative capacitors within a microelectronic interconnect structure can be used to make high capacity DRAM memory cells.