Soft-breakdown-suppressed ultrathin atomic-layer-deposited silicon-nitride/SiO2 stack gate dielectrics for advanced complementary metal-oxide-semiconductor technology

We report a high-quality, ultrathin atomic-layer-deposited silicon-nitride/SiO2 stack gate dielectric. p(+)-polycrystalline silicon gate metal-oxide-semiconductor (MOS) capacitors with the proposed dielectrics showed enhanced reliability with respect to conventional SiO2. An exciting feature of suppressed soft-breakdown (SBD) events is observed in ramped voltage stressing which has been reconfirmed during time-dependent-dielectric breakdown measurements under constant field stressing. Introducing the idea of injected-carrier-induced localized physical damages resulting in the formation of conductive filaments near both Si/SiO2 and poly-Si/SiO2 interfaces, a model has been proposed to explain the SBD phenomena observed in the conventional SiO2 dielectrics. It is then consistently extended to explain the suppressed SBD in the proposed dielectrics. The reported dielectric can be a good choice to meet the urgent need for highly reliable ultrathin gate dielectrics in nanoscale complementary-MOS technology. (C) 2001 American Institute of Physics.