The impact of nitrogen profile engineering on ultrathin nitrided oxide films for dual-gate CMOS ULSI

We studied nitrogen profile engineering to make an ultra-thin silicon nitrided oxide (SiNO) film for 0.25 μm dual-gate CMOS device applications. It was found that high concentration nitrogen atoms piled up near the polysilicon/dielectric interface in the SiNO film can effectively prevent boron diffusion from the p⁺ gate electrode into the dielectric film, and consequently more than 3 times charge-to-breakdown (Q_bd) improvement can be achieved. The SiNO film enables surface channel PMOS and can reduce the minimum gate dielectric thickness by 1.5 nm