Superior performance and reliability of MOSFETs with ultrathin gate oxides prepared by conventional furnace oxidation of Si in pure N2 O ambient

A novel technique for the fabrication of ultrathin MOS gate dielectrics for ULSI applications has been developed by oxidizing Si substrates in pure N₂O. This technique has several advantages over conventional thermal oxidation of Si in O₂. Si oxidation rate in N₂O is significantly lower than in O₂, allowing for excellent control of oxide thickness in deep nanometer region. Auger electron spectroscopy (AES) shows that 3 at.% nitrogen piles up at the Si/SiO₂ interface, similar to reoxidized nitrided oxides, resulting in a considerable improvement in the immunity to charge trapping and interface state generation and superior time-dependent dielectric breakdown (TDDB) characteristics. MOSFETs with gate oxides grown in N₂O exhibit less transconductance degradation under hot electron stressing and superior current drive capability as compared with devices with conventional SiO₂ gate dielectric