Evidence that N2O is a stronger oxidizing agent than O2 for both Ta2O5 and bare Si below 1000 °C and temperature for minimum low-K interfacial oxide for high-K dielectric on Si

N₂O is known to be the stronger oxidizing agent than O₂ for the post-deposition annealing of Ta₂O₅·N₂O should also be stronger than O₂ for Si oxidation. However, NO released from N₂O is also a nitridation agent which can produce silicon oxynitride at a temperature above 1000 °C and silicon oxynitride can be a diffusion barrier for oxygen. Below 1000 °C, SiO sublimation can make the comparison of N₂O oxidation and O₂ oxidation of Si difficult. Below 750 °C, N₂O is obviously the faster oxidizing agent than O₂ for bare Si. Furthermore, our results show that minimum interfacial SiO_x, which has a low dielectric constant, occurs at about 800 °C or 950 °C for high-K metallic oxide gate insulator for future generations of CMOS because rapid thermal oxidation at these two temperatures can help to reduce leakage current or charge trapping by suppressing oxygen vacancies without too much low-K interfacial SiO_x formation.