Nitrogen-atom incorporation at Si–SiO2 interfaces by a low-temperature (300 °C), pre-deposition, remote-plasma oxidation using N2O

Nitrogen-atom incorporation at Si–SiO2 interfaces has been achieved using a N2O remote-plasma-assisted oxidation at 300 °C prior to remote plasma enhanced chemical vapor deposition of thin SiO2 gate dielectric films. The N2O remote plasma pre-deposition treatment removed residual hydrocarbon contamination, oxidized the Si surface, and incorporated nitrogen atoms at the Si–SiO2 interface. The amount of N incorporated at the Si–SiO2 interface was similar to amounts reported in the literature for oxides nitrided at much higher temperatures (800–1200 °C), where improved diffusion barrier properties and improved resistance to hot-carrier degradation were attributed to the presence of this N. The N2O remote plasma pre-deposition treatment was compared to previously developed, in situ H2 and O2 remote plasma surface treatments by Auger electron spectroscopy and secondary ion mass spectrometry measurements. Metal–oxide–semiconductor (MOS) capacitors were also fabricated to compare the electrical properties of interfaces formed with these different techniques. MOS C–V tests revealed that the interface formed by the N2O remote plasma-assisted oxidation had a low density of interface trapping states, midgap Dit=1×1010 cm−2 eV−1.