Katia F. Albertin

MOS capacitors with PECVD SiOxNy insulating layer

In this work metal/oxide/silicon (MOS) capacitors using SiO x N y and SiO 2 films with different nitrogen concentrations as gate dielectrics were deposited by the plasma-enhanced chemical vapor deposition (PECVD) technique,fabricated and characterized. These films were obtained through the variation of the N 2 O/SiH 4 flow ratio (R) at low temperatures ( ∼ 320 °C). The refractive index results show that by varying the N 2 O/SiH 4 flow ratio it is possible to obtain a precise control of this parameter in the 1.46-1.57 range. From the low- and high-frequency C- V curves, the interface state density (D i t ), the effective charge density (N s s ), dielectric constant (k), among others were extracted. Optimized properties were found for the capacitor with a low nitrogen concentration ( ∼ 8%) SiO x N y gate dielectric.