Room temperature plasma oxynitridation process, (RTPON), to obtain ultrathin dielectric films

Recently we reported a room temperature plasma oxidation (RTPO) process to obtain less than 2.5 nm SiO₂ films, with good interface properties and current density values similar to theoretical for direct tunneling mechanism. In this paper we first report a similar process for nitride and oxynitride growth at room temperature, in a barrel reactor in a mixture of N₂ and O₂ gases. The value of refractive index of the film, is a function of the O₂/N₂ flow ratio and exponentially decays from 2.0 to 1.46, which indicates that composition of grown films can be varied from silicon nitride to silicon oxide. From C-V measurements, a maximum value of effective dielectric constant of 5 was obtained. The current density observed is about 1 order of magnitude lower than the corresponding for SiO₂ films with the same equivalent oxide thickness.