Conductance transient comparative analysis of ECR-PECVD deposited SiN_x, SiO_2VSiN_x and SiO_xN_y dielectric films on silicon substrates

摘要

A study of metal-insulator-semiconductor (MIS) structures based on SiN_x, SiO_2/SiN_x and SiO_xN_y films deposited on silicon by electron cyclotron resonance plasma-enhanced chemical vapour deposition (ECR-PECVD) is presented. Interface trap densities measured by deep level transient spectroscopy (DLTS) are higher for silicon oxynitride-based MIS capacitors than for silicon nitride and silicon oxide-silicon nitride-based ones. However, conductance transient analysis demonstrated that Al/SiN_x/Si devices exhibit the highest disordered-induced gap states (DIGS) density, whereas the lowest one corresponds to AVSiN_x/SiO_2/Si, and silicon oynitride-based MIS capacitors show an intermediate behaviour. In addition, thermal treatments applied to Al/SiO_xN_y/Si samples reduce DIGS densities to values even lower than those corresponding to Al/SiN_x/SiO_2/Si devices.