On the ion implantation of phosphorus as a method for the passivation of states at the interface between 4H-SiC and SiO$_2$ produced by thermal oxidation in dry oxygen

A method is suggested for reducing the density of surface states at the 4H-SiC/SiO$_2$ interface by the implantation of phosphorus ions into a 4H-SiC epitaxial layer immediately before the growth of a gate insulator in an atmosphere of dry oxygen. A significant decrease in the density of surface states is observed at a phosphor-ion concentration at the SiO$_2$/SiC interface exceeding 10$^{18}$ cm$^{-3}$. However, together with the passivation of surface states, the introduction of phosphorus ions leads to an increase in the built-in charge in the insulator and also slightly deteriorates the reliability of the gate insulator fabricated by this technique.