UV radiation effects of argon plasma on Si−SiO2 structures

Radiation damage is investigated in Si−SiO 2 structures with thin (34 nm) SiO 2 film exposed to the action of the ultraviolet component of a “soft” argon plasma. To obtain information about the electrical properties of the structures, inversion channel current-voltage characteristics are measured. It is found that low energy ultraviolet readiation (up to 8.7 eV) from the low-temperature argon plasma creates shallow acceptor-like interface states. As a result of the screening effect of the trapped electrons in these states a significant increase of the channel mobility is observed. It is assumed that the plasma-induced defects are connected with breaking of weak and strained bonds in the oxide and at the Si−SiO 2 interface. The temperature dependence of the channel mobility is interpreted in terms of several scattering mechanisms.