Ion bombardment or backsputtering of SiO2films has been shown to result in severe insulator degradation in device processing. Here we have investigated the effects of low‐energy neutral‐particle bombardment on device quality SiO2films and have compared degradation produced by neutral‐particle bombardment with that produced by ion bombardment. These results show that (1) neutral‐particle bombardment produces substantially less (by two or three orders of magnitude) fixed charge at the SiO2/Si interface than does ion bombardment; (2) the most prominent degradation produced by neutral bombardment is the creation of a large interface state density across the band gap which is not related to a nonuniform charge distribution at the interface; (3) metal‐oxide‐semiconductor degradation produced by neutral bombardment may be removed by annealing at temperatures ?400 °C. Comparison of oxide charge degradation produced in SiO2by ion and neutral‐particle bombardment suggests that the neutralization processes at the vacuum‐SiO2interface, which take place only in ion bombardment, have the dominant role in this degradation. As a result of these processes, in ion bombarded samples, charge carriers migrate to the SiO2/Si interface in the field across the oxide film. This mechanism is absent in the case of neutral bombardment.
展开▼
