Interface state generation by negative gate-bias irradiation of MOS structures

Irradiation of MOS structures under a negative gate-bias results in trapped positive charge at both the Al-SiO/sub 2/ and Si-SiO/sub 2/ interfaces. It is shown that the trapped charge at the Si-SiO/sub 2/ interface can be converted to interface states in a manner consistent with trapped hole models. This finding is significant because it appears to contradict other models which implicate H/sup +/ ions (in contrast to holes) as being primarily responsible for radiation-induced interface state generation. It is also demonstrated that trapped positive charge at the Al-SiO/sub 2/ interface can play a role in the interface state formation.