Observation of H+ motion during interface trap formation

The time dependence of changes in the oxide trapped charge during interface trap formation is investigated. Changes in MOSFET threshold voltage V_th and number of interface traps N _it are measured in the same sample as a function of time following pulsed irradiation. When the gate bias during irradiation V_gl is positive, the initial |ΔV_th| is large due to trapping of radiation-induced holes at the Si-SiO₂ interface and the postirradiation time dependence of ΔV_th is dominated by hole detrapping, as expected. When V_gl is negative, interfacial hole trapping is minimized. In this case, an unusual peak in the ΔV_th vs. time curve provides evidence of the involvement of H⁺ ions in the N _it formation process