The Effect of Ionizing Irradiation on the Charge Distribution and Breakdown of MOSFETs

Abstract—

The effect of ionizing irradiation (IIr) on the formation of charges at the internal SiO₂–Si (substrate) and external SiO₂–SiPSi (gate) interfacial boundaries (IFBs) and on the gate breakdown of MOSFET transistors has been studied. It is shown that with an increase in the dose of IIr near the internal IFBs, a monotonic increase of the positive charge in p-MOSFETs, the accumulation of positive charges at first, and the accumulation of negative charges in n-MOSFETs at doses above 10⁵ rad is observed. Near the outer IFB, the positive charge accumulation is observed at low radiation doses, and at doses higher than 10⁶ rad, a negative charge in both p-and n-MOSFETs is observed. It is shown that up to a dose of 10⁸ rad, IR does not have a noticeable effect on the gate breakdown voltage in both p- and n-MOSFETs at both polarities. The absence of influence is explained by a breakdown by the mechanism of anode hole injection.