Oxide charging induced by electron exposure in ion implantation: quantification and qualification

The use of electron showers (a.k.a. flood guns) during ion implantation has been used industry-wide to compensate for the parasitic effects of electrostatic charging caused by energetic ion beams impinging on the wafer surface during processing. Moreover, the wafer surface may be covered by a protective oxide which inhibits the majority of secondary electrons from reaching the wafer surface. Previous work has shown that the surface barrier of the oxidized surface is not significantly changed when flood guns are used which supports this premise. This work is concerned with the effects of the electron exposure on the oxide potential.