Neutralization theory of static surface charges by an ionizer under wide gas pressure environments

The neutralization of static-charges by an ionizer under wide gas pressure environments has been investigated theoretically, where the time required for the surface charge neutralization and the value of charge in-balance were predicted in terms of Knudsen Numbers (Kn: mean free path of ion/characteristics length). The results show that (1) the steady state potential due to the charge in-balance increases with increasing Kn for the positive and negative ion generating gas environments (electronegative gas such as air, oxygen, etching gases etc.); (2) the steady state imbalance potential decreases with increasing Kn for electron-positive ion generating gas such as nitrogen, noble gas, etc.; and (3) the charge neutralisation time is much faster for electron-positive ion generating gas than that of the negative-positive ions generation under wide gas pressure conditions