Vapor Phase Homo- and Heteroepitaxies of ZnSe Films

Abstract

In a toroidal-type geometry, the closed magnetic field lines inhibit the loss of cold ions from the system. The resulting cold plasma gives rise to the basic difference between the plasma 'build-up' equations for neutral-atom injection into a toroidal system and those for magnetic-mirror geometry. If the cold-ion containment tima is long compared with the charge-exchange time with beam atoms, {hen charge exchange of the hot ions with background gas is not a serious loss process since the cold ions resulting from charge exchange will have a high probability of being reconverted to hot ions. Therefore, the cold plasma makes it much easier to satisfy the conditions for which the hot ions will exponentiate to a high density, as compared to the mirror-geometry case. The derived exponentiating condition has the surprising feature that the required cold-ion containment time decreases as the neutral gas density is increased.