Electron effects in sputtering and cosputtering

Abstract

Morphology and structure evolution of Cu(In,Ga)S2 films deposited by reactive magnetron co-sputtering with electron cyclotron resonance plasma assistance J. Appl. Phys. 115, 084902 (2014); 10.1063/1.4866717The electronic structure of co-sputtered zinc indium tin oxide thin films Abstract: Electron effects in sputteringWe had previously observed, when cosputtering from a single target, that the deposited film was far from uniform, even showing a pattern resembling that of the target. Having subsequently made some energy and power measurements of the negative particles bombarding the anode in a sputtering system, we have concluded that the patterning is due to fast secondary electrons from the target. These secondary electrons are of importance in all types of sputter deposition, since a significant number of them travel in straight lines to the anode without collision. They are responsible for almost all of the power input into the anode and can dominate the growth of a thin film on a substrate at the anode.

Macro-effects of resputtering due to negative ion bombardment of growing thin films

“…The phenomenon of what they termed focused secondary electron emission was observed by Chapman et al 6 Positive ions bombarding the target cause the emission of secondary electrons that are then accelerated across the plasma toward the substrate. Hanak 7 reported that focused negative ions produced at the target are accelerated to the substrate.…”

Granular Metal Films

“…3. 98 Numerical estimates of the effect on the composition of the sputtered films due to cross contamination of the target and remission from substrate have been made by Hanak et al" Chapman et al 100 observed that secondary electron emission can produce an image of the target on the substrate when the insulator has high secondary electron emission characteris tics. The open circles and squares represent resistivities measured on films whose compositions were calculated from Eq.…”

Structure formation upon reactive direct current magnetron sputteringof transition metal oxide films

“…However the energy and flux of such Ar neutrals mainly scales with the target mass 17 and neighboring oxides such as zirconia and niobia should hence be exposed to similar amounts and consequently exhibit a similar structure, which is in contrast to our finding. Most of the secondary electrons formed 18,19 are trapped by the magnetic field and those that escape to the substrate caused no significant substrate heating. 1,8 Hence only negative ions have to be considered.…”