Material-related effects during ion beam treatment by an end-Hall ion source

• Material related electrical characteristics of the Mark I+ end-Hall ion source were evaluated.
• Dependent on neutralization etch-rates for CuTi, Si(100), LiNbO3 were measured.
• Etch rates for a wide process parameter range were given.
• A dependence of surface roughening and the degree of neutralization was shown.
• Metallic surface contaminations were indicated.

Reproducibility and accuracy of dry etching processes are a challenge for the operators of end-Hall ion sources with hot filament (HF) neutralizer. The variation of the neutralization current IN, e.g. due to filament aging as well as the properties of the substrate material lead to changes in the resulting etch rate of the substrate. Therefore a special controller setup was developed to automatically neutralize the ion beam of an end-Hall ion source with HF by measurement of the substrate current and control of an introduced difference current (ID). In this study, the influence of conductive (amorphous CuTi-film), semi-conductive (B-doped Si(100)) and non-conductive material (128°YX LiNbO3) on ID is demonstrated. Additionally, the etch rate for a wide process regime (VA and IA) for Si(100), the surface roughness for defined under- and overneutralization and the properties of the etched sidewalls were investigated. The effect of the gas distributor ring material on the etch rate is also shown.