Focused ion beam based sputtering yield measurements
on ZnO and Mo thin films
JournalName :
Superlattices and Microstructures
PubDateYear :
2007
PubDateOther :
Volume :
42
Issue :
StartPage :
392
EndPage :
397
Keywords :
Notes :
Abstract :
In order to facilitate the lateral structuring of solar cell multilayer structures, the ion beam sputtering
behaviour of Mo and ZnO thin films deposited onto soda-lime glass and single crystalline Si substrates was
studied. Prior to ion beam processing the layers were analyzed by Energy Dispersive X-Ray Spectrometry
(EDS), X-Ray Diffractometry (XRD) and Rutherford Backscattering (RBS). In order to characterize the ion
beam sputtering of the investigated layers, 2×2 μm2 fractions of the thin films were removed by a scanned
30 keV focused Ga+ ion beam (FIB) in a dual beam system. SEM images taken during the milling process
allowed continuous monitoring of the process without breaking the vacuum. The depth of the groove after
removal of the layers was measured by Atomic Force Microscopy (AFM) and was plotted as a function of
the ion dose. The sputtering depth has a dependence on the ion dose that is close to linear. The deviation
from linearity is produced by heating effects at high beam currents. Sputtering yield values calculated from
the experiments and simulations showed good agreement in the case of Mo but deviation was found in the
case of ZnO.