depositing said source material on {HEAD ~ a base} in {TAIL ~ the form} of a precursor film; and 
in
depositing said source material on { HEAD ~ a base } in { TAIL ~ the form } of a precursor film ; and
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH