The assembly includes a source 24 of {HEAD ~ one or more solid materials} such as {TAIL ~ silicon}, germanium and carbon within the chamber 14 
The assembly includes a source 24 of { HEAD ~ one or more solid materials } such as { TAIL ~ silicon } , germanium and carbon within the chamber 14
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH