 repeating steps through until {TAIL ~ the desired thickness} of {HEAD ~ stacked monolayers} have been grown 
repeating steps through until { TAIL ~ the desired thickness } of { HEAD ~ stacked monolayers } have been grown
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH