A collar layer 12, preferably including {HEAD ~ a silicon oxide} deposited by {TAIL ~ a CVD method}, is, subsequently, applied to the side walls of the trench 5 
deposited by
A collar layer 12 , preferably including { HEAD ~ a silicon oxide } deposited by { TAIL ~ a CVD method } , is , subsequently , applied to the side walls of the trench 5
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH