The polysilicon layer 32 is made of {HEAD ~ polysilicon} doped with {TAIL ~ impurity ions}, for example 
The polysilicon layer 32 is made of { HEAD ~ polysilicon } doped with { TAIL ~ impurity ions } , for example
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH