{HEAD ~ An emitter} and {TAIL ~ an extrinsic base layer} are formed in respective contacting relationships with the first and second portions of the intrinsic base layer 
{ HEAD ~ An emitter } and { TAIL ~ an extrinsic base layer } are formed in respective contacting relationships with the first and second portions of the intrinsic base layer
HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH