The method 2 further including {HEAD ~ the step} of maintaining a negative bias with respect to the first electrode and {TAIL ~ a positive bias} with respect to the second electrode 
The method 2 further including { HEAD ~ the step } of maintaining a negative bias with respect to the first electrode and { TAIL ~ a positive bias } with respect to the second electrode
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH