A method of controlling a plasma doping process using a time-of-flight ion
detector includes generating a plasma comprising dopant ions in a plasma
chamber proximate to a platen supporting a substrate. The platen is
biased with a bias voltage waveform having a negative potential that
attracts ions in the plasma to the substrate for plasma doping. A
spectrum of ions present in the plasma is measured as a function of ion
mass with a time-of-flight ion detector. The total number ions impacting
the substrate is measured with a Faraday dosimetry system. An implant
profile is determined from the measured spectrum of ions. An integrated
dose is determined from the measured total number of ions and the
calculated implant profile. At least one plasma doping parameter is
modified in response to the calculated integrated dose.