If ions are implanted in a silicon wafer as the term 'ion implantation' suggests, how can the wafer be electrically neutral after the semiconductor doping? Aren't the ions ions electrically charged? Or do we add/remove electrons from the wafer at the same time to keep the wafer neutral?
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$\begingroup$ Electrons flow back into the wafer to the site where the ion implants. $\endgroup$– PhysicsDaveCommented Mar 30, 2019 at 13:28
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Yes, an electrical current neutralizes the wafer.
One uses ions in order to accelerate them to kinetic energies that will penetrate the wafer to a certain depth. The ions in this technique are positive. The wafer should not repel the ion beam, so it is kept at ground potential.
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$\begingroup$ Indeed, if you don’t bad things happen like luttle lightening bolt discharges vainly trying to keep the wafer closer to ground... $\endgroup$ Commented Mar 31, 2019 at 1:00