Plasma immersion ion implantation reactor design considerations for oxide charging

Abstract

The effects of wafer bias and plasma parameters on thin oxide charging during plasma immersion ion implantation (PHI) are simulated. The simulator has been shown to determine accurately the charging currents generated during PHI. The dependence of the plasma electron temperature, ion density and plasma uniformity on charging damage in metal oxide semiconductor capacitor structures is investigated. A lower plasma electron temperature is shown to reduce charging damage. Simulation and experimental results show that for a given voltage pulse waveform there is a range of bias repetition rates allowed by limiting the charging damage below a threshold value. Within this range there exists a switch-over repetition rate that minimizes the charging damage.