DEVICE CHARGE-TO-BREAKDOWN STUDIES ON A HIGH-CURRENT IMPLANTER

Wafer charging studies on a high-current ion implanter were performed using charge-sensitive MOS structures with various charge multiplier ratios. Charge-to-breakdown measurements were made, both before and after implantation, to characterize the charging damage. The shifts observed in these measurements yielded information about the magnitude and polarity of the charge induced in the oxide during the implant. Such shifts have been correlated to the various implant parameters and electron flood conditions chosen for this study. For all the implants, a real-time monitoring of the disk current and the potential developed on each wafer was also made. The relationship between these parameters and the observed shifts in charge-to-breakdown will be discussed.