Energy contamination control system in deceleration beam line

Energy contamination should be controlled in deceleration implants below 5 keV to make shallow junctions. Surface SIMS profiles of B/sup +/ 0.2 keV and 0.5 keV were obtained under various experimental conditions to evaluate the quantity of energy contamination. It is consequently found that the quantity of energy contamination correlates strongly with efficiency of beam transmission from the flag faraday to the disk faraday, and from ion source to the flag faraday. Based on this result, an energy contamination control system is developed for the NV-GSDIII-LE and 90E. Energy purity in an operation of the decel mode can be kept higher than 99% on these machines. The effectiveness of the transmission-control system is shown in this paper, showing the experimental results.