In situ process monitoring in plasma immersion ion implantation based on measurements of secondary electron emission coefficient

This paper reported measurements of secondary electron emission coefficient (SEEC) during plasma immersion ion implantation and its application to in situ process monitoring of surface conditions. In order to obtain the SEEC, the ratio of a target total current to its secondary electron current component was measured. The secondary electron current was measured with a semiconductor detector located in front of the target. In the PIII process based on an oxygen-mixtured discharge, the SEEC increased with the process time, then saturated. The time variation of the SEEC shows a fairly good agreement with that of the oxygen implantation depth measured by XPS analysis. This result suggests that the SEEC measurement is applicable to end-point detection for the PIII process.