Indium implantation process performance on the 8250HT

Indium is a possible alternative to boron for SSRCP, halo, and other ion implantation applications. However, indium implantation normally requires the use of indium tri-chloride, a hygroscopic solid, as a source material. Machine memory effects can occur with indium ion implants, leading to cross contamination problems when an implanter is used for both indium and other species. This paper focuses on issues related to implanting indium on Axcelis Technologies´ 8250_HT medium current implanter. This implanter has several features that minimize indium cross-contamination. We present evidence for the significance of two of these features: an actively cooled vaporizer and an angular energy filter (AEF). The actively cooled vaporizer is able to keep indium tri-chloride below 110°C even during operation near maximum arc power. Without active cooling, the temperature of indium tri-chloride present in the vaporizer during maximum arc power operation could exceed 200°C, and sublimation of the indium tri-chloride could occur. The AEF reduces energetic indium that can be present during implants of other species that follow indium implants for the same reason that the AEF improves the energy purity performance of the 8250 _HT. Indium ions present in the beam downstream of the analyzing magnet have a lower energy than the energy of a species being implanted, and the AEF is designed to remove off-energy ions