Slow positron beams—a versatile tool for studying ion implantation defect related phenomena

Positron annihilation spectroscopy (PAS) with beams of controllable energy positrons has shown great promise as a technique for providing information on the concentration and distribution of vacancy-type, open-volume defects following the implantation of silicon. PAS is entirely non-destructive, requires no pre-measurement treatment of the sample and has a range of sensitivity of approximately 1015–1019 defects cm−3. The Surrey Ion Beam Center in collaboration with the University of Bath positron group has been investigating a number of novel applications of PAS such as ion beam dosimetry (including both low energy ion implantation and SIMOX production). Resulting from this work has been the development of a novel wafer-mapping tool compatible with a commercial environment. This paper will discuss applications of a prototype instrument which may make the use of PAS common in the fabrication plant.