Radiation protection for high energy implantation of light ions in a production environment

In recent years the irradiation of semiconductor devices by light ions with high energies has increasingly become a well-established method to adjust charge carrier lifetimes in semiconductor devices. To introduce this process into the end of frontend production environment several measures in terms of radiation safety will have to be obeyed. An overview on thresholds for particles induced gamma emission will be given, starting with the 11B(p,γ)12C reaction at 163keV. The environment has to be shielded from gamma rays, therefore those implanters have to be situated in adequate enclosures. Calculations for specific implant energies are done to define the thicknesses of tool enclosures. A set of radiation detectors monitors the values at well-defined positions online and radiation values are fed into a superordinate system that is directly coupled to the main power supply of the implanter.