An automatic implantation dose monitor for ion implanters

摘要

Ion implantation is one of the widely employed tools in materials research for doping, defect production and surface modification on a wide range of materials, bulk as well as thin films. The implantation dose or the ion fluence received by the material and its effect on the characteristics of the material are the often carried out studies with ion implanters. An automatic implantation dose monitor has been successfully developed to monitor the ion fluence and ion beam current for the ion implanters at the Particle Irradiation Facility, Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam. Based on the electrometer principle for low current measurement, this dose monitor has been designed to measure wide ranging ion beam currents (and negative currents as well) over 7 decades spanning from 0.1nA to 1mA with the current ranges selectable automatically or manually. Implantation dose is obtained by integrating the ion beam induced current using digital integration technique which overcomes the problem encountered with analog integration of low currents over a long period. The design concept, working principle of the dose monitor are presented in this paper.