Direct measurement of the ion current density distribution of broad beam ion sources

A Faraday cup array with 256 measuring points has been developed and tested to measure the ion current density distribution of broad beam ion sources. The ion beam profiler consists of a measuring head and an evaluation unit. The signals are fed into a computer via an RS 232 interface and then visualised with a comfortable software. There is good qualitative correspondence between the etch profiles on silicon wafers and the measured ion current density distribution. Measurements that have been made at various ion sources clearly show that the ion current density distribution on the target surface varies greatly and essentially depends on the operational parameters and the type of source. With the ion beam profiler it is possible to find the operational parameters which ensure the technologically necessary ion current density distribution, in a very short time.