Characterization of a broad ion beam source by determination of the energy flux

The radial distribution of the energy influx by a broad Ar ion beam towards a substrate surface has been determined. The procedure is based on the measurement of temporal slope of a thermal probe (substrate) during beam operation. The deposited power has been measured to be in the order of ∼0.1–0.4 J cm−2 s−1 in dependence on typical process parameters of the ion source, as supplied microwave power, beam voltage, substrate voltage, and gas flow, respectively. The experimentally determined radial beam profiles show a characteristic change at the edge of the beam. This profile can also be visualized by the interaction of the ion beam with a micro-disperse particle cloud which has been charged and confined in an additional r.f.-plasma.