An open 800-kV ion-implantation machine

Since the high-voltage section of the ion-implantation machine developed at Philips Research Laboratories is not insulated by gas under pressure in a tank, changing the ion source is relatively easy. The machine is therefore particularly suitable for research. The accelerating voltage is high, 800 kV, so that heavy elements can be implanted in heavy substrates. There are two target chambers, one designed for treating silicon slices for IC manufacture, the other designed for other samples, including metals. Implantations in metals can improve properties such as hardness or resistance to corrosion. The half-width of the beam cross-section and the location of the pattern of the beam scan on the sample are evaluated with the aid of a wire frame around the sample; the wire frame is earthed through a milliammeter. The implantation dose is measured with a Faraday cup. Five ion sources have been tested: the hollow-cathode source, the Penning source, the radial-extraction Penning source, the sputter source and the microwave source. Some examples are given to demonstrate the usefulness of the machine: implantation of buried oxygen layers in a silicon slice, implantation of aluminium to improve the corrosion resistance of copper, and the determination of a number of concentration profiles for phosphorus in silicon at different energies. 12 refs.; 15 figs