Abstract: An ion implanter, the total return current between the substrate holder and flight tube is measured. Measuring the total current returned to the flight tube provides a useful indication of the total ion current in the ion beam leaving the flight tube as well as any electrons travelling back to, and being absorbed by, the flight tube. This in turn permits the quality of the ion beam post mass selection to be monitored, continuously if desired. The total current returned to the flight tube can be compared with the current measured by the beam, the latter varying rapidly with time as the beam stop is periodically occluded by the rotating substrate wheel. In order to general a potential difference between the substrate holder and the flight tube, either a power supply or an active resistance such as an FET chain can be employed.

Abstract: An ion beam generation apparatus comprising an ion source (20) for generating ions, and a tetrode extraction assembly (11) comprising four electrodes for extracting and accelerating ions from the ion source. The extraction assembly comprises a source electrode (22) at the potential of the ion source, an extraction electrode (23) adjacent to the source electrode to extract ions from the ion source (20), a ground electrode (25), and a suppression electrode (24) between the extraction electrode and the ground electrode. Each electrode has an aperture to allow the ion beam to pass therethrough. The gap between the extraction (23) and suppression (24) electrodes is variable in the direction of ion beam travel.

Abstract: Ion implantation equipment is modified so as to provide filament reflectors to a filament inside of an arc chamber, and to remove the electrical insulators for the filament outside of the arc chamber and providing a means of shielding, thereby reducing the formation of a conductive layer on said insulators and greatly extending the lifetime and reducing downtime of the equipment. The efficiency of the equipment is further enhanced by means of an interchangeable liner for the arc chamber that increases the wall temperature of the arc chamber and thus the electron temperature. The use of tungsten parts inside the arc chamber, obtained either by making the arc chamber itself or portions thereof of tungsten, particularly the front plate having the exit aperture for the ion beam, or by inserting a removable tungsten liner therein, decreases contamination of the ion beam. Serviceability of the arc chamber is improved by means of a unitary clamp that separately grips both the filament and filament reflectors.