An ion implantation source used in an ion implantation system. The source produces multiple beam portions which combine to form a large diameter beam of the size of a workpiece. By controlling beam neutralization of the individual beam portions the ion density as a function of position within the cross-section of the beam can be controlled.

A grid gates a stream of ions when a D.C. potential is applied between two sets of interdigitated wires included in the grid to produce a D.C. field. The improved grid disclosed herein contains the two sets of interdigitated wires in a single plane so that the D.C. field is precisely normal to the ion current flow direction to prevent a residual ion current flow when the grid provides the gating effect.

An ion beam implant system having a source for producing multiple beamlets. The beamlets are emitted from the source and their intensity is controlled by an electrode array under control of a control apparatus. Downstream from the electrode array a resolving magnet shapes the beamlets and directs them to a region where they undergo further acceleration before impinging upon a workpiece. In a preferred technique, the workpiece is typically a silicon wafer and the ions are utilized for controlled doping of that wafer without need for ion beam scanning to selected portions of the workpiece or wafer movement through the ion beam during implantation.

An ion implanter for implanting ions in a target substrate is arranged to scan the ion beam at the point of extraction of the beam from the ion source. The ion beam extraction assembly includes a tectrode construction in which an extraction electrode adjacent the ion source aperture is split into two halves. A differential voltage is applied across the two halves of the extraction electrode to deflect the ion beam being extracted from the ion source electrostatically. The plane of deflection is arranged to coincide with the plane if dispersion of the ions in a mass analyser magnet downstream of the extraction point and the deflected beam of ions of desired mass/charge ratio is still brought to focus at a common mass selection slit at the exit of the analyser magnet.

Ion erosion of grids is reduced in an ion thruster with a multiple-grid ion-optics system. The thruster has an array of aperture sets in which aperture areas change in a perimeter region of the array. In one ion-optics system embodiment, a screen aperture area is reduced and a decelerator aperture area is increased in aperture sets that are proximate to the perimeter of the array. Prototype tests of this embodiment have illustrated significant reduction of ion erosion.