Abstract: A signal generator 16 is disclosed. The invention is adapted for use with industrial positioning systems and includes an integrating circuit 22 for integrating an input error signal to provide an output error signal and a limiting circuit 24, connected between the input and output of the integrating circuit 22 for limiting the output error signal. The output error signal is then used in a conventional manner to control a work piece or an implement. The integration of the low level input error signal rapidly increases the power delivered to the positioning system to overcome initial static friction. When the amplitude of the error signal indicates that the industrial apparatus is within a predetermined tolerance, the amplitude of output error signal decreases exponentially to diminish rapidly the power delivered to the positioning system. The apparatus will therefore be positioned within a given tolerance range.

Abstract: An ion evaporation source for tin ions is prepared by coating a source element with a wettability enhancing gallium coating, and then loading the source with tin. The tin may be the naturally occurring tin, but can be an enriched tin containing a higher concentration of Sn.sup.120. The source produces a beam having a high fraction of Sn.sup.+ and Sn.sup.++ ions, and a small amount of the ionized wettability coating material. All but the desired ions are readily separated from the beam.

Abstract: A charge-coupled device (CCD) is provided with a dopant implant gradient, lateral channel stops and blocking implants by means of a focused ion beam (FIB). The FIB is repeatedly scanned across each cell of the CCD as a succession of overlapping but discrete implant scans. The doping levels of the FIB implants accumulate to a stepwise approximation of a desired dopant density profile, the widths of the steps being no greater than about half the widths of the discrete FIB implants. With a FIB pixel of about 750-1,500 Angstroms, the widths of the steps are preferably about 250-500 Angstroms; the dimension of the cells in the dopant gradient direction can be made less than about 5 microns. The lateral channel stops and back blocking implants can be as narrow as single FIB pixel widths, thus freeing up more of the cell for charge carrying capacity.

Abstract: A liquid metal ion source and alloy, wherein the species to be emitted from the ion source is contained in a congruently vaporizing alloy. In one embodiment, the liquid metal ion source acts as a source of arsenic, and in a source alloy the arsenic is combined with palladium, preferably in a liquid alloy having a range of compositions from about 24 to about 33 atomic percent arsenic. Such an alloy may be readily prepared by a combustion synthesis technique. Liquid metal ion sources thus prepared produce arsenic ions for implantation, have long lifetimes, and are highly stable in operation.

Abstract: A liquid metal ion source and alloy for the simultaneous ion evaporation of arsenic and boron, arsenic and phosphorus, or arsenic, boron and phosphorus. The ionic species to be evaporated are contained in palladium-arsenic-boron and palladium-arsenic-boron-phosphorus alloys. The ion source, including an emitter means such as a needle emitter and a source means such as U-shaped heater element, is preferably constructed of rhenium and tungsten, both of which are readily fabricated. The ion sources emit continuous beams of ions having sufficiently high currents of the desired species to be useful in ion implantation of semiconductor wafers for preparing integrated circuit devices. The sources are stable in operation, experience little corrosion during operation, and have long operating lifetimes.

Abstract: Apparatus for controlling the gap between localized vacuum processing envelope apparatus and a workpiece as the workpiece, typically a semiconductor wafer, is moved laterally with respect to the envelope apparatus. The envelope apparatus includes an envelope which defines an internal vacuum processing zone and a generally planar tip spaced from the workpiece during processing by the gap. The gap control apparatus includes a gap sensor for measuring the gap, a control circuit for comparing the measured gap with a required gap and generating an error signal, and an actuating means for varying the gap in response to the error signal. The gap can be sensed by sensing the pressure level in the vacuum processing apparatus. The actuating means can include a plurality of piezoelectric actuators which can vary both the gap and the angle of the workpiece with respect to the tip of the vacuum processing apparatus.