Diagnostic wafer

摘要

The wafer (100) includes a placebo wafer (102), several ion current probes (106n) and ion energy analysers (104m), both probes and analysers being mounted on the wafer. At least one extension extends from a circumference of the wafer (110). The ion current probe is coaxially mounted to the analyzer which is itself mounted to the placebo wafer. A collector plate is provided with the analyser and is mounted to the placebo wafer. A discriminator grid annular insulator attached to the plate has a central aperture aligned with a centre of the plate. A discriminator grid spans the central aperture and is spaced apart from the plate. Attached to the grid, a floating grid annular insulator has a central aperture aligned with a central aperture centre of the discriminator insulator. A floating grid attached to floating grid insulator spans the central aperture and is spaced apart from the discriminator grid.