| 摘要 |
1280013 Ion-beam apparatus UNITED KINGDOM ATOMIC ENERGY AUTHORITY 21 Aug 1970 [5 Sept 1969] 44171/69 Heading H1D [Also in Division G3] Apparatus for bombarding a target 89 with ions comprises an ion beam source, a magnet for deflecting the ion beam 91 towards a window, means for stabilizing the ion beam to maintain substantially constant the ion beam current passing through the window, a holder 87 for a target 89 behind the window, and drive means for imparting controlled movement to the target holder to scan the target through the ion beam according to a predetermined scan pattern. A cylindrical enclosure 81 with a pipe 82 for connection to a vacuum pump has a tubular extension 83 housing a lens assembly with a window or mass-defining slit of width equal to that of the target. Target holder 87 is secured to a lead screw 84 driven by a motor 85 controlled by a programmer 86. Rotation of the target holder is prevented by a torque resisting tube 88, but it is free to slide up and down as indicated by arrow B. The holder supports a plurality of racks filled with wafers 89. After implantation of one row of wafers the holder is indexed one step by fingers 92 and 93 engaging cam surfaces 94 and 95 fixed to the enclosure 81. The wafers may be heated by radiation or may be cooled by plates cooled with liquid nitrogen. An alternative embodiment (Figs. 2 to 5, not shown) comprises a magnetic separator as described in Specification 6,280,011, an ion source as described in Specification 6,280,012, and a target chamber in which means are provided for loading and unloading wafers to and from a carrier which is mounted on an X-Y drive mechanism which may be automatically programmed. The ion beam is swept over the window by superimposing an alternating voltage from a sweep generator on the stabilized D.C. supply to an accelerating electrode of the ion gun. The beam stabilizing means may comprise a probe (Fig. 1, not shown-see Division G3) which samples the ion beam at the window and passes a signal through an amplifier to a sweep control which controls the amplitude of the sweep in such a way as to tend to reduce variations in the ion beam intensity.
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