| 摘要 |
A detector for charged particles, i.e. secondary electons ir ions emitted from a bombardment area of a specimen in an instrument such as a scanning electron microscope or analytical instrument, consists of a collector, e.g. a scintillation surface highly charged with a voltage of the opposite polarity from that of the particles, for receiving the particles and providing an output proportional to the number thereof. A grid, charged with a voltage of the same sign as the scintillation surface, but to a lower value, is located between the scintillation surface and the bombardment area, and a probe in the form of a wire electrically connected to the grid projects into the vicinity of the bombardment area which is in a confined space between the specimen and the instrument. The result is to set up an electrostatic field around the wire, causing a significant number of the charged particles to orbit the wire and travel to the scintillation surface. The detector has better performance in situations requiring a relatively long "reach" into a confined space than has been attainable with previously known detectors. As a result, the detector is especially useful when the speciment under examination is relatively large, e.g. a large silicon wafer.
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