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US 6,365,898 B1Granted
Scanning electron microscope
AssigneeLEO Electron Microscopy Limited
InventorsPierre Sudraud, Antoine Corbin, Rainer Sailer, David John Bate
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AssigneeLEO Electron Microscopy Limited
InventorsPierre Sudraud, Antoine Corbin, Rainer Sailer, David John Bate
Estimating the term…
A scanning electron microscope has means for generating a beam of electrons which is scanned over a specimen held within a holder in a chamber which contains a gaseous medium. A negative potential is applied to the holder so as to generate an electric field which accelerates secondary electrons, formed by the interaction or the primary beam with the specimen, in a direction away from the specimen surface and into a collision zone in the chamber. In that zone, the accelerated secondary electrons collide with gas molecules of the gaseous medium, thereby initiating a cascade of collisions which, in effect, amplifies the secondary electron signal. That signal (which may take the form of photons generated as a result of the collisions) is detected by detecting means, such as a photo-multiplier.
A scanning electron microscope comprising
A method of analysing a specimen by a scanning electron microscope, the method comprising generating a scanning beam of electrons, directing the beam into a chamber containing a gaseous medium and including a holder carrying the specimen, applying a negative bias potential to the holder so as to provide an electric field within the chamber, the scanning beam impinging on the specimen and producing on the specimen surface secondary electrons which are accelerated by the electric field in a direction taking the secondary electrons away from the specimen surface and into a collision zone in the chamber where collisions between the accelerated secondary electrons and the gas molecules of the gaseous medium initiate a cascade of collisions, and detecting and analysing the resulting signal.
Dependencies are inferred from the claim text.