Electron microscopy

Claim 2

Electron beam mirror microscopy apparatus comprising means for generating and forming an electron beam, means for holding a specimen at an electric potential close to the potential of said beam-generating means, such that electrons of said beam are subjected to a retarding and reversing action on approaching said specimen, means for deflecting said beam laterally such as to cause said beam to scan a region of the surface of said specimen, and means for detecting electrons reversed by the action of said specimen, said deflecting means comprising at least three discrete deflecting stages spaced apart along the path of said beam and placed such as to cause said beam to be deflected in a non-linear path around said detecting means.

Claim 3

Electron beam apparatus as set forth in claim 1 wherein at least that stage of said deflection means which is traversed last by said beam is electromagnetic, such as to divert said reversed electrons into a path differing from that of said beam.

Claim 4

ElectrOn beam apparatus comprising means for forming an electron beam, deflecting means for causing said beam to scan a region of a specimen surface, driving means coupled to said deflection means, detecting means observing the results of the mutual influence of said beam and specimen surface, said deflecting means comprising at least three discrete deflection stages spaced apart along the path of said beam, switching means coupled to said driving means and to said detecting means and serving to cause said beam to impinge on said specimen surface at two alternate angles, the detecting means comprising means for producing two stereoscopically related images of said specimen surface in response to the effect of said beam on said surface at the two angles respectively under the control of said switching means.

Claim 5

ElectrOn beam apparatus comprising means for forming an electron beam, deflecting means for causing said beam to scan a region of a specimen surface, driving means coupled to said deflection means, detecting means observing the results of the mutual influence of said beam and specimen surface, said deflecting means comprising at least three discrete deflection stages spaced apart along the path of said beam, switching means coupled to said driving means and to said detecting means and serving to cause said beam to impinge on said specimen surface at two alternate angles, the detecting means comprising means for producing two stereoscopically related images of said specimen surface in response to the effect of said beam on said surface at the two angles respectively under the control of said switching means.

Claim 6

Electron beam apparatus comprising means for forming an electron beam, final lens means focusing said beam on the surface of a specimen placed in the path of said beam, said final lens means defining a final aperture, deflecting means for causing said beam to scan a region of said specimen surface, and detecting means observing the results of the mutual influence of said beam and specimen surface, said deflection means comprising at least three discrete deflection stages of which first and second stages lie in the path of said beam ahead of said final aperture and act in opposite directions on said beam such as to cause said beam to pass through a substantially fixed point in said final aperture and a third one of said stages lies in the path of said beam following said final aperture.

Claim 7

Electron beam apparatus comprising means for forming an electron beam, final lens means focusing said beam on the surface of a specimen placed in the path of said beam, said final lens means defining a final aperture, deflecting means for causing said beam to scan a region of said specimen surface, and detecting means observing the results of the mutual influence of said beam and specimen surface, said deflection means comprising at least three discrete deflection stages of which first and second stages lie in the path of said beam ahead of said final aperture and act in opposite directions on said beam such as to cause said beam to pass through a substantially fixed point in said final aperture and a third one of said stages lies in the path of said beam following said final aperture.

Claim 8

Electron beam apparatus as set forth in claim 4 wherein said third one of said stages is energised to act on said beam in such a direction as to deflect said beam into a path parallel to the initial direction of said beam prior to its deflection by said deflection means.