Patent ID: 8530867

Claim:
An electron beam system, comprising: a field emitter unit including an emitter tip configured to generate an electron beam, wherein the emitter unit includes a vacuum cone-type field emitter; an electron beam column having an electrode with a beam defining aperture; an electron collector located proximate to the beam defining aperture; between the electrode and the field emitter unit; an electron deflector located between the emitter tip and the electron collector; and a controller coupled to the field emitter, electron collector and deflector, wherein the controller is configured to, at regular predetermined intervals to: i) cause the electron deflector to deflect the electron beam away from a path through the beam defining aperture and onto the electron collector; ii) determine an electron beam current to the electron collector; and iii) cause the emitter unit to flash heat if the current to the electron collector is below a threshold, wherein the predetermined interval and the threshold current is selected such that the flash heating is sufficient to remove contaminants built up on the emitter tip during the predetermined interval when the emitter tip is operated in an environment at a pressure that lies within a range between 10 −6 torr and 10 −8 torr.