Particle detector suitable for detecting ions and electrons
AssigneeFEI Company
InventorsRobert L. Gerlach, Mark W. Utlaut, Trevor Dingle, Marek Uncovsky
Life of this patent
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Abstract
A particle detector switchable from an ion detector to an electron detector includes an ion-to-electron converter and a scintillator detector. With one set of voltages on the components, the converter has minimal impact on the electron trajectories so the electrons are efficiently detected by the scintillator detector. With different voltage settings on the components, the detector can be operated in positive ion mode to collect positive ions with adequate efficiency for most FIB applications. The ion-to-electron converter is preferably in the shape of a cylinder or includes multiple parallel plates
Claims21
A charged particle detector suitable for use in a focused ion beam system including a focused ion beam that can be directed to a target and that produces secondary particles upon impact of the ion beam with the target, the charged particle detector comprising:
- an input screen to which voltages can be selectively applied relative to the target so as to attract positive or negative secondary charged particles emitted from the target;
- an ion-to-electron converter including a material that emits electrons when impacted by charged particles from the target, said ion-to-electron coverter being configurable in a first configuration to convert ions and configurable in a second configuration to pass electrons from the target through the ion-to-electron converter;
- and
- a scintillator detector for detecting electrons originating at the target and passing through the ion-to-electron converter or electrons originating in the ion-to-electron converter, the ion-to-electron converter being positioned between the input screen and the scintillator detector.
An ion-to-electron converter for use with an electron detector to detect ions originating from a target by causing the ions to generate electrons to be detected by the electron detector, the ion-to-electron converter comprising a material that when struck by an ion generates electrons for detection and having a structure such that when a first voltage is applied to the ion-to-electron converter, ions are attracted to the ion-to-electron converter, collide with a surface of the ion-to-electron converter, and generate electrons that are detected by the electron detector, and when a second voltage is applied, electrons pass through the ion-to-electron converter and are detected by the electron detector, the ion-to-electron converter adapted to be positioned between an input electrode and the electron detector.
A method of detecting positive or negative charged particles, comprising
- selectively attracting positive ions or electrons from a target using an input electrode;
- if positive ions are selectively attracted, converting the positive ions to electrons by causing the positive ions to impact on a surface not part of the input electrode, the impact causing the emission of electrons;
- and
- detecting using an electron detector either the electrons emitted by the impact of the positive ions from the surface or electrons selectively attracted from the target and not impacting the surface.
A charged particle detector suitable for use in a focused ion beam system including a focused ion beam that can be directed to a target and that produces secondary particles upon impact of the ion beam with the target, the charged particle detector comprising:
- an input screen to which voltages can be selectively applied relative to the target so as to attract positive or negative secondary charged particles emitted from the target;
- an ion-to-electron converter having at least one surface comprising a material that emits electrons when impacted by charged particles from the target, said ion-to-electron converter being configurable in a first configuration to convert ions emitted from a target to electrons and configurable in a second configuration to pass substantially all of the electrons traveling from the target through the ion-to-electron converter without impacting said surface of the ion-to-electron converter, the ion-to-electron converter not being the input screen;
- and
- a scintillator detector for detecting electrons originating at the target and passing through the ion-to-electron converter or electrons originating in the ion-to-electron converter.
Dependencies are inferred from the claim text.