EMISSION NOISE CORRECTION OF A CHARGED PARTICLE SOURCE
A method of operating a charged particle microscope comprising the following steps: - Providing a specimen on a specimen holder; - Using a source to produce a beam of charged particles that is subject to beam current fluctuations; - Employing a beam current sensor, located between said source and sp...
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Main Authors | , , , , |
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Format | Patent |
Language | English |
Published |
16.08.2018
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Subjects | |
Online Access | Get full text |
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Summary: | A method of operating a charged particle microscope comprising the following steps:
- Providing a specimen on a specimen holder;
- Using a source to produce a beam of charged particles that is subject to beam current fluctuations;
- Employing a beam current sensor, located between said source and specimen holder, to intercept a part of the beam and produce an intercept signal proportional to a current of the intercepted part of the beam, the beam current sensor comprising a hole arranged to pass a beam probe with an associated probe current;
- Scanning said probe over the specimen, thereby irradiating the specimen with a specimen current, with a dwell time associated with each scanned location on the specimen;
- Using a detector to detect radiation emanating from the specimen in response to irradiation by said probe, and producing an associated detector signal;
- Using said intercept signal as input to a compensator to suppress an effect of said current fluctuations in said detector signal,
wherein:
- The beam current sensor is configured as a semiconductor device with a sensing layer that is oriented toward the source, in which:
ª Each charged particle of said intercepted part of the beam generates electron/hole pairs in said sensing layer;
ª Generated electrons are drawn to an anode of the semiconductor device;
ª Generated holes are drawn to a cathode of the semiconductor device,
thereby producing said intercept signal. |
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Bibliography: | Application Number: US201715435018 |