Patent ID: 11227740

Abstract:
In order to provide an electron gun capable of maintaining a small spot diameter of a beam converged on a sample even when a probe current applied to the sample is increased, a magnetic field generation source 301 is provided with respect to an electron gun including: an electron source 101; an extraction electrode 102 configured to extract electrons from the electron source 101; an acceleration electrode 103 configured to accelerate the electrons extracted from the electron source 101; and a first coil 104 and a first magnetic path 201 having an opening on an electron source side, the first coil 104 and the first magnetic path 201 forming a control lens configured to converge an electron beam emitted from the acceleration electrode 103. The magnetic field generation source is provided for canceling a magnetic field, at an installation position of the electron source 101, generated by the first coil 104 and the first magnetic path 201.