Secondary-ion mass spectrometry apparatus using field limiting method

Claim 1

A secondary-ion mass spectrometry apparatus using a field limiting method, comprising: an optical system for primary ions for converging primary ion emitted from an ion source as a primary ion beam to irradiate a sample with the primary ion beam; a sample chamber for accommodating said sample irradiated with the primary ion beam from said optical system for primary ions, said sample chamber including electron spray means for effecting a spray of electrons onto said sample; an optical system for secondary ions including an optical imaging system for imaging secondary ions emitted from said sample by irradiation thereof with the primary ion beam, an exit slit for passing therethrough only secondary ions emitted from a predetermined secondary ion emitting area on said sample, an electric sector for energy-separating secondary ions passed through said exit slit and a β slit for passing there-through those ones of the secondary ions energy-separated by said electric sector which have a predetermined energy; displaying means for displaying a sample image field-limited by said exit slit on the basis of secondary ions captured by said β slit; a magnetic sector for analyzing secondary ions passed through said β slit; and means for adjusting the electron spray means while displaying said sample image.