POSITION SENSITIVE STEM DETECTOR

摘要

A STEM system is disclosed wherein an imaging system is used to image the electron scatter pattern plane of the HAADF detector onto a two-dimensional array detector. A data acquisition system stores and processes the data from the two-dimensional array detector. For each illumination pixel of the STEM, one frame of data is generated and stored Each frame includes data of all scattered angles and can be analyzed in real time or in off-line at any time after the scan. A method is disclosed for detecting electrons emitted from a sample by detecting electrons scattered from the sample and generating plurality of corresponding signals, each signal indicative of scattering angle of a scattered electron; generating a plurality of signal groups, each signal group being a collection of signals of a user selected scattering angle.

主权项

1. A High Angle Annular Dark Field (HAADF) detector assembly operating within a Scanning Transmitting Electron Microscope (STEM), provided to detect electrons emitted from a sample that is being scanned by an electron beam, comprising:
a scintillator comprising an annular scintillating plate having a scintillating surface and a central aperture configured to enable passage of non-scattered electrons, the scintillating surface emitting light signals corresponding to impingement of scattered electrons thereupon; a two-dimensional sensor having a light sensing surface and plurality of electrical outputs; an optical imaging system configured to form an image of the scintillating surface on the light sensing surface of the two-dimensional sensor by transferring light signals produced in any specific location of the scintillating surface onto a corresponding position on the light sensing surface and thereby maintaining spatial information of the light signals; and, an image processing unit receiving output signals from plurality of electrical outputs of the two-dimensional sensor and providing information of images related to selected positions of the electrons impinging the scintillation surface.