title: Simultaneous Scanning Electron Microscope Imaging of Topographical and Chemical Contrast Using In-Lens, In-Column, and Everhart-Thornley Detector Systems.
abstract: The scanning electron microscope provides a platform for subnanometer resolution characterization of material morphology with excellent topographic and chemical contrast dependent on the used detectors. For imaging applications, the predominantly utilized signals are secondary electrons (SEs) and backscattered electrons (BSEs) that are emitted from the sample surface. Recent advances in detector technology beyond the traditional Everhart-Thornley geometry have enabled the simultaneous acquisition and discrimination of SE and BSE signals. This study demonstrates the imaging capabilities of a recently introduced new detector system that consists of the combination of two in-lens (I-L) detectors and one in-column (I-C) detector. Coupled with biasing the sample stage to reduce electron-specimen interaction volumes, this trinity of detector geometry allows simultaneous acquisition of signals to distinguish chemical contrast from topographical changes of the sample, including the identification of surface contamination. The I-C detector provides 4× improved topography, whereas the I-L detector closest to the sample offers excellent simultaneous chemical contrast imaging while not limiting the minimization of working distance to obtain optimal lateral resolution. Imaging capabilities and contrast mechanisms for all three detectors are discussed quantitatively in direct comparison to each other and the conventional Everhart-Thornley detector.
authors.affiliation: 1Department of Materials Science and Engineering,University of California,Davis,CA 95616,USA.
authors.forename: Xinming
authors.initials: X
authors.lastname: Zhang
authors.affiliation: 1Department of Materials Science and Engineering,University of California,Davis,CA 95616,USA.
authors.forename: Xi
authors.initials: X
authors.lastname: Cen
authors.affiliation: 2Center for Nano-MicroManufacturing,University of California,Davis,CA 95616,USA.
authors.forename: Rijuta
authors.initials: R
authors.lastname: Ravichandran
authors.affiliation: 1Department of Materials Science and Engineering,University of California,Davis,CA 95616,USA.
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Hughes
authors.affiliation: 1Department of Materials Science and Engineering,University of California,Davis,CA 95616,USA.
authors.forename: Klaus
authors.initials: K
authors.lastname: van Benthem
keywords: SEM; backscattered electrons; in-column detector; in-lens detector; secondary electrons