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Analytical Instrumentation Facility

Variable Pressure Scanning Electron Microscope – Hitachi SU3900

The Hitachi SU3900 variable pressure scanning electron microscope (VPSEM) is a conventional high resolution thermionic SEM, which allows the operator to control the specimen chamber vacuum level.

Location: MRC room 321

For conductive samples, the instrument is typically operated in high vacuum mode and images are collected with the Everhart-Thornley secondary electron detector.  For insulating samples, the instrument is typically operated in variable pressure mode and images are collected with the Robinson backscattered electron detector.  When operating in variable pressure mode, the chamber is back filled with a gas in order to allow imaging with little or no charging of the sample.  Typically, the back fill gas is either N2 or He, but any non-corrosive, non-reactive gas can be used.  Elemental analysis using the energy dispersive X-ray detector can be done in either high vacuum or variable pressure mode.

The Hitachi SU3900N SEM is equipped with the standard Everhard-Thornley secondary electron detector, a five segment solid state backscattered electron detector, Hitachi’s proprietary ultra-variable detector (gives a secondary electron image in variable pressure mode), an Oxford energy dispersive X-ray spectrometer, and a GW specimen current meter. 

Equipment Specifications

  • Everhart-Thornley secondary electron detector
  • Solid state (5-segment) backscattered electron detector
  • Ultra-variable detector (UVD)
  • Oxford energy dispersive X-ray spectrometer
  • GW Specimen current meter
  • Backscattered electron images (atomic number contrast, configurable for topographic contrast)
  • Elemental analysis (X-ray spectra)
  • Elemental mapping (X-ray mapping)
  • Other standard and non-standard SEM techniques such as EBIC are possible
  • 3.0 nm @ 30kV
  • 15 nm @ 1 keV
    • Both are in high vacuum mode using the secondary electron detector
  • Five axis motor drive
  • Movable range
    • Rotate 360º
    • X = 150 mm
    • Y = 150 mm
    • Z (WD) = 5 to 85 mm
    • Eucentric tilt -20º to +90º
  • Observable sample area = 203 mm diameter
  • Maximum sample diameter = 300 mm
  • Maximum sample height = 130 mm
  • Maximum sample weight = 5 kg
  • Accepts most samples: conductors, semiconductors, and insulators can be observed
  • Including, but not limited to metals, semiconductor devices, ceramics, biological, polymer, textile, pharmaceuticals, food, etc.
  • Accelerating Voltage
    • 0.3 – 30 kV
  • Magnification
    • 20X – 300,000X
  • Resolution (BSE)
    • 4.0 nm @ 30kV in variable pressure mode using the backscattered electron detector
  • Working Distance
    • 3-60 mm

Documentation