Glow Discharge Optical Emission Spectrometry (GD-OES)

In a glow discharge spectrometer sample atoms are sputtered continuously or in pulsed mode and then transferred into the plasma. The following analysis of the emitted light of the plasma is used for the depth resolved analysis of the chemical composition of the sample.

Features:

  • Homogeneous and soft sputtering (ca. 50 eV) @ high current density (up to 100 mA/cm2)

    • depth profiling of thin layers > 10 nm @ depth resolution of about 10% of depth
    • fast analysis 10 -100 nm/s and analysis of thick layers < 200 µm

  • Atomisation and excitation separated in space and time

    • matrix independent calibration from µg/g up to 100 %

Applications:

  • Quantitative determination of bulk material from µg/g up to 100 % by calibration
  • Depth profiles at laterally homogeneous layers d = 10 nm - 100 µm, erosion rate of about 1 µm/min

Elements: nearly all elements including H, C, N and O

Detection limits: (1 - 100) µg/g in dependence on element and matrix

Samples requirements: conductors and non-conductors (rf sputtering), thermally and mechanically stable, diam. > 4 mm

Instruments:

  • GDA 750HR (45 PMTs, high resolution CCD from 215-780 nm, monochromator, RF and DC mode)
  • GDA 650 (high resolution CCD from 120 -690 nm) both from Spectruma
  • Optical profilometer MicroProf from FRT (lateral resolution 2 µm, depth resolution 100 nm)
Principle of Glow Discharge Optical Emission Spectrometry
Calibration curve for Mn in steel and zinc matrix
Qualitative depth profile with Zn, Al, Fe, Mn and H, O, C, N
Quantified depth profile without H, O, N