In situ depth measurements for GD-OES†
For a glow discharge source we present a new instrument to measure the depth during sputtering. The developed system is based on a laser interferometer and a Grimm type GD source. We developed a mathematical model, which corrects the signal disturbances due to the thermal expansion of GD source and sample surface. Another model describes dependence of the sample surface temperature on discharge power, material constants and position. The in situ depth measurement instrument is used to measure the thickness of zinc layers in the micrometer range.