Chapter/Index: Introduction | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Appendix
| X-ray reflectivity can be employed to measure the thickness of films, e.g. ALD and MBE-deposited layers, in order to adjust growth rates. In this technique, monochromatic X-rays reflected from the sample surface at low incident angles are measured and analyzed with a typical accuracy of ≤1 nm for layer thicknesses between ~2 and 500 nm. To obtain the thickness of a layer, the interference of the X-rays reflected from the surface of the layer and the X-rays reflected from the interface between the layer and substrate is measured in the form of intensity oscillations. The oscillation separation (Δθ) is given by, where, An example of such instruments is GE Inspection technology high-resolution X-ray diffractometer. However, to obtain the thicknesses, the measured data needs to be analyzed with software, e.g. Parratt 32. Most tool and software combinations can extract not only the film thicknesses but also the surface roughness and the number of layers.
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