Measurement of Silicon Epitaxial Layers Less Than 1-μ Thick by Infrared Interference

Abstract
An analysis of the infrared-interference method of measuring epitaxial layer thickness is given which shows that the technique is useful for measurement of layers thinner than one micron. The connection between plasma resonance and infrared interference is established. A new method of interpreting the infrared spectra is given which produces both the layer thickness and substrate impurity concentration.