SEDL / STP / STP1028-EB / STP18535S

CaF²: An ESCA Study

Raj, T
Martin Marietta Aerospace, Laser Systems Technology, Albuquerque, NM

Law, M
Martin Marietta Aerospace, Laser Systems Technology, Albuquerque, NM

Pages: 5    Published: Jan 1988

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Abstract

This paper describes two observations made on CaF² during electron spectroscopy for chemical analysis (ESCA) studies. The first observation is that an ion-etched CaF² surface adsorbs several layers of water even in an ultrahigh vacuum (UHV) chamber (P ∼ 2×10^-10 torr). This water at the sputter-etched surface is responsible for the presence of oxygen peaks in the ESCA data. The presence of oxygen in the ESCA data can easily be misinterpreted as an impurity in the CaF² bulk. This observation is detailed in Part I of the paper.

The second observation is that CaF² (whether substrate, source material or coating) in a UHV environment releases a small amount of fluorine-containing gas. This is discussed in Part II of the paper.