RF MAGNETRON DEPOSITION OF CALCIUM-FLUORIDE

Magnetron sputtering has been used to grow calcium fluoride films. The presence of calcium emission lines in the discharge and the absence of calcium fluoride lines indicate that deposition occurs largely atomically, rather than by molecules. Films grown without fluorine make-up are strongly fluorine deficient and contain 10 at.% O. Adding carbon tetrafluoride to the discharge results in F:Ca ratios near 2.0, reduced oxygen levels (less than 1 at.%). but some carbon contamination. The films are optically absorbing (alpha almost-equal-to 10(4) cm-1 near 500 nm), and poor electrical insulators (rho < 10(9) OMEGA cm).