Exactually

Not exactually; but it must be about twenty years ago, or a little more.

1970, Materials Research Corporation, Conference and School on Sputtering for Electronics, January 25, 27, 28, 1970, Del Monte Lodge, Pebble Beach, California Because of such problems as fabrication of large area dielectric targets, source purity control, the need to exactually control film composition, and expense of dielectric targets vs. metal targets […]