Disclosed is a method for manufacturing a diamond film of electronic
quality at a high rate using a pulsed microwave plasma. The plasma that
has a finite volume is formed near a substrate (in a vacuum chamber) by
subjecting a gas containing at least hydrogen and carbon to a pulsed
discharge. The pulsed discharge has a succession of low-power states and
of high-power states and a peak absorbed power P.sub.C, in order to
obtain carbon-containing radicals in the plasma. These carbon-containing
radicals are deposited on the substrate in order to form a diamond film.
Power is injected into the volume of the plasma with a peak power density
of at least 100 W/cm.sup.3, while maintaining the substrate to a
substrate temperature of between 700.degree. C. and 1000 .degree. C.