Increasing applications of chemical
vapour deposited (CVD) diamond have raised the need for
efficient and robust microwave plasma reactors which are
optimized for the large area deposition of diamond films
and wafers. On the basis of extended numerical
simulations Fraunhofer IAF has developed a novel
microwave plasma CVD technology. An ellipsoidal cavity
is used to focus the microwave energy into an intense
and extended plasma. These ellipsoidal plasma reactors
exhibit a combination of beneficial properties including
Large area deposition:
homogeneous deposition of CVD diamond on 3" (2.45
GHz) and 6" (915 MHz) substrates possible.
Stability: Long-term operation
possible, no plasma instabilities.
Versatility: The reactor can be
run under various conditions (pressure, power
Growth of high-purity diamond:
Properties of CVD diamond disks are identical to
those of perfect single diamond crystals.
patented reactor technology has been successfully commercialized. The
two figures show ellipsoidal plasma reactors which are
fully computer controlled and equipped with all the
safety units necessary for the operation in an
industrial environment. The reactors are operated at
2.45 GHz, 6 kW (upper figure) and 915 MHz, 30-60 kW
(lower figure), respectively.