FORMATION OF DIAMOND FILMS BY INTERMITTENT DISCHARGE PLASMA CHEMICAL-VAPOR-DEPOSITION

Formation of diamond film by DC plasma chemical vapor deposition (CVD), wherein the waveform of the power supply is half-wave-rectified (HWR), has been investigated. When HWR voltage is applied to the electrodes, the waveforms of the discharge voltage (V-d) and current (I-d) are intermittent and show a large peak at the beginning of the discharge. The films deposited by intermittent discharge (ID) are superior in crystalline quality compared with that by conventional continuous discharge (CD). The average value of electron temperature (T-c) in ID, measured by a Langmuir probe (LP) in the plasma of hydrogen gas, is higher than that of CD. The LP current shows a very high peak at the beginning of the ID process, and the value of T-c and density of electrons (N-c) at this peak are very large. These rises in T-c by ID are effective in enhancing the dissociation of the source gas by electron collision. It has been concluded from the present study that ID is an effectual method to obtain high-quality diamond film.