Effect of early methane introduction on the properties of nano-seeded MPCVD-diamond films

Diamond films are attractive for both electronic and mechanical application s because of their superior hardness, strength, chemical stability, etc. Fo r applications in MEMS, very smooth thin films are desired. Our main object ive was to deposit a smooth and thin diamond film. Diamond films were depos ited on 3-inch diameter, p-type, [100] oriented silicon substrates using a microwave plasma disk reactor (MPDR). Four-nanometer diamond powder was use d for seeding the silicon wafers. In this paper, we study the effects of th e early introduction of methane. The deposition conditions were changed to introduce methane right at the beginning instead of introducing it after ab out 5 min as was done previously. Due to this change, there was a considera ble increase in nucleation density and growth rate. Very smooth films were obtained in the shorter duration depositions. The initial phase deposition revealed some graphite content in the films, which decreased with increasin g deposition time. (C) 1999 Elsevier Science S.A. All rights reserved.