Nucleation and growth of diamond on carbon-implanted single crystal copper surfaces

Abstract

The nucleation and growth of diamond crystals on single crystal copper surfaces has been studied. Microwave plasma enhanced chemical vapor deposition (MPECVD) was used for diamond nucleation and growth. Prior to diamond nucleation, the single crystal copper surface is modified by carbon ion implantation at an elevated temperature (~820 °C). This procedure leads to the formation of a graphite film on the copper surface, resulting in an enhancement of diamond crystallite nucleation. A simple lattice model has been constructed to describe the mechanism of diamond nucleation on graphite as (lll)diamond parallel to (0001) grap hite and (110) d iamond parallel to (1120) gra phite-This leads to a good understanding of diamond growth on carbon-implanted copper surfaces.

Studies on nucleation process in diamond CVD: an overview of recent developments

“…The deposit subsequently disappeared, and the final deposit contained only polycrystalline diamond. Several other experiments on Ni and Pt in HFCVD [17], on Si [19] and Cu [32,34,62] in MW PACVD have also provided direct evidence for the formation of graphite on the substrates prior to diamond nucleation. It was found that the graphite film formed initially on the substrate surface greatly enhanced diamond nucleation [32,34].…”

“…Volmer-Weber 3-D island growth [58] is the mode of nucleation and growth of polycrystalline diamond films directly on non-diamond substrates due to the highest surface energies of diamond among any known materials (see Tables 3 and 4 Diamond nucleation on non-diamond substrates is generally proposed to occur mostly on an intermediate layer of diamond-like amorphous carbon [9][10][11]30,35,61], metal carbides [12,14,16,22,23,25,28,29,40,[62][63][64][65][66][67][68][69][70], or graphite [13,17,19,32,34,62,71] formed at the substrate surface due to chemical interactions between activated gas species and the surface during the incubation period. Such intermediate layers provide nucleation sites for diamond crystallite growth [9,17,70], and hence enhance diamond nucleation densities on non-diamond substrates [21,37,70,71] and offer an opportunity for controlling the morphology [21,37], orientation and texture [28,<...>…”

“…Diamond nuclei grow preferentially on the prism planes of graphite, with kinetically preferential nucleation at the emerging graphite stacking faults, and with an almost perfect interface between graphite and the diamond nuclei. There exists a preferential epitaxial lattice registry relationship between graphite and diamond, i.e., (111) diamond || (0001) graphite and (110) diamond || (1120) graphite [32,34,71].…”

“…Nucleation occurs readily on substrates forming amorphous DLC (mostly Mo and Si) without any pretreatment [21,35,37]. Graphite interlayers or particles form mostly on Ni, Pt, Cu, and Si [17,19,32,34,62,71], and favor diamond nucleation [13,32,34,71]. …”

“…As a result, technology problems associated with the nucleation of polycrystalline diamond films have been adequately addressed. A number of nucleation enhancement methods [26][27][28][29][30][31][32][33][34][35][36][37][38] have been developed that enable the control of nucleation density over several orders of magnitude. Nucleation density has been increased from <10 5 cm -2 on untreated substrates up to 10 11 cm -2 on scratched or biased substrates [39,40].…”