Effect of pretreatment process parameters on diamond nucleation on unscratched silicon substrates coated with amorphous carbon films
- Department of Mechanical Engineering, University of California, Berkeley, California 94720 (United States)
- Lawrence Berkeley Laboratory, University of California, Berkeley, California 94720 (United States)
Diamond nucleation on unscratched silicon substrates was investigated using a conventional microwave plasma-enhanced chemical vapor deposition system. Silicon substrates were coated with thin films of amorphous carbon using a vacuum arc technique. The carbon-coated silicon substrates were pretreated with a methane-rich plasma at relatively low temperatures and were subsequently exposed to the diamond nucleation conditions. The significance of the pretreatment on the diamond nucleation density was examined by varying the methane concentration, chamber pressure, and exposure time. Scanning electron microscopy demonstrated that densely packed spherical nanoparticles on the pretreated surfaces played the role of diamond nucleation seeds. Raman spectroscopy analysis showed that the nucleation seeds consisted of nonhydrogenated carbon and that their structure was influenced by the pretreatment conditions. Transmission electron microscopy revealed that the nucleation seeds comprised disordered graphitic carbon and ultrafine diamond crystallites. Submicrometer films of good quality diamond possessing significantly higher nucleation densities ({approximately}5{times}10{sup 10} cm{sup -2}) were grown from nanoparticles produced under optimum pretreatment conditions. The enhancement of the diamond nucleation density is mainly attributed to the formation of a large number of nanoparticles, which provided sufficient high-surface free-energy sites for diamond nucleation, in conjunction with their high etching resistance to atomic hydrogen stemming from the significant percentage of {ital sp}{sup 3} atomic carbon configurations, as evidenced by the presence of nanocrystalline diamond in the nanoparticle structure. {copyright} {ital 1996 American Institute of Physics.}
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 253442
- Journal Information:
- Journal of Applied Physics, Vol. 79, Issue 1; Other Information: PBD: Jan 1996
- Country of Publication:
- United States
- Language:
- English
Similar Records
Diamond nucleation on unscratched silicon substrates coated with various non-diamond carbon films by microwave plasma-enhanced chemical vapor deposition
Characterization of bias-enhanced nucleation of diamond on silicon by invacuo surface analysis and transmission electron microscopy