Combined experimental and modeling studies of microwave activated CH4/H2/Ar plasmas for microcrystalline, nanocrystalline, and ultrananocrystalline diamond deposition
| Autor: | James C. Richley, Yuri A. Mankelevich, Oliver J. L. Fox, Michael N. R. Ashfold |
|---|---|
| Rok vydání: | 2011 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 109:063307 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.3562185 |
| Popis: | A comprehensive study of microwave (MW) activated CH4/H2/Ar plasmas used for diamond chemical vapor deposition is reported, focusing particularly on the effects of gross variations in the H2/Ar ratio in the input gas mixture (from H2/Ar mole fraction ratios of > 10:1, through to ∼1:99). Absolute column densities of C2(a) and CH(X) radicals and of H(n = 2) atoms have been determined by cavity ringdown spectroscopy, as functions of height (z) above a substrate and of process conditions (CH4, H2, and Ar input mole fractions, total pressure, p, and input microwave power, P). Optical emission spectroscopy has also been used to explore the relative densities of electronically excited H atoms, and CH, C2, and C3 radicals, as functions of these same process conditions. These experimental data are complemented by extensive 2D (r, z) modeling of the plasma chemistry, which provides a quantitative rationale for all of the experimental observations. Progressive replacement of H2 by Ar (at constant p and P) leads to a... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|