Thermodynamic limits for the substrate temperature in the CVD diamond process
| Autor: | Latifa Gueroudji, Nong M. Hwang |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Chemistry
Mechanical Engineering Thermodynamics Diamond General Chemistry Chemical vapor deposition engineering.material Electronic Optical and Magnetic Materials Metastability Torr Thermodynamic limit Materials Chemistry engineering Deposition (phase transition) Graphite Electrical and Electronic Engineering Phase diagram |
| Zdroj: | Diamond and Related Materials. 9:205-211 |
| ISSN: | 0925-9635 |
| DOI: | 10.1016/s0925-9635(00)00232-6 |
| Popis: | Although which of diamond and graphite is dominantly precipitated from the gas phase is a problem of kinetics or a kinetic barrier, the condition under which diamond or graphite is not stable with respect to the gas phase can be specified by thermodynamics. The thermodynamic limit of the substrate temperature that diamond can deposit is evaluated in the CH and CHO systems by assuming that the limit is defined by the metastable CVD diamond phase diagram. In the CH system, the pressure of the CVD reactor is the most important parameter for the lower limit of the substrate temperature. For the gas mixture of 1% CH 4 –99% H 2 , the lower limits are ∼1400 K, ∼900 K and ∼600 K under 760 torr, 7.6 torr and 76 mtorr, respectively. Increasing the methane concentration to 5% decreases the limit only slightly. In the CHO system, the thermodynamic lower limit can decrease as low as room temperature. Although decreasing the O/C ratio is favorable for the low-temperature deposition, the non-diamond is expected to form according to Bachmann’s CHO diagram. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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