The Study Of Diamond Films And Carbon Nitride Films Deposited By HFCVD

In this paper, diamond films deposited by hot filament chemical vapordeposition (HFCVD) with ethanol were investigated. The influence of ethanol dosage,substrate temperature, deposition pressure on nucleation, deposition rate and surfacemorphology of the grown diamond films was investigated. The experimentalconditions were as follow: ethanol 3.0-5.1 cm³(nucleation), 16.9-29.5 cm³(growth), theH₂ flow rate 200 sccm, sample temperature 710-860℃, deposition pressure 2.0-5.0KPa.The films were characterized by filed emission scanning electron microscopy(FE-SEM) and X-ray diffraction measurements (XRD). Since the decompoundedtemperature of ethanol is lower than that of methane, the nucleation time of thediamond film deposited with ethanol as carbon source is less than that with methane ascarbon source. In the condition of the H₂ flow rate 200 sccm, substrate temperature 810℃, deposition pressure 4.0 KPa and bias 0 V, the diamond nucleation density was 10¹²cm^-2 by ethanol in 15 min, but 10⁸ cm^-2 by methane in 30 min and the deposition rateof diamond films by ethanol was higher than that by methane.The following results can be obtained in the experiment: the optimal condition ofthe diamond nucleation by ethanol was: ethanol dosage 3.8 cm³(0.5h), the H₂ flow rate200 sccm, sample temperature 810℃, deposition pressure 3.0 KPa; the optimalcondition of the diamond deposition by ethanol is: ethanol dosage 25.3 cm³(4h), the H₂flow rate 200 sccm, substrate temperature 860℃, pressure 3.0 KPa.Carbon nitride films were prepared on Si substrate by plasma chemical vapordeposition (PCVD) with the gaseous mixture of nitrogen and hydrogen as balanced gas.The samples were characterized by filed emission scanning electron microscopy (FE-SEM), X-ray diffraction measurements (XRD). The results showed that nitrogenelement existed in the carbon nitride films by EDX.