The OES Of Addition Auxiliary Gas On Diamond Growth By HFCVD

The diamond films deposited by HFCVD have great application in many fields,and various research groups did a lot of works on each aspects.At present,the growth rate of diamond films can achieve 0.9-1.4?m/h through HFCVD without bias effect.The application of bias to the substrate or RF can enhance the energy electron,as well as the growth rate on the substrate.However,these technology can not be used on the irregular surface or complex workpieces.In this article,we use acetone as the carbon source and the argon as auxiliary gas during the growth of diamond.Optical emission spectroscopy was employed to investigate the effect of different argon concentration on the growth rate of diamond?the spatial distribution of plasma and the effect of different carbon concentration on diamond growth.The surface and cross section of deposited diamond films were characterized by scanning electron microscopy(SEM)and their quality was tested by Raman spectroscopy.The results of the study showed as follows:The argon addition does not only responsible to raise the secondary nucleation which leads to nano-crystalline,but also can improve the growth rate of mirocrystalline diamond films on the right amount(8%~32%).When the concentration Ar is added to the 8%~32%,the growth rate of the diamond film is proportional to the concentration,and the maximum rate is 3.75?m/h,and H2:Ar:(H2+acetone)=140:60:50.Obtained relations identified by OES are found that CO(228-370nm),CH(387.0nm),H?(486.1nm),H?(656.3nm)are main groups,The spectral intensity of these groups increased nearly one fold after the addition of argon.The electron temperature(Te)which provides a more favorable condition for the growth of diamond films is proportional to the argon content under the argon content is7%~30%.OES results showed that the intensity of active species near the center is higher than that in marginal area in the case of linear array of hot filament.It is due to thehigher temperature and stronger cracking ability near the filament.The variety of the characteristic peak intensity in central region is more gently than that of the plasma ball.Thermal radiation decreased when the distance from the hot filament increases,which results in less CH?CO groups cracked from acetone,lower intensity of H??H?excited by hydrogen and higher concentration of C2 group produced by reaction.SEM and Raman results showed that the quality of deposited diamond films deteriorated when the distance between hot filament and substrate varies from 4.5,5.5 to 6.5 mm,which matches well with the OES results.When the other parameters are kept constant,with the increasing of the gas flux of the carbon source,the electron temperature is generally decreased.However,during the carbon source flow between 50 sccm and 70 sccm appear abnormal which first increase then decline,in the vicinity of the 60 sccm there is a maximum peak value and the charged particles reach the substrate with the maximum flux and energy at this time.With the increasing of carbon source mixed gas flow,CO,C2,CH groups with several carbon groups for the spectral intensity first decreases increases and in the near 60 sccm minimum,vapor deposition process toward the diamond film growth direction,diamond films with maximum deposition rate of 4.06 ?m/h,and H2:Ar:(H2+acetone)=140:60:50.