Computer Simulation of Temperature Parameter for Diamond Formation by Using Hot-Filament Chemical Vapor Deposition

Abstract

To optimize the deposition parameters of diamond films, the temperature, pressure, and distance between the filament and the susceptor need to be considered. However, it is difficult to precisely measure and predict the filament and susceptor temperature in relation to the applied power in a hot filament chemical vapor deposition (HF-CVD) system. In this study, the temperature distribution inside the system was numerically calculated for the applied powers of 12, 14, 16, and 18 kW. The applied power needed to achieve the appropriate temperature at a constant pressure and other conditions was deduced, and applied to actual experimental depositions. The numerical simulation was conducted using the commercial computational fluent dynamics software ANSYS-FLUENT. To account for radiative heat-transfer in the HF-CVD reactor, the discrete ordinate (DO) model was used. The temperatures of the filament surface and the susceptor at different power levels were predicted to be 2512-2802 K and 1076-1198 K, respectively. Based on the numerical calculations, experiments were performed. The simulated temperatures for the filament surface were in good agreement with the experimental temperatures measured using a two-color pyrometer. The results showed that the highest deposition rate and the lowest deposition of non-diamond was obtained at a power of 16 kW.

Formation of Pentagonal Dimples in Icosahedral Diamond Crystals Grown by Hot Filament Chemical Vapor Deposition: Approach by Non-Classical Crystallization

“…For 80 sccm of acetone, the diamond does not completely cover the substrate and a continuous film is not formed, as shown in Figure 2a. This incomplete coverage of diamond on the substrate is known to occur when the substrate temperature is too low or when the distance between the susceptor and the filament is too far [20,21]. However, a continuous diamond film was formed at the same substrate temperature and the same distance between the susceptor and the filament when the flux of acetone was above 90 sccm.…”

“…The schematic of the experimental HFCVD reactor is shown in Figure 1a. The temperature of the filament was calculated by computer analysis through computation fluid dynamics (CFD) code FLUNT (17.0) in ANSYS software (17.0) [20,21]. During diamond deposition, the filament temperature was measured using a 2-color pyrometer (E1RH-F1-L-0-0, Fluke, Berlin, Germany).…”

“…The substrate temperature was measured by an infrared thermometer (RAYR312ML3U, Raytek, Everett, WA, USA), which fluctuates in the range of 1149-1164 K. The computational analysis was made to determine the susceptor temperature. The temperature distributions of the horizontal plane of the substrate and the vertical plane (away from the filaments) were calculated using the CFD code via ANSYS-FLUENT [20,21], and are shown respectively in Figure 1b,c. The temperature of the susceptor was estimated to be 1160 K during diamond deposition, which was within the range of the measured temperature.…”

“…The deposition conditions were as follows. The power applied to the filament was 16 kW, the distance between the filament and the susceptor was 1 cm and the reactor pressure was 4000 Pa, which were the optimum conditions for diamond deposition according to previous experiments [20,21]. The depositon time was 8 h. Table 1 shows the conditions for the process variables used in this experiment.…”

Interaction of Methane Concentration and Deposition Temperature in Atmospheric Laser Based CVD Diamond Deposition on Hard Metal

“…The interaction between the deposition temperature and the methane concentration needs to be known to be able to find the best processing conditions for the chemical vapour deposition (CVD) of diamond coatings, according to the desired coating thickness, deposition duration, and the medium diamond crystal size. According to Song et al [1], the dependence of the deposition temperature on the diamond deposition is still of current interest.…”