Song Byeong-Kwan, Kim Hwan-Young, Kim Kun-Su, Yang Jeong-Woo, Hwang Nong-Moon
Department of Materials Science and Engineering, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
Research Institute of Advanced Materials, 599 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
Materials (Basel). 2021 Jan 16;14(2):426. doi: 10.3390/ma14020426.
Although the growth rate of diamond increased with increasing methane concentration at the filament temperature of 2100 °C during a hot filament chemical vapor deposition (HFCVD), it decreased with increasing methane concentration from 1% CH -99% H to 3% CH -97% H at 1900 °C. We investigated this unusual dependence of the growth rate on the methane concentration, which might give insight into the growth mechanism of a diamond. One possibility would be that the high methane concentration increases the non-diamond phase, which is then etched faster by atomic hydrogen, resulting in a decrease in the growth rate with increasing methane concentration. At 3% CH -97% H, the graphite was coated on the hot filament both at 1900 °C and 2100 °C. The graphite coating on the filament decreased the number of electrons emitted from the hot filament. The electron emission at 3% CH -97% H was 13 times less than that at 1% CH -99% H at the filament temperature of 1900 °C. The lower number of electrons at 3% CH -97% H was attributed to the formation of the non-diamond phase, which etched faster than diamond, resulting in a lower growth rate.
在热丝化学气相沉积（HFCVD）过程中，当丝温为2100℃时，金刚石的生长速率随甲烷浓度的增加而增大；但在1900℃时，从1%CH₄-99%H₂到3%CH₄-97%H₂，生长速率却随甲烷浓度的增加而降低。我们研究了生长速率对甲烷浓度这种异常的依赖性，这可能有助于深入了解金刚石的生长机制。一种可能性是，高甲烷浓度会增加非金刚石相，然后被原子氢更快地蚀刻，导致生长速率随甲烷浓度增加而降低。在3%CH₄-97%H₂时，在1900℃和2100℃下，石墨都沉积在热丝上。丝上的石墨涂层减少了热丝发射的电子数量。在1900℃的丝温下，3%CH₄-97%H₂时的电子发射比1%CH₄-99%H₂时少13倍。3%CH₄-97%H₂时电子数量较少归因于非金刚石相的形成，其蚀刻速度比金刚石快，导致生长速率较低。
