Effect of temperature on defects in homoepitaxial single crystal diamond by MPCVD

Homogeneous epitaxial growth experiments were performed by microwave plasma chemical vapor deposition (MPCVD) on seeds of single crystal diamonds with defects. The effects of temperature on such defects were studied under the same depositing parameters. The diamonds were characterized by emission spectroscopy, Raman spectroscopy, and SEM. Results show that the higher the diamond temperature is, the higher the spectral intensity ratio I(C₂)/I(H_α) in the plasma emission spectrum of the diamond surface is, and that as the electron temperature decreases, the collision between particles in the plasma become more intense. When deposited at 740℃, there appear surface cracks running through defects after homoepitaxial growth. At 780 and 820℃, the defects are inhibited and covered, whose area decreases. At 860℃, the defect area is enlarged and the protrusion is more obvious. In conclusion, the single crystal diamond grown at medium temperature has better quality, such as smaller offset of diamond characteristic peak and smaller stress. Otherwise, the peak is obviously shifted to low wave number, and the tensile stress is larger.