Effect of arc characteristics on the properties of large size diamond wafer prepared by DC arc plasma jet CVD

Diamond wafer with 100 mm in diameter and 1 mm in thickness was prepared by DC arc plasma jet CVD. The area arc distribution above the surface space of substrate, consisting of arc center, arc main and arc edge, directly determined the quality and homogeneity of diamond wafer. As the distance to the central area increased, the crystal size of diamond increased firstly and then decreased. Meanwhile, “dark feature” texture quantity of polished diamond film corresponding to arc main was lower than that corresponding to arc center and arc edge. XRD results showed the ratio of I(220)/I(111) of diamond films increased from edge to center gradually. The intrinsic stress of diamond film corresponding to arc main was greater than the other two areas according to the Raman spectrum, and the highest transmittance in the 10.6 micron wavelength was obtained in the area corresponding to arc main by Fourier infrared. The difference of fracture strength in three areas was less than 20 MPa, which reveals the arc characteristics have less effect on fracture strength.