| 摘要 |
<p>A plurality of single-crystalline diamond plates (52) having principal surfaces consisting essentially of {100} planes are prepared. The plurality of single-crystalline diamond plates (52) are so arranged that the respective principal surfaces are substantially flush with each other. At this time, an angle formed by crystal orientations in relation to the principal surfaces between adjacent plates (52) is not more than 5 DEG , a clearance between the adjacent plates is not more than 30 mu m, and difference in height in relation to the principal surfaces is not more than 30 mu m between the adjacent plates. In order to fix such a state, it is possible to join the plurality of diamond plates with each other by depositing diamond on these plates. After such joining, the principal surfaces of the diamond plates are polished in order to eliminate steps. Then, diamond is epitaxially grown on a polished surface of a large diamond plate (53) which is formed by the plurality of diamond plates (52) from a vapor phase. In this vapor phase, proportions A, B and C obtained from the following equations I, II and III respectively satisfy the following conditions: 0.5 </= A </= 2.0 0.3 </= B </= 2.0 C </= 1.0 A = ([C]/[H]) x 100 % I B = ([C] - [O]/[H]) x 100 % II C = ([O]/[H]) x 100 % III where [C], [O] and [H] represent molar numbers of carbon, oxygen and hydrogen atoms respectively. According to this method, it is possible to obtain vapor-deposited diamond which exhibits a maximum diameter of at least 15 mm, transmittance of at least 20 % with respect to ultraviolet light of 250 nm in wavelength, and a peak having an angular half-width of not more than 100 seconds in an X-ray rocking curve in a (400) plane or a half-width of not more than 2 cm<-><1> at 1332 cm<-><1> in a Raman scattering spectrum. <IMAGE></p> |
