DIAMOND COMPOSITE SUBSTRATE AND PROCESS FOR PRODUCING THE SAME

摘要

A highly tough diamond substrate of large area and high quality for use in semiconductor materials, electronic components, optical parts, etc.; and a process for producing the same. A diamond composite substrate is produced by superimposing a diamond polycrystal film on a surface of diamond single-crystal substrate. With respect to this diamond composite substrate, it is preferred that plane opposite in parallel relationship to the main plane of largest area of diamond single-crystal substrate as {100} plane be formed by the superimposed diamond polycrystal film. Diamond composite substrate (2) may be provided by forming diamond single-crystal substrate (3) from multiple diamond single crystals with the orientations of main planes uniformalized and joining the multiple diamond single crystals by means of diamond polycrystal layer (4). Further, using the diamond single crystals as seed crystals, diamond single crystals formed by a vapor-phase synthesis may be superimposed on a surface thereof.