摘要 |
An improved gas phase synthesized diamond, CBN, BCN, or CN thin film having a modified region in which strain, defects, color and the like are reduced and/or eliminated. The thin film can be formed on a substrate or be a free-standing thin film from which the substrate has been removed. The thin film can be stably and reproducibly modified to have an oriented polycrystal structure or a single crystal structure. The thin film is modified by being subjected to and heated by microwave irradiation in a controlled atmosphere. The thin film has a modified region in which a line width of the diamond spectrum evaluated by Raman spectroscopy of 0.1 microns or greater is substantially constant along a film thickness direction of the thin film, and the line width of the modified region is 85% or less of a maximum line width of the residual portion of the film thickness.
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