Carbon materials are light in weight and excellent in chemical and thermal stability, and moreover, they show good thermal conductivity and electrical conductivity even though they are non-metal materials. However, their uses are limited in, for example, semiconductor manufacturing processes because they have the characteristic of dust emission.
In view of the problem, it has been proposed that, as shown in Patent Documents 1 and 2 listed below, a chromium carbide layer composed of Cr23C6 is provided on the surface of a carbon substrate by treating the carbon substrate with a chromium halide gas. However, when a chromium carbide with a high composition ratio of chromium, such as Cr23C6, is formed, the hardness of the chromium carbide becomes high, so chipping tends to occur easily in handling or the like. As a consequence, particles are produced, so a problem with the material is that the material cannot be used for the members for which their characteristic of emitting less dust are considered important, such as the members (for example, jigs) used in a semiconductor manufacturing apparatus.