Selective doping of 6H-SiC by diffusion of boron into SiC has been realized at 1800-2100 degreesC using graphite film as a protecting mask. The minimum thickness of graphite film preventing the boron penetration into the substrate was found. Cathodoluminescence measurements as well as an anodic oxidation technique have been employed to identify the local doped regions. A diffused planar p-n diode based on the local p-type emitter region was fabricated. The I-V characteristic of the formed diode has been measured at room temperature.