| 摘要 |
PURPOSE:To obtain a uniform thin film of thermally decomposed boron nitride having flat surface by subjecting ammonia and a boron halide to thermal decomposition reaction and depositing the reaction product on a substrate made of a thermally decomposed boron nitride. CONSTITUTION:A substrate made of thermally decomposed boron nitride is placed in a furnace, the furnace is evacuated and a gaseous mixture of ammonia and boron halide (e.g. boron trichloride) is introduced into the furnace. The mixture is heated at a high temperature to bring about the thermal decomposition reaction of ammonia and boron halide. The reaction product is deposited on the substrate to obtain a thin film of the thermally decomposed boron nitride. The local adhesion of the produced thermally decomposed boron nitride and the substrate can be prevented and, accordingly, the thin film can be peeled off from the substrate without causing the wrinkle and crack, etc., of the thin film. The thermally decomposed boron nitride thin film produced by this process is suitable as an insulation material of a heating device provided with an electrically conductive heater. |
