THERMAL DECOMPOSITION DEPOSITION METHOD OF VAPOR PHASE SUBSTANCE

PURPOSE:To control the properties and speed of deposition of a growing crystal by introducing a heating-medium vapor phase substance generating a thermal decomposition reaction to a vapor phase substance for forming a solid phase substance into a reaction chamber together with the vapor phase substance mainly forming the solid phase substance. CONSTITUTION:A substrate 1 is placed on a surface-temperature regulating plate 8 functioning as the support of the substrate in combination in a vacuum tank 3, and the periphery of the regulating plate 8 is partitioned into small sections and a reaction chamber 2 is formed. Supply pipings 5-7 penetrate the walls of the vacuum tank 3 and the reaction chamber 2 in an airtight manner, and gases A-C are mixed in the reaction chamber 2, and made to act on the surface of the substrate. A gas for generating a solid-phase substance is fed as the gas A, a gas for addition as the gas C and a heated heating-medium gas generating a thermal decomposition reaction to the gases A, C as the gas B, and these gases are deposited on the surface of the substrate 1. Accordingly, the properties of a crystal can be controlled by the surface temperature of the substrate 1 while the speed of deposition can also be controlled by the introduction of the gas B.