Method of chemical vapor deposition

Claim 1

A method of forming a thin film on a substantially flat substrate by chemical vapor deposition comprising the steps of feeding into a reaction chamber (1) a first reactive gas containing a metal element and a second reactive gas containing no metal element, both in a laminar flow condition substantially parallel to and along the surface of the flat substrate (3) disposed in said reaction chamber (1) under reduced pressure, feeding an inert gas or a gas containing the inert gas as a main component downwardly so as to cross substantially perpendicularly to the flows of the first and second reactive gases and to maintain the laminar flow condition of the first and second reactive gases, and radiating a light beam from at least one heating lamp (8) to the substrate in the reaction chamber (1) to heat the substrate (3) and thus produce chemical reaction on the surface of the substrate (3), characterized in that a thin film containing the metal element is grown along a substantially flat surface of the substrate (3).