Image Number 2 for United States Patent #6375756.
A method for efficiently and completely removing a film deposited inside a film forming chamber and an in-situ cleaning method of a hot element CVD apparatus. A hot element is disposed in a chamber is heated up to a temperature of 2000.degree. C. or higher after the chamber is exhausted. Thereafter a cleaning gas which is decomposed and/or activated by the hot element to generate an activated species that converts the deposited film into gaseous substance is introduced into the chamber.