Abstract: A method of forming an insulating film containing silicon oxy-nitride includes a loading step, temperature raising step, oxidation step, cycle purge step, and annealing step, in this order. The temperature raising step is performed while supplying nitrogen gas and oxygen gas for preventing a silicon layer surface from being nitrided, at a supply ratio 100:1 to 1000:1. The oxidation step is performed at a temperature of 700 to 950° C. while supplying a gas that contains 1 to 5 vol % of water vapor and 95 to 99 vol % of nitrogen gas, to form a silicon oxide film. The annealing step is performed at a temperature of 800 to 950° C. while supplying a gas that contains 10 to 100 vol % of nitrogen monoxide gas, to convert a portion of the silicon oxide film into silicon oxy-nitride.

Abstract: A method of forming an insulating film containing silicon oxy-nitride first forms a silicon oxide film on the surface of a silicon wafer by oxidizing the water. In this oxidation, the atmosphere in a process chamber accommodating the silicon wafer is set at a first temperature of from 700 to 950° C. and a first pressure of from 0.7 to a value of [atmospheric pressure −0.375] Torr for a first processing time of from 0.5 to 30 min, and a first processing gas for oxidation is supplied into the process chamber. This first processing gas contains 1 to 5 vol % of water vapor and 95 to 99 vol % of nitrogen gas. After the silicon oxide film is formed, annealing is performed to convert at least a portion of the silicon oxide film into silicon oxy-nitride. In this annealing, the atmosphere in the process chamber is set at a second heating temperature of from 800 to 950° C. and a second pressure of from 0.

Abstract: A cleaning method cleans a reaction tube and dummy wafers by removing therefrom tungsten and tungsten compound deposited on the inner surface of the reaction tube and the surfaces of the dummy wafer in a process of selectively oxidizing the side walls of a silicon layer included in an electrode of a layered structure consisting of a polysilicon layer and a tungsten layer. The interior of the reaction tube is heated, and a cleaning gas containing hydrogen chloride gas and oxygen gas is supplied through a cleaning gas supply port into the reaction tube to remove the tungsten and the tungsten compound adhering to the inner surface of the reaction tube and the surfaces of the dummy wafers.