| 摘要 |
PROBLEM TO BE SOLVED: To estimate nitrogen concentration on the basis of a simply calculated reoxidated film thickness rate by a method wherein the nitrogen concentration is judged on the basis of the deposition speed of a thermal oxide film. SOLUTION: A thermal oxide film 2 is formed on a semiconductor substrate 1 by a CVD method. After that, the thermal oxide film 2 is heated for a short time in a nitrous oxide atmosphere, and an oxynitride film 3 is formed. After that, when the oxynitride film is heated for a short time in an oxygen atmosphere, the oxynitride film is reoxigized, and a reoxidation film 4 is formed. A reoxidation film thickness rate is found on the basis of a film thickness L1 after the oxynitride film is formed by oxidizing N2O and on the basis of a film thickness L2 after a reoxidation treatment performed thereafter. A thermal oxide film thickness which is found by an optical film-thickness measuring device is 40Åas a target film thickness. A linear relationship is established between the concentration of nitrogen in a gate oxide film and a reoxidation rate. When the reoxidation rate with reference to the oxynitride film by a treatment under an oxynitriding condition is calculated, the concentration of the nitrogen can be estimated. By using this characteristic, the concentration of the nitrogen in the gate oxide film is judged.
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