| 摘要 |
PURPOSE:To improve a thin gate insulating film in its response to thickness control by a method wherein impurity-diffused layers are provided on both sides of a polycrystalline tungsten film gate electrode formed on a single-crystal silicon substrate and heat treatment is accomplished for the formation of an tungsten oxide film between the polycrystalline tungsten film and the single-crystal silicon substrate. CONSTITUTION:A silicon oxide film 2, a region 3 to develop into a transistor, and an isolating region 4 are formed on a single-crystal silicon substrate 1, and then a polycrystalline tungsten film 5 is attached by evaporation to the entire surface of the silicon substrate 1. The tungsten film 5 is selectively removed by etching for the construction of a gate electrode 6, and ions are implanted for the formation of an impurity-diffused layer that is opposite to the silicon substrate 1 in the type of conductivity for the formation of regions 7 to serve as a source or drain region. A heat treatment process follows, whereby the impurity-diffused layer is annealed and, simultaneously, a thin tungsten oxide film 8 is formed between the gate electrode 6 and silicon substrate 1. The tungsten oxide film 8 is very slow in its growth, and its thickness hardly increases after reaching a certain value. This design allows the tungsten oxide film 8 to be greatly improved in its response to thickness control.
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