| 摘要 |
PURPOSE:To improve the reliability of an MOS type semiconductor element by using a high melting point metal which contains at least one selected from a group consisting of B, P and As as a gate electrode to reduce mobile ion contamination amount of the element. CONSTITUTION:After an oxide film 2 is formed on a P-type Si substrate 1, a tungsten film 3 is deposited, phosphorus is added by ion implantation, it is coated with a photoresist, a resist pattern 4 is formed by a photoetching method, a tungsten film 3 is formed by dry etching as a mask to form an MOS capacitor. When the ion implantation is not executed, the variation amount DELTAVFb of a flat band voltage in capacity/voltage characteristic of the MOS capacitor is 0.27 volt, while it is 0.03 volt in a sample to which phosphorus is ion- implanted by 5X10<14>cm<2> to largely improve the reliability of an MOS element.
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