| 摘要 |
PURPOSE:To form a deep and highly concentrated diffusion layer in a substrate, thereby keeping the above layer from a gate electrode by forming a nitriding film on the whole surface of a substrate after forming a gate oxide film, the gate electrode as well as shallow, low-concentrated diffusion layers on the semiconductor substrate in the case of an MIS-type transistor having an LDD structure, and by performing an impurity ion implantation in such a state as mentioned above and conducting heat treatment. CONSTITUTION:A gate electrode 25 having a polyside structure is formed after causing a gate oxide film 22 to grow on a P-type silicon substrate 21 and poly silicon 23 to grow on the above film 22 and then, tungsten polyside 24 to grow on the above poly silicon 23. After that, low-concentrated impurity phosphorus is ion-implanted into the substrate 21 by using the gate electrode 25 as a mask and a shallow N<-> layer 26 (low-concentrated diffusion layer) is formed. Subsequently, the nitriding film 27 is formed at the whose surface located on the substrate 21 including the gate electrode 25 and highly concentrated impurity arsenic is ion-implanted into the substrate 21 by using a gate electrode side wall part-thick film part 27a and the gate electrode 25 as the masks in such a state as mentioned above. Then heat treatment allows impurity arsenic to be activated and forms a deep N<+> layer 28 (highly concentrated diffusion layer) in the substrate 21 by keeping its layer 28 from the gate electrode 25.
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