| 摘要 |
PURPOSE:To improve alpha-ray-resistant characteristics by forming a memory element in an impurity region shaped in a nondefective region on the substrate surface side. CONSTITUTION:An internal defective region 1 and a nondefective region 2 in the vicinity of the surface are prepared in a P-type semiconductor substrate 20 through low-temperature long-time heat treatment and high-temperature heat treatment. When a P<+> region 3 in a high-concentration impurity region is formed in the region 2 through ion implantation and a memory element is shaped in the region 3, the region 2 functions as a barrier to electrons diffused by alpha-rays passing through the region 2. Accordingly, the alpha-ray-resistant characteristics of a MOS type dynamic RAM are improved. |
