| 摘要 |
PURPOSE:To absorb the electrons diffused through the deep part of a substrate using a guard band by a metohd wherein a recessed region is formed by boring a groove on the surface of a semiconductor substrate, and an N<+> type region is formed in the recessed region as the guard band. CONSTITUTION:A recessed region 17 is formed by deeply boring the part to be used as a guard band on a P type semiconductor substrate 1. Then, an N<+> type region 18 is formed in said recessed region 17 as a guard band, and the groove is filled up by a field oxide film 14. By having the above-mentioned constitution, the electrons of minority carrier are injected and diffused into the substrate 16 from a circumferential circuit and a decoder 15 by performing an impact ionization when the memory device is dinamically operated. Also, as a guard band 18 is deeply formed in the substrate 16, the electrons which will be diffused at the deep part can be absorbed easily. |
