| 摘要 |
PURPOSE:To obtain a higher resistant memory cell against alpha-rays, by forming only the memory cell in the well with the same conductivity as the semiconductor substrate but with the higher impurities concentration, while forming a semiconductor memory device with the memory cell portion using a number of the FET and the control circuit. CONSTITUTION:The SiO2 film 104 is adhered on the P<-> type Si substrate with the impurities concentration of approximately 2X10<14>/cm<3> to enable high velocity. The P<+> type well region 102 with the impurities concentration of 1X10<15>-1X10<16>/cm<3> is formed by implanting P type impurity ions 105 on to the memory cell portion only through the film 104. In the region 102 the memory cell 103 consisting of the transfer Kent transistor, flip-flop transistor etc. are mounted in a matrix manner, and around them are mounted the peripheral circuit portion B. Thus a higher resistant memory cell against the alpha-rays can be obtained without sacrificing the speedy operation of the peripheral circuits. |
